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Sample records for sagnac loop interferometer

  1. Novel birefringence interrogation for Sagnac loop interferometer sensor with unlimited linear measurement range.

    Science.gov (United States)

    He, Haijun; Shao, Liyang; Qian, Heng; Zhang, Xinpu; Liang, Jiawei; Luo, Bin; Pan, Wei; Yan, Lianshan

    2017-03-20

    A novel demodulation method for Sagnac loop interferometer based sensor has been proposed and demonstrated, by unwrapping the phase changes with birefringence interrogation. A temperature sensor based on Sagnac loop interferometer has been used to verify the feasibility of the proposed method. Several tests with 40 °C temperature range have been accomplished with a great linearity of 0.9996 in full range. The proposed scheme is universal for all Sagnac loop interferometer based sensors and it has unlimited linear measurable range which overwhelming the conventional demodulation method with peak/dip tracing. Furthermore, the influence of the wavelength sampling interval and wavelength span on the demodulation error has been discussed in this work. The proposed interrogation method has a great significance for Sagnac loop interferometer sensor and it might greatly enhance the availability of this type of sensors in practical application.

  2. Arrayed waveguide Sagnac interferometer.

    Science.gov (United States)

    Capmany, José; Muñoz, Pascual; Sales, Salvador; Pastor, Daniel; Ortega, Beatriz; Martinez, Alfonso

    2003-02-01

    We present a novel device, an arrayed waveguide Sagnac interferometer, that combines the flexibility of arrayed waveguides and the wide application range of fiber or integrated optics Sagnac loops. We form the device by closing an array of wavelength-selective light paths provided by two arrayed waveguides with a single 2 x 2 coupler in a Sagnac configuration. The equations that describe the device's operation in general conditions are derived. A preliminary experimental demonstration is provided of a fiber prototype in passive operation that shows good agreement with the expected theoretical performance. Potential applications of the device in nonlinear operation are outlined and discussed.

  3. Removing left-right asymmetry in a Sagnac interferometer applied to cancel its reflectance dependence on birefringence.

    Science.gov (United States)

    Golub, Ilya; Exir, Hourieh

    2013-05-01

    We present a left-right symmetry restoring method, which removes the detrimental birefringence in the single-mode fiber Sagnac interferometer, achieved with the aid of a half waveplate oriented at a specific angle. We show theoretically and demonstrate experimentally that adding a π-shift between clockwise and counterclockwise propagating, horizontally (in fiber loop plane) polarized field components, the Sagnac loop mirror's reflection becomes independent on birefringence of an element placed in the loop.

  4. Theory of the Sagnac's interferometer of low birefringence and twist fiber; Teoria del interferometro de Sagnac de fibra de baja birrefrigencia y torcida

    Energy Technology Data Exchange (ETDEWEB)

    Estudillo-Ayala, J. M.; Kuzin, E. A.; Ibarra-Escamilla, B. [Instituto Nacional de Astrofisica, Optica y Electronica, Puebla (Mexico); Rojas-Laguna, R. [Universidad de Guanajuato, Guanajuato (Mexico)

    2001-06-01

    The fibre Sagnac interferometer of low birefringence and twist in the lineal region is examined numerically, a method is shown to measure the birefringence in the fibers and rotation of the axes inside of the interferometer fibre loop. [Spanish] El interferometro de Sagnac de fibra de baja birrefrigencia y torcida en la region lineal es numericamente examinado, se muestra un metodo para medir la birrefrigencia en las fibras y rotacion de los ejes dentro de la fibra del lazo del interferometro.

  5. Synchronization of femtosecond laser pulses and RF signal by using a Sagnac loop Mach-Zehnder interferometer

    International Nuclear Information System (INIS)

    Dai Hui; Hajima, Ryoichi

    2008-11-01

    For future advanced energy recovery linac to generate femtosecond X-ray pulses, precise synchronization between sub-systems is highly desired. Typical synchronization methods based on direct photo detection are limited by detector nonlinearities, which lead to amplitude-to-phase conversion and introduce excess timing jitter. In this paper, we experimentally demonstrate an optical-electronic mixed phase lock loop to synchronize the RF signal and laser pulses. In this synchronism setup, a Sagnac-loop Mach-Zehnder interferometer has been used to suppress the excess noise of direct photo detection. This scheme transfers the timing information into a intensity imbalance between the two output beams of the interferometer. As experimental demonstration, the single side-band phase noise of RF signal from the VCO is locked to the mode-locked Ti:Sapphire laser in the spectrum covering the range of 10 kHz to 1 MHz. This synchronization scheme greatly reduces the phase noise and timing jitter of the RF signal. (author)

  6. Sagnac interferometer as a speed-meter-type, quantum-nondemolition gravitational-wave detector

    Science.gov (United States)

    Chen, Yanbei

    2003-06-01

    According to quantum measurement theory, “speed meters”—devices that measure the momentum, or speed, of free test masses—are immune to the standard quantum limit (SQL). It is shown that a Sagnac-interferometer gravitational-wave detector is a speed meter and therefore in principle it can beat the SQL by large amounts over a wide band of frequencies. It is shown, further, that, when one ignores optical losses, a signal-recycled Sagnac interferometer with Fabry-Perot arm cavities has precisely the same performance, for the same circulating light power, as the Michelson speed-meter interferometer recently invented and studied by Purdue and the author. The influence of optical losses is not studied, but it is plausible that they be fairly unimportant for the Sagnac interferometer, as for other speed meters. With squeezed vacuum (squeeze factor e-2R=0.1) injected into its dark port, the recycled Sagnac interferometer can beat the SQL by a factor (10)≃3 over the frequency band 10 Hz≲f≲150 Hz using the same circulating power Ic˜820 kW as is to be used by the (quantum limited) second-generation Advanced LIGO interferometers—if other noise sources are made sufficiently small. It is concluded that the Sagnac optical configuration, with signal recycling and squeezed-vacuum injection, is an attractive candidate for third-generation interferometric gravitational-wave detectors (LIGO-III and EURO).

  7. Self-alignment of a compact large-area atomic Sagnac interferometer

    International Nuclear Information System (INIS)

    Tackmann, G; Berg, P; Schubert, C; Abend, S; Gilowski, M; Ertmer, W; Rasel, E M

    2012-01-01

    We report on the realization of a compact atomic Mach-Zehnder-type Sagnac interferometer of 13.7 cm length, which covers an area of 19 mm 2 previously reported only for large thermal beam interferometers. According to Sagnac's formula, which holds for both light and atoms, the sensitivity for rotation rates increases linearly with the area enclosed by the interferometer. The use of cold atoms instead of thermal atoms enables miniaturization of Sagnac interferometers without sacrificing large areas. In comparison with thermal beams, slow atoms offer better matching of the initial beam velocity and the velocity with which the matter waves separate. In our case, the area is spanned by a cold atomic beam of 2.79 m s -1 , which is split, deflected and combined by driving a Raman transition between the two hyperfine ground states of 87 Rb in three spatially separated light zones. The use of cold atoms requires a precise angular alignment and high wave front quality of the three independent light zones over the cloud envelope. We present a procedure for mutually aligning the beam splitters at the microradian level by making use of the atom interferometer itself in different configurations. With this method, we currently achieve a sensitivity of 6.1×10 -7 rad s -1 Hz -1/2 . (paper)

  8. Multi-Stress Monitoring System with Fiber-Optic Mandrels and Fiber Bragg Grating Sensors in a Sagnac Loop.

    Science.gov (United States)

    Kim, Hyunjin; Sampath, Umesh; Song, Minho

    2015-07-29

    Fiber Bragg grating sensors are placed in a fiber-optic Sagnac loop to combine the grating temperature sensors and the fiber-optic mandrel acoustic emission sensors in single optical circuit. A wavelength-scanning fiber-optic laser is used as a common light source for both sensors. A fiber-optic attenuator is placed at a specific position in the Sagnac loop in order to separate buried Bragg wavelengths from the Sagnac interferometer output. The Bragg wavelength shifts are measured with scanning band-pass filter demodulation and the mandrel output is analyzed by applying a fast Fourier transform to the interference signal. This hybrid-scheme could greatly reduce the size and the complexity of optical circuitry and signal processing unit, making it suitable for low cost multi-stress monitoring of large scale power systems.

  9. Reducing the first-order Doppler shift in a Sagnac interferometer

    NARCIS (Netherlands)

    Hannemann, S.; Salumbides, E.J.; Ubachs, W.M.G.

    2007-01-01

    We demonstrate a technique to reduce first-order Doppler shifts in crossed atomic/molecular and laser beam setups by aligning two counterpropagating laser beams as part of a Sagnac interferometer. Interference fringes on the exit port of the interferometer reveal minute deviations from perfect

  10. Symmetry consideration in zero loop-area Sagnac interferometry at oblique incidence for detecting magneto-optic Kerr effects.

    Science.gov (United States)

    Zhu, X D

    2017-08-01

    I present a detailed account of a zero loop-area Sagnac interferometer operated at oblique incidence for detecting magneto-optic Kerr effects arising from a magnetized sample. In particular, I describe the symmetry consideration and various optical arrangements available to such an interferometer that enables measurements of magneto-optic effects due to both in-plane and out-of-plane magnetization of the sample with optimizable signal-to-noise ratios.

  11. Temperature Compensated Strain Sensor Based on Cascaded Sagnac Interferometers and All-Solid Birefringent Hybrid Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Gu, Bobo; Yuan, Wu; He, Sailing

    2012-01-01

    We demonstrate a temperature compensated strain sensor with two cascaded Sagnac interferometers, that provide strain sensing and temperature compensation, respectively. The Sagnac interferometers use an all-solid hybrid photonic crystal fiber with stress-induced birefringence. The stress-induced ...

  12. Modelling of Extrinsic Fiber Optic Sagnac Ultrasound Interferometer ...

    African Journals Online (AJOL)

    Ultrasonic waves are used extensively in nondestructive testing both for characterization of material properties, in this paper, we describe a fiber optic sensor suitable for detection of ultrasonic waves. This sensor is based on an extrinsic fiber optic sagnac interferometer. The proposed sensor model can act as a conventional ...

  13. Sagnac Interferometer Based Generation of Controllable Cylindrical Vector Beams

    Directory of Open Access Journals (Sweden)

    Cristian Acevedo

    2016-01-01

    Full Text Available We report on a novel experimental geometry to generate cylindrical vector beams in a very robust manner. Continuous control of beams’ properties is obtained using an optically addressable spatial light modulator incorporated into a Sagnac interferometer. Forked computer-generated holograms allow introducing different topological charges while orthogonally polarized beams within the interferometer permit encoding the spatial distribution of polarization. We also demonstrate the generation of complex waveforms obtained by combining two orthogonal beams having both radial modulations and azimuthal dislocations.

  14. A differential weak measurement system based on Sagnac interferometer for self-referencing biomolecule detection

    Science.gov (United States)

    Li, Dongmei; Guan, Tian; He, Yonghong; He, Qinghua; Zhang, Yilong; Wang, Xiangnan; Shen, Zhiyuan; Yang, Yuxuan; Qiao, Zhen; Ji, Yanhong

    2017-12-01

    A differential weak measurement system was presented, exhibiting the self-referencing function for biomolecule real time detection as a label-free optical biosensor. We built a Sagnac interferometer, which limited horizontal (H) and vertical (V) polarization to propagating along the common path but in opposite directions to realize weak measurements with two measuring channels installed in two corners of this Sagnac interferometer. By introducing two half wave plates into the system alternately with the two channels to convert between H and V polarization, we obtained a differential measurement for phase delay, which could quantitatively characterize the refractive index change corresponding to the concentration of samples in the channels. With this system, a real time monitor of molecule concentration in the dialysis process was accomplished, demonstrating the function of self-referencing, which is important for optical label-free molecule detection in a complex biological sample solution.

  15. Dissipative optomechanics in a Michelson-Sagnac interferometer.

    Science.gov (United States)

    Xuereb, André; Schnabel, Roman; Hammerer, Klemens

    2011-11-18

    Dissipative optomechanics studies the coupling of the motion of an optical element to the decay rate of a cavity. We propose and theoretically explore a realization of this system in the optical domain, using a combined Michelson-Sagnac interferometer, which enables a strong and tunable dissipative coupling. Quantum interference in such a setup results in the suppression of the lower motional sideband, leading to strongly enhanced cooling in the non-sideband-resolved regime. With state-of-the-art parameters, ground-state cooling and low-power quantum-limited position transduction are both possible. The possibility of a strong, tunable dissipative coupling opens up a new route towards observation of such fundamental optomechanical effects as nonlinear dynamics. Beyond optomechanics, the suggested method can be readily transferred to other setups involving nonlinear media, atomic ensembles, or single atoms.

  16. Optical logic gates based on electro-optic modulation with Sagnac interferometer.

    Science.gov (United States)

    Li, Qiliang; Zhu, Mengyun; Li, Dongqiang; Zhang, Zhen; Wei, Yizhen; Hu, Miao; Zhou, Xuefang; Tang, Xianghong

    2014-07-20

    In this work, we present a new structure to realize optical logic operation in a Sagnac interferometer with electro-optical modulation. In the scheme, we divide two counterpropagation signals in a Sagnac loop to two different arms with the electro-optical crystal by using two circulators. Lithium niobate materials whose electro-optical coefficient can be as large as 32.2×10(-12)  m/V make up the arms of the waveguides. Using the transfer matrix of the fiber coupler, we analyze the propagation of signals in this system and obtain the transmission characteristic curves and the extinction ratio. The results indicate that this optical switching has a high extinction ratio of about 60 dB and an ultrafast response time of 2.036 ns. In addition, the results reveal that the change of the dephasing between the two input signals and the modification of the modulation voltage added to the electro-optical crystal leads to the change of the extinction ratio. We also conclude that, in cases of the dephasing of two initial input signals Δφ=0, we can obtain the various logical operations, such as the logical operations D=A¯·B, D=A·B¯, C=A+B, and D=A⊕B in ports C and D of the system by adjusting the modulation voltage. When Δφ≠0, we obtain the arithmetic operations D=A+B, C=A⊕B, D=A·B¯, and C=A¯·B in ports C and D. This study is significant for the design of all optical networks by adjusting the modulation voltage.

  17. Bulk optic Sagnac interferometer for tests of general relativity

    International Nuclear Information System (INIS)

    Ranganathan, D.; Mehta, C.L.

    1986-01-01

    Ring laser and Sagnac interferometer gyroscopes have been suggested for a possible experiment to test metric theories of gravity. As emphasized in recent reviews, neither ring lasers nor fiber gyroscopes seem to provide the required accuracy. The same appears to be true of passive cavity resonators or nonlinear variants. The primary problem with fiber Sagnac interferometers is that the permissible power before onset or nonlinearities is quite limited (10-100 mW). Thus the SNR possible is also limited. To overcome this limitation, the authors suggest use of a bulk optic device. Specifically, the author' suggest the use of a silica block with a square cross section. Each of its faces is polished to form a segment of a sphere whose center is at the center of the opposite face. Rays originating at the center of a face and incident on the next adjacent face near its center are totally internally reflected and focused on the center of the third face in sequence. Thus the light rotates about the cavity before coming back to the point of incidence. If a light beam is introduced slightly off-axis in such an arrangement, it must complete many rotations before coming back to its starting point. Such off-axis delay lines have been used in laser gravitational wave detectors. A similar resonator has been used by another group. In the authors' configuration, the internal reflections minimize reflection and scattering losses. The spherical surfaces can be figured extremely accurately. The system is achromatic, and thus multifrequency operation to eliminate cavity drifts is possible. A model analysis for this cavity is presented including estimates of the error due to Rayleigh scattering. Generalization of this configuration to include cavities with a greater number of faces and their advantages are discussed

  18. Sagnac interferometer as a speed-meter-type, quantum-nondemolition gravitational-wave detector

    International Nuclear Information System (INIS)

    Chen Yanbei

    2003-01-01

    According to quantum measurement theory, 'speed meters' - devices that measure the momentum, or speed, of free test masses - are immune to the standard quantum limit (SQL). It is shown that a Sagnac-interferometer gravitational-wave detector is a speed meter and therefore in principle it can beat the SQL by large amounts over a wide band of frequencies. It is shown, further, that, when one ignores optical losses, a signal-recycled Sag nac interferometer with Fabry-Perot arm cavities has precisely the same performance, for the same circulating light power, as the Michelson speed-meter interferometer recently invented and studied by Purdue and the author. The influence of optical losses is not studied, but it is plausible that they be fairly unimportant for the Sag nac interferometer, as for other speed meters. With squeezed vacuum (squeeze factor e -2R =0.1) injected into its dark port, the recycled Sag nac interferometer can beat the SQL by a factor √(10)≅3 over the frequency band 10 Hz c ∼820 kw as is to be used by the (quantum limited) second-generation Advanced LIGO interferometers--if other noise sources are made sufficiently small. It is concluded that the Sag nac optical configuration, with signal recycling and squeezed-vacuum injection, is an attractive candidate for third-generation interferometric gravitational-wave detectors (LIGO-III and EURO)

  19. Optical design constrains in triangular Sagnac imaging interferometers for earth observation

    Science.gov (United States)

    Barducci, A.; Guzzi, D.; Lastri, C.; Nardino, V.; Pippi, I.

    2017-11-01

    The Italian Space Agency selected the imaging interferometer ALISEO (Aerospace Leap-frog Imaging Stationary interferometer for Earth Observation) as the main payload for a technological optical mission based on the small satellite MIOsat. The simple design of such an instrument, based on Sagnac configuration, makes it a promising for Earth observation missions. The ALISEO instrument acquires an image of 10 Km by 10 Km with a spatial resolution better than 10 m and a spectral resolution of 200 cm-1 (7 nm @ 0.6 μm) in the 0.4 - 1 μm spectral range. ALISEO does not employ any moving part to generate the phase delays between the two interfering beams. The sensor acquires target images modulated by a pattern of autocorrelation functions of the energy coming from each scene pixel, and the resulting fringe pattern remains fixed with respect to the instrument's field-of-view. The complete interferogram of each target location is retrieved by introducing a relative source-observer motion, which allows any image pixels to be observed under different viewing-angles corresponding to different Optical Path Differences (OPDs). In this paper various optical configurations are analyzed in order to meet the mission requirements. Optical configurations are discussed taking into account: detector size, spatial resolution, and entrance pupil aperture. The proposed configurations should avoid vignetting, reduce geometric and chromatic aberrations, and comply with the size and weight constrains requested by space mission. Optical configurations, based on both refractive and reflective focusing elements, are presented and discussed. Finally, some properties pertaining to the selected Sagnac configuration are discussed in conjunction with spectral estimations and data processing.

  20. Tunable erbium-doped fiber laser based on optical fiber Sagnac interference loop with angle shift spliced polarization maintaining fibers

    Science.gov (United States)

    Ding, Zhenming; Wang, Zhaokun; Zhao, Chunliu; Wang, Dongning

    2018-05-01

    In this paper, we propose and experimentally demonstrate a tunable erbium-doped fiber laser (EDFL) with Sagnac interference loop with 45° angle shift spliced polarization maintaining fibers (PMFs). In the Sagnac loop, two PMFs with similar lengths. The Sagnac loop outputs a relatively complex interference spectrum since two beams transmitted in clockwise and counterclockwise encounter at the 3 dB coupler, interfere, and form two interference combs when the light transmitted in the Sagnac loop. The laser will excite and be stable when two interference lines in these two interference combs overlap together. Then by adjusting the polarization controller, the wide wavelength tuning is realized. Experimental results show that stable single wavelength laser can be realized in the wavelength range of 1585 nm-1604 nm under the pump power 157.1 mW. The side-mode suppression ratio is not less than 53.9 dB. The peak power fluctuation is less than 0.29 dB within 30 min monitor time and the side-mode suppression ratio is great than 57.49 dB when the pump power is to 222.7 mW.

  1. Standing waves in fiber-optic interferometers

    NARCIS (Netherlands)

    De Haan, V.; Santbergen, R.; Tijssen, M.; Zeman, M.

    2011-01-01

    A study is presented giving the response of three types of fiber-optic interferometers by which a standing wave through an object is investigated. The three types are a Sagnac, Mach–Zehnder and Michelson–Morley interferometer. The response of the Mach–Zehnder interferometer is similar to the Sagnac

  2. Optical polarimetry for noninvasive glucose sensing enabled by Sagnac interferometry.

    Science.gov (United States)

    Winkler, Amy M; Bonnema, Garret T; Barton, Jennifer K

    2011-06-10

    Optical polarimetry is used in pharmaceutical drug testing and quality control for saccharide-containing products (juice, honey). More recently, it has been proposed as a method for noninvasive glucose sensing for diabetic patients. Sagnac interferometry is commonly used in optical gyroscopes, measuring minute Doppler shifts resulting from mechanical rotation. In this work, we demonstrate that Sagnac interferometers are also sensitive to optical rotation, or the rotation of linearly polarized light, and are therefore useful in optical polarimetry. Results from simulation and experiment show that Sagnac interferometers are advantageous in optical polarimetry as they are insensitive to net linear birefringence and alignment of polarization components.

  3. The generation of a lower threshold multiwavelength fiber laser in the L-band region assisted by a Sagnac loop mirror

    International Nuclear Information System (INIS)

    Aziz, Siti Narimah; Arsad, Norhana; Bakar, Ahmad Ashrif Abu; Elias, Sayidatul Nadia; Menon, P Sushita; Shaari, Sahbudin

    2015-01-01

    A low threshold multiwavelength laser generated with the assistance of a Sagnac loop mirror is proposed. Two simple ring cavity designs are studied, namely a standard design ring cavity (design A) and a ring cavity with a Sagnac loop mirror (design B). Design B, which integrates a Sagnac loop mirror together with a polarization controller, exhibits the most optimum performance, generating seven lasing modes. Using only a 40 mW pump power from the erbium-doped fiber amplifier (EDFA), design B is the preferred ring cavity design, as it successfully produces seven lasing modes simultaneously within a 0.42 nm channel spacing in the L-band region. The ring cavity is characterized by investigating the lasing threshold through the tuning output power of the EDFA, the percentages of extracted power and cavity loss. (paper)

  4. In-line microfluidic refractometer based on C-shaped fiber assisted photonic crystal fiber Sagnac interferometer.

    Science.gov (United States)

    Wu, Chuang; Tse, Ming-Leung Vincent; Liu, Zhengyong; Guan, Bai-Ou; Lu, Chao; Tam, Hwa-Yaw

    2013-09-01

    We propose and demonstrate a highly sensitive in-line photonic crystal fiber (PCF) microfluidic refractometer. Ultrathin C-shaped fibers are spliced in-between the PCF and standard single-mode fibers. The C-shaped fibers provide openings for liquid to flow in and out of the PCF. Based on a Sagnac interferometer, the refractive index (RI) response of the device is investigated theoretically and experimentally. A high sensitivity of 6621 nm/RIU for liquid RI from 1.330 to 1.333 is achieved in the experiment, which agrees well with the theoretical analysis.

  5. Quantum noise of a Michelson-Sagnac interferometer with a translucent mechanical oscillator

    International Nuclear Information System (INIS)

    Yamamoto, Kazuhiro; Friedrich, Daniel; Westphal, Tobias; Gossler, Stefan; Danzmann, Karsten; Schnabel, Roman; Somiya, Kentaro; Danilishin, Stefan L.

    2010-01-01

    Quantum fluctuations in the radiation pressure of light can excite stochastic motions of mechanical oscillators thereby realizing a linear quantum opto-mechanical coupling. When performing a precise measurement of the position of an oscillator, this coupling results in quantum radiation pressure noise. Up to now this effect has not been observed yet. Generally speaking, the strength of radiation pressure noise increases when the effective mass of the oscillator is decreased or when the power of the reflected light is increased. Recently, extremely light SiN membranes (≅100 ng) with high mechanical Q values at room temperature (≥10 6 ) have attracted attention as low thermal noise mechanical oscillators. However, the power reflectance of these membranes is much lower than unity (<0.4 at a wavelength of 1064 nm) which makes the use of advanced interferometer recycling techniques to amplify the radiation pressure noise in a standard Michelson interferometer inefficient. Here, we propose and theoretically analyze a Michelson-Sagnac interferometer that includes the membrane as a common end mirror for the Michelson interferometer part. In this topology, both power and signal recycling can be used even if the reflectance of the membrane is much lower than unity. In particular, signal recycling is a useful tool because it does not involve a power increase at the membrane. We derive the formulas for the quantum radiation pressure noise and the shot noise of an oscillator position measurement and compare them with theoretical models of the thermal noise of a SiN membrane with a fundamental resonant frequency of 75 kHz and an effective mass of125 ng. We find that quantum radiation pressure noise should be observable with a power of 1 W at the central beam splitter of the interferometer and a membrane temperature of 1 K.

  6. Optical Ramsey spectroscopy in a rotating frame: Sagnac effect in a matter-wave interferometer

    International Nuclear Information System (INIS)

    Riehle, F.; Kisters, T.; Witte, A.; Helmcke, J.; Borde, C.J.

    1991-01-01

    A calcium atomic beam excited in an optical Ramsey geometry was rotated about an axis perpendicular to the plane defined by the laser beams and the atomic beam. A frequency shift of the Ramsey fringes of several kHz has been measured which is proportional to the rotation frequency of the apparatus and to the distance between the laser beams. The results can be interpreted in three equivalent ways as the Sagnac effect in a calcium-atomic-beam interferometer: in the rotating frame of the laser beams either along straight paths or along the curved trajectories of the atoms, or in the inertial atomic frame

  7. Advanced photonic filters based on cascaded Sagnac loop reflector resonators in silicon-on-insulator nanowires

    Science.gov (United States)

    Wu, Jiayang; Moein, Tania; Xu, Xingyuan; Moss, David J.

    2018-04-01

    We demonstrate advanced integrated photonic filters in silicon-on-insulator (SOI) nanowires implemented by cascaded Sagnac loop reflector (CSLR) resonators. We investigate mode splitting in these standing-wave (SW) resonators and demonstrate its use for engineering the spectral profile of on-chip photonic filters. By changing the reflectivity of the Sagnac loop reflectors (SLRs) and the phase shifts along the connecting waveguides, we tailor mode splitting in the CSLR resonators to achieve a wide range of filter shapes for diverse applications including enhanced light trapping, flat-top filtering, Q factor enhancement, and signal reshaping. We present the theoretical designs and compare the CSLR resonators with three, four, and eight SLRs fabricated in SOI. We achieve versatile filter shapes in the measured transmission spectra via diverse mode splitting that agree well with theory. This work confirms the effectiveness of using CSLR resonators as integrated multi-functional SW filters for flexible spectral engineering.

  8. Study of lineal and non-lineal transmission of an optical fiber Sagnac interferometer as a bidirectional device

    International Nuclear Information System (INIS)

    Ramos-Beltran, J; Beltran-Perez, G; Castillo-Mixcoatl, J; Munoz-Aguirre, S; Zaca-Moran, P; Felipe, C

    2011-01-01

    The optical fiber Sagnac interferometer is a versatile system that has been investigated for a variety of applications such as optical switchers, filters, demultiplexers and passive mode-locked laser. In many cases, this arrangement is designed using a symmetrical coupler with two of their ports connected making a loop and generally the analysis have been focused in the transmission of the signal propagated in only one direction. Therefore in the present work a complementary study of the system considering the analysis for the lineal and non-lineal transmission as a bidirectional device has been performed. The experimental setup consists of different optical fiber lengths inside the cavity loop (between 100 and 500 m) with highly twisted singlemode fiber, a quarter wave retarder placed asymmetrically in one arm and a 50/50 coupler. The results have shown that for low optical powers, it is possible to adjust the system transmission in both propagation directions with the rotation of the retarder wave. On the other hand, in high optical power levels, this arrangement showed that the transmission increases slowly for the case when both the input and the output beams have the same polarization. This behavior can be used for pedestal suppression in a light pulse. Furthermore, for the case when the output signal polarization is orthogonal respect to the input one, the transmission changes quite fast. This effect can be used for applications such as the passive mode-locking.

  9. Advanced photonic filters based on cascaded Sagnac loop reflector resonators in silicon-on-insulator nanowires

    Directory of Open Access Journals (Sweden)

    Jiayang Wu

    2018-04-01

    Full Text Available We demonstrate advanced integrated photonic filters in silicon-on-insulator (SOI nanowires implemented by cascaded Sagnac loop reflector (CSLR resonators. We investigate mode splitting in these standing-wave (SW resonators and demonstrate its use for engineering the spectral profile of on-chip photonic filters. By changing the reflectivity of the Sagnac loop reflectors (SLRs and the phase shifts along the connecting waveguides, we tailor mode splitting in the CSLR resonators to achieve a wide range of filter shapes for diverse applications including enhanced light trapping, flat-top filtering, Q factor enhancement, and signal reshaping. We present the theoretical designs and compare the CSLR resonators with three, four, and eight SLRs fabricated in SOI. We achieve versatile filter shapes in the measured transmission spectra via diverse mode splitting that agree well with theory. This work confirms the effectiveness of using CSLR resonators as integrated multi-functional SW filters for flexible spectral engineering.

  10. Generation of singular optical beams from fundamental Gaussian beam using Sagnac interferometer

    Science.gov (United States)

    Naik, Dinesh N.; Viswanathan, Nirmal K.

    2016-09-01

    We propose a simple free-space optics recipe for the controlled generation of optical vortex beams with a vortex dipole or a single charge vortex, using an inherently stable Sagnac interferometer. We investigate the role played by the amplitude and phase differences in generating higher-order Gaussian beams from the fundamental Gaussian mode. Our simulation results reveal how important the control of both the amplitude and the phase difference between superposing beams is to achieving optical vortex beams. The creation of a vortex dipole from null interference is unveiled through the introduction of a lateral shear and a radial phase difference between two out-of-phase Gaussian beams. A stable and high quality optical vortex beam, equivalent to the first-order Laguerre-Gaussian beam, is synthesized by coupling lateral shear with linear phase difference, introduced orthogonal to the shear between two out-of-phase Gaussian beams.

  11. A Fiber Optic PD Sensor Using a Balanced Sagnac Interferometer and an EDFA-Based DOP Tunable Fiber Ring Laser

    Science.gov (United States)

    Wang, Lutang; Fang, Nian; Wu, Chunxu; Qin, Haijuan; Huang, Zhaoming

    2014-01-01

    A novel fiber-optic acoustic sensor using an erbium-doped fiber amplifier (EDFA)-based fiber ring laser and a balanced Sagnac interferometer for acoustic sensing of the partial discharge (PD) in power transformers is proposed and demonstrated. As a technical background, an experimental investigation on how the variations of the fiber birefringence affect the sensor performances was carried out, and the results are discussed. The operation principles are described, and the relevant formulas are derived. The analytical results show that an EDFA-based fiber ring laser operating in chaotic mode can provide a degree of polarization (DOP) tunable light beam for effectively suppressing polarization fading noises. The balanced Sagnac interferometer can eliminate command intensity noises and enhance the signal-to-noise ratio (SNR). Furthermore, it inherently operates at the quadrature point of the response curve without any active stabilizations. Several experiments are conducted for evaluating the performances of the sensor system, as well as for investigating the ability of the detection of high-frequency acoustic emission signals. The experimental results demonstrate that the DOP of the laser beam can be continuously tuned from 0.2% to 100%, and the power fluctuation in the whole DOP tuning range is less than 0.05 dBm. A high-frequency response up to 300 kHz is reached, and the high sensing sensitivity for detections of weak corona discharges, as well as partial discharges also is verified. PMID:24824371

  12. Coherence holography by achromatic 3-D field correlation of generic thermal light with an imaging Sagnac shearing interferometer.

    Science.gov (United States)

    Naik, Dinesh N; Ezawa, Takahiro; Singh, Rakesh Kumar; Miyamoto, Yoko; Takeda, Mitsuo

    2012-08-27

    We propose a new technique for achromatic 3-D field correlation that makes use of the characteristics of both axial and lateral magnifications of imaging through a common-path Sagnac shearing interferometer. With this technique, we experimentally demonstrate, for the first time to our knowledge, 3-D image reconstruction of coherence holography with generic thermal light. By virtue of the achromatic axial shearing implemented by the difference in axial magnifications in imaging, the technique enables coherence holography to reconstruct a 3-D object with an axial depth beyond the short coherence length of the thermal light.

  13. Temperature Sensor Based on an Asymmetric Two-Hole Fiber Using a Sagnac Interferometer

    Directory of Open Access Journals (Sweden)

    René Domínguez-Cruz

    2018-01-01

    Full Text Available We report in this paper a temperature sensor based on an asymmetric two-hole fiber (ATHF using a Sagnac interferometer (SI configuration. The operation principle is based on the birefringence change induced by the temperature difference between the air holes and the silica fiber. As a result, the transmitted spectrum of the SI exhibits a sinusoidal profile which is shifted when the temperature is increased. A linear wavelength shift as a function of temperature is observed, and a sensitivity of 2.22 nm/°C was achieved using a 2 m long asymmetric THF, which is in the same order as those previously reported using similar microstructured fibers. The advantage of this system is a linear response, the use of a microstructured fiber with a simpler transverse geometry, and the use of bigger holes which can facilitate the insertion of several materials and improve the sensitivity of the sensor for different applications.

  14. Multi-wavelength laser based on an arrayed waveguide grating and Sagnac loop reflectors monolithically integrated on InP

    NARCIS (Netherlands)

    Muñoz, P.; García-Olcina, R.; Doménech, J.D.; Rius, M.; Capmany, J.; Chen, L.R.; Habib, C.; Leijtens, X.J.M.; Vries, de T.; Heck, M.J.R.; Augustin, L.M.; Nötzel, R.; Robbins, D.J.

    2010-01-01

    In this paper, a multi-wavelength laser monolithically integrated on InP is presented. A linear laser cavity is built between two integrated Sagnac loop reflectors, with an Arrayed Waveguide Grating (AWG) as frequency selective device, and Semiconductor Optical Amplifiers (SOA) as gain sections. The

  15. Naturally stable Sagnac-Michelson nonlinear interferometer.

    Science.gov (United States)

    Lukens, Joseph M; Peters, Nicholas A; Pooser, Raphael C

    2016-12-01

    Interferometers measure a wide variety of dynamic processes by converting a phase change into an intensity change. Nonlinear interferometers, making use of nonlinear media in lieu of beamsplitters, promise substantial improvement in the quest to reach the ultimate sensitivity limits. Here we demonstrate a new nonlinear interferometer utilizing a single parametric amplifier for mode mixing-conceptually, a nonlinear version of the conventional Michelson interferometer with its arms collapsed together. We observe up to 99.9% interference visibility and find evidence for noise reduction based on phase-sensitive gain. Our configuration utilizes fewer components than previous demonstrations and requires no active stabilization, offering new capabilities for practical nonlinear interferometric-based sensors.

  16. Sagnac secret sharing over telecom fiber networks.

    Science.gov (United States)

    Bogdanski, Jan; Ahrens, Johan; Bourennane, Mohamed

    2009-01-19

    We report the first Sagnac quantum secret sharing (in three-and four-party implementations) over 1550 nm single mode fiber (SMF) networks, using a single qubit protocol with phase encoding. Our secret sharing experiment has been based on a single qubit protocol, which has opened the door to practical secret sharing implementation over fiber telecom channels and in free-space. The previous quantum secret sharing proposals were based on multiparticle entangled states, difficult in the practical implementation and not scalable. Our experimental data in the three-party implementation show stable (in regards to birefringence drift) quantum secret sharing transmissions at the total Sagnac transmission loop distances of 55-75 km with the quantum bit error rates (QBER) of 2.3-2.4% for the mean photon number micro?= 0.1 and 1.7-2.1% for micro= 0.3. In the four-party case we have achieved quantum secret sharing transmissions at the total Sagnac transmission loop distances of 45-55 km with the quantum bit error rates (QBER) of 3.0-3.7% for the mean photon number micro= 0.1 and 1.8-3.0% for micro?= 0.3. The stability of quantum transmission has been achieved thanks to our new concept for compensation of SMF birefringence effects in Sagnac, based on a polarization control system and a polarization insensitive phase modulator. The measurement results have showed feasibility of quantum secret sharing over telecom fiber networks in Sagnac configuration, using standard fiber telecom components.

  17. Long-range transverse spin Seebeck effect in permalloy stripes using Sagnac interferometer microscopy

    Science.gov (United States)

    Liu, Haoliang; McLaughlin, Ryan; Sun, Dali; Valy Vardeny, Z.

    2018-04-01

    Coupling of spins and phonons in ferromagnets (FM) may persist up to mm length scale, thus generating macroscopic spatially distributed spin accumulation along the direction of an applied thermal gradient to an FM slab. This typical feature of transverse spin Seebeck effect (TSSE) has been demonstrated so far using electrical detection methods in FM films, in particular in a patterned structure, in which FM stripes grown onto a substrate perpendicular to the applied thermal gradient direction are electrically and magnetically isolated. Here we report optically detected TSSE response in isolated FM stripes based on permalloy deposited on SiN substrate, upon the application of a thermal gradient. For these measurements we used the magneto-optic Kerr effect measured by an ultrasensitive Sagnac interferometer microscope that is immune to thermo-electrics artefacts. We found that the optical TSSE coefficient in the NiFe stripes geometry is about one order of magnitude smaller than that in the continuous NiFe film, which is due to the limited phonons path in the FM stripes along the thermal gradient direction. Our results further confirm the existence of TSSE response in conducting FM compounds.

  18. Uniform spacing interrogation of a Fourier domain mode-locked fiber Bragg grating sensor system using a polarization-maintaining fiber Sagnac interferometer

    Science.gov (United States)

    Lee, Hwi Don; Jung, Eun Joo; Jeong, Myung Yung; Chen, Zhongping; Kim, Chang-Seok

    2014-01-01

    A novel linearized interrogation method is presented for a Fourier domain mode-locked (FDML) fiber Bragg grating (FBG) sensor system. In a high speed regime over several tens of kHz modulations, a sinusoidal wave is available to scan the center wavelength of an FDML wavelength-swept laser, instead of a conventional triangular wave. However, sinusoidal wave modulation suffers from an exaggerated non-uniform wavelength-spacing response in demodulating the time-encoded parameter to the absolute wavelength. In this work, the calibration signal from a polarization-maintaining fiber Sagnac interferometer shares the FDML wavelength-swept laser for FBG sensors to convert the time-encoded FBG signal to the wavelength-encoded uniform-spacing signal. PMID:24489440

  19. Uniform spacing interrogation of a Fourier domain mode-locked fiber Bragg grating sensor system using a polarization-maintaining fiber Sagnac interferometer

    International Nuclear Information System (INIS)

    Lee, Hwi Don; Jeong, Myung Yung; Chen, Zhongping; Kim, Chang-Seok; Jung, Eun Joo

    2013-01-01

    A novel linearized interrogation method is presented for a Fourier domain mode-locked (FDML) fiber Bragg grating (FBG) sensor system. In a high speed regime over several tens of kHz modulations, a sinusoidal wave is available to scan the center wavelength of an FDML wavelength-swept laser, instead of a conventional triangular wave. However, sinusoidal wave modulation suffers from an exaggerated non-uniform wavelength-spacing response in demodulating the time-encoded parameter to the absolute wavelength. In this work, the calibration signal from a polarization-maintaining fiber Sagnac interferometer shares the FDML wavelength-swept laser for FBG sensors to convert the time-encoded FBG signal to the wavelength-encoded uniform-spacing signal. (paper)

  20. Uniform spacing interrogation of a Fourier domain mode-locked fiber Bragg grating sensor system using a polarization-maintaining fiber Sagnac interferometer

    Science.gov (United States)

    Lee, Hwi Don; Jung, Eun Joo; Jeong, Myung Yung; Chen, Zhongping; Kim, Chang-Seok

    2013-06-01

    A novel linearized interrogation method is presented for a Fourier domain mode-locked (FDML) fiber Bragg grating (FBG) sensor system. In a high speed regime over several tens of kHz modulations, a sinusoidal wave is available to scan the center wavelength of an FDML wavelength-swept laser, instead of a conventional triangular wave. However, sinusoidal wave modulation suffers from an exaggerated non-uniform wavelength-spacing response in demodulating the time-encoded parameter to the absolute wavelength. In this work, the calibration signal from a polarization-maintaining fiber Sagnac interferometer shares the FDML wavelength-swept laser for FBG sensors to convert the time-encoded FBG signal to the wavelength-encoded uniform-spacing signal.

  1. Detecting a stochastic gravitational wave background with the Laser Interferometer Space Antenna

    International Nuclear Information System (INIS)

    Cornish, Neil J.

    2002-01-01

    The random superposition of many weak sources will produce a stochastic background of gravitational waves that may dominate the response of the LISA (Laser Interferometer Space Antenna) gravitational wave observatory. Unless something can be done to distinguish between a stochastic background and detector noise, the two will combine to form an effective noise floor for the detector. Two methods have been proposed to solve this problem. The first is to cross-correlate the output of two independent interferometers. The second is an ingenious scheme for monitoring the instrument noise by operating LISA as a Sagnac interferometer. Here we derive the optimal orbital alignment for cross-correlating a pair of LISA detectors, and provide the first analytic derivation of the Sagnac sensitivity curve

  2. Design of a speed meter interferometer proof-of-principle experiment

    International Nuclear Information System (INIS)

    Gräf, C; Barr, B W; Bell, A S; Campbell, F; Cumming, A V; Gordon, N A; Hammond, G D; Hennig, J; Houston, E A; Huttner, S H; Jones, R A; Leavey, S S; Macarthur, J; Marwick, M; Rigby, S; Sorazu, B; Spencer, A; Danilishin, S L; Lück, H; Schilling, R

    2014-01-01

    The second generation of large scale interferometric gravitational wave (GW) detectors will be limited by quantum noise over a wide frequency range in their detection band. Further sensitivity improvements for future upgrades or new detectors beyond the second generation motivate the development of measurement schemes to mitigate the impact of quantum noise in these instruments. Two strands of development are being pursued to reach this goal, focusing both on modifications of the well-established Michelson detector configuration and development of different detector topologies. In this paper, we present the design of the world's first Sagnac speed meter (SSM) interferometer, which is currently being constructed at the University of Glasgow. With this proof-of-principle experiment we aim to demonstrate the theoretically predicted lower quantum noise in a Sagnac interferometer compared to an equivalent Michelson interferometer, to qualify SSM for further research towards an implementation in a future generation large scale GW detector, such as the planned Einstein telescope observatory. (paper)

  3. High-spatial-resolution localization algorithm based on cascade deconvolution in a distributed Sagnac interferometer invasion monitoring system.

    Science.gov (United States)

    Pi, Shaohua; Wang, Bingjie; Zhao, Jiang; Sun, Qi

    2016-10-10

    In the Sagnac fiber optic interferometer system, the phase difference signal can be illustrated as a convolution of the waveform of the invasion with its occurring-position-associated transfer function h(t); deconvolution is introduced to improve the spatial resolution of the localization. In general, to get a 26 m spatial resolution at a sampling rate of 4×106  s-1, the algorithm should mainly go through three steps after the preprocessing operations. First, the decimated phase difference signal is transformed from the time domain into the real cepstrum domain, where a probable region of invasion distance can be ascertained. Second, a narrower region of invasion distance is acquired by coarsely assuming and sweeping a transfer function h(t) within the probable region and examining where the restored invasion waveform x(t) gets its minimum standard deviation. Third, fine sweeping the narrow region point by point with the same criteria is used to get the final localization. Also, the original waveform of invasion can be restored for the first time as a by-product, which provides more accurate and pure characteristics for further processing, such as subsequent pattern recognition.

  4. Displacement measurement using an optoelectronic oscillator with an intra-loop Michelson interferometer.

    Science.gov (United States)

    Lee, Jehyun; Park, Sooyoung; Seo, Dae Han; Yim, Sin Hyuk; Yoon, Seokchan; Cho, D

    2016-09-19

    We report on measurement of small displacements with sub-nanometer precision using an optoelectronic oscillator (OEO) with an intra-loop Michelson interferometer. In comparison with conventional homodyne and heterodyne detection methods, where displacement appears as a power change or a phase shift, respectively, in the OEO detection, the displacement produces a shift in the oscillation frequency. In comparison with typical OEO sensors, where the frequency shift is proportional to the OEO oscillation frequency in radio-frequency domain, the frequency shift in our method with an intra-loop interferometer is proportional to an optical frequency. We constructed a hybrid apparatus and compared characteristics of the OEO and heterodyne detection methods.

  5. Highly stable polarization independent Mach-Zehnder interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Mičuda, Michal, E-mail: micuda@optics.upol.cz; Doláková, Ester; Straka, Ivo; Miková, Martina; Dušek, Miloslav; Fiurášek, Jaromír; Ježek, Miroslav, E-mail: jezek@optics.upol.cz [Department of Optics, Faculty of Science, Palacký University, 17. listopadu 1192/12, 77146 Olomouc (Czech Republic)

    2014-08-15

    We experimentally demonstrate optical Mach-Zehnder interferometer utilizing displaced Sagnac configuration to enhance its phase stability. The interferometer with footprint of 27×40 cm offers individually accessible paths and shows phase deviation less than 0.4° during a 250 s long measurement. The phase drift, evaluated by means of Allan deviation, stays below 3° or 7 nm for 1.5 h without any active stabilization. The polarization insensitive design is verified by measuring interference visibility as a function of input polarization. For both interferometer's output ports and all tested polarization states the visibility stays above 93%. The discrepancy in visibility for horizontal and vertical polarization about 3.5% is caused mainly by undesired polarization dependence of splitting ratio of the beam splitter used. The presented interferometer device is suitable for quantum-information and other sensitive applications where active stabilization is complicated and common-mode interferometer is not an option as both the interferometer arms have to be accessible individually.

  6. Beating of Aharonov-Bohm oscillations in a closed-loop interferometer

    International Nuclear Information System (INIS)

    Jo, Sanghyun; Chang, Dong-In; Lee, Hu-Jong; Khym, Gyong Luck; Kang, Kicheon; Chung, Yunchul; Mahalu, Diana; Umansky, Vladimir

    2007-01-01

    One of the points at issue with closed-loop-type interferometers is beating in the Aharonov-Bohm (AB) oscillations. Recent observations suggest the possibility that the beating results from the Berry-phase pickup by the conducting electrons in materials with the strong spin-orbit interaction (SOI). In this study, we also observed beats in the AB oscillations in a gate-defined closed-loop interferometer fabricated on a GaAs/Al 0.3 Ga 0.7 As two-dimensional electron-gas heterostructure. Since this heterostructure has very small SOI, the picture of the Berry-phase pickup is ruled out. The observation of beats in this study, with the controllability of forming a single transverse subband mode in both arms of our gate-defined interferometer, also rules out the often-claimed multiple transverse subband effect. It is observed that nodes of the beats with an h/2e period exhibit a parabolic distribution for varying the side gate. These results are shown to be well interpreted, without resorting to the SOI effect, by the existence of two-dimensional multiple longitudinal modes in a single transverse subband. The Fourier spectrum of measured conductance, despite showing multiple h/e peaks with the magnetic-field dependence that are very similar to that from strong-SOI materials, can also be interpreted as the two-dimensional multiple-longitudinal-modes effect

  7. Three-color Sagnac source of polarization-entangled photon pairs.

    Science.gov (United States)

    Hentschel, Michael; Hübel, Hannes; Poppe, Andreas; Zeilinger, Anton

    2009-12-07

    We demonstrate a compact and stable source of polarization-entangled pairs of photons, one at 810 nm wavelength for high detection efficiency and the other at 1550 nm for long-distance fiber communication networks. Due to a novel Sagnac-based design of the interferometer no active stabilization is needed. Using only one 30 mm ppKTP bulk crystal the source produces photons with a spectral brightness of 1.13 x 10(6) pairs/s/mW/THz with an entanglement fidelity of 98.2%. Both photons are single-mode fiber coupled and ready to be used in quantum key distribution (QKD) or transmission of photonic quantum states over large distances.

  8. Multi-wavelength fiber laser in the S-band region using a Sagnac loop mirror as a comb generator in an SOA gain medium

    International Nuclear Information System (INIS)

    Zulkifli, M Z; Hassan, N A; Awang, N A; Ahmad, H; Ghani, Z A; Harun, S W

    2010-01-01

    A simple design of multi-wavelength generation in the S-band region of the optical network transmission is proposed. The design consists of broad-band fiber Bragg grating (BB-FBG), which acts as a filter to enhance operation in the S-band region. A Sagnac loop mirror (SLM) is used to generate multiple wavelength oscillations in the ring cavity. The output consists of 60 lasing wavelengths oscillating simultaneously between 1464 nm and 1521 nm with a spacing of 0.92 nm and an output linewidth of 0.66 nm

  9. White light Sagnac interferometer—a common (path) tale of light

    International Nuclear Information System (INIS)

    Schwartz, Eyal

    2017-01-01

    White or polychromatic light sources are vastly abundant in nature and lie in our most basic understanding of the theory of light, beginning from stars like our Sun and extending to every common household light bulb or street lamp. In this paper, I present concepts of white light interferometery using a common-path Sagnac interferometer, manifested in a straightforward laboratory experiment. I further show the use of this as a Fourier transform spectrometer while presenting a basic overview of the theoretical concepts and spectrum of different light sources obtained experimentally. This work, both experimentally and analytically, is suitable for upper-level undergraduate physics or engineering courses where electromagnetic theory and optics are discussed. The experiment and theory presents important deep concepts and aspects in modern optics and physics that every science student should acquire. (paper)

  10. White light Sagnac interferometer—a common (path) tale of light

    Science.gov (United States)

    Schwartz, Eyal

    2017-11-01

    White or polychromatic light sources are vastly abundant in nature and lie in our most basic understanding of the theory of light, beginning from stars like our Sun and extending to every common household light bulb or street lamp. In this paper, I present concepts of white light interferometery using a common-path Sagnac interferometer, manifested in a straightforward laboratory experiment. I further show the use of this as a Fourier transform spectrometer while presenting a basic overview of the theoretical concepts and spectrum of different light sources obtained experimentally. This work, both experimentally and analytically, is suitable for upper-level undergraduate physics or engineering courses where electromagnetic theory and optics are discussed. The experiment and theory presents important deep concepts and aspects in modern optics and physics that every science student should acquire.

  11. Quadratic Sagnac effect — the influence of the gravitational potential of the Coriolis force on the phase difference between the arms of a rotating Michelson interferometer (an explanation of D C Miller's experimental results, 1921 – 1926)

    International Nuclear Information System (INIS)

    Malykin, G B; Pozdnyakova, V I

    2015-01-01

    It is shown that when an equal-arm Michelson interferometer is involved in rotation (for example, Earth's rotation around its axis or around the Sun) and its arms are oriented differently with respect to the plane of rotation, a phase difference arises between the light rays that pass through different arms. This phase difference is due to the fact that the arms experience variously the Newtonian (nonrelativistic) scalar gravitational potential of the Coriolis forces. It is shown that the phase difference is proportional to the length of the interferometer arm, the square of the angular velocity of the rotation, and the square of the distance from the center of rotation — hence, the proposal to call this phenomenon the quadratic Sagnac effect. In the present paper, we consider, as an illustrative example, the results of the once well-known experiments of D C Miller, who claimed to observe the translational motion of Earth relative to the hypothetical ‘luminiferous ether’. It is shown that this claim can actually be explained by the fact that, because of the orbital revolution of Earth, the time dilations in the orthogonal arms of the Michelson interferometer are influenced differently by the scalar gravitational potential of the Coriolis forces. (methodological notes)

  12. The Sagnac effect and its interpretation by Paul Langevin

    Science.gov (United States)

    Pascoli, Gianni

    2017-11-01

    The French physicist Georges Sagnac is nowdays frequently cited by the engineers who work on devices such as ring-laser gyroscopes. These systems operate on the principle of the Sagnac effect. It is less known that Sagnac was a strong opponent to the theory of special relativity proposed by Albert Einstein. He set up his experiment to prove the existence of the aether discarded by the Einsteinian relativity. An accurate explanation of the phenomenon was provided by Paul Langevin in 1921.

  13. Supplement to the paper 'Quadratic Sagnac effect — the influence of the gravitational potential of the Coriolis force on the phase difference between the arms of a rotating Michelson interferometer (an explanation of D C Miller's experimental results, 1921 – 1926)' (Usp. Fiz. Nauk185 431 (2015) [Phys. Usp.58 398 (2015)])

    International Nuclear Information System (INIS)

    Malykin, G B; Pozdnyakova, V I

    2015-01-01

    The paper 'Quadratic Sagnac effect — the influence of the gravitational potential of the Coriolis force on the phase difference between the arms of a rotating Michelson interferometer (an explanation of D C Miller's experimental results, 1921 – 1926)' (Usp. Fiz. Nauk 185 431 (2015) [Phys. Usp. 58 398 (2015)]) is amended and supplemented with information concerning earlier work on the influence of rotation on Michelson – Morley's nonzero results. (letters to the editors)

  14. Sagnac interferometry with coherent vortex superposition states in exciton-polariton condensates

    Science.gov (United States)

    Moxley, Frederick Ira; Dowling, Jonathan P.; Dai, Weizhong; Byrnes, Tim

    2016-05-01

    We investigate prospects of using counter-rotating vortex superposition states in nonequilibrium exciton-polariton Bose-Einstein condensates for the purposes of Sagnac interferometry. We first investigate the stability of vortex-antivortex superposition states, and show that they survive at steady state in a variety of configurations. Counter-rotating vortex superpositions are of potential interest to gyroscope and seismometer applications for detecting rotations. Methods of improving the sensitivity are investigated by targeting high momentum states via metastable condensation, and the application of periodic lattices. The sensitivity of the polariton gyroscope is compared to its optical and atomic counterparts. Due to the large interferometer areas in optical systems and small de Broglie wavelengths for atomic BECs, the sensitivity per detected photon is found to be considerably less for the polariton gyroscope than with competing methods. However, polariton gyroscopes have an advantage over atomic BECs in a high signal-to-noise ratio, and have other practical advantages such as room-temperature operation, area independence, and robust design. We estimate that the final sensitivities including signal-to-noise aspects are competitive with existing methods.

  15. Planar location of the simulative acoustic source based on fiber optic sensor array

    Science.gov (United States)

    Liang, Yi-Jun; Liu, Jun-feng; Zhang, Qiao-ping; Mu, Lin-lin

    2010-06-01

    A fiber optic sensor array which is structured by four Sagnac fiber optic sensors is proposed to detect and locate a simulative source of acoustic emission (AE). The sensing loops of Sagnac interferometer (SI) are regarded as point sensors as their small size. Based on the derived output light intensity expression of SI, the optimum work condition of the Sagnac fiber optic sensor is discussed through the simulation of MATLAB. Four sensors are respectively placed on a steel plate to structure the sensor array and the location algorithms are expatiated. When an impact is generated by an artificial AE source at any position of the plate, the AE signal will be detected by four sensors at different times. With the help of a single chip microcomputer (SCM) which can calculate the position of the AE source and display it on LED, we have implemented an intelligent detection and location.

  16. Georges Sagnac: A life for optics

    Science.gov (United States)

    Darrigol, Olivier

    2014-12-01

    Georges Sagnac is mostly known for the optical effect in rotating frames that he demonstrated in 1913. His scientific interests were quite diverse: they included photography, optical illusions, X-ray physics, radioactivity, the blue of the sky, anomalous wave propagation, interferometry, strioscopy, and acoustics. An optical theme nonetheless pervaded his entire œuvre. Within optics, an original theory of the propagation of light motivated most of his investigations, from an ingenious explanation of the Fresnel drag, through the discovery of the Sagnac effect, to his quixotic defense of an alternative to relativity theory. Optical analogies efficiently guided his work in other domains. Optics indeed was his true passion. He saw himself as carrying the torch of the two great masters of French optics, Augustin Fresnel and Hippolyte Fizeau. In this mission he overcame his poor health and labored against the modernist tide, with much success originally and bitter isolation in the end. xml:lang="fr"

  17. Terrestrial Sagnac delay constraining modified gravity models

    Science.gov (United States)

    Karimov, R. Kh.; Izmailov, R. N.; Potapov, A. A.; Nandi, K. K.

    2018-04-01

    Modified gravity theories include f(R)-gravity models that are usually constrained by the cosmological evolutionary scenario. However, it has been recently shown that they can also be constrained by the signatures of accretion disk around constant Ricci curvature Kerr-f(R0) stellar sized black holes. Our aim here is to use another experimental fact, viz., the terrestrial Sagnac delay to constrain the parameters of specific f(R)-gravity prescriptions. We shall assume that a Kerr-f(R0) solution asymptotically describes Earth's weak gravity near its surface. In this spacetime, we shall study oppositely directed light beams from source/observer moving on non-geodesic and geodesic circular trajectories and calculate the time gap, when the beams re-unite. We obtain the exact time gap called Sagnac delay in both cases and expand it to show how the flat space value is corrected by the Ricci curvature, the mass and the spin of the gravitating source. Under the assumption that the magnitude of corrections are of the order of residual uncertainties in the delay measurement, we derive the allowed intervals for Ricci curvature. We conclude that the terrestrial Sagnac delay can be used to constrain the parameters of specific f(R) prescriptions. Despite using the weak field gravity near Earth's surface, it turns out that the model parameter ranges still remain the same as those obtained from the strong field accretion disk phenomenon.

  18. LISA Pathfinder: OPD loop characterisation

    Science.gov (United States)

    Born, Michael; LPF Collaboration

    2017-05-01

    The optical metrology system (OMS) of the LISA Pathfinder mission is measuring the distance between two free-floating test masses with unprecedented precision. One of the four OMS heterodyne interferometers reads out the phase difference between the reference and the measurement laser beam. This phase from the reference interferometer is common to all other longitudinal interferometer read outs and therefore subtracted. In addition, the phase is fed back via the digital optical pathlength difference (OPD) control loop to keep it close to zero. Here, we analyse the loop parameters and compare them to on-ground measurement results.

  19. Coriolis force and Sagnac effect

    International Nuclear Information System (INIS)

    Gogberashvili, Merab

    2002-02-01

    The optical Sagnac effect is considered, when the fictitious gravitational field simulates the reflections from the mirrors. It is shown that no contradiction exists between the conclusions of the laboratory and rotated observers. Because of the acting of gravity-like Coriolis force the trajectories of co- and anti-rotating photons have different radii in the rotating reference frame, while in the case of the equal radius the effective gravitational potentials for the photons have to be different. (author)

  20. Analysis of threshold curves for superconducting interferometers

    International Nuclear Information System (INIS)

    Peterson, R.L.; Hamilton, C.A.

    1979-01-01

    Threshold curves for multijunction superconducting interferometers have been calculated previously, showing general agreement with observed features, especially in symmetric cases. We here add some more details to the analysis, paying particular attention to the effects of asymmetries in coupling, inductance, or critical currents. Feed-loop inductance and flux quantization in the feed loop can be important. A changing lobe pattern over many periods, asymmetries within a period, shifting patterns between runs spanning a warm-up, and sudden changes in pattern because of noise in the environment are all quantitatively explainable on the basis of this model. By use of a single ''calibration curve'', the inductance for symmetric two- or three-junction interferometers can be obtained immediately

  1. Upper limit on NUT charge from the observed terrestrial Sagnac effect

    Science.gov (United States)

    Kulbakova, A.; Karimov, R. Kh; Izmailov, R. N.; Nandi, K. K.

    2018-06-01

    The exact Sagnac delay in the Kerr–Taub–NUT (Newman–Unti–Tamburino) spacetime is derived in the equatorial plane for non-geodesic as well as geodesic circular orbits. The resulting formula, being exact, can be directly applied to motion in the vicinity of any spinning object including black holes but here we are considering only the terrestrial case since observational data are available. The formula reveals that, in the limit of spin , the delay does not vanish. This fact is similar to the non-vanishing of Lense–Thirring precession under even though the two effects originate from different premises. Assuming a reasonable input that the Kerr–Taub–NUT corrections are subsumed in the average residual uncertainty in the measured Sagnac delay, we compute upper limits on the NUT charge n. It is found that the upper limits on n are far larger than the Earth’s gravitational mass, which has not been detected in observations, implying that the Sagnac effect cannot constrain n to smaller values near zero. We find a curious difference between the delays for non-geodesic and geodesic clock orbits and point out its implication for the well known ‘twin paradox’ of special relativity.

  2. Vertical Josephson Interferometer for Tunable Flux Qubit

    Energy Technology Data Exchange (ETDEWEB)

    Granata, C [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I- 80078, Pozzuoli (Italy); Vettoliere, A [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I- 80078, Pozzuoli (Italy); Lisitskiy, M [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I- 80078, Pozzuoli (Italy); Rombetto, S [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I- 80078, Pozzuoli (Italy); Russo, M [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I- 80078, Pozzuoli (Italy); Ruggiero, B [Istituto di Cibernetica ' E. Caianiello' del Consiglio Nazionale delle Ricerche, I- 80078, Pozzuoli (Italy); Corato, V [Dipartimento di Ingegneria dell' Informazione, Seconda Universita di Napoli, I-8 1031, Aversa (Italy) and Istituto di Cibernetica ' E. Caianiello' del CNR, I-80078, Pozzuoli (Italy); Russo, R [Dipartimento di Ingegneria dell' Informazione, Seconda Universita di Napoli, I-8 1031, Aversa (Italy) and Istituto di Cibernetica ' E. Caianiello' del CNR, I-80078, Pozzuoli (Italy); Silvestrini, P [Dipartimento di Ingegneria dell' Informazione, Seconda Universita di Napoli, I-8 1031, Aversa (Italy) and Istituto di Cibernetica ' E. Caianiello' del CNR, I-80078, Pozzuoli (Italy)

    2006-06-01

    We present a niobium-based Josephson device as prototype for quantum computation with flux qubits. The most interesting feature of this device is the use of a Josephson vertical interferometer to tune the flux qubit allowing the control of the off-diagonal Hamiltonian terms of the system. In the vertical interferometer, the Josephson current is precisely modulated from a maximum to zero with fine control by a small transversal magnetic field parallel to the rf superconducting loop plane.

  3. Perfect crystal interferometer and its applications

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Yuji [Atominstitut der Oesterreichischen Universitaeten, Vienna (Austria)

    1996-08-01

    The interferometry with angstrom scale wavelength has developed steadily, and various types of interferometers have been investigated. Among them, LLL interferometers are widely used. The first neutron interferometry was achieved in 1962 by Maier-Leibnitz et al. A new type of neutron interferometers was constructed with a perfect crystal, and experimentally performed in 1974 by Rauch et al. The precise measurements with LLL neutron interferometers were performed on scattering length, gravitational effect, coherence, Fizeau effects, spin superposition, complementarity, and post-selection effects. Since the early stage of quantum physics, the double-slit experiment has served as the example of the epistemologically strange features of quantum phenomena, and its course of study is described. The time-delayed interferometry with nuclear resonant scattering of synchrotron radiation and phase transfer in time-delayed interferometry with nuclear resonant scattering were experimented, and are briefly reported. A geometric phase factor was derived for a split beam experiment as an example of cyclic evolution. The geometric phase was observed with a two-loop neutron interferometer. All the experimental results showed complete agreement with the theoretical treatment. (K.I.)

  4. ALISEO on MIOSat: an imaging interferometer for earth observation

    Science.gov (United States)

    Barducci, A.; Castagnoli, F.; Castellini, G.; Guzzi, D.; Marcoionni, P.; Pippi, I.

    2017-11-01

    The Italian Space Agency (ASI) decided to perform an low cost Earth observation mission based on a new mini satellite named MIOsat which will carry various technological payloads. Among them an imaging interferometer designed and now ready to be assembled and tested by our Institute. The instrument, named ALISEO (Aerospace Leap-frog Imaging Stationary interferometer for Earth Observation), operates in the common-path Sagnac configuration, and it does not utilize any moving part to scan the phase delays between the two interfering beams. The sensor acquires target images modulated by a pattern of autocorrelation functions of the energy coming from each scene pixel, and the resulting fringe pattern remains spatially fixed with respect to the instrument's field-of-view. The complete interferogram of each target location is retrieved by introducing a relative source-observer motion, which allows any image pixels to be observed under different viewing-angles and experience discrete path differences. The paper describes the main characteristics of the imaging interferometer as well as the overall optical configuration and the electronics layout. Moreover some theoretical issues concerning sampling theory in "common path" imaging interferometry are investigated. The experimental activity performed in laboratory is presented and its outcomes are analysed. Particularly, a set of measurements has been carried out using both standard (certificate) reflectance tiles and natural samples of different volcanic rocks. An algorithm for raw data pre-processing aimed at retrieving the at-sensor radiance spectrum is introduced and its performance is addressed by taking into account various issues such as dark signal subtraction, spectral instrument response compensation, effects of vignetting, and Fourier backtransform. Finally, examples of retrieved absolute reflectance of several samples are sketched at different wavelengths.

  5. All-fibre source of amplitude squeezed light pulses

    Energy Technology Data Exchange (ETDEWEB)

    Meissner, Markus; Marquardt, Christoph; Heersink, Joel; Gaber, Tobias; Wietfeld, Andre; Leuchs, Gerd; Andersen, Ulrik L [Institut fuer Optik, Information und Photonik, Max-Planck Forschungsgruppe Universitaet Erlangen-Nuernberg, Staudtstrasse 7/B2, 91058, Erlangen (Germany)

    2004-08-01

    An all-fibre source of amplitude squeezed solitons utilizing the self-phase modulation in an asymmetric Sagnac interferometer is experimentally demonstrated. The asymmetry of the interferometer is passively controlled by an integrated fibre coupler, allowing for the optimization of the noise reduction. We have carefully studied the dependence of the amplitude noise on the asymmetry and the power launched into the Sagnac interferometer. Qualitatively, we find good agreement between the experimental results, a semi-classical theory and earlier numerical calculations (Schmitt et al 1998 Phys. Rev. Lett. 81 2446). The stability and flexibility of this all-fibre source makes it particularly well suited to applications in quantum information science.

  6. Elimination of drift in a fiber-Bragg-grating-based multiplexed Michelson interferometer measurement system.

    Science.gov (United States)

    Ren, Junyu; Xie, Fang; Chen, Zhimin

    2010-02-01

    Random phase drift in single-mode optical fiber interferometers used with measurement systems, which is resulted from various types of environmental disturbances, should be eliminated in order to obtain high measurement precision. We propose an optical fiber interferometric measurement system which has the function of self-eliminating the random phase drift and is stable and robust enough for real-time precision measurement. By employing the characteristics of fiber Bragg gratings, the system interleaves two fiber Michelson interferometers together that share the common-interferometric-optical path. The signal of one of the interferometers is used to stabilize the system while the signal of the other interferometer is used for measurement. An electronic feedback loop for the stabilizing action is designed. The bandwidth of the feedback loop is 5 kHz, sufficiently wide to eliminate random phase drift resulted from various environmental disturbances. The system is endowed with high stability and therefore suitable for real-time precision measurement. By means of an active phase tracking technique to measure displacement, the linear regression coefficient of the displacement measurement results is 0.9998.

  7. Vernier effect-based multiplication of the Sagnac beating frequency in ring laser gyroscope sensors

    Science.gov (United States)

    Adib, George A.; Sabry, Yasser M.; Khalil, Diaa

    2018-02-01

    A multiplication method of the Sagnac effect scale factor in ring laser gyroscopes is presented based on the Vernier effect of a dual-coupler passive ring resonator coupled to the active ring. The multiplication occurs when the two rings have comparable lengths or integer multiples and their scale factors have opposite signs. In this case, and when the rings have similar areas, the scale factor is multiplied by ratio of their length to their length difference. The scale factor of the presented configuration is derived analytically and the lock-in effect is analyzed. The principle is demonstrated using optical fiber rings and semiconductor optical amplifier as gain medium. A scale factor multiplication by about 175 is experimentally measured, demonstrating larger than two orders of magnitude enhancement in the Sagnac effect scale factor for the first time in literature, up to the authors' knowledge.

  8. Analysis of Acousto-Optic Errors in Laser Gyroscopes.

    Science.gov (United States)

    1982-12-01

    2 2 Sagnac’s Interferometer ................................ 4 3 Harress ’ Prism Ring.................................... 5 4...years before Sagnac’s experiment, Harress , a German graduate student formed a ring of partially reflecting prisms to measure the dispersive properties of...glass (Figure 3). Harress noticed a fringe shift when he rotated the ring, and he assumed that the shift was caused by the *dragging" of the light

  9. Frequency-modulated laser ranging sensor with closed-loop control

    Science.gov (United States)

    Müller, Fabian M.; Böttger, Gunnar; Janeczka, Christian; Arndt-Staufenbiel, Norbert; Schröder, Henning; Schneider-Ramelow, Martin

    2018-02-01

    Advances in autonomous driving and robotics are creating high demand for inexpensive and mass-producible distance sensors. A laser ranging system (Lidar), based on the frequency-modulated continuous-wave (FMCW) method is built in this work. The benefits of an FMCW Lidar system are the low-cost components and the performance in comparison to conventional time-of-flight Lidar systems. The basic system consists of a DFB laser diode (λ= 1308 nm) and an asymmetric fiber-coupled Mach-Zehnder interferometer with a fixed delay line in one arm. Linear tuning of the laser optical frequency via injection current modulation creates a beat signal at the interferometer output. The frequency of the beat signal is proportional to the optical path difference in the interferometer. Since the laser frequency-to-current response is non-linear, a closed-loop feed-back system is designed to improve the tuning linearity, and consequently the measurement resolution. For fast active control, an embedded system with FPGA is used, resulting in a nearly linear frequency tuning, realizing a narrow peak in the Fourier spectrum of the beat signal. For free-space measurements, a setup with two distinct interferometers is built. The fully fiber-coupled Mach-Zehnder reference interferometer is part of the feed-back loop system, while the other - a Michelson interferometer - has a free-space arm with collimator lens and reflective target. A resolution of 2:0 mm for a 560 mm distance is achieved. The results for varying target distances show high consistency and a linear relation to the measured beat-frequency.

  10. Heterodyne interferometer laser source with a pair of two phase locked loop coupled He–Ne lasers by 632.8 nm

    International Nuclear Information System (INIS)

    Sternkopf, C; Diethold, C; Gerhardt, U; Manske, E; Wurmus, J

    2012-01-01

    Two He–Ne lasers are frequency and phase coupled by phase locking loop technique for a heterodyne laser interferometer. The heterodyne He–Ne laser is built of stabilized commercially used laser tubes. The two lasers create a high frequency stable heterodyne laser source with an output power of 2 mW. The laser source is coupled by two fibers (one fiber per laser) to the heterodyne laser head. This paper describes the configuration and the control theory basics of the laser system. The experimental setup and the equipment used are also described. First, experimental results with different parameters are represented. Then we discuss a novel heterodyne laser source which has achieved a master laser frequency stability of Δf 1 /f 1 = 1 · 10 −8 and a beat frequency stability of approximately Δf beat /f beat ≈ 4.5 · 10 −5 . (paper)

  11. The MIDAS Instrument Design and Characterization

    Science.gov (United States)

    Honniball, C. I.; Wright, R.; Lucey, P. G.

    2016-10-01

    The Miniaturized Infrared detector of Atmospheric Species (MIDAS) utilizes an uncooled microbolometer coupled with a Sagnac interferometer. MIDAS will be used to detect and quantify atmospheric constituents for a variety of science applications.

  12. Interferometry with atoms

    International Nuclear Information System (INIS)

    Helmcke, J.; Riehle, F.; Witte, A.; Kisters, T.

    1992-01-01

    Physics and experimental results of atom interferometry are reviewed and several realizations of atom interferometers are summarized. As a typical example of an atom interferometer utilizing the internal degrees of freedom of the atom, we discuss the separated field excitation of a calcium atomic beam using four traveling laser fields and demonstrate the Sagnac effect in a rotating interferometer. The sensitivity of this interferometer can be largely increased by use of slow atoms with narrow velocity distribution. We therefore furthermore report on the preparation of a laser cooled and deflected calcium atomic beam. (orig.)

  13. Modulated Source Interferometry with Combined Amplitude and Frequency Modulation

    Science.gov (United States)

    Gutierrez, Roman C. (Inventor)

    1998-01-01

    An improved interferometer is produced by modifying a conventional interferometer to include amplitude and/or frequency modulation of a coherent light source at radio or higher frequencies. The phase of the modulation signal can be detected in an interfering beam from an interferometer and can be used to determine the actual optical phase of the beam. As such, this improvement can be adapted to virtually any two-beam interferometer, including: Michelson, Mach-Zehnder, and Sagnac interferometers. The use of an amplitude modulated coherent tight source results in an interferometer that combines the wide range advantages of coherent interferometry with the precise distance measurement advantages of white light interferometry.

  14. MEMS Gyroscopes Based on Acoustic Sagnac Effect

    Directory of Open Access Journals (Sweden)

    Yuanyuan Yu

    2016-12-01

    Full Text Available This paper reports on the design, fabrication and preliminary test results of a novel microelectromechanical systems (MEMS device—the acoustic gyroscope. The unique operating mechanism is based on the “acoustic version” of the Sagnac effect in fiber-optic gyros. The device measures the phase difference between two sound waves traveling in opposite directions, and correlates the signal to the angular velocity of the hosting frame. As sound travels significantly slower than light and develops a larger phase change within the same path length, the acoustic gyro can potentially outperform fiber-optic gyros in sensitivity and form factor. It also promises superior stability compared to vibratory MEMS gyros as the design contains no moving parts and is largely insensitive to mechanical stress or temperature. We have carried out systematic simulations and experiments, and developed a series of processes and design rules to implement the device.

  15. On quantum effects in the dynamics of macroscopic test masses

    International Nuclear Information System (INIS)

    Mueller-Ebhardt, Helge

    2009-01-01

    This thesis provides theoretically a link between the increase of the sensitivity of gravitational-wave detectors and the possibility of preparing macroscopic quantum states in such detectors. In the first part of this thesis, we theoretically explore the quantum measurement noise of an optical speed meter topology, the Sagnac interferometer, equipped with an additional detuned cavity at the output port. This detuned signal-recycling technique was already investigated when applying it to a Michelson interferometer and is used in the gravitational-wave detector GEO600. Together with the quantum noise analysis of the simple Sagnac interferometer, it is the basis of our study: we optimize the Sagnac interferometer's sensitivity towards the detection of a certain gravitational-wave source in the vicinity of a realistic classical noise environment. Motivated by the fact that the Michelson interferometer, as a position meter, with detuned signal-recycling can transduce the gravitational-wave strain into real mirror motion, we compare the transducer effect in a speed and in a position meter. Furthermore, we theoretically investigate the conditional output squeezing of a cavity which is detuned with respect to its carrier and its subcarrier. Therewith we pursue the theoretical analysis of the ponderomotive squeezer. With the knowledge gained in the first part about the quantum measurement process in laser interferometers, the second part of this thesis comprises a theoretical analysis of the conditonal state in positon and momentum of the interferometer's test masses. We motivate not to obtain the conditional states from a stochastic master equation but with the help of the so-called Wiener filtering method. Using this method, we calculate the most general expression for the conditional covariance matrix of the Gaussian state of a test mass under any linear Markovian measurement process. Then we specify to the interferometry and theoretically show under which circumstances

  16. Design, Construction, and Analysis of an Ultra-Low Expansion Quartz Resonant Cavity Passive Ring Resonator Laser Gyroscope.

    Science.gov (United States)

    1982-03-01

    Gyroscopes .... ....... 2 1.2 Sagnac’s Interferometer ....... ........ . . 4 1.3 Harress ’ Ring Interferometer ....... ...... 5 1.4 Michelson & Gale...graduate student, Harress , performed an experi- ment in which he attempted to measure the dispersion properties of glass. Figure 1.3 shows Harress ...8217 experiment. The results from his experiment did not agree-with data obtained from other methods, and Harress did not live long enough to find the discrepancy

  17. Observing a Gravitational Wave Background With Lisa

    National Research Council Canada - National Science Library

    Tinto, M; Armstrong, J; Estabrook, F

    2000-01-01

    .... Comparison of the conventional Michelson interferometer observable with the fully-symmetric Sagnac data-type allows unambiguous discrimination between a gravitational wave background and instrumental noise. The method presented here can be used to detect a confusion-limited gravitational wave background.

  18. Beating quantum limits in interferometers with quantum locking of mirrors

    International Nuclear Information System (INIS)

    Heidmann, Antoine; Courty, Jean-Michel; Pinard, Michel; Lebars, Julien

    2004-01-01

    The sensitivity in interferometric measurements such as those made by gravitational-wave detectors is ultimately limited by the quantum noise of light. We discuss the use of feedback mechanisms to reduce the quantum effects of radiation pressure. Recent experiments have shown that it is possible to reduce the thermal motion of a mirror by cold damping. The mirror motion is measured with an optomechanical sensor based on a high-finesse cavity, and reduced by a feedback loop. We show that this technique can be extended to lock the mirror at the quantum level. In gravitational-wave interferometers with Fabry-Perot cavities in each arm, it is even possible to use a single feedback mechanism to lock one cavity mirror on the other. This quantum locking greatly improves the sensitivity of the interferometric measurement. It is furthermore insensitive to imperfections such as losses in the interferometer

  19. Japanese large-scale interferometers

    CERN Document Server

    Kuroda, K; Miyoki, S; Ishizuka, H; Taylor, C T; Yamamoto, K; Miyakawa, O; Fujimoto, M K; Kawamura, S; Takahashi, R; Yamazaki, T; Arai, K; Tatsumi, D; Ueda, A; Fukushima, M; Sato, S; Shintomi, T; Yamamoto, A; Suzuki, T; Saitô, Y; Haruyama, T; Sato, N; Higashi, Y; Uchiyama, T; Tomaru, T; Tsubono, K; Ando, M; Takamori, A; Numata, K; Ueda, K I; Yoneda, H; Nakagawa, K; Musha, M; Mio, N; Moriwaki, S; Somiya, K; Araya, A; Kanda, N; Telada, S; Sasaki, M; Tagoshi, H; Nakamura, T; Tanaka, T; Ohara, K

    2002-01-01

    The objective of the TAMA 300 interferometer was to develop advanced technologies for kilometre scale interferometers and to observe gravitational wave events in nearby galaxies. It was designed as a power-recycled Fabry-Perot-Michelson interferometer and was intended as a step towards a final interferometer in Japan. The present successful status of TAMA is presented. TAMA forms a basis for LCGT (large-scale cryogenic gravitational wave telescope), a 3 km scale cryogenic interferometer to be built in the Kamioka mine in Japan, implementing cryogenic mirror techniques. The plan of LCGT is schematically described along with its associated R and D.

  20. Calibration of atomic trajectories in a large-area dual-atom-interferometer gyroscope

    Science.gov (United States)

    Yao, Zhan-Wei; Lu, Si-Bin; Li, Run-Bing; Luo, Jun; Wang, Jin; Zhan, Ming-Sheng

    2018-01-01

    We propose and demonstrate a method for calibrating atomic trajectories in a large-area dual-atom-interferometer gyroscope. The atom trajectories are monitored by modulating and delaying the Raman transition, and they are precisely calibrated by controlling the laser orientation and the bias magnetic field. To improve the immunity to the gravity effect and the common phase noise, the symmetry and the overlap of two large-area atomic interference loops are optimized by calibrating the atomic trajectories and by aligning the Raman-laser orientations. The dual-atom-interferometer gyroscope is applied in the measurement of the Earth's rotation. The sensitivity is 1.2 ×10-6 rad s -1 Hz-1/2, and the long-term stability is 6.2 ×10-8 rad/s at 2000 s.

  1. Special relativity and interferometers

    Science.gov (United States)

    Han, D.; Kim, Y. S.

    1988-01-01

    A new generation of gravitational wave detectors is expected to be based on interferometers. Yurke et al. (1986) introduced a class of interferometers characterized by SU(1,1) which can in principle achieve a phase sensitivity approaching 1/N, where N is thte total number of photons entering the interferometer. It is shown here that the SU(1,1) interferometer can serve as an analog computer for Wigner's little group of the Poincare\\'| group.

  2. Stable fiber interferometer

    International Nuclear Information System (INIS)

    Izmajlov, G.N.; Nikolaev, F.A.; Ozolin, V.V.; Grigor'yants, V.V.; Chamorovskij, Yu.K.

    1989-01-01

    The problem of construction the long-base Michelson interferometer for gravitational wave detection is discussed. Possible sources of noise and instability are considered. It is shown that evacuation of fiber interferometer, the winding of its arms on the glass ceramic bases, stabilization of radiation source frequency and seismic isolation of the base allow one to reduce its instability to the level, typical of mirror interferometer with the comparable optical base. 10 refs.; 2 figs

  3. Comparative Sensitivities of Gravitational Wave Detectors Based on Atom Interferometers and Light Interferometers

    Science.gov (United States)

    Baker, John G.; Thorpe, J. I.

    2012-01-01

    We consider a class of proposed gravitational wave detectors based on multiple atomic interferometers separated by large baselines and referenced by common laser systems. We compute the sensitivity limits of these detectors due to intrinsic phase noise of the light sources, non-inertial motion of the light sources, and atomic shot noise and compare them to sensitivity limits for traditional light interferometers. We find that atom interferometers and light interferometers are limited in a nearly identical way by intrinsic phase noise and that both require similar mitigation strategies (e.g. multiple arm instruments) to reach interesting sensitivities. The sensitivity limit from motion of the light sources is slightly different and favors the atom interferometers in the low-frequency limit, although the limit in both cases is severe. Whether this potential advantage outweighs the additional complexity associated with including atom interferometers will require further study.

  4. Comparison of Atom Interferometers and Light Interferometers as Space-Based Gravitational Wave Detectors

    Science.gov (United States)

    Baker, John G.

    2012-01-01

    We consider a class of proposed gravitational wave detectors based on multiple atomic interferometers separated by large baselines and referenced by common laser systems. We compute the sensitivity limits of these detectors due to intrinsic phase noise of the light sources, non-inertial motion of the light sources, and atomic shot noise and compare them to sensitivity limits for traditional light interferometers. We find that atom interferometers and light interferometers are limited in a nearly identical way by intrinsic phase noise and that both require similar mitigation strategies (e.g. multiple arm instruments) to reach interesting sensitivities. The sensitivity limit from motion of the light sources is slightly different and favors the atom interferometers in the low-frequency limit, although the limit in both cases is severe.

  5. Double-grating interferometer with a one-to-one correspondence with a Michelson interferometer.

    Science.gov (United States)

    Xu, Yande; Sasaki, Osami; Suzuki, Takamasa

    2003-10-01

    We describe a double-grating interferometer that has a one-to-one correspondence with a Michelson interferometer. The half spatial periods of the gratings are equivalent to the wavelengths of the interferometer. The widths of the interference fringes can be changed easily. The intensity distribution of the interference pattern is independent of the wavelength of the light source used. The surface profile of an object can be measured because two interference beams can coincide precisely on the image plane of the object. The measuring range is much larger than that of a Michelson interferometer.

  6. Self-calibrating interferometer

    International Nuclear Information System (INIS)

    Nussmeier, T.A.

    1982-01-01

    A self-calibrating interferometer is disclosed which forms therein a pair of Michelson interferometers with one beam length of each Michelson interferometer being controlled by a common phase shifter. The transfer function measured from the phase shifter to either of a pair of detectors is sinusoidal with a full cycle for each half wavelength of phase shifter travel. The phase difference between these two sinusoidal detector outputs represents the optical phase difference between a path of known distance and a path of unknown distance

  7. Geometric phase in a split-beam experiment measured with coupled neutron interference loops

    International Nuclear Information System (INIS)

    Hasegawa, Yuji; Zawisky, M.; Rauch, H.; Ioffe, A.

    1996-01-01

    A geometric phase factor is derived for a split-beam experiment as an example of cyclic evolutions. The geometric phase is given by one half of the solid angle independent of the spin of the beam. We observe this geometric phase with a two-loop neutron interferometer, where a reference beam can be added to the beam from one interference loop. All the experimental results show complete agreement with our theoretical treatment. (author)

  8. Method for determination of the polarisation nonreciprocity in a fibre ring interferometer

    International Nuclear Information System (INIS)

    Andronova, Irina A; Gelikonov, V M; Gelikonov, G V

    2000-01-01

    A method is proposed for observation of the polarisation nonreciprocity of fibre ring interferometers (FRIs) by placing a rotating polariser at the output of an interferometer ahead of a photodetector. It is demonstrated theoretically and experimentally that the absence of a signal for any position of the transmission axis of the polariser at the FRI output is a criterion of the absence of the polarisation nonreciprocity. It is suggested that the coaxial alignment of the anisotropic FRI components be monitored during assembly to ensure the polarisation nonreciprocity on the basis of the absence of a signal at the output of a rotating polariser. It is also shown that, when the conditions for the polarisation nonreciprocity are fulfilled, the signal from the output of a beam splitter located flush against the fibre loop output carries information about the phase characteristics of the beam splitter. (laser gyroscopes)

  9. Fidelity of quantum interferometers

    International Nuclear Information System (INIS)

    Bahder, Thomas B.; Lopata, Paul A.

    2006-01-01

    For a generic interferometer, the conditional probability density distribution p(φ|m), for the phase φ given measurement outcome m will generally have multiple peaks. Therefore, the phase sensitivity of an interferometer cannot be adequately characterized by the standard deviation, such as Δφ∼1/√(N) (the standard limit), or Δφ∼1/N (the Heisenberg limit). We propose an alternative measure of phase sensitivity--the fidelity of an interferometer--defined as the Shannon mutual information between the phase shift φ and the measurement outcomes m. As an example application of interferometer fidelity, we consider a generic optical Mach-Zehnder interferometer, used as a sensor of a classical field. For the case where there exists no a priori information on the phase shift, we find the surprising result that maximally entangled state input leads to a lower fidelity than Fock state input, for the same photon number

  10. X-ray interferometers

    International Nuclear Information System (INIS)

    Franks, A.

    1980-01-01

    An improved type of amplitude-division x-ray interferometer is described. The wavelength at which the interferometer can operate is variable, allowing the instrument to be used to measure x-ray wavelength, and the angle of inclination is variable for sample investigation. (U.K.)

  11. Intrinsically stable phase-modulated polarization encoding system for quantum key distribution

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiaobao [Laboratory of Photonic Information Technology, School for Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006 (China); Liao Changjun [Laboratory of Photonic Information Technology, School for Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006 (China)], E-mail: chliao@scnu.edu.cn; Mi Jinglong; Wang Jindong; Liu Songhao [Laboratory of Photonic Information Technology, School for Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006 (China)

    2008-12-22

    We demonstrate experimentally an intrinsically stable polarization coding and decoding system composed of optical-fiber Sagnac interferometers with integrated phase modulators for quantum key distribution. An interference visibility of 98.35% can be kept longtime during the experiment without any efforts of active compensation for coding all four desired polarization states.

  12. Author Details

    African Journals Online (AJOL)

    Benhamida, S. Vol 4, No 1 (2012) - Articles Modelling of Extrinsic Fiber Optic Sagnac Ultrasound Interferometer Used for Displacement Measurements Abstract PDF. ISSN: 1112-9867. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

  13. Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI): Monolithic Interferometer Design and Test

    Science.gov (United States)

    Harlander, John M.; Englert, Christoph R.; Brown, Charles M.; Marr, Kenneth D.; Miller, Ian J.; Zastera, Vaz; Bach, Bernhard W.; Mende, Stephen B.

    2017-10-01

    The design and laboratory tests of the interferometers for the Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) instrument which measures thermospheric wind and temperature for the NASA-sponsored Ionospheric Connection (ICON) Explorer mission are described. The monolithic interferometers use the Doppler Asymmetric Spatial Heterodyne (DASH) Spectroscopy technique for wind measurements and a multi-element photometer approach to measure thermospheric temperatures. The DASH technique and overall optical design of the MIGHTI instrument are described in an overview followed by details on the design, element fabrication, assembly, laboratory tests and thermal control of the interferometers that are the heart of MIGHTI.

  14. Schemes for fibre-based entanglement generation in the telecom band

    International Nuclear Information System (INIS)

    Chen, Jun; Lee, Kim Fook; Li Xiaoying; Voss, Paul L; Kumar, Prem

    2007-01-01

    We investigate schemes for generating polarization-entangled photon pairs in standard optical fibres. The advantages of a double-loop scheme are explored through comparison with two other schemes, namely, the Sagnac-loop scheme and the counter-propagating scheme. Experimental measurements with the double-loop scheme verify the predicted advantages

  15. Atmospheric Fluctuation Measurements with the Palomar Testbed Interferometer

    Science.gov (United States)

    Linfield, R. P.; Lane, B. F.; Colavita, M. M.; PTI Collaboration

    Observations of bright stars with the Palomar Testbed Interferometer, at a wavelength of 2.2 microns, have been used to measure atmospheric delay fluctuations. The delay structure function Dτ(Δ t) was calculated for 66 scans (each >= 120s in length) on seven nights in 1997 and one in 1998. For all except one scan, Dτ exhibited a clean power law shape over the time interval 50-500 msec. Over shorter time intervals, the effect of the delay line servo loop corrupts Dτ. Over longer time intervals (usually starting at > 1s), the slope of Dτ decreases, presumably due to some combination of saturation e.g. finite turbulent layer thickness) and the effect of the finite wind speed crossing time on our 110 m baseline. The mean power law slopes for the eight nights ranged from 1.16 to 1.36, substantially flatter than the value of 1.67 for three dimensional Kolmogorov turbulence. Such sub-Kolmogorov slopes will result in atmospheric seeling (θ) that improves rapidly with increasing wavelength: θ propto λ1-(2β), where β is the observed power law slope of Dτ. The atmospheric errors in astrometric measurements with an interferometer will average down more quickly than in the Kolmogorov case.

  16. Generalized Sagnac effect with the ring-laser and other optradiches in the PPN gravitational theory

    International Nuclear Information System (INIS)

    Campbell, S.O.

    1976-01-01

    The scope of study is: The object under study is an experiment to measure the ''dragging of inertial frames'' effect (a post-Newtonian gravitational effect) using two closed-loop optical beams traveling in opposite directions (such a device is denoted an ''optradich''; an example is the ringlaser). A theoretical viewpoint with simple formulas based on the Parametrized Post-Newtonian (PPN) formalism is developed from a study of the literature: the Sagnac effect is generalized to the Post-Newtonian level of approximation. Some differences with a few previous papers are noted and sometimes discussed. Then the formulas are applied to two simple cases. Numerical results are given for an optradich attached to earth, and for optradiches orbiting earth, jupiter, and the sun. The ringlaser, whose further development may make the experiment feasible, is discussed briefly: its basic principle, its potential sensitivity, and some practical considerations. Some aspects of the experiment are also discussed briefly: land optradiches versus orbiting optradiches, Schiff's gyroscope experiment versus the optradich experiment, the present outlook for optradich experiments, and possible scientific benefits of optradich and experiments. Findings and conclusions are the numerical results (see above) are so small that it appears quite doubtful that optradich experiments could verify them in the balance of this century. There seem to be a few interesting effects which Schiff's gyroscope at present cannot measure, but which an assumed ''super'' optradich can measure. Orbiting optradiches and land optradiches may be complementary, but further study is recommended. Despite the discouraging prospects for optradich experiments, efforts should be made to develop sufficiently sensitive optradiches because of the scientific benefits that could be had

  17. The Fourier-Kelvin Stellar Interferometer (FKSI) Nulling Testbed II: Closed-loop Path Length Metrology And Control Subsystem

    Science.gov (United States)

    Frey, B. J.; Barry, R. K.; Danchi, W. C.; Hyde, T. T.; Lee, K. Y.; Martino, A. J.; Zuray, M. S.

    2006-01-01

    The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for an imaging and nulling interferometer in the near to mid-infrared spectral region (3-8 microns), and will be a scientific and technological pathfinder for upcoming missions including TPF-I/DARWIN, SPECS, and SPIRIT. At NASA's Goddard Space Flight Center, we have constructed a symmetric Mach-Zehnder nulling testbed to demonstrate techniques and algorithms that can be used to establish and maintain the 10(exp 4) null depth that will be required for such a mission. Among the challenges inherent in such a system is the ability to acquire and track the null fringe to the desired depth for timescales on the order of hours in a laboratory environment. In addition, it is desirable to achieve this stability without using conventional dithering techniques. We describe recent testbed metrology and control system developments necessary to achieve these goals and present our preliminary results.

  18. Analysis and Optimization of Dynamic Measurement Precision of Fiber Optic Gyroscope

    Directory of Open Access Journals (Sweden)

    Hui Li

    2013-01-01

    Full Text Available In order to improve the dynamic performance of high precision interferometer fiber optic gyroscope (IFOG, the influencing factors of the fast response characteristics are analyzed based on a proposed assistant design setup, and a high dynamic detection method is proposed to suppress the adverse effects of the key influencing factors. The assistant design platform is built by using the virtual instrument technology for IFOG, which can monitor the closed-loop state variables in real time for analyzing the influence of both the optical components and detection circuit on the dynamic performance of IFOG. The analysis results indicate that nonlinearity of optical Sagnac effect, optical parameter uncertainty, dynamic characteristics of internal modules and time delay of signal detection circuit are the major causes of dynamic performance deterioration, which can induce potential system instability in practical control systems. By taking all these factors into consideration, we design a robust control algorithm to realize the high dynamic closed-loop detection of IFOG. Finally, experiments show that the improved 0.01 deg/h high precision IFOG with the proposed control algorithm can achieve fast tracking and good dynamic measurement precision.

  19. Turbulence-Free Double-slit Interferometer

    Science.gov (United States)

    Smith, Thomas A.; Shih, Yanhua

    2018-02-01

    Optical turbulence can be detrimental for optical observations. For instance, atmospheric turbulence may reduce the visibility or completely blur out the interference produced by an interferometer in open air. However, a simple two-photon interference theory based on Einstein's granularity picture of light makes a turbulence-free interferometer possible; i.e., any refraction index, length, or phase variations along the optical paths of the interferometer do not have any effect on its interference. Applying this mechanism, the reported experiment demonstrates a two-photon double-slit interference that is insensitive to atmospheric turbulence. The turbulence-free mechanism and especially the turbulence-free interferometer would be helpful in optical observations that require high sensitivity and stability such as for gravitational-wave detection.

  20. Theorem of comparative sensitivity of fibre sensors

    Science.gov (United States)

    Belovolov, M. I.; Paramonov, V. M.; Belovolov, M. M.

    2017-12-01

    We report an analysis of sensitivity of fibre sensors of physical quantities based on different types of interferometers. We formulate and prove the following theorem: under the time-dependent external physical perturbations at nonzero frequencies (i.e., except the static and low-frequency ones) on the sensitive arms of an interferometer in the form of multiturn elements (coils), there exist such lengths L of the measuring arms of the fibre interferometers at which the sensitivity of sensors based on the Sagnac fibre interferometers can be comparable with the sensitivity of sensors based on Michelson, Mach - Zehnder, or Fabry - Perot fibre interferometers, as well as exceed it under similar other conditions (similar-type perturbations, similar arm lengths and single-mode fibre types). The consequences that follow from the theorem, important for practical implementation of arrays of fibre sensors for measurement purposes and the devices with stable metrological properties, are discussed.

  1. Bias voltage dependence of a flux-sensitive Al/GaAs/Al (SNS) interferometer

    DEFF Research Database (Denmark)

    Kutchinsky, Jonatan; Taboryski, Rafael Jozef; Hansen, Jørn Bindslev

    1999-01-01

    bias voltage the fabricated interferometers typically exhibit 3% sinusoidal modulation of the conductance as a function of a magnetic field applied perpendicular to the loop. The conductance modulation is caused by resonant Andreev states in the normal GaAs region of the device. With increasing bias...... voltage of the order of a few microvolts the device is driven out of resonance and the conductance oscillations are extinguished. However, at higher bias voltage corresponding to the superconducting energy gap of Al (178 mu V) the conductance oscillations reappear but with reduced amplitude...

  2. Study of Optical Fiber Sensors for Cryogenic Temperature Measurements.

    Science.gov (United States)

    De Miguel-Soto, Veronica; Leandro, Daniel; Lopez-Aldaba, Aitor; Beato-López, Juan Jesus; Pérez-Landazábal, José Ignacio; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; Lopez-Amo, Manuel

    2017-11-30

    In this work, the performance of five different fiber optic sensors at cryogenic temperatures has been analyzed. A photonic crystal fiber Fabry-Pérot interferometer, two Sagnac interferometers, a commercial fiber Bragg grating (FBG), and a π-phase shifted fiber Bragg grating interrogated in a random distributed feedback fiber laser have been studied. Their sensitivities and resolutions as sensors for cryogenic temperatures have been compared regarding their advantages and disadvantages. Additionally, the results have been compared with the given by a commercial optical backscatter reflectometer that allowed for distributed temperature measurements of a single mode fiber.

  3. Study of Optical Fiber Sensors for Cryogenic Temperature Measurements

    Directory of Open Access Journals (Sweden)

    Veronica De Miguel-Soto

    2017-11-01

    Full Text Available In this work, the performance of five different fiber optic sensors at cryogenic temperatures has been analyzed. A photonic crystal fiber Fabry-Pérot interferometer, two Sagnac interferometers, a commercial fiber Bragg grating (FBG, and a π-phase shifted fiber Bragg grating interrogated in a random distributed feedback fiber laser have been studied. Their sensitivities and resolutions as sensors for cryogenic temperatures have been compared regarding their advantages and disadvantages. Additionally, the results have been compared with the given by a commercial optical backscatter reflectometer that allowed for distributed temperature measurements of a single mode fiber.

  4. A variable partially polarizing beam splitter

    Science.gov (United States)

    Flórez, Jefferson; Carlson, Nathan J.; Nacke, Codey H.; Giner, Lambert; Lundeen, Jeff S.

    2018-02-01

    We present designs for variably polarizing beam splitters. These are beam splitters allowing the complete and independent control of the horizontal and vertical polarization splitting ratios. They have quantum optics and quantum information applications, such as quantum logic gates for quantum computing and non-local measurements for quantum state estimation. At the heart of each design is an interferometer. We experimentally demonstrate one particular implementation, a displaced Sagnac interferometer configuration, that provides an inherent instability to air currents and vibrations. Furthermore, this design does not require any custom-made optics but only common components which can be easily found in an optics laboratory.

  5. Michelson-type Radio Interferometer for University Education

    Science.gov (United States)

    Koda, Jin; Barrett, J. W.; Hasegawa, T.; Hayashi, M.; Shafto, G.; Slechta, J.

    2013-01-01

    Despite the increasing importance of interferometry in astronomy, the lack of educational interferometers is an obstacle to training the futue generation of astronomers. Students need hands-on experiments to fully understand the basic concepts of interferometry. Professional interferometers are often too complicated for education, and it is difficult to guarantee access for classes in a university course. We have built a simple and affordable radio interferometer for education and used it for an undergraduate and graduate laboratory project. This interferometer's design is based on the Michelson & Peace's stellar optical interferometer, but operates at a radio wavelength using a commercial broadcast satellite dish and receiver. Two side mirrors are surfaced with kitchen aluminum foil and slide on a ladder, providing baseline coverage. This interferometer can resolve and measure the diameter of the Sun, a nice daytime experiment which can be carried out even under a marginal weather (i.e., partial cloud coverage). Commercial broadcast satellites provide convenient point sources. By comparing the Sun and satellites, students can learn how an interferometer works and resolves structures in the sky.

  6. Study on talbot pattern for grating interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Ju; Oh, Oh Sung; Lee, Seung Wook [Dept. of School of Mechanical Engineering, Pusan National University, Busan (Korea, Republic of); Kim, Jong Yul [Neutron Instrument Division, Korea Atomic Energy Reserch Institute, Daejeon (Korea, Republic of)

    2015-04-15

    One of properties which X-ray and Neutron can be applied nondestructive test is penetration into the object with interaction leads to decrease in intensity. X-ray interaction with the matter caused by electrons, Neutron caused by atoms. They share applications in nondestructive test area because of their similarities of interaction mechanism. Grating interferometer is the one of applications produces phase contrast image and dark field image. It is defined by Talbot interferometer and Talbot-Lau interferometer according to Talbot effect and Talbot-Lau effect respectively. Talbot interferometer works with coherence beam like X-ray, and Talbot-Lau has an effect with incoherence beam like Neutron. It is important to expect the interference in grating interferometer compared normal nondestructive system. In this paper, simulation works are conducted according to Talbot and Talbot-Lau interferometer in case of X-ray and Neutron. Variation of interference intensity with X-ray and Neutron based on wave theory is constructed and calculate elements consist the system. Additionally, Talbot and Talbot-Lau interferometer is simulated in different kinds of conditions.

  7. Liquid-helium-cooled Michelson interferometer

    Science.gov (United States)

    Augason, G. C.; Young, N.

    1972-01-01

    Interferometer serves as a rocket-flight spectrometer for examination of the far infrared emission spectra of astronomical objects. The double beam interferometer is readily adapted to make spectral scans and for use as a detector of discrete line emissions.

  8. Interferometric architectures based All-Optical logic design methods and their implementations

    Science.gov (United States)

    Singh, Karamdeep; Kaur, Gurmeet

    2015-06-01

    All-Optical Signal Processing is an emerging technology which can avoid costly Optical-electronic-optical (O-E-O) conversions which are usually compulsory in traditional Electronic Signal Processing systems, thus greatly enhancing operating bit rate with some added advantages such as electro-magnetic interference immunity and low power consumption etc. In order to implement complex signal processing tasks All-Optical logic gates are required as backbone elements. This review describes the advances in the field of All-Optical logic design methods based on interferometric architectures such as Mach-Zehnder Interferometer (MZI), Sagnac Interferometers and Ultrafast Non-Linear Interferometer (UNI). All-Optical logic implementations for realization of arithmetic and signal processing applications based on each interferometric arrangement are also presented in a categorized manner.

  9. Mariner 9 Michelson interferometer.

    Science.gov (United States)

    Hanel, R.; Schlachman, B.; Rodgers, D.; Breihan, E.; Bywaters, R.; Chapman, F.; Rhodes, M.; Vanous, D.

    1972-01-01

    The Michelson interferometer on Mariner 9 measures the thermal emission spectrum of Mars between 200 and 2000 per cm (between 5 and 50 microns) with a spectral resolution of 2.4 per cm in the apodized mode. A noise equivalent radiance of 0.5 x 10 to the minus 7th W/sq cm/ster/cm is deduced from data recorded in orbit around Mars. The Mariner interferometer deviates in design from the Nimbus 3 and 4 interferometers in several areas, notably, by a cesium iodide beam splitter and certain aspects of the digital information processing. Special attention has been given to the problem of external vibration. The instrument performance is demonstrated by calibration data and samples of Mars spectra.

  10. Polarization encoded all-optical quaternary successor with the help of SOA assisted Sagnac switch

    Science.gov (United States)

    Chattopadhyay, Tanay; Roy, Jitendra Nath

    2011-06-01

    The application of multi-valued (non-binary) signals can provide a considerable relief in transmission, storage and processing of large amount of information in digital signal processing. Optical multi-valued logical operation is an interesting challenge for future optical signal processing where we can expect much innovation. A novel all-optical quaternary successor (QSUC) circuit with the help of semiconductor optical amplifier (SOA)-assisted Sagnac switch is proposed and described. This circuit exploits the polarization properties of light. Different logical states are represented by different polarization state of light. Simulation result confirming described method is given in this paper. Proposed all-optical successor circuit can take an important and significant role in designing of all-optical quaternary universal inverter and modulo arithmetic unit (addition and multiplication).

  11. Optical configurations for the Virgo interferometer

    International Nuclear Information System (INIS)

    Hello, P.

    1993-01-01

    We present, in this paper, the potential optical configurations for the VIRGO interferometer, as well as for other similar antennas (LIGO...), and the implications for its sensitivity for the detection of gravitational waves (GW's). The dual recycling arrangement may particularly relax the severe optical specifications required in a power recycling interferometer. Finally, a new idea to improve the symmetry of the interferometer is presented. (author). 11 refs., 2 figs

  12. Picometre displacement measurements using a differential Fabry-Perot optical interferometer and an x-ray interferometer

    Science.gov (United States)

    Çelik, Mehmet; Hamid, Ramiz; Kuetgens, Ulrich; Yacoot, Andrew

    2012-08-01

    X-ray interferometry is emerging as an important tool for dimensional nanometrology both for sub-nanometre measurement and displacement. It has been used to verify the performance of the next generation of displacement measuring optical interferometers within the European Metrology Research Programme project NANOTRACE. Within this project a more detailed set of comparison measurements between the x-ray interferometer and a dual channel Fabry-Perot optical interferometer (DFPI) have been made to demonstrate the capabilities of both instruments for picometre displacement metrology. The results show good agreement between the two instruments, although some minor differences of less than 5 pm have been observed.

  13. Magdalena Ridge Observatory Interferometer: Status Update

    National Research Council Canada - National Science Library

    Creech-Eakman, M. J; Bakker, E. J; Buscher, D. F; Coleman, T. A; Haniff, C. A; Jurgenson, C. A; Klinglesmith, III, D. A; Parameswariah, C. B; Romero, V. D; Shtromberg, A. V; Young, J. S

    2006-01-01

    The Magdalena Ridge Observatory Interferometer (MROI) is a ten element optical and near-infrared imaging interferometer being built in the Magdalena mountains west of Socorro, NM at an altitude of 3230 m...

  14. Two-path plasmonic interferometer with integrated detector

    Science.gov (United States)

    Dyer, Gregory Conrad; Shaner, Eric A.; Aizin, Gregory

    2016-03-29

    An electrically tunable terahertz two-path plasmonic interferometer with an integrated detection element can down convert a terahertz field to a rectified DC signal. The integrated detector utilizes a resonant plasmonic homodyne mixing mechanism that measures the component of the plasma waves in-phase with an excitation field that functions as the local oscillator in the mixer. The plasmonic interferometer comprises two independently tuned electrical paths. The plasmonic interferometer enables a spectrometer-on-a-chip where the tuning of electrical path length plays an analogous role to that of physical path length in macroscopic Fourier transform interferometers.

  15. Picometre displacement measurements using a differential Fabry–Perot optical interferometer and an x-ray interferometer

    International Nuclear Information System (INIS)

    Çelik, Mehmet; Hamid, Ramiz; Kuetgens, Ulrich; Yacoot, Andrew

    2012-01-01

    X-ray interferometry is emerging as an important tool for dimensional nanometrology both for sub-nanometre measurement and displacement. It has been used to verify the performance of the next generation of displacement measuring optical interferometers within the European Metrology Research Programme project NANOTRACE. Within this project a more detailed set of comparison measurements between the x-ray interferometer and a dual channel Fabry–Perot optical interferometer (DFPI) have been made to demonstrate the capabilities of both instruments for picometre displacement metrology. The results show good agreement between the two instruments, although some minor differences of less than 5 pm have been observed. (paper)

  16. Two-wavelength HeNe laser interferometer

    International Nuclear Information System (INIS)

    Granneman, E.H.A.

    1981-01-01

    This paper presents an interferometer set-up in which two wavelengths are used simultaneously. This enables one to determine separately the phase shifts caused by changes in plasma density and by mechanical vibrations of the interferometer structure

  17. In-fiber integrated Michelson interferometer.

    Science.gov (United States)

    Yuan, Libo; Yang, Jun; Liu, Zhihai; Sun, Jiaxing

    2006-09-15

    A novel fiber-optic in-fiber integrated Michelson interferometer has been proposed and demonstrated. It consists of a segment of two-core fiber with a mirrored fiber end. The sensing characteristics based on the two-core fiber bending, corresponding to the shift of the phase of the two-core in-fiber integrated Michelson interferometer, are investigated.

  18. Dispersion cancellation in a triple Laue interferometer

    International Nuclear Information System (INIS)

    Lemmel, Hartmut

    2014-01-01

    The concept of dispersion cancellation has been established in light optics to improve the resolution of interferometric measurements on dispersive media. Odd order dispersion cancellation allows to measure phase shifts without defocusing the interferometer due to wave packet displacements, while even order dispersion cancellation allows to measure time lags without losing resolution due to wave packet spreading. We report that either type of dispersion cancellation can be realized very easily in a triple Laue interferometer. Such interferometers are Mach–Zehnder interferometers based on Bragg diffraction, and are commonly used for neutrons and x-rays. Although the first x-ray interferometer was built nearly five decades ago, the feature of dispersion cancellation hasn't been recognized so far because the concept was hardly known in the neutron and x-ray community. However, it explains right away the surprising decoupling of phase shift and spatial displacement that we have discovered recently in neutron interferometry (Lemmel and Wagh 2010 Phys. Rev. A 82 033626). Furthermore, this article might inspire the light optics community to consider whether a triple Laue interferometer for laser light would be useful and feasible. We explain how dispersion cancellation works in neutron interferometry, and we describe the setup rigorously by solving the Schrödinger equation and by calculating the path integral. We point out, that the latter has to be evaluated with special care since in our setup the beam trajectory moves with respect to the crystal lattice of the interferometer. (paper)

  19. Development of stable monolithic wide-field Michelson interferometers.

    Science.gov (United States)

    Wan, Xiaoke; Ge, Jian; Chen, Zhiping

    2011-07-20

    Bulk wide-field Michelson interferometers are very useful for high precision applications in remote sensing and astronomy. A stable monolithic Michelson interferometer is a key element in high precision radial velocity (RV) measurements for extrasolar planets searching and studies. Thermal stress analysis shows that matching coefficients of thermal expansion (CTEs) is a critical requirement for ensuring interferometer stability. This requirement leads to a novel design using BK7 and LAK7 materials, such that the monolithic interferometer is free from thermal distortion. The processes of design, fabrication, and testing of interferometers are described in detail. In performance evaluations, the field angle is typically 23.8° and thermal sensitivity is typically -2.6×10(-6)/°C near 550 nm, which corresponds to ∼800 m/s/°C in the RV scale. Low-cost interferometer products have been commissioned in multiple RV instruments, and they are producing high stability performance over long term operations. © 2011 Optical Society of America

  20. Michelson interferometer based spatial phase shift shearography.

    Science.gov (United States)

    Xie, Xin; Yang, Lianxiang; Xu, Nan; Chen, Xu

    2013-06-10

    This paper presents a simple spatial phase shift shearography based on the Michelson interferometer. The Michelson interferometer based shearographic system has been widely utilized in industry as a practical nondestructive test tool. In the system, the Michelson interferometer is used as a shearing device to generate a shearing distance by tilting a small angle in one of the two mirrors. In fact, tilting the mirror in the Michelson interferometer also generates spatial frequency shift. Based on this feature, we introduce a simple Michelson interferometer based spatial phase shift shearography. The Fourier transform (FT) method is applied to separate the spectrum on the spatial frequency domain. The phase change due to the loading can be evaluated using a properly selected windowed inverse-FT. This system can generate a phase map of shearography by using only a single image. The effects of shearing angle, spatial resolution of couple charge device camera, and filter methods are discussed in detail. The theory and the experimental results are presented.

  1. A nanofabricated, monolithic, path-separated electron interferometer

    OpenAIRE

    Agarwal, Akshay; Kim, Chung-Soo; Hobbs, Richard; Dyck, Dirk van; Berggren, Karl K.

    2017-01-01

    Progress in nanofabrication technology has enabled the development of numerous electron optic elements for enhancing image contrast and manipulating electron wave functions. Here, we describe a modular, self-aligned, amplitude-division electron interferometer in a conventional transmission electron microscope. The interferometer consists of two 45-nm-thick silicon layers separated by 20??m. This interferometer is fabricated from a single-crystal silicon cantilever on a transmission electron m...

  2. All-optical switching in Sagnac loop mirror containing an ytterbium-doped fiber and fiber Bragg grating.

    Science.gov (United States)

    Zang, Zhigang

    2013-08-10

    A configuration of all-optical switching based on a Signac loop mirror that incorporates an ytterbium-doped fiber and uniform fiber Bragg grating (FBG) is proposed in this paper. It is found that the transmission spectrum of this structure is the narrow splitting of the reflection spectrum of the FBG. The shift of this ultranarrow transmission spectrum is very sensitive to the intensity of the pump power. Thus, the threshold switching power can be greatly reduced by shifting such narrow transmission spectrum. Compared with the single FBG, the threshold switching power of this configuration is reduced by 4 orders of magnitude. In addition, the results indicate that this optical switching has a high extinction ratio of 20 dB and a ultrafast response time of 3 ns. The operation regime and switching performance under the cross-phase modulation cases are also investigated.

  3. A Michelson interferometer for ultracold neutrons

    International Nuclear Information System (INIS)

    Steyerl, A.; Malik, S.S.; Steinhauser, K.A.; Berger, L.

    1979-01-01

    We propose a neutron Michelson Interferometer installed within a focussing 'gravity diffractometer' for ultracold neutrons. In this arrangement the expected interference pattern depends only on the well-defined vertical component of neutron wavevector. Possible applications of such an interferometer are discussed. (orig.)

  4. Atom Wave Interferometers

    National Research Council Canada - National Science Library

    Pritchard, David

    1999-01-01

    Matter wave interferometers, in which de Broglie waves are coherently split and then recombined to produce interference fringes, have opened exciting new possibilities for precision and fundamental...

  5. 2-mm microwave interferometer

    International Nuclear Information System (INIS)

    Futch, A.H.; Mortensen, W.K.

    1977-01-01

    A 2-mm microwave interferometer has been developed, and phase shift measurements have been made on the Baseball II experiment. The interferometer system employs a 140-GHz receiver for double down conversion of the plasma signal to a 60-MHz, IF frequency. The 140-GHz references signal is also down-converted and compared with the plasma signal to provide the desired phase change of the signal passing through the plasma. A feedback voltage from a 60-MHz discriminator to a voltage-controlled oscillator in the receiver provides frequency stability of the 60-MHz IF signals

  6. Conversion of conventional gravitational-wave interferometers into quantum nondemolition interferometers by modifying their input and/or output optics

    Science.gov (United States)

    Kimble, H. J.; Levin, Yuri; Matsko, Andrey B.; Thorne, Kip S.; Vyatchanin, Sergey P.

    2002-01-01

    The LIGO-II gravitational-wave interferometers (ca. 2006-2008) are designed to have sensitivities near the standard quantum limit (SQL) in the vicinity of 100 Hz. This paper describes and analyzes possible designs for subsequent LIGO-III interferometers that can beat the SQL. These designs are identical to a conventional broad band interferometer (without signal recycling), except for new input and/or output optics. Three designs are analyzed: (i) a squeezed-input interferometer (conceived by Unruh based on earlier work of Caves) in which squeezed vacuum with frequency-dependent (FD) squeeze angle is injected into the interferometer's dark port; (ii) a variational-output interferometer (conceived in a different form by Vyatchanin, Matsko and Zubova), in which homodyne detection with FD homodyne phase is performed on the output light; and (iii) a squeezed-variational interferometer with squeezed input and FD-homodyne output. It is shown that the FD squeezed-input light can be produced by sending ordinary squeezed light through two successive Fabry-Pérot filter cavities before injection into the interferometer, and FD-homodyne detection can be achieved by sending the output light through two filter cavities before ordinary homodyne detection. With anticipated technology (power squeeze factor e-2R=0.1 for input squeezed vacuum and net fractional loss of signal power in arm cavities and output optical train ɛ*=0.01) and using an input laser power Io in units of that required to reach the SQL (the planned LIGO-II power, ISQL), the three types of interferometer could beat the amplitude SQL at 100 Hz by the following amounts μ≡(Sh)/(SSQLh) and with the following corresponding increase V=1/μ3 in the volume of the universe that can be searched for a given noncosmological source: Squeezed input-μ~=(e-2R)~=0.3 and V~=1/0.33~=30 using Io/ISQL=1. Variational-output-μ~=ɛ1/4*~=0.3 and V~=30 but only if the optics can handle a ten times larger power: Io/ISQL~=1/(ɛ*)=10

  7. Conversion of conventional gravitational-wave interferometers into quantum nondemolition interferometers by modifying their input and/or output optics

    International Nuclear Information System (INIS)

    Kimble, H.J.; Levin, Yuri; Thorne, Kip S.; Matsko, Andrey B.; Vyatchanin, Sergey P.

    2002-01-01

    The LIGO-II gravitational-wave interferometers (ca. 2006-2008) are designed to have sensitivities near the standard quantum limit (SQL) in the vicinity of 100 Hz. This paper describes and analyzes possible designs for subsequent LIGO-III interferometers that can beat the SQL. These designs are identical to a conventional broad band interferometer (without signal recycling), except for new input and/or output optics. Three designs are analyzed: (i) a squeezed-input interferometer (conceived by Unruh based on earlier work of Caves) in which squeezed vacuum with frequency-dependent (FD) squeeze angle is injected into the interferometer's dark port; (ii) a variational-output interferometer (conceived in a different form by Vyatchanin, Matsko and Zubova), in which homodyne detection with FD homodyne phase is performed on the output light; and (iii) a squeezed-variational interferometer with squeezed input and FD-homodyne output. It is shown that the FD squeezed-input light can be produced by sending ordinary squeezed light through two successive Fabry-Perot filter cavities before injection into the interferometer, and FD-homodyne detection can be achieved by sending the output light through two filter cavities before ordinary homodyne detection. With anticipated technology (power squeeze factor e -2R =0.1 for input squeezed vacuum and net fractional loss of signal power in arm cavities and output optical train ε * =0.01) and using an input laser power I o in units of that required to reach the SQL (the planned LIGO-II power, I SQL ), the three types of interferometer could beat the amplitude SQL at 100 Hz by the following amounts μ≡√(S h )/√(S h SQL ) and with the following corresponding increase V=1/μ 3 in the volume of the universe that can be searched for a given noncosmological source: Squeezed input--μ≅√(e -2R )≅0.3 and V≅1/0.3 3 ≅30 using I o /I SQL =1. Variational-output--μ≅ε * 1/4 ≅0.3 and V≅30 but only if the optics can handle a ten

  8. Applied research of quantum information based on linear optics

    International Nuclear Information System (INIS)

    Xu, Xiao-Ye

    2016-01-01

    This thesis reports on outstanding work in two main subfields of quantum information science: one involves the quantum measurement problem, and the other concerns quantum simulation. The thesis proposes using a polarization-based displaced Sagnac-type interferometer to achieve partial collapse measurement and its reversal, and presents the first experimental verification of the nonlocality of the partial collapse measurement and its reversal. All of the experiments are carried out in the linear optical system, one of the earliest experimental systems to employ quantum communication and quantum information processing. The thesis argues that quantum measurement can yield quantum entanglement recovery, which is demonstrated by using the frequency freedom to simulate the environment. Based on the weak measurement theory, the author proposes that white light can be used to precisely estimate phase, and effectively demonstrates that the imaginary part of the weak value can be introduced by means of weak measurement evolution. Lastly, a nine-order polarization-based displaced Sagnac-type interferometer employing bulk optics is constructed to perform quantum simulation of the Landau-Zener evolution, and by tuning the system Hamiltonian, the first experiment to research the Kibble-Zurek mechanism in non-equilibrium kinetics processes is carried out in the linear optical system.

  9. Applied research of quantum information based on linear optics

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xiao-Ye

    2016-08-01

    This thesis reports on outstanding work in two main subfields of quantum information science: one involves the quantum measurement problem, and the other concerns quantum simulation. The thesis proposes using a polarization-based displaced Sagnac-type interferometer to achieve partial collapse measurement and its reversal, and presents the first experimental verification of the nonlocality of the partial collapse measurement and its reversal. All of the experiments are carried out in the linear optical system, one of the earliest experimental systems to employ quantum communication and quantum information processing. The thesis argues that quantum measurement can yield quantum entanglement recovery, which is demonstrated by using the frequency freedom to simulate the environment. Based on the weak measurement theory, the author proposes that white light can be used to precisely estimate phase, and effectively demonstrates that the imaginary part of the weak value can be introduced by means of weak measurement evolution. Lastly, a nine-order polarization-based displaced Sagnac-type interferometer employing bulk optics is constructed to perform quantum simulation of the Landau-Zener evolution, and by tuning the system Hamiltonian, the first experiment to research the Kibble-Zurek mechanism in non-equilibrium kinetics processes is carried out in the linear optical system.

  10. Assessment of magneto-optic Faraday effect-based drift on interferometric single-mode fiber optic gyroscope (IFOG) as a function of variable degree of polarization (DOP)

    International Nuclear Information System (INIS)

    Çelikel, Oğuz; Sametoğlu, Ferhat

    2012-01-01

    In this study, a novel interferometric fiber optic gyroscope (IFOG), which has a different depolarizer structure, is designed in TUBITAK UME (National Metrology Institute of Turkey) to experimentally and relatively evaluate the effect of the degree of polarization on the Faraday effect-based drift of the light waves injected into both arms of a Sagnac interferometer. In order to observe whether or not any change occurs in the Faraday-based drift, depending on the variations in degree of polarization (DOP), a triple structure-depolarizer IFOG possessing adjustable DOP is firstly designed and prototyped. The minimum DOP achieved with triple structure-depolarizers is typically 0.15% for both clockwise (CW) and counterclockwise (CCW) light waves at both arms of the Sagnac interferometer. The experimental evaluations about the drift are given for DOP changes extending from 78.00% to 0.15% together with two main and different theoretical approaches in the literature. According to the experimental evaluations given herein, it is experimentally proved that the Faraday-based drift does not change depending on DOP values of both CW and CCW light waves injected into the single-mode (SM) sensing coil and it is impossible to state a concept of a depolarized IFOG by considering the polarization state at the entrance arms of the SM sensing coil. (paper)

  11. A generalized, periodic nonlinearity-reduced interferometer for straightness measurements

    International Nuclear Information System (INIS)

    Wu Chienming

    2008-01-01

    Periodic nonlinearity is a systematic error limiting the accuracy of displacement measurements at the nanometer level. However, an interferometer with a displacement measurement accuracy of less than 1 nm is required in nanometrology and in fundamental scientific research. To meet this requirement, a generalized, periodic nonlinearity-reduced interferometer, based on three construction principles has been developed for straightness measurements. These three construction principles have resulted in an interferometer with a highly stable design with reduced periodic nonlinearity. Verifications by a straightness interferometer have demonstrated that the periodic nonlinearity was less than 40 pm. The results also demonstrate that the interferometer design is capable of subnanometer accuracy and is useful in nanometrology

  12. Unequal-Arms Michelson Interferometers

    Science.gov (United States)

    Tinto, Massimo; Armstrong, J. W.

    2000-01-01

    Michelson interferometers allow phase measurements many orders of magnitude below the phase stability of the laser light injected into their two almost equal-length arms. If, however, the two arms are unequal, the laser fluctuations can not be removed by simply recombining the two beams. This is because the laser jitters experience different time delays in the two arms, and therefore can not cancel at the photo detector. We present here a method for achieving exact laser noise cancellation, even in an unequal-arm interferometer. The method presented in this paper requires a separate readout of the relative phase in each arm, made by interfering the returning beam in each arm with a fraction of the outgoing beam. By linearly combining the two data sets with themselves, after they have been properly time shifted, we show that it is possible to construct a new data set that is free of laser fluctuations. An application of this technique to future planned space-based laser interferometer detector3 of gravitational radiation is discussed.

  13. High accuracy step gauge interferometer

    Science.gov (United States)

    Byman, V.; Jaakkola, T.; Palosuo, I.; Lassila, A.

    2018-05-01

    Step gauges are convenient transfer standards for the calibration of coordinate measuring machines. A novel interferometer for step gauge calibrations implemented at VTT MIKES is described. The four-pass interferometer follows Abbe’s principle and measures the position of the inductive probe attached to a measuring head. The measuring head of the instrument is connected to a balanced boom above the carriage by a piezo translation stage. A key part of the measuring head is an invar structure on which the inductive probe and the corner cubes of the measuring arm of the interferometer are attached. The invar structure can be elevated so that the probe is raised without breaking the laser beam. During probing, the bending of the probe and the interferometer readings are recorded and the measurement face position is extrapolated to zero force. The measurement process is fully automated and the face positions of the steps can be measured up to a length of 2 m. Ambient conditions are measured continuously and the refractive index of air is compensated for. Before measurements the step gauge is aligned with an integrated 2D coordinate measuring system. The expanded uncertainty of step gauge calibration is U=\\sqrt{{{(64 nm)}2}+{{(88× {{10}-9}L)}2}} .

  14. Michelson interferometer for measuring temperature

    Science.gov (United States)

    Xie, Dong; Xu, Chunling; Wang, An Min

    2017-09-01

    We investigate that temperature can be measured by a modified Michelson interferometer, where at least one reflected mirror is replaced by a thermalized sample. Both of two mirrors replaced by the corresponding two thermalized samples can help to approximatively improve the resolution of temperature up to twice than only one mirror replaced by a thermalized sample. For further improving the precision, a nonlinear medium can be employed. The Michelson interferometer is embedded in a gas displaying Kerr nonlinearity. We obtain the analytical equations and numerically calculate the precision with parameters within the reach of current technology, proving that the precision of temperature can be greatly enhanced by using a nonlinear medium. Our results show that one can create an accurate thermometer by measuring the photons in the Michelson interferometer, with no need to directly measure the population of thermalized sample.

  15. Fiber Fabry-Perot interferometer with controllable temperature sensitivity.

    Science.gov (United States)

    Zhang, Xinpu; Peng, Wei; Zhang, Yang

    2015-12-01

    We proposed a fiber taper based on the Fabry-Perot (FP) interferometer structure with controllable temperature sensitivity. The FP interferometer is formed by inserting a segment of tapered fiber tip into the capillary and subsequently splicing the other end of the capillary to a single-mode fiber (SMF), the tapered fiber endface, and the spliced face form the FP cavity. Through controlling the inserted tapered fiber length, a series of FP interferometers were made. Because the inserted taper tip has the degree of freedom along the fiber axial, when the FP interferometer is subjected to temperature variation, the thermal expansion of the fiber taper tip will resist the FP cavity length change caused by the evolution of capillary length, and we can control the temperature sensitivity by adjusting the inserted taper length. In this structure, the equivalent thermal expansion coefficient of the FP interferometer can be defined; it was used to evaluate the temperature sensitivity of the FP interferometer, which provides an effective method to eliminate the temperature effect and to enhance other measurement accuracy. We fabricated the FP interferometers and calibrated their temperature characters by measuring the wavelength shift of the resonance dips in the reflection spectrum. In a temperature range of 50°C to 150°C, the corresponding temperature sensitivities can be controlled between 0 and 1.97 pm/°C when the inserted taper is between 75 and 160 μm. Because of its controllable temperature sensitivity, ease of fabrication, and low cost, this FP interferometer can meet different temperature sensitivity requirements in various application areas, especially in the fields which need temperature insensitivity.

  16. Atom Wave Interferometers

    National Research Council Canada - National Science Library

    Pritchard, David

    2000-01-01

    Long-term research objective: Matter wave interferometers, in which de Broglie waves are coherently split and then recombined to produce interference fringes, have opened exciting new possibilities for precision and fundamental...

  17. Computerized lateral-shear interferometer

    Science.gov (United States)

    Hasegan, Sorin A.; Jianu, Angela; Vlad, Valentin I.

    1998-07-01

    A lateral-shear interferometer, coupled with a computer for laser wavefront analysis, is described. A CCD camera is used to transfer the fringe images through a frame-grabber into a PC. 3D phase maps are obtained by fringe pattern processing using a new algorithm for direct spatial reconstruction of the optical phase. The program describes phase maps by Zernike polynomials yielding an analytical description of the wavefront aberration. A compact lateral-shear interferometer has been built using a laser diode as light source, a CCD camera and a rechargeable battery supply, which allows measurements in-situ, if necessary.

  18. Data combinations accounting for LISA spacecraft motion

    International Nuclear Information System (INIS)

    Shaddock, Daniel A.; Tinto, Massimo; Estabrook, Frank B.; Armstrong, J.W.

    2003-01-01

    The laser interferometer space antenna is an array of three spacecraft in an approximately equilateral triangle configuration which will be used as a low-frequency gravitational wave detector. We present here new generalizations of the Michelson- and Sagnac-type time-delay interferometry data combinations. These combinations cancel laser phase noise in the presence of different up and down propagation delays in each arm of the array, and slowly varying systematic motion of the spacecraft. The gravitational wave sensitivities of these generalized combinations are the same as previously computed for the stationary cases, although the combinations are now more complicated. We introduce a diagrammatic representation to illustrate that these combinations are actually synthesized equal-arm interferometers

  19. A Study on non-contact measurements of laser-generated lamb waves

    International Nuclear Information System (INIS)

    Jang, Tae Seong; Lee, Jung Ju; Lee, Seung Seok

    2002-01-01

    Generation and detection of Lamb waves offer an effective non-destructive testing technique that will detect defects quickly and reliably. Lamb waves are generated in a thin plate by Q-switched Nd:YAG pulsed laser. Symmetric and antisymmetric Lamb modes in low-frequency-thickness regime are excited by illuminating a thin plate with an array of laser-generated line sources. The propagation of laser-generated Lamb waves is detected by measuring the out-of-plane displacements in a non-contact manner using the fiber optic Sagnac interferometer and all commercial adaptive reference-beam interferometer. The characteristics of laser-generated Lamb wave due to its frequency are investigated. Fundamental understanding of laser-generated Lamb modes is presented.

  20. Phase considerations in a rotating system

    International Nuclear Information System (INIS)

    Page, L.A.

    1978-01-01

    A neutron interferometer in constant absolute rotation will exhibit a certain phase-shift between its two beams, a phenomenon shared with the classic Sagnac or Michelson-Gale-Pearson experiments or with the modern laser-gyrocompass composed of lasers in a ring. To first order in the rotational frequency, it is possible to understand by employing only rudimentary theory, the essence of this phenomenon to any degree of relativistiness of the participating particle. This paper is mainly paedagogical, noting the similarity due to permanent rotation between photon-, electron and neutron-interferometers. Future experimentation, aside from corroborating well believed tenets, may hope with improving precision to bring new approaches to measurement of fundamental effects

  1. Optical Fiber Sensors Based on Fiber Ring Laser Demodulation Technology.

    Science.gov (United States)

    Xie, Wen-Ge; Zhang, Ya-Nan; Wang, Peng-Zhao; Wang, Jian-Zhang

    2018-02-08

    A review for optical fiber sensors based on fiber ring laser (FRL) demodulation technology is presented. The review focuses on the principles, main structures, and the sensing performances of different kinds of optical fiber sensors based on FRLs. First of all, the theory background of the sensors has been discussed. Secondly, four different types of sensors are described and compared, which includes Mach-Zehnder interferometer (MZI) typed sensors, Fabry-Perot interferometer (FPI) typed sensors, Sagnac typed sensors, and fiber Bragg grating (FBG) typed sensors. Typical studies and main properties of each type of sensors are presented. Thirdly, a comparison of different types of sensors are made. Finally, the existing problems and future research directions are pointed out and analyzed.

  2. Two-Particle Four-Mode Interferometer for Atoms

    Science.gov (United States)

    Dussarrat, Pierre; Perrier, Maxime; Imanaliev, Almazbek; Lopes, Raphael; Aspect, Alain; Cheneau, Marc; Boiron, Denis; Westbrook, Christoph I.

    2017-10-01

    We present a free-space interferometer to observe two-particle interference of a pair of atoms with entangled momenta. The source of atom pairs is a Bose-Einstein condensate subject to a dynamical instability, and the interferometer is realized using Bragg diffraction on optical lattices, in the spirit of our recent Hong-Ou-Mandel experiment. We report on an observation ruling out the possibility of a purely mixed state at the input of the interferometer. We explain how our current setup can be extended to enable a test of a Bell inequality on momentum observables.

  3. Using the Talbot_Lau_interferometer_parameters Spreadsheet

    Energy Technology Data Exchange (ETDEWEB)

    Kallman, Jeffrey S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-06-04

    Talbot-Lau interferometers allow incoherent X-ray sources to be used for phase contrast imaging. A spreadsheet for exploring the parameter space of Talbot and Talbot-Lau interferometers has been assembled. This spreadsheet allows the user to examine the consequences of choosing phase grating pitch, source energy, and source location on the overall geometry of a Talbot or Talbot-Lau X-ray interferometer. For the X-ray energies required to penetrate scanned luggage the spacing between gratings is large enough that the mechanical tolerances for amplitude grating positioning are unlikely to be met.

  4. Fizeau plasma interferometer

    International Nuclear Information System (INIS)

    Frank, A.M.

    1980-01-01

    This paper describes a technique by which the sensitivity of plasma interferometers can be increased. Stabilization and fractional fringe measurement techniques have improved to the point where additional optical sensitivity could be useful

  5. Michelson interferometer for measuring temperature

    OpenAIRE

    Xie, Dong; Xu, Chunling; wang, Anmin

    2016-01-01

    We investigate that temperature can be measured by a modified Michelson interferometer, where at least one reflected mirror is replaced by a thermalized sample. Both of two mirrors replaced by the corresponding two thermalized samples can help to approximatively improve the resolution of temperature up to twice than only one mirror replaced by a thermalized sample. For further improving the precision, a nonlinear medium can be employed. The Michelson interferometer is embedded in a gas displa...

  6. Heterodyne displacement interferometer, insensitive for input polarization

    NARCIS (Netherlands)

    Meskers, A.J.H.; Spronck, J.W.; Munnig Schmidt, R.H.

    2014-01-01

    Periodic nonlinearity (PNL) in displacement interferometers is a systematic error source that limits measurement accuracy. The PNL of coaxial heterodyne interferometers is highly influenced by the polarization state and orientation of the source frequencies. In this Letter, we investigate this error

  7. Results from a multi aperture Fizeau interferometer ground testbed: demonstrator for a future space-based interferometer

    Science.gov (United States)

    Baccichet, Nicola; Caillat, Amandine; Rakotonimbahy, Eddy; Dohlen, Kjetil; Savini, Giorgio; Marcos, Michel

    2016-08-01

    In the framework of the European FP7-FISICA (Far Infrared Space Interferometer Critical Assessment) program, we developed a miniaturized version of the hyper-telescope to demonstrate multi-aperture interferometry on ground. This setup would be ultimately integrated into a CubeSat platform, therefore providing the first real demonstrator of a multi aperture Fizeau interferometer in space. In this paper, we describe the optical design of the ground testbed and the data processing pipeline implemented to reconstruct the object image from interferometric data. As a scientific application, we measured the Sun diameter by fitting a limb-darkening model to our data. Finally, we present the design of a CubeSat platform carrying this miniature Fizeau interferometer, which could be used to monitor the Sun diameter over a long in-orbit period.

  8. Step index fibre using laser interferometer

    Indian Academy of Sciences (India)

    2014-03-04

    Mar 4, 2014 ... We propose the following model to describe the cladded fibre placed inside a liquid wedge interferometer. For simplicity, we assume square interferometer plates of dimensions 2a,. 2b and refractive index μL. The fibre radius is rf and the core radius is rc with skin and core indices μs, μc respectively. Hence ...

  9. Algorithms for Unequal-Arm Michelson Interferometers

    Science.gov (United States)

    Giampieri, Giacomo; Hellings, Ronald W.; Tinto, Massimo; Bender, Peter L.; Faller, James E.

    1994-01-01

    A method of data acquisition and data analysis is described in which the performance of Michelson-type interferometers with unequal arms can be made nearly the same as interferometers with equal arms. The method requires a separate readout of the relative phase in each arm, made by interfering the returning beam in each arm with a fraction of the outgoing beam.

  10. The effects of orbital motion on LISA time delay interferometry

    International Nuclear Information System (INIS)

    Cornish, Neil J; Hellings, Ronald W

    2003-01-01

    In an effort to eliminate laser phase noise in laser interferometer spaceborne gravitational wave detectors, several combinations of signals have been found that allow the laser noise to be cancelled out while gravitational wave signals remain. This process is called time delay interferometry (TDI). In the papers that defined the TDI variables, their performance was evaluated in the limit that the gravitational wave detector is fixed in space. However, the performance depends on certain symmetries in the armlengths that are available if the detector is fixed in space, but that will be broken in the actual rotating and flexing configuration produced by the LISA orbits. In this paper we investigate the performance of these TDI variables for the real LISA orbits. First, addressing the effects of rotation, we verify Daniel Shaddock's result that the Sagnac variables α (t), β (t) and γ (t) will not cancel out the laser phase noise, and we also find the same result for the symmetric Sagnac variable ζ (t). The loss of the latter variable would be particularly unfortunate since this variable also cancels out gravitational wave signal, allowing instrument noise in the detector to be isolated and measured. Fortunately, we have found a set of more complicated TDI variables, which we call Δ Sagnac variables, one of which accomplishes the same goal as ζ (t) to good accuracy. Finally, however, as we investigate the effects of the flexing of the detector arms due to non-circular orbital motion, we show that all variables, including the interferometer variables, X(t), Y(t) and Z(t), which survive the rotation-induced loss of direction symmetry, will not completely cancel laser phase noise when the armlengths are changing with time. This unavoidable problem will place a stringent requirement on laser stability of ∼5 Hz Hz -1/2

  11. 102(ℎ/2π)k Large Area Atom Interferometers

    International Nuclear Information System (INIS)

    Chiow, Sheng-wey; Kovachy, Tim; Chien, Hui-Chun; Kasevich, Mark A.

    2011-01-01

    We demonstrate atom interferometers utilizing a novel beam splitter based on sequential multiphoton Bragg diffractions. With this sequential Bragg large momentum transfer (SB-LMT) beam splitter, we achieve high contrast atom interferometers with momentum splittings of up to 102 photon recoil momenta (102(ℎ/2π)k). To our knowledge, this is the highest momentum splitting achieved in any atom interferometer, advancing the state-of-the-art by an order of magnitude. We also demonstrate strong noise correlation between two simultaneous SB-LMT interferometers, which alleviates the need for ultralow noise lasers and ultrastable inertial environments in some future applications. Our method is intrinsically scalable and can be used to dramatically increase the sensitivity of atom interferometers in a wide range of applications, including inertial sensing, measuring the fine structure constant, and detecting gravitational waves.

  12. Experimental implementation of phase locking in a nonlinear interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hailong; Jing, Jietai, E-mail: jtjing@phy.ecnu.edu.cn [State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062 (China); Marino, A. M. [Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, 440 West Brooks Street, Norman, Oklahoma 73019 (United States)

    2015-09-21

    Based upon two cascade four-wave mixing processes in two identical hot rubidium vapor cells, a nonlinear interferometer has been experimentally realized [Jing et al., Appl. Phys. Lett. 99, 011110 (2011); Hudelist et al., Nat. Commun. 5, 3049 (2014)]. It has a higher degree of phase sensitivity than a traditional linear interferometer and has many potential applications in quantum metrology. Phase locking of the nonlinear interferometer is needed before it can find its way into applications. In this letter, we investigate the experimental implementation of phase locking of the relative phase between the three beams at different frequencies involved in such a nonlinear interferometer. We have utilized two different methods, namely, beat note locking and coherent modulation locking. We find that coherent modulation locking can achieve much better phase stability than beat note locking in our system. Our results pave the way for real applications of a nonlinear interferometer in precision measurement and quantum manipulation, for example, phase control in phase-sensitive N-wave mixing process, N-port nonlinear interferometer and quantum-enhanced real-time phase tracking.

  13. LTP interferometer-noise sources and performance

    International Nuclear Information System (INIS)

    Robertson, David; Killow, Christian; Ward, Harry; Hough, Jim; Heinzel, Gerhard; Garcia, Antonio; Wand, Vinzenz; Johann, Ulrich; Braxmaier, Claus

    2005-01-01

    The LISA Technology Package (LTP) uses laser interferometry to measure the changes in relative displacement between two inertial test masses. The goals of the mission require a displacement measuring precision of 10 pm Hz -1/2 at frequencies in the 3-30 mHz band. We report on progress with a prototype LTP interferometer optical bench in which fused silica mirrors and beamsplitters are fixed to a ZERODUR (registered) substrate using hydroxide catalysis bonding to form a rigid interferometer. The couplings to displacement noise of this interferometer of two expected noise sources-laser frequency noise and ambient temperature fluctuations-have been investigated, and an additional, unexpected, noise source has been identified. The additional noise is due to small amounts of signal at the heterodyne frequency arriving at the photodiode preamplifiers with a phase that quasistatically changes with respect to the optical signal. The phase shift is caused by differential changes in the external optical paths the beams travel before they reach the rigid interferometer. Two different external path length stabilization systems have been demonstrated and these allowed the performance of the overall system to meet the LTP displacement noise requirement

  14. Michelson Interferometer

    Science.gov (United States)

    Rogers, Ryan

    2007-01-01

    The Michelson Interferometer is a device used in many applications, but here it was used to measure small differences in distance, in the milli-inch range, specifically for defects in the Orbiter windows. In this paper, the method of using the Michelson Interferometer for measuring small distances is explained as well as the mathematics of the system. The coherence length of several light sources was calculated in order to see just how small a defect could be measured. Since white light is a very broadband source, its coherence length is very short and thus can be used to measure small defects in glass. After finding the front and back reflections from a very thin glass slide with ease and calculating the thickness of it very accurately, it was concluded that this system could find and measure small defects on the Orbiter windows. This report also discusses a failed attempt for another use of this technology as well as describes an area of promise for further analysis. The latter of these areas has applications for finding possible defects in Orbiter windows without moving parts.

  15. Wave–particle duality in a Raman atom interferometer

    International Nuclear Information System (INIS)

    Jia Ai-Ai; Yang Jun; Yan Shu-Hua; Hu Qing-Qing; Luo Yu-Kun; Zhu Shi-Yao

    2015-01-01

    We theoretically investigate the wave–particle duality based on a Raman atom interferometer, via the interaction between the atom and Raman laser, which is similar to the optical Mach–Zehnder interferometer. The wave and which-way information are stored in the atomic internal states. For the φ − π − π/2 type of atom interferometer, we find that the visibility (V) and predictability (P) still satisfy the duality relation, P 2 + V 2 ≤ 1. (paper)

  16. The effect of rotations on Michelson interferometers

    Energy Technology Data Exchange (ETDEWEB)

    Maraner, Paolo, E-mail: pmaraner@unibz.it

    2014-11-15

    In the contest of the special theory of relativity, it is shown that uniform rotations induce a phase shift in Michelson interferometers. The effect is second order in the ratio of the interferometer’s speed to the speed of light, further suppressed by the ratio of the interferometer’s arms length to the radius of rotation and depends on the interferometer’s position in the co-rotating frame. The magnitude of the phase shift is just beyond the sensitivity of turntable rotated optical resonators used in present tests of Lorentz invariance. It grows significantly large in Earth’s rotated kilometer-scale Fabry–Perot enhanced interferometric gravitational-wave detectors where it appears as a constant bias. The effect can provide the means of sensing center and radius of rotations. - Highlights: • Rotations induce a phase shift in Michelson interferometers. • Earth’s rotation induces a constant bias in Michelson interferometers. • Michelson interferometers can be used to sense center and radius of rotations.

  17. The effect of rotations on Michelson interferometers

    International Nuclear Information System (INIS)

    Maraner, Paolo

    2014-01-01

    In the contest of the special theory of relativity, it is shown that uniform rotations induce a phase shift in Michelson interferometers. The effect is second order in the ratio of the interferometer’s speed to the speed of light, further suppressed by the ratio of the interferometer’s arms length to the radius of rotation and depends on the interferometer’s position in the co-rotating frame. The magnitude of the phase shift is just beyond the sensitivity of turntable rotated optical resonators used in present tests of Lorentz invariance. It grows significantly large in Earth’s rotated kilometer-scale Fabry–Perot enhanced interferometric gravitational-wave detectors where it appears as a constant bias. The effect can provide the means of sensing center and radius of rotations. - Highlights: • Rotations induce a phase shift in Michelson interferometers. • Earth’s rotation induces a constant bias in Michelson interferometers. • Michelson interferometers can be used to sense center and radius of rotations

  18. Six-channel adaptive fibre-optic interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Romashko, R V; Bezruk, M N; Kamshilin, A A; Kulchin, Yurii N

    2012-06-30

    We have proposed and analysed a scheme for the multiplexing of orthogonal dynamic holograms in photorefractive crystals which ensures almost zero cross talk between the holographic channels upon phase demodulation. A six-channel adaptive fibre-optic interferometer was built, and the detection limit for small phase fluctuations in the channels of the interferometer was determined to be 2.1 Multiplication-Sign 10{sup -8} rad W{sup 1/2} Hz{sup -1/2}. The channel multiplexing capacity of the interferometer was estimated. The formation of 70 channels such that their optical fields completely overlap in the crystal reduces the relative detection limit in the working channel by just 10 %. We found conditions under which the maximum cross talk between the channels was within the intrinsic noise level in the channels (-47 dB).

  19. Adiabatic radio-frequency potentials for the coherent manipulation of matter waves

    DEFF Research Database (Denmark)

    Lesanovsky, Igor; Schumm, Thorsten; Hofferberth, S.

    2006-01-01

    Adiabatic dressed state potentials are created when magnetic substates of trapped atoms are coupled by a radio-frequency field. We discuss their theoretical foundations and point out fundamental advantages over potentials purely based on static fields. The enhanced flexibility enables one...... to implement numerous configurations, including double wells, Mach-Zehnder, and Sagnac interferometers which even allows for internal state-dependent atom manipulation. These can be realized using simple and highly integrated wire geometries on atom chips....

  20. Vibrometer based on a self-mixing effect interferometer

    International Nuclear Information System (INIS)

    Marti-Lopez, Luis; Gonzalez-Penna, R.; Martinez-Celorio, R. A.

    2009-01-01

    We outline the basic principles of the self-mixing effect and present the design and construction of an interferometer based on this phenomenon. It differs from the previously reported in the literature by the use of two photodetectors, located at different arms of the interferometer. This feature allows widening the arsenal of strategies for the digital processing of the signal. The interferometer is used as vibrometer for the characterization of professional loudspeakers. Experimental results are presented as an illustration. (Author)

  1. Gravitational Wave Detection with Single-Laser Atom Interferometers

    Science.gov (United States)

    Yu, Nan; Tinto, Massimo

    2011-01-01

    A new design for a broadband detector of gravitational radiation relies on two atom interferometers separated by a distance L. In this scheme, only one arm and one laser are used for operating the two atom interferometers. The innovation here involves the fact that the atoms in the atom interferometers are not only considered as perfect test masses, but also as highly stable clocks. Atomic coherence is intrinsically stable, and can be many orders of magnitude more stable than a laser.

  2. Special topics in infrared interferometry. [Michelson interferometer development

    Science.gov (United States)

    Hanel, R. A.

    1985-01-01

    Topics in IR interferometry related to the development of a Michelson interferometer are treated. The selection and reading of the signal from the detector to the analog to digital converter is explained. The requirements for the Michelson interferometer advance speed are deduced. The effects of intensity modulation on the interferogram are discussed. Wavelength and intensity calibration of the interferometer are explained. Noise sources (Nyquist or Johnson noise, phonon noise), definitions of measuring methods of noise, and noise measurements are presented.

  3. Superconducting on-chip microwave interferometers

    Energy Technology Data Exchange (ETDEWEB)

    Menzel, Edwin P.; Fischer, Michael; Schneider, Christian; Baust, Alexander; Eder, Peter; Goetz, Jan; Haeberlein, Max; Schwarz, Manuel; Wulschner, Karl Friedrich; Xie, Edwar; Zhong, Ling; Deppe, Frank; Fedorov, Kirill; Huebl, Hans; Marx, Achim; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany)

    2015-07-01

    In the realm of all-microwave quantum computation, information is encoded in itinerant microwave photons propagating along transmission lines. In such a system unitary operations are implemented by linear elements such as beam splitters or interferometers. However, for two-qubit operations non-linear gates, e.g., c-phase gates are required. In this work, we investigate superconducting interferometers as a building block of a c-phase gate. We experimentally characterize their scattering properties and compare them to simulation results. Finally, we discuss our progress towards the realization of a c-phase gate.

  4. A double-pass interferometer for measurement of dimensional changes

    International Nuclear Information System (INIS)

    Ren, Dongmei; Lawton, K M; Miller, J A

    2008-01-01

    A double-pass interferometer was developed for measuring dimensional changes of materials in a nanoscale absolute interferometric dilatometer. This interferometer realized the double-ended measurement of a sample using a single-detection double-pass interference system. The nearly balanced design, in which the measurement beam and the reference beam have equal optical path lengths except for the path difference caused by the sample itself, makes this interferometer have high stability, which is verified by the measurement of a quasi-zero-length sample. The preliminary experiments and uncertainty analysis show that this interferometer should be able to measure dimensional changes with characteristic uncertainty at the nanometer level

  5. An absolute distance interferometer with two external cavity diode lasers

    International Nuclear Information System (INIS)

    Hartmann, L; Meiners-Hagen, K; Abou-Zeid, A

    2008-01-01

    An absolute interferometer for length measurements in the range of several metres has been developed. The use of two external cavity diode lasers allows the implementation of a two-step procedure which combines the length measurement with a variable synthetic wavelength and its interpolation with a fixed synthetic wavelength. This synthetic wavelength is obtained at ≈42 µm by a modulation-free stabilization of both lasers to Doppler-reduced rubidium absorption lines. A stable reference interferometer is used as length standard. Different contributions to the total measurement uncertainty are discussed. It is shown that the measurement uncertainty can considerably be reduced by correcting the influence of vibrations on the measurement result and by applying linear regression to the quadrature signals of the absolute interferometer and the reference interferometer. The comparison of the absolute interferometer with a counting interferometer for distances up to 2 m results in a linearity error of 0.4 µm in good agreement with an estimation of the measurement uncertainty

  6. Dual-recycled cavity-enhanced Michelson interferometer for gravitational-wave detection.

    Science.gov (United States)

    Müller, Guido; Delker, Tom; Tanner, David B; Reitze, David

    2003-03-01

    The baseline design for an Advanced Laser Interferometer Gravitational-Wave Observatory (Advanced LIGO) is a dual-recycled Michelson interferometer with cavities in each of the Michelson interferometer arms. We describe one possible length-sensing and control scheme for such a dual-recycled, cavity-enhanced Michelson interferometer. We discuss the principles of this scheme and derive the first-order sensing signals. We also present a successful experimental verification of our length-sensing system using a prototype tabletop interferometer. Our results demonstrate the robustness of the scheme against deviations from the idealized design. We also identify potential weaknesses and discuss possible improvements. These results as well as other benchtop experiments that we present form the basis for a sensing and control scheme for Advanced LIGO.

  7. Polydyne displacement interferometer using frequency-modulated light

    Science.gov (United States)

    Arablu, Masoud; Smith, Stuart T.

    2018-05-01

    A radio-frequency Frequency-Modulated (FM) signal is used to diffract a He-Ne laser beam through an Acousto-Optic Modulator (AOM). Due to the modulation of the FM signal, the measured spectra of the diffracted beams comprise a series of phase-synchronized harmonics that have exact integer frequency separation. The first diffraction side-beam emerging from the AOM is selected by a slit to be used in a polydyne displacement interferometer in a Michelson interferometer topology. The displacement measurement is derived from the phase measurement of selected modulation harmonic pairs. Individual harmonic frequency amplitudes are measured using discrete Fourier transform applied to the signal from a single photodetector. Phase signals are derived from the changes in the amplitudes of different harmonic pairs (typically odd-even pairs) with the phase being extracted using a standard quadrature method. In this study, two different modulation frequencies of 5 and 10 kHz are used at different modulation depths. The measured displacements by different harmonic pairs are compared with a commercial heterodyne interferometer being used as a reference for these studies. Measurements obtained from five different harmonic pairs when the moving mirror of the interferometer is scanned over ranges up to 10 μm all show differences of less than 50 nm from the reference interferometer measurements. A drift test was also used to evaluate the differences between the polydyne interferometer and reference measurements that had different optical path lengths of approximately 25 mm and 50 mm, respectively. The drift test results indicate that about half of the differences can be attributed to temperature, pressure, and humidity variations. Other influences include Abbe and thermal expansion effects. Rough magnitude estimates using simple models for these two effects can account for remaining observed deviations.

  8. Wide Angle Michelson Doppler Imaging Interferometer (WAMDII)

    Science.gov (United States)

    Roberts, B.

    1986-01-01

    The wide angle Michelson Doppler imaging interferometer (WAMDII) is a specialized type of optical Michelson interferometer working at sufficiently long path difference to measure Doppler shifts and to infer Doppler line widths of naturally occurring upper atmospheric Gaussian line emissions. The instrument is intended to measure vertical profiles of atmospheric winds and temperatures within the altitude range of 85 km to 300 km. The WAMDII consists of a Michelson interferometer followed by a camera lens and an 85 x 106 charge coupled device photodiode array. Narrow band filters in a filter wheel are used to isolate individual line emissions and the lens forms an image of the emitting region on the charge coupled device array.

  9. Advanced Gouy phase high harmonics interferometer

    Science.gov (United States)

    Mustary, M. H.; Laban, D. E.; Wood, J. B. O.; Palmer, A. J.; Holdsworth, J.; Litvinyuk, I. V.; Sang, R. T.

    2018-05-01

    We describe an extreme ultraviolet (XUV) interferometric technique that can resolve ∼100 zeptoseconds (10‑21 s) delay between high harmonic emissions from two successive sources separated spatially along the laser propagation in a single Gaussian beam focus. Several improvements on our earlier work have been implemented in the advanced interferometer. In this paper, we report on the design, characterization and optimization of the advanced Gouy phase interferometer. Temporal coherence for both atomic argon and molecular hydrogen gases has been observed for several harmonic orders. It has been shown that phase shift of XUV pulses mainly originates from the emission time delay due to the Gouy phase in the laser focus and the observed interference is independent of the generating medium. This interferometer can be a useful tool for measuring the relative phase shift between any two gas species and for studying ultrafast dynamics of their electronic and nuclear motion.

  10. Parallel Wavefront Analysis for a 4D Interferometer

    Science.gov (United States)

    Rao, Shanti R.

    2011-01-01

    This software provides a programming interface for automating data collection with a PhaseCam interferometer from 4D Technology, and distributing the image-processing algorithm across a cluster of general-purpose computers. Multiple instances of 4Sight (4D Technology s proprietary software) run on a networked cluster of computers. Each connects to a single server (the controller) and waits for instructions. The controller directs the interferometer to several images, then assigns each image to a different computer for processing. When the image processing is finished, the server directs one of the computers to collate and combine the processed images, saving the resulting measurement in a file on a disk. The available software captures approximately 100 images and analyzes them immediately. This software separates the capture and analysis processes, so that analysis can be done at a different time and faster by running the algorithm in parallel across several processors. The PhaseCam family of interferometers can measure an optical system in milliseconds, but it takes many seconds to process the data so that it is usable. In characterizing an adaptive optics system, like the next generation of astronomical observatories, thousands of measurements are required, and the processing time quickly becomes excessive. A programming interface distributes data processing for a PhaseCam interferometer across a Windows computing cluster. A scriptable controller program coordinates data acquisition from the interferometer, storage on networked hard disks, and parallel processing. Idle time of the interferometer is minimized. This architecture is implemented in Python and JavaScript, and may be altered to fit a customer s needs.

  11. Comparison of the performance of the next generation of optical interferometers

    Science.gov (United States)

    Pisani, Marco; Yacoot, Andrew; Balling, Petr; Bancone, Nicola; Birlikseven, Cengiz; Çelik, Mehmet; Flügge, Jens; Hamid, Ramiz; Köchert, Paul; Kren, Petr; Kuetgens, Ulrich; Lassila, Antti; Bartolo Picotto, Gian; Şahin, Ersoy; Seppä, Jeremias; Tedaldi, Matthew; Weichert, Christoph

    2012-08-01

    Six European National Measurement Institutes (NMIs) have joined forces within the European Metrology Research Programme funded project NANOTRACE to develop the next generation of optical interferometers having a target uncertainty of 10 pm. These are needed for NMIs to provide improved traceable dimensional metrology that can be disseminated to the wider nanotechnology community, thereby supporting the growth in nanotechnology. Several approaches were followed in order to develop the interferometers. This paper briefly describes the different interferometers developed by the various partners and presents the results of a comparison of performance of the optical interferometers using an x-ray interferometer to generate traceable reference displacements.

  12. Development of holographic interferometer for non-destructive testing

    International Nuclear Information System (INIS)

    Kim, Cheol Jung; Baik, Sung Hoon; Shin, Jang Soo; Cho, Jai Wan; Kim, Duk Hyeon; Hong, Suck Kyoung; Lee, Sang Kil; Kim, Heon Jun; Park, Chang Jin

    1993-02-01

    This project sets the goal at development of holographic interferometer. In this interferometer, fringe localization and imaging of object are considered. And collimated beam and wedge are used for the high-speed recording and formation of carrier fringes, respectively. With this real-time holographic interferometer, not only experiments were conducted on natural convection and flame jet, but also on high speed flow phenomena such as shock wave propagation. Visualization of high-speed flow is recorded in high-speed camera with framing rate ∼ 35000f/s. And to analyze axis symmetric phase object, analysis program was developed. (Author)

  13. A Michelson interferometer for X-rays and thermal neutrons

    International Nuclear Information System (INIS)

    Appel, A.

    1992-01-01

    The introduced interferometer consists of an LLL interferometer and a phase-displacing Bragg groove component. A part of the radiation path between the Lane mirrors in the Bragg grooves is replaced by a radiation path, whose wave number vector has a slightly different direction compared to the Lane case by the refraction correction. If the angles of incidence in the two grooves are different, then a difference in path is produced between the beams producing interference. This is the first X-ray interferometer which works like an optical Michelson interferometer. As there are no basic limits to resolution by absorption or dispersion, for example, it opens up the possibility of carrying out Fourier spectroscopy in the A wavelength range. (orig.) [de

  14. Analysis of a four-mirror-cavity enhanced Michelson interferometer.

    Science.gov (United States)

    Thüring, André; Lück, Harald; Danzmann, Karsten

    2005-12-01

    We investigate the shot-noise-limited sensitivity of a four-mirror-cavity enhanced Michelson interferometer. The intention of this interferometer topology is the reduction of thermal lensing and the impact of the interferometers contrast although transmissive optics are used with high circulating powers. The analytical expressions describing the light fields and the frequency response are derived. Although the parameter space has 11 dimensions, a detailed analysis of the resonance feature gives boundary conditions allowing systematic parameter studies.

  15. A heterodyne interferometer with periodic nonlinearities smaller than ±10 pm

    International Nuclear Information System (INIS)

    Weichert, C; Köchert, P; Köning, R; Flügge, J; Andreas, B; Kuetgens, U; Yacoot, A

    2012-01-01

    The PTB developed a new optical heterodyne interferometer in the context of the European joint research project ‘Nanotrace’. A new optical concept using plane-parallel plates and spatially separated input beams to minimize the periodic nonlinearities was realized. Furthermore, the interferometer has the resolution of a double-path interferometer, compensates for possible angle variations between the mirrors and the interferometer optics and offers a minimal path difference between the reference and the measurement arm. Additionally, a new heterodyne phase evaluation based on an analogue to digital converter board with embedded field programmable gate arrays was developed, providing a high-resolving capability in the single-digit picometre range. The nonlinearities were characterized by a comparison with an x-ray interferometer, over a measurement range of 2.2 periods of the optical interferometer. Assuming an error-free x-ray interferometer, the nonlinearities are considered to be the deviation of the measured displacement from a best-fit line. For the proposed interferometer, nonlinearities smaller than ±10 pm were observed without any quadrature fringe correction. (paper)

  16. A heterodyne interferometer with periodic nonlinearities smaller than ±10 pm

    Science.gov (United States)

    Weichert, C.; Köchert, P.; Köning, R.; Flügge, J.; Andreas, B.; Kuetgens, U.; Yacoot, A.

    2012-09-01

    The PTB developed a new optical heterodyne interferometer in the context of the European joint research project ‘Nanotrace’. A new optical concept using plane-parallel plates and spatially separated input beams to minimize the periodic nonlinearities was realized. Furthermore, the interferometer has the resolution of a double-path interferometer, compensates for possible angle variations between the mirrors and the interferometer optics and offers a minimal path difference between the reference and the measurement arm. Additionally, a new heterodyne phase evaluation based on an analogue to digital converter board with embedded field programmable gate arrays was developed, providing a high-resolving capability in the single-digit picometre range. The nonlinearities were characterized by a comparison with an x-ray interferometer, over a measurement range of 2.2 periods of the optical interferometer. Assuming an error-free x-ray interferometer, the nonlinearities are considered to be the deviation of the measured displacement from a best-fit line. For the proposed interferometer, nonlinearities smaller than ±10 pm were observed without any quadrature fringe correction.

  17. Quantum Spin Transport in Mesoscopic Interferometer

    Directory of Open Access Journals (Sweden)

    Zein W. A.

    2007-10-01

    Full Text Available Spin-dependent conductance of ballistic mesoscopic interferometer is investigated. The quantum interferometer is in the form of ring, in which a quantum dot is embedded in one arm. This quantum dot is connected to one lead via tunnel barrier. Both Aharonov- Casher and Aharonov-Bohm e ects are studied. Our results confirm the interplay of spin-orbit coupling and quantum interference e ects in such confined quantum systems. This investigation is valuable for spintronics application, for example, quantum information processing.

  18. Improved synthetic-heterodyne Michelson interferometer vibrometer using phase and gain control feedback.

    Science.gov (United States)

    Galeti, José Henrique; Kitano, Cláudio; Connelly, Michael J

    2015-12-10

    Synthetic-heterodyne demodulation is a useful technique for dynamic displacement and velocity measurement using interferometric sensors as it can provide an output signal which is immune to interferometric drift. With the advent of cost effective, high-speed real-time signal processing systems and software, processing of the complex signals encountered in interferometry has become more feasible. In conventional synthetic-heterodyne demodulation schemes, to obtain the dynamic displacement or vibration of the object under test requires knowledge of the interferometer visibility and also the argument of two Bessel functions. In this paper, a new synthetic-heterodyne demodulation method is described leading to an expression for the dynamic displacement and velocity of the object under test that is significantly less sensitive to the received optical power. In addition, the application of two independent phase and gain feedback loops is used to compensate for the nonideal gain and phase response of the anti-aliasing filter required for the signal acquisition of the received wideband interferometer signal. The efficacy of the improved system is demonstrated by measuring the displacement sensitivity frequency response and linearity of a Piezoelectric Mirror-Shifter (PMS) over a range of 200 Hz-9 kHz. In addition, the system is used to measure the response of the PMS to triangular and impulse type stimuli. The experimental results show excellent agreement with measurements taken using two independent industry standard calibration methods.

  19. Talbot Carpet Simulation for X-ray grating interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youngju; Oh, Ohsung; Jeong, Hanseong; Kim, Jeongho; Lee, Seung Wook [Pusan National University, Busan (Korea, Republic of); Kim, Jongyul; Moon, Myungkook [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    In this study, Talbot carpet simulator has been developed to visualize the X-ray grating interference patterns in grating interferometer. We have simulated X-ray interference for a variety of simulations and demonstrated a few examples in this summary. Grating interferometer produces interference of X-ray called Talbot pattern with gratings manufactured in micro scale. Talbot pattern is self-images of phase grating which develops interference as beam splitter that is one of gratings consisted of interferometer. As the other gratings, there are source grating makes coherence and analyze grating is used to analyze interference onto detector. Talbot carpet has been studied as the beam behavior which is distinguished with common X-ray imaging systems. It is helpful to understand grating interferometer and possible to expect beams' oscillation for designing theoretically. We confirm pattern has periodicity produced by interference after pi and pi/2 phase grating and changes in the perpendicular direction to entrance face according to phase objects.

  20. Very small beam-size measurement by a reflective synchrotron radiation interferometer

    Directory of Open Access Journals (Sweden)

    T. Naito

    2006-12-01

    Full Text Available A synchrotron radiation (SR interferometer with Herschelian reflective optics has been developed for the measurement of beams of several μm in size. In a conventional refractive SR interferometer, the dispersion effect of the objective lens limits the instrument to a smaller range of beam-size measurements. To avoid this problem, we designed a Herschelian arrangement of reflective optics for the interferometer. The effectiveness of the reflective SR interferometer was confirmed at the KEK Accelerator Test Facility (ATF damping ring. The measured vertical beam size obtained using the reflective SR interferometer was 4.7   μm and the estimated vertical emittance was 0.97×10^{-11}   m.

  1. Local readout enhancement for detuned signal-recycling interferometers

    International Nuclear Information System (INIS)

    Rehbein, Henning; Mueller-Ebhardt, Helge; Schnabel, Roman; Danzmann, Karsten; Somiya, Kentaro; Chen Yanbei; Li Chao

    2007-01-01

    High power detuned signal-recycling interferometers currently planned for second-generation interferometric gravitational-wave detectors (for example Advanced LIGO) are characterized by two resonances in the detection band, an optical resonance and an optomechanical resonance which is upshifted from the suspension pendulum frequency due to the so-called optical-spring effect. The detector's sensitivity is enhanced around these two resonances. However, at frequencies below the optomechanical resonance frequency, the sensitivity of such interferometers is significantly lower than non-optical-spring configurations with comparable circulating power; such a drawback can also compromise high-frequency sensitivity, when an optimization is performed on the overall sensitivity of the interferometer to a class of sources. In this paper, we clarify the reason for such a low sensitivity, and propose a way to fix this problem. Motivated by the optical-bar scheme of Braginsky, Gorodetsky, and Khalili, we propose to add a local readout scheme which measures the motion of the arm-cavity front mirror, which at low frequencies moves together with the arm-cavity end mirror, under the influence of gravitational waves. This scheme improves the low-frequency quantum-noise-limited sensitivity of optical-spring interferometers significantly and can be considered as an incorporation of the optical-bar scheme into currently planned second-generation interferometers. On the other hand it can be regarded as an extension of the optical-bar scheme. Taking compact binary inspiral signals as an example, we illustrate how this scheme can be used to improve the sensitivity of the planned Advanced LIGO interferometer, in various scenarios, using a realistic classical-noise budget. We also discuss how this scheme can be implemented in Advanced LIGO with relative ease

  2. CO laser interferometer for REB-plasma experiments

    International Nuclear Information System (INIS)

    Burmasov, V.S.; Kruglyakov, E.P.

    1996-01-01

    The Michelson carbon oxide laser interferometer for measuring plasma density in studies on REB-plasma interaction is described. A detail description of the interferometer and CO laser is presented. For a selection of a single wavelength laser operation the CaF 2 prism is applied. A Ge:Au photoconductor at 77 deg K is applied as the detector. The CO laser radiation at λ 5.34 μm coincides with the detector maximum sensitivity (of the order of 1000 V/W). This increases the interferometer sensitivity about ten times with respect to the He-Ne laser (λ = 3.39 μm) used as the source of light. The typical interferogram and time evolution of plasma density obtained at GOL-M device are presented. (author). 3 figs., 5 refs

  3. CO laser interferometer for REB-plasma experiments

    Energy Technology Data Exchange (ETDEWEB)

    Burmasov, V S; Kruglyakov, E P [Budker Inst. of Nuclear Physics, Novosibirsk (Russian Federation)

    1997-12-31

    The Michelson carbon oxide laser interferometer for measuring plasma density in studies on REB-plasma interaction is described. A detail description of the interferometer and CO laser is presented. For a selection of a single wavelength laser operation the CaF{sub 2} prism is applied. A Ge:Au photoconductor at 77 deg K is applied as the detector. The CO laser radiation at {lambda} 5.34 {mu}m coincides with the detector maximum sensitivity (of the order of 1000 V/W). This increases the interferometer sensitivity about ten times with respect to the He-Ne laser ({lambda} = 3.39 {mu}m) used as the source of light. The typical interferogram and time evolution of plasma density obtained at GOL-M device are presented. (author). 3 figs., 5 refs.

  4. Precision Attitude Control for the BETTII Balloon-Borne Interferometer

    Science.gov (United States)

    Benford, Dominic J.; Fixsen, Dale J.; Rinehart. Stephen

    2012-01-01

    The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-meter baseline far-infrared interferometer to fly on a high altitude balloon. Operating at wavelengths of 30-90 microns, BETTII will obtain spatial and spectral information on science targets at angular resolutions down to less than half an arcsecond, a capability unmatched by other far-infrared facilities. This requires attitude control at a level ofless than a tenth of an arcsecond, a great challenge for a lightweight balloon-borne system. We have designed a precision attitude determination system to provide gondola attitude knowledge at a level of 2 milliarcseconds at rates up to 100Hz, with accurate absolute attitude determination at the half arcsecond level at rates of up to 10Hz. A mUlti-stage control system involving rigid body motion and tip-tilt-piston correction provides precision pointing stability to the level required for the far-infrared instrument to perform its spatial/spectral interferometry in an open-loop control. We present key aspects of the design of the attitude determination and control and its development status.

  5. Time-domain multiplexed high resolution fiber optics strain sensor system based on temporal response of fiber Fabry-Perot interferometers.

    Science.gov (United States)

    Chen, Jiageng; Liu, Qingwen; He, Zuyuan

    2017-09-04

    We developed a multiplexed strain sensor system with high resolution using fiber Fabry-Perot interferometers (FFPI) as sensing elements. The temporal responses of the FFPIs excited by rectangular laser pulses are used to obtain the strain applied on each FFPI. The FFPIs are connected by cascaded couplers and delay fiber rolls for the time-domain multiplexing. A compact optoelectronic system performing closed-loop cyclic interrogation is employed to improve the sensing resolution and the frequency response. In the demonstration experiment, 3-channel strain sensing with resolutions better than 0.1 nε and frequency response higher than 100 Hz is realized.

  6. High-resolution quantization based on soliton self-frequency shift and spectral compression in a bi-directional comb-fiber architecture

    Science.gov (United States)

    Zhang, Xuyan; Zhang, Zhiyao; Wang, Shubing; Liang, Dong; Li, Heping; Liu, Yong

    2018-03-01

    We propose and demonstrate an approach that can achieve high-resolution quantization by employing soliton self-frequency shift and spectral compression. Our approach is based on a bi-directional comb-fiber architecture which is composed of a Sagnac-loop-based mirror and a comb-like combination of N sections of interleaved single-mode fibers and high nonlinear fibers. The Sagnac-loop-based mirror placed at the terminal of a bus line reflects the optical pulses back to the bus line to achieve additional N-stage spectral compression, thus single-stage soliton self-frequency shift (SSFS) and (2 N - 1)-stage spectral compression are realized in the bi-directional scheme. The fiber length in the architecture is numerically optimized, and the proposed quantization scheme is evaluated by both simulation and experiment in the case of N = 2. In the experiment, a quantization resolution of 6.2 bits is obtained, which is 1.2-bit higher than that of its uni-directional counterpart.

  7. Michelson and His Interferometer

    Science.gov (United States)

    Shankland, Robert S.

    1974-01-01

    Presents a brief historical account of Michelson's invention of his interferometer with some subsequent ingenious applications of its capabilities for precise measurement discussed in details, including the experiment on detrmination of the diameters for heavenly bodies. (CC)

  8. A combined scanning tunnelling microscope and x-ray interferometer

    Science.gov (United States)

    Yacoot, Andrew; Kuetgens, Ulrich; Koenders, Ludger; Weimann, Thomas

    2001-10-01

    A monolithic x-ray interferometer made from silicon and a scanning tunnelling microscope have been combined and used to calibrate grating structures with periodicities of 100 nm or less. The x-ray interferometer is used as a translation stage which moves in discrete steps of 0.192 nm, the lattice spacing of the silicon (220) planes. Hence, movements are traceable to the definition of the metre and the nonlinearity associated with the optical interferometers used to measure displacement in more conventional metrological scanning probe microscopes (MSPMs) removed.

  9. Polar cap mesosphere wind observations: comparisons of simultaneous measurements with a Fabry-Perot interferometer and a field-widened Michelson interferometer.

    Science.gov (United States)

    Fisher, G M; Killeen, T L; Wu, Q; Reeves, J M; Hays, P B; Gault, W A; Brown, S; Shepherd, G G

    2000-08-20

    Polar cap mesospheric winds observed with a Fabry-Perot interferometer with a circle-to-line interferometer optical (FPI/CLIO) system have been compared with measurements from a field-widened Michelson interferometer optimized for E-region winds (ERWIN). Both instruments observed the Meinel OH emission emanating from the mesopause region (approximately 86 km) at Resolute Bay, Canada (74.9 degrees N, 94.9 degrees W). This is the first time, to our knowledge, that winds measured simultaneously from a ground-based Fabry-Perot interferometer and a ground-based Michelson interferometer have been compared at the same location. The FPI/CLIO and ERWIN instruments both have a capability for high temporal resolution (less than 10 min for a full scan in the four cardinal directions and the zenith). Statistical comparisons of hourly mean winds for both instruments by scatterplots show excellent agreement, indicating that the two optical techniques provide equivalent observations of mesopause winds. Small deviations in the measured wind can be ascribed to the different zenith angles used by the two instruments. The combined measurements illustrate the dominance of the 12-h wave in the mesopause winds at Resolute Bay, with additional evidence for strong gravity wave activity with much shorter periods (tens of minutes). Future operations of the two instruments will focus on observation of complementary emissions, providing a unique passive optical capability for the determination of neutral winds in the geomagnetic polar cap at various altitudes near the mesopause.

  10. Nonlinear Michelson interferometer for improved quantum metrology

    OpenAIRE

    Luis, Alfredo; Rivas, Ángel

    2015-01-01

    We examine quantum detection via a Michelson interferometer embedded in a gas with Kerr nonlinearity. This nonlinear interferometer is illuminated by pulses of classical light. This strategy combines the robustness against practical imperfections of classical light with the improvement provided by nonlinear processes. Regarding ultimate quantum limits, we stress that, as a difference with linear schemes, the nonlinearity introduces pulse duration as a new variable into play along with the ene...

  11. A study of microwave interferometers for electron density measurements in REB-plasma experiments

    International Nuclear Information System (INIS)

    Saxena, A.C.; Paithankar, A.S.; Iyyengar, S.K.; Rohatgi, V.K.

    1981-01-01

    In order to select a suitable microwave interferometer for electron density measurements in Relativistic Electron Beam (REB)-Plasma Experiments, a study has been carried out of four types of interferometers, viz. simple interferometer, standing-wave interferometer, frequency and phase modulated interferometers. Various direct reading interferometers which give a voltage proportional to the phase shift, are also discussed. Systems have been analysed in terms of time resolution, phase sensitivity, system stability, ease of measurement etc. Theoretical and experimental limitations of various systems have been indicated. Summary of the various systems is presented in a table to aid the experimentalist to select the most appropriate system for the prevailina experimental conditions. Finally, an attempt has been made to find out the interferometer system best suited for REB-Plasma Experiments. (author)

  12. Performance evaluation of a thermal Doppler Michelson interferometer system.

    Science.gov (United States)

    Mani, Reza; Dobbie, Steven; Scott, Alan; Shepherd, Gordon; Gault, William; Brown, Stephen

    2005-11-20

    The thermal Doppler Michelson interferometer is the primary element of a proposed limb-viewing satellite instrument called SWIFT (Stratospheric Wind Interferometer for Transport studies). SWIFT is intended to measure stratospheric wind velocities in the altitude range of 15-45 km. SWIFT also uses narrowband tandem etalon filters made of germanium to select a line out of the thermal spectrum. The instrument uses the same technique of phase-stepping interferometry employed by the Wind Imaging Interferometer onboard the Upper Atmosphere Research Satellite. A thermal emission line of ozone near 9 microm is used to detect the Doppler shift due to winds. A test bed was set up for this instrument that included the Michelson interferometer and the etalon filters. For the test bed work, we investigate the behavior of individual components and their combination and report the results.

  13. Development of a suspended-mass RSE interferometer using third harmonic demodulation

    CERN Document Server

    Miyakawa, O; Heinzel, G; Kawamura, S

    2002-01-01

    The most important point of a resonant sideband extraction (RSE) experiment is the signal extraction for control of the interferometer. We proposed a new signal-sensing method for the single modulation scheme. This method uses the third harmonic demodulation (THD) with a particular asymmetry in the interferometer which makes the third-order sidebands vanish at the detecting port. We have successfully locked a suspended-mass RSE interferometer for the first time by the THD method. The transfer function of the interferometer was measured to confirm the RSE effect.

  14. Development of a suspended-mass RSE interferometer using third harmonic demodulation

    International Nuclear Information System (INIS)

    Miyakawa, Osamu; Somiya, Kentaro; Heinzel, Gerhard; Kawamura, Seiji

    2002-01-01

    The most important point of a resonant sideband extraction (RSE) experiment is the signal extraction for control of the interferometer. We proposed a new signal-sensing method for the single modulation scheme. This method uses the third harmonic demodulation (THD) with a particular asymmetry in the interferometer which makes the third-order sidebands vanish at the detecting port. We have successfully locked a suspended-mass RSE interferometer for the first time by the THD method. The transfer function of the interferometer was measured to confirm the RSE effect

  15. Optical diameters of stars measured with the Mt. Wilson Mark III interferometer

    International Nuclear Information System (INIS)

    Simon, R.S.; Mozurkewich, D.; Johnston, K.J.; Gaume, R.; Hutter, D.J.; Bowers, P.F.; Colavita, M.M.; Shao, M.

    1990-01-01

    Reliable stellar angular diameters can now be determined using the Mark III Optical Interferometer located on Mt. Wilson, California. The Mark III is a Michelson Interferometer capable of measuring the interferometric fringe visibility for stars using interferometer baselines varying from 3 to 31.5 meters in length. Angular diameters measured with the Mark III Optical Interferometer are presented for 12 stars at wavelengths of 450 and 800 nm. 10 refs

  16. Naval Prototype Optical Interferometer (NPOI)

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Used for astrometry and astronomical imaging, the Naval Prototype Optical Interferometer (NPOI) is a distributed aperture optical telescope. It is operated...

  17. Phase-Shifting Liquid Crystal Interferometers for Microgravity Fluid Physics

    Science.gov (United States)

    Griffin, DeVon W.; Marshall, Keneth L.

    2002-01-01

    The initial focus of this project was to eliminate both of these problems in the Liquid Crystal Point-Diffraction Interferometer (LCPDI). Progress toward that goal will be described, along with the demonstration of a phase shifting Liquid Crystal Shearing Interferometer (LCSI) that was developed as part of this work. The latest LCPDI, other than a lens to focus the light from a test section onto a diffracting microsphere within the interferometer and a collimated laser for illumination, the pink region contained within the glass plates on the rod-mounted platform is the complete interferometer. The total width is approximately 1.5 inches with 0.25 inches on each side for bonding the electrical leads. It is 1 inch high and there are only four diffracting microspheres within the interferometer. As a result, it is very easy to align, achieving the first goal. The liquid crystal electro-optical response time is a function of layer thickness, with thinner devices switching faster due to a reduction in long-range viscoelastic forces between the LC molecules. The LCPDI has a liquid crystal layer thickness of 10 microns, which is controlled by plastic or glass microspheres embedded in epoxy 'pads' at the corners of the device. The diffracting spheres are composed of polystyrene/divinyl benzene polymer with an initial diameter of 15 microns. The spheres deform slightly when the interferometer is assembled to conform to the spacing produced by the microsphere-filled epoxy spacer pads. While the speed of this interferometer has not yet been tested, previous LCPDIs fabricated at the Laboratory for Laser Energetics switched at a rate of approximately 3.3 Hz, a factor of 10 slower than desired. We anticipate better performance when the speed of these interferometers is tested since they are approximately three times thinner. Phase shifting in these devices is a function of the AC voltage level applied to the liquid crystal. As the voltage increases, the dye in the liquid crystal

  18. Dispersion interferometer for controlled fusion devices

    International Nuclear Information System (INIS)

    Drachev, V.P.; Krasnikov, Yu.I.; Bagryansky, P.A.

    1992-01-01

    A common feature in interferometry is the presence of two independent optical channels. Since wave phase in a medium depends on the geometrical path, polarization and radiation frequency, respectively, one can distinguish three types of interferometric schemes when the channels are geometrically separated, or separation occurs in polarizations or radiation frequencies. We have developed a measurement scheme based on a dispersion interferometer (DI) for plasma diagnostics in the experiments on controlled fusion. DI optical channels have the same geometrical path and are separated in radiation frequency. Use of a common optical path causes the main advantage of the DI technique - low sensitivity to vibrations of optical elements. The use of the DI technique for diagnostics of a laser spark in air and of arc discharges has shown its essential advantages as compared to classical interferometers. Interest in the DI technique from the viewpoint of its application in controlled fusion devices is determined also generated by the possibility of developing a compact multichannel interferometer not requiring a vibration isolation structure. (author) 14 refs., 3 figs

  19. Spin filtering in a Rashba–Dresselhaus–Aharonov–Bohm double-dot interferometer

    International Nuclear Information System (INIS)

    Matityahu, Shlomi; Aharony, Amnon; Entin-Wohlman, Ora; Tarucha, Seigo

    2013-01-01

    We study the spin-dependent transport of spin-1/2 electrons through an interferometer made of two elongated quantum dots or quantum nanowires, which are subject to both an Aharonov–Bohm flux and (Rashba and Dresselhaus) spin–orbit interactions. Similar to the diamond interferometer proposed in our previous papers (Aharony et al 2011 Phys. Rev. B 84 035323; Matityahu et al 2013 Phys. Rev. B 87 205438), we show that the double-dot interferometer can serve as a perfect spin filter due to a spin interference effect. By appropriately tuning the external electric and magnetic fields which determine the Aharonov–Casher and Aharonov–Bohm phases, and with some relations between the various hopping amplitudes and site energies, the interferometer blocks electrons with a specific spin polarization, independent of their energy. The blocked polarization and the polarization of the outgoing electrons is controlled solely by the external electric and magnetic fields and do not depend on the energy of the electrons. Furthermore, the spin filtering conditions become simpler in the linear-response regime, in which the electrons have a fixed energy. Unlike the diamond interferometer, spin filtering in the double-dot interferometer does not require high symmetry between the hopping amplitudes and site energies of the two branches of the interferometer and thus may be more appealing from an experimental point of view. (paper)

  20. EIT Based Gas Detector Design by Using Michelson Interferometer

    International Nuclear Information System (INIS)

    Abbasian, K.; Rostami, A.; Abdollahi, M. H.

    2011-01-01

    Electromagnetically induced transparency (EIT) is one of the interesting phenomena of light-matter interaction which modifies matter properties for propagation of light. In other words, we can change the absorption and refractive index (RI) in neighborhood of the resonant frequency using EIT. In this paper, we have doped 3-level quantum dots in one of the Michelson Interferometer's mirror and used EIT to change its RI. So, a controllable phase difference between lights in two arms of interferometer is created. Long response time is the main drawback of Michelson interferometer based sensor, which is resolved by this technique.

  1. Streak camera recording of interferometer fringes

    International Nuclear Information System (INIS)

    Parker, N.L.; Chau, H.H.

    1977-01-01

    The use of an electronic high-speed camera in the streaking mode to record interference fringe motion from a velocity interferometer is discussed. Advantages of this method over the photomultiplier tube-oscilloscope approach are delineated. Performance testing and data for the electronic streak camera are discussed. The velocity profile of a mylar flyer accelerated by an electrically exploded bridge, and the jump-off velocity of metal targets struck by these mylar flyers are measured in the camera tests. Advantages of the streak camera include portability, low cost, ease of operation and maintenance, simplified interferometer optics, and rapid data analysis

  2. PEGASE: a free flying interferometer for the spectroscopy of giant exo-planets

    Science.gov (United States)

    Le Duigou, J.-M.; Ollivier, M.; Léger, A.; Cassaing, F.; Sorrente, B.; Fleury, B.; Rousset, G.; Absil, O.; Mourard, D.; Rabbia, Y.; Escarrat, L.; Malbet, F.; Rouan, D.; Clédassou, R.; Delpech, M.; Duchon, P.; Meyssignac, B.; Guidotti, P.-Y.; Gorius, N.

    2017-11-01

    This paper presents a summary of the phase-0 performed in 2005 for the Pegase mission. The main scientific goal is the spectroscopy of hot Jupiters (Pegasides) and brown dwarfs from 2.5 to 5 μm. The mission can extend to the exploration of the inner part of protoplanetary disks, the study of dust clouds around AGN,... The instrument is basically a two-aperture (D=40 cm) interferometer composed of two siderostats and one beam-combiner. The formation is linear and orbits around L2, pointing in the anti-solar direction within a +/-30° cone. The baseline is adjustable from 50 to 500 m in both nulling and visibility measurement modes. The angular resolution ranges from 1 to 20 mas and the spectral resolution is 60. in the nulling mode, a 2.5 nm rms stability of the optical path difference (OPD) and a pointing stability of 30 mas rms impose a two level control architecture. It combines control loops implemented at satellite level and control loops operating inside the payload using fine mechanisms. According to our preliminary study, this mission is feasible within an 8 to 9 years development plan using existing or slightly improved space components, but its cost requires international cooperation. Pegase could be a valuable Darwin/TPF-I pathfinder, with a less demanding, but still ambitious, technological challenge and a highly associated scientific return.

  3. 30-lens interferometer for high energy x-rays

    Energy Technology Data Exchange (ETDEWEB)

    Lyubomirskiy, M., E-mail: lyubomir@esrf.fr; Snigireva, I., E-mail: irina@esrf.fr; Vaughan, G. [European Synchrotron Radiation facility (ESRF), CS 40220, 71, av des Martyrs, F-38043, Grenoble (France); Kohn, V. [National Research Centre “Kurchatov Institute”, 123182, Moscow (Russian Federation); Kuznetsov, S.; Yunkin, V. [Institute of Microelectronics Technology RAS, 142432, Chernogolovka (Russian Federation); Snigirev, A. [Baltic Federal University, 236041, Kaliningrad (Russian Federation)

    2016-07-27

    We report a hard X-ray multilens interferometer consisting of 30 parallel compound refractive lenses. Under coherent illumination each CRL creates a diffraction limited focal spot - secondary source. An overlapping of coherent beams from these sources resulting in the interference pattern which has a rich longitudinal structure in accordance with the Talbot imaging formalism. The proposed interferometer was experimentally tested at ID11 ESRF beamline for the photon energies 32 keV and 65 keV. The fundamental and fractional Talbot images were recorded with the high resolution CCD camera. An effective source size in the order of 15 µm was determined from the first Talbot image proving that the multilens interferometer can be used as a high resolution beam diagnostic tool.

  4. Direct-reading type microwave interferometer

    International Nuclear Information System (INIS)

    Matsuura, Kiyokata; Fujita, Junji; Ogata, Atsushi; Haba, Kiichiro.

    1977-10-01

    A new microwave interferometer has been developed and applied to the electron density measurement on JIPP T-II plasma device. The interferometer generates an output voltage proportional to the number of fringe shifts and also output pulses which indicate the change of electron density for the convenience of data processing, where the resolution is a quarter of fringe shift. The principle is based on the digitization of fringe shifts utilizing the phase detection of microwave signals with two-level modulation of source frequency. With this system and 70 GHz microwave source, a change of electron density as rapid as about 2 x 10 13 cm -3 in 1 ms has been measured at the tokamak operation of JIPP T-II. (auth.)

  5. Plasmonic interferometers: From physics to biosensing applications

    Science.gov (United States)

    Zeng, Xie

    Optical interferometry has a long history and wide range of applications. In recent years, plasmonic interferometer arouses great interest due to its compact size and enhanced light-matter interaction. They have demonstrated attractive applications in biomolecule sensing, optical modulation/switching, and material characterization, etc. In this work, we first propose a practical far-field method to extract the intrinsic phase dispersion, revealing important phase information during interactions among free-space light, nanostructure, and SPs. The proposed approach is confirmed by both simulation and experiment. Then we design novel plasmonic interferometer structure for sensitive optical sensing applications. To overcome two major limitations suffered by previously reported double-slit plasmonic Mach-Zehnder interferometer (PMZI), two new schemes are proposed and investigated. (1) A PMZI based on end-fire coupling improves the SP coupling efficiency and enhance the interference contrast more than 50 times. (2) In another design, a multi-layered metal-insulator-metal PMZI releases the requirement for single-slit illumination, which enables sensitive, high-throughput sensing applications based on intensity modulation. We develop a sensitive, low-cost and high-throughput biosensing platform based on intensity modulation using ring-hole plasmonic interferometers. This biosensor is then integrated with cell-phone-based microscope, which is promising to develop a portable sensor for point-of-care diagnostics, epidemic disease control and food safety monitoring.

  6. An extreme ultraviolet Michelson interferometer for experiments at free-electron lasers

    International Nuclear Information System (INIS)

    Hilbert, Vinzenz; Fuchs, Silvio; Paulus, Gerhard G.; Zastrau, Ulf; Blinne, Alexander; Feigl, Torsten; Kämpfer, Tino; Rödel, Christian; Uschmann, Ingo; Wünsche, Martin; Förster, Eckhart

    2013-01-01

    We present a Michelson interferometer for 13.5 nm soft x-ray radiation. It is characterized in a proof-of-principle experiment using synchrotron radiation, where the temporal coherence is measured to be 13 fs. The curvature of the thin-film beam splitter membrane is derived from the observed fringe pattern. The applicability of this Michelson interferometer at intense free-electron lasers is investigated, particularly with respect to radiation damage. This study highlights the potential role of such Michelson interferometers in solid density plasma investigations using, for instance, extreme soft x-ray free-electron lasers. A setup using the Michelson interferometer for pseudo-Nomarski-interferometry is proposed

  7. Dispersed single-phase-step Michelson interferometer for Doppler imaging using sunlight.

    Science.gov (United States)

    Wan, Xiaoke; Ge, Jian

    2012-09-15

    A Michelson interferometer is dispersed with a fiber array-fed spectrograph, providing 59 Doppler sensing channels using sunlight in the 510-570 nm wavelength region. The interferometer operates at a single-phase-step mode, which is particularly advantageous in multiplexing and data processing compared to the phase-stepping mode of other interferometer spectrometer instruments. Spectral templates are prepared using a standard solar spectrum and simulated interferometer modulations, such that the correlation function with a measured 1D spectrum determines the Doppler shift. Doppler imaging of a rotating cylinder is demonstrated. The average Doppler sensitivity is ~12 m/s, with some channels reaching ~5 m/s.

  8. An extreme ultraviolet Michelson interferometer for experiments at free-electron lasers.

    Science.gov (United States)

    Hilbert, Vinzenz; Blinne, Alexander; Fuchs, Silvio; Feigl, Torsten; Kämpfer, Tino; Rödel, Christian; Uschmann, Ingo; Wünsche, Martin; Paulus, Gerhard G; Förster, Eckhart; Zastrau, Ulf

    2013-09-01

    We present a Michelson interferometer for 13.5 nm soft x-ray radiation. It is characterized in a proof-of-principle experiment using synchrotron radiation, where the temporal coherence is measured to be 13 fs. The curvature of the thin-film beam splitter membrane is derived from the observed fringe pattern. The applicability of this Michelson interferometer at intense free-electron lasers is investigated, particularly with respect to radiation damage. This study highlights the potential role of such Michelson interferometers in solid density plasma investigations using, for instance, extreme soft x-ray free-electron lasers. A setup using the Michelson interferometer for pseudo-Nomarski-interferometry is proposed.

  9. A laser interferometer for measuring straightness and its position based on heterodyne interferometry

    International Nuclear Information System (INIS)

    Chen Benyong; Zhang Enzheng; Yan Liping; Li Chaorong; Tang Wuhua; Feng Qibo

    2009-01-01

    Not only the magnitude but also the position of straightness errors are of concern to users. However, current laser interferometers used for measuring straightness seldom give the relative position of the straightness error. To solve this problem, a laser interferometer for measuring straightness and its position based on heterodyne interferometry is proposed. The optical configuration of the interferometer is designed and the measurement principle is analyzed theoretically. Two experiments were carried out. The first experiment verifies the validity and repeatability of the interferometer by measuring a linear stage. Also, the second one for measuring a flexure-hinge stage demonstrates that the interferometer is capable of nanometer measurement accuracy. These results show that this interferometer has advantages of simultaneously measuring straightness error and the relative position with high precision, and a compact structure.

  10. Phase-modulation interferometer for ICF-target characterization

    International Nuclear Information System (INIS)

    Cooper, D.E.

    1981-01-01

    Characterization requirements for high gain laser fusion targets are severe. We are required to detect defects on the surfaces of opaque and transparent shells with an amplitude resolution of +- 5 nm and a spatial resolution of 1 to 10 μm. To achieve this we have developed a laser-illuminated phase-modulation interferometer. This instrument is based on a photoelastic polarization modulation technique which allows one to convert phase information into an intensity modulation which can be easily and sensitively measured using ac signal processing techniques. This interferometer has detected path length changes as small as 1 nm and the required spatial resolution is assured by using a microscope objective to focus the probe laser beam down to a small (approx. 1 μm) spot on the surface of a microballoon. The interferometer will soon be coupled to an LSI-11 controlled 4π sphere manipulator which will allow us to automatically inspect the entire surface area of a target sphere

  11. In-line femtosecond common-path interferometer in reflection mode.

    Science.gov (United States)

    Chandezon, J; Rampnoux, J-M; Dilhaire, S; Audoin, B; Guillet, Y

    2015-10-19

    An innovative method to perform femtosecond time-resolved interferometry in reflection mode is proposed. The experiment consists in the combined use of a pump-probe setup and of a fully passive in-line femtosecond common-path interferometer. The originality of this interferometer relies on the use of a single birefringent crystal first to generate a pair of phase-locked pulses and second to recombine them to interfere. As predicted by analytical modeling, this interferometer measures the temporal derivative of the ultrafast changes of the complex optical reflection coefficient of the sample. Working conditions are illustrated through picosecond opto-acoustic experiments on a thin film.

  12. Phase-contrast tomographic imaging using an X-ray interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Momose, A. [Hitachi Ltd, Advanced Research Lab., Saitama (Japan); Takeda, T.; Itai, Y. [Univ. of Tsukuba, Inst. of Clinical Medicine, Ibaraki (Japan); Yoneyama, A. [Hitachi Ltd, Central Resarch Lab., Tokyo (Japan); Hirano, K. [High Energy Accelerator Research Organization, Inst. of Materials Structure Science, Ibaraki (Japan)

    1998-05-01

    Apparatus for phase-contrast X-ray computed tomography using a monolithic X-ray interferometer is presented with some observational results for human breast tissues. Structures characteristic of the tissues were revealed in the phase-contrast tomograms. The procedure of image analysis consists of phase retrieval from X-ray interference patterns and tomographic image reconstruction from the retrieved phase shift. Next, feasibility of phase-contrast imaging using a two-crystal X-ray interferometer was studied aiming at in vivo observation in the future. In a preliminary study, the two-crystal X-ray interferometer was capable of generating fringes of 70% visibility using synchrotron X-rays. 35 refs.

  13. Phase-contrast tomographic imaging using an X-ray interferometer

    International Nuclear Information System (INIS)

    Momose, A.; Takeda, T.; Itai, Y.; Yoneyama, A.; Hirano, K.

    1998-01-01

    Apparatus for phase-contrast X-ray computed tomography using a monolithic X-ray interferometer is presented with some observational results for human breast tissues. Structures characteristic of the tissues were revealed in the phase-contrast tomograms. The procedure of image analysis consists of phase retrieval from X-ray interference patterns and tomographic image reconstruction from the retrieved phase shift. Next, feasibility of phase-contrast imaging using a two-crystal X-ray interferometer was studied aiming at in vivo observation in the future. In a preliminary study, the two-crystal X-ray interferometer was capable of generating fringes of 70% visibility using synchrotron X-rays

  14. A novel polarization interferometer for measuring upper atmospheric winds

    International Nuclear Information System (INIS)

    Ting-Kui, Mu; Chun-Min, Zhang

    2010-01-01

    A static polarization interferometer for measuring upper atmospheric winds is presented, based on two Savart plates with their optical axes perpendicular to each other. The principle and characteristics of the interferometer are described. The interferometer with a wide field of view can offer a stable benchmark optical path difference over a specified spectral region of 0.55–0.63 μm because there are no quarter wave plates. Since the instrument employs a straight line common-path configuration but without moving parts and slits, it is very compact, simple, inherently robust and has high throughput. The paper is limited to a theoretical analysis. (general)

  15. The comparison of environmental effects on michelson and fabry-perot interferometers utilized for the displacement measurement.

    Science.gov (United States)

    Wang, Yung-Cheng; Shyu, Lih-Horng; Chang, Chung-Ping

    2010-01-01

    The optical structure of general commercial interferometers, e.g., the Michelson interferometers, is based on a non-common optical path. Such interferometers suffer from environmental effects because of the different phase changes induced in different optical paths and consequently the measurement precision will be significantly influenced by tiny variations of the environmental conditions. Fabry-Perot interferometers, which feature common optical paths, are insensitive to environmental disturbances. That would be advantageous for precision displacement measurements under ordinary environmental conditions. To verify and analyze this influence, displacement measurements with the two types of interferometers, i.e., a self-fabricated Fabry-Perot interferometer and a commercial Michelson interferometer, have been performed and compared under various environmental disturbance scenarios. Under several test conditions, the self-fabricated Fabry-Perot interferometer was obviously less sensitive to environmental disturbances than a commercial Michelson interferometer. Experimental results have shown that induced errors from environmental disturbances in a Fabry-Perot interferometer are one fifth of those in a Michelson interferometer. This has proved that an interferometer with the common optical path structure will be much more independent of environmental disturbances than those with a non-common optical path structure. It would be beneficial for the solution of interferometers utilized for precision displacement measurements in ordinary measurement environments.

  16. A SIMPLE HETERODYNE TEMPORAL SPECKLE-PATTERN INTERFEROMETER

    International Nuclear Information System (INIS)

    Wong, W. O.; Gao, Z.; Lu, J.

    2010-01-01

    A common light path design of heterodyne speckle pattern interferometer based on temporal speckle pattern interferometry is proposed for non-contact, full-field and real-time continuous displacement measurement. Double frequency laser is produced by rotating a half wave plate. An experiment was carried out to measure the dynamic displacement of a cantilever plate for testing the proposed common path heterodyne speckle pattern interferometer. The accuracy of displacement measurement was checked by measuring the motion at the mid-point of the plate with a point displacement sensor.

  17. Multiple reflection Michelson interferometer with picometer resolution.

    Science.gov (United States)

    Pisani, Marco

    2008-12-22

    A Michelson interferometer based on an optical set-up allowing multiple reflection between two plane mirrors performs the multiplication of the optical path by a factor N, proportionally increasing the resolution of the measurement. A multiplication factor of almost two orders of magnitude has been demonstrated with a simple set-up. The technique can be applied to any interferometric measurement where the classical interferometer limits due to fringe nonlinearities and quantum noise are an issue. Applications in precision engineering, vibration analysis, nanometrology, and spectroscopy are foreseen.

  18. dc readout experiment at the Caltech 40m prototype interferometer

    International Nuclear Information System (INIS)

    Ward, R L; Adhikari, R; Abbott, B; Abbott, R; Bork, R; Fricke, T; Heefner, J; Ivanov, A; Miyakawa, O; Smith, M; Taylor, R; Vass, S; Waldman, S; Weinstein, A; Barron, D; Frolov, V; McKenzie, K; Slagmolen, B

    2008-01-01

    The Laser Interferometer Gravitational Wave Observatory (LIGO) operates a 40m prototype interferometer on the Caltech campus. The primary mission of the prototype is to serve as an experimental testbed for upgrades to the LIGO interferometers and for gaining experience with advanced interferometric techniques, including detuned resonant sideband extraction (i.e. signal recycling) and dc readout (optical homodyne detection). The former technique will be employed in Advanced LIGO, and the latter in both Enhanced and Advanced LIGO. Using dc readout for gravitational wave signal extraction has several technical advantages, including reduced laser and oscillator noise couplings as well as reduced shot noise, when compared to the traditional rf readout technique (optical heterodyne detection) currently in use in large-scale ground-based interferometric gravitational wave detectors. The Caltech 40m laboratory is currently prototyping a dc readout system for a fully suspended interferometric gravitational wave detector. The system includes an optical filter cavity at the interferometer's output port, and the associated controls and optics to ensure that the filter cavity is optimally coupled to the interferometer. We present the results of measurements to characterize noise couplings in rf and dc readout using this system

  19. Broadband sensitivity enhancement of detuned dual-recycled Michelson interferometers with EPR entanglement

    Science.gov (United States)

    Brown, Daniel D.; Miao, Haixing; Collins, Chris; Mow-Lowry, Conor; Töyrä, Daniel; Freise, Andreas

    2017-09-01

    We demonstrate the applicability of the EPR entanglement squeezing scheme for enhancing the shot-noise-limited sensitivity of detuned dual-recycled Michelson interferometers. In particular, this scheme is applied to the GEO600 interferometer. The effect of losses throughout the interferometer, arm length asymmetries, and imperfect separation of the signal and idler beams is considered.

  20. Noise cancellation properties of displacement noise free interferometer

    International Nuclear Information System (INIS)

    Sato, Shuichi; Kawamura, Seiji; Nishizawa, Atsushi; Chen Yanbei

    2010-01-01

    We have demonstrated the practical feasibility of a displacement- and frequency-noise-free laser interferometer (DFI) by partially implementing a recently proposed optical configuration using bi-directional Mach-Zehnder interferometers (MZIs). The noise cancellation efficiency was evaluated by comparing the displacement noise spectrum of the MZIs and the DFI, demonstrating up to 50 dB of noise cancellation. In addition, the possible extension of DFI as QND device is explored.

  1. Germanium on silicon mid-infrared waveguides and Mach-Zehnder interferometers

    NARCIS (Netherlands)

    Malik, A.; Muneeb, M.; Shimura, Y.; Campenhout, van J.; Loo, van de R.; Roelkens, G.C.

    2013-01-01

    In this paper we describe Ge-on-Si waveguides and Mach-Zehnder interferometers operating in the 5.2 - 5.4 µm wavelength range. 3dB/cm waveguide losses and Mach-Zehnder interferometers with 20dB extinction ratio are presented.

  2. Improved double-pass michelson interferometer

    Science.gov (United States)

    Schindler, R. A.

    1978-01-01

    Interferometer design separates beams by offsetting centerlines of cat's-eye retroreflectors vertically rather than horizontally. Since beam splitter is insensitive to minimum-thickness condition in this geometry, relatively-low-cost, optically flat plate can be used.

  3. Quasi-quadrature interferometer for plasma density radial profile measurements

    International Nuclear Information System (INIS)

    Lowenthal, D.D.; Hoffman, A.L.

    1979-01-01

    A cw Mach Zehnder multichannel interferometer has been developed to measure time-dependent fractional fringe shifts with an accuracy of one-fortieth fringe. The design is quasi-quadrature in that known phase shifts, introduced in the reference beam, are time multiplexed with the normal reference beam. This technique requires only one detector per interferometer channel as compared to two detectors for most quadrature designs. The quadrature information makes the sense of density changes unambiguous, it automatically calibrates the instrument during the plasma event, and it makes fringe shift measurements virtually independent of fringe contrast fluctuations caused by plasma refractive and/or absorptive effects. The interferometer optical design is novel in that the electro-optic crystal used to introduce the 90 0 phase shifts is located in the common 2-mm-diam HeNe entrance beam to the interferometer, by exploiting polarization techniques, rather than in the expanded 1--2-cm reference beam itself. This arrangement greatly reduces the size, cost, and high-voltage requirements for the phase modulating crystal

  4. Instrument development for atmospheric radiation measurement (ARM): Status of the Atmospheric Emitted Radiance Interferometer - extended Resolution (AERI-X), the Solar Radiance Transmission Interferometer (SORTI), and the Absolute Solar Transmission Inferometer (ASTI)

    Energy Technology Data Exchange (ETDEWEB)

    Murcray, F.; Stephen, T.; Kosters, J. [Univ. of Denver, CO (United States)

    1996-04-01

    This paper describes three instruments currently under developemnt for the Atmospheric Radiation Measurement (ARM) Program at the University of Denver: the AERI-X (Atmospheric Emitted Radiance Interferometer-Extended Resolution) and the SORTI (Solar R adiance Transmission Interferometer), and ASTI (Absolute Solar transmission Interferometer).

  5. Parametric instability in GEO 600 interferometer

    International Nuclear Information System (INIS)

    Gurkovsky, A.G.; Vyatchanin, S.P.

    2007-01-01

    We present analysis of undesirable effect of parametric instability in signal recycled GEO 600 interferometer. The basis for this effect is provided by excitation of additional (Stokes) optical mode, having frequency ω 1 , and mirror elastic mode, having frequency ω m , when the optical energy stored in the main FP cavity mode, having frequency ω 0 , exceeds a certain threshold and detuning Δ=ω 0 -ω 1 -ω m is small. We discuss the potential of observing parametric instability and its precursors in GEO 600 interferometer. This approach provides the best option to get familiar with this phenomenon, to develop experimental methods to depress it and to test the effectiveness of these methods in situ

  6. All-silicon thermal independent Mach-Zehnder interferometer with multimode waveguides

    DEFF Research Database (Denmark)

    Guan, Xiaowei; Frandsen, Lars Hagedorn

    2016-01-01

    A novel all-silicon thermal independent Mach-Zehnder interferometer consisting of two multimode waveguide arms having equal lengths and widths but transmitting different modes is proposed and experimentally demonstrated. The interferometer has a temperature sensitivity smaller than 8pm/°C in a wa...

  7. Optical displacement measurement with GaAs/AlGaAs-based monolithically integrated Michelson interferometers

    OpenAIRE

    Hofstetter, Daniel; Zappe, H. P.; Dändliker, René

    2008-01-01

    Two monolithically integrated optical displacement sensors fabricated in the GaAs/AlGaAs material system are reported. These single-chip microsystems are configured as Michelson interferometers and comprise a distributed Bragg reflector (DBR) laser, photodetectors, phase shifters, and waveguide couplers. While the use of a single Michelson interferometer allows measurement of displacement magnitude only, a double Michelson interferometer with two interferometer signals in phase quadrature als...

  8. Fine art of computing nulling interferometer maps

    Science.gov (United States)

    Hénault, F.

    2008-07-01

    Spaceborne nulling interferometers are often characterized by means of their nulling ratio, which is defined as the deepest possible extinction of one target star supposed to harbor an extra-solar system. Herein is shown that another parameter, which is the transmitting efficiency of nearby bright fringes, is also of prime importance. More generally, "nulling maps" formed by the whole destructive and constructive fringe pattern projected on-sky, are found to be very sensitive on the design of some subsystems constituting the interferometer. In particular, we consider Spatial Filtering (SF) and Achromatic Phase Shifter (APS) devices, both required achieving planet detection and characterization. Consequences of the SF choice (pinhole or single-mode optical fiber) and APS properties (with or without induced pupil-flip) are discussed, for both monochromatic and polychromatic cases. Examples of numerical simulations are provided for single Bracewell interferometer, Angel cross and X-array configurations, demonstrating noticeable differences in the aspect of resulting nulling maps. It is concluded that both FS and APS designs exhibit variable capacities for serendipitous planet discovery.

  9. Quantum noise in laser-interferometer gravitational-wave detectors with a heterodyne readout scheme

    International Nuclear Information System (INIS)

    Buonanno, Alessandra; Chen Yanbei; Mavalvala, Nergis

    2003-01-01

    We analyze and discuss the quantum noise in signal-recycled laser interferometer gravitational-wave detectors, such as Advanced LIGO, using a heterodyne readout scheme and taking into account the optomechanical dynamics. Contrary to homodyne detection, a heterodyne readout scheme can simultaneously measure more than one quadrature of the output field, providing an additional way of optimizing the interferometer sensitivity, but at the price of additional noise. Our analysis provides the framework needed to evaluate whether a homodyne or heterodyne readout scheme is more optimal for second generation interferometers from an astrophysical point of view. As a more theoretical outcome of our analysis, we show that as a consequence of the Heisenberg uncertainty principle the heterodyne scheme cannot convert conventional interferometers into (broadband) quantum non-demolition interferometers

  10. A Fabry-Perot interferometer system for high-speed velocity measurement

    NARCIS (Netherlands)

    Cheng, L.K.; Bruinsma, A.J.A.; Prinse, W.C.; Smorenburg, C.

    1997-01-01

    The Fabry-Perot Velocity Interferometer System (F-PVIS) is designed and built for measuring the Doppler shift of light by recording positional changes in the interferometric pattern behind the Fabry-Perot interferometer. The velocity of a surface can be deduced from the Doppler shift which is caused

  11. Comment on "Rovibrational quantum interferometers and gravitational waves"

    OpenAIRE

    Khriplovich, I. B.; Lamoreaux, S. K.; Sushkov, A. O.; Sushkov, O. P.

    2009-01-01

    In a recent paper, Wicht, L\\"ammerzahl, Lorek, and Dittus [Phys. Rev. {\\bf A 78}, 013610 (2008)] come to the conclusion that a molecular rotational-vibrational quantum interferometer may possess the sensitivity necessary to detect gravitational waves. We do not agree with their results and demonstrate here that the true sensitivity of such interferometer is many orders of magnitude worse than that claimed in the mentioned paper. In the present comment we estimate the expected energy shifts an...

  12. Two-photon quantum interference in a Michelson interferometer

    International Nuclear Information System (INIS)

    Odate, Satoru; Wang Haibo; Kobayashi, Takayoshi

    2005-01-01

    We have observed two-photon quantum interference in a Michelson interferometer. For the first time, we experimentally demonstrated two-photon quantum interference patterns, which show the transition from nonsubwavelength interference fringes to the general subwavelength interference. At the same time, a photon bunching effect was also shown by a postselection. The |1, 1> state with a single photon in a mode corresponding to each arm of the interferometer was exclusively postselected by using path difference between two arms

  13. The POLIS interferometer for ponderomotive squeezed light generation

    Energy Technology Data Exchange (ETDEWEB)

    Calloni, Enrico [Dipartimento di Fisica, Università degli Studi di Napoli “Federico II”, Napoli (Italy); INFN, Sezione di Napoli (Italy); Conte, Andrea [Dipartimento di Fisica, Università di Roma “Sapienza”, Roma (Italy); INFN, Sezione di Roma1 (Italy); De Laurentis, Martina, E-mail: martina.delaurentis@na.infn.it [Dipartimento di Fisica, Università degli Studi di Napoli “Federico II”, Napoli (Italy); INFN, Sezione di Napoli (Italy); Naticchioni, Luca [Dipartimento di Fisica, Università di Roma “Sapienza”, Roma (Italy); INFN, Sezione di Roma1 (Italy); Puppo, Paola [INFN, Sezione di Roma1 (Italy); Ricci, Fulvio [Dipartimento di Fisica, Università di Roma “Sapienza”, Roma (Italy); INFN, Sezione di Roma1 (Italy)

    2016-07-11

    POLIS (POnderomotive LIght Squeezer) is a suspended interferometer, presently under construction, devoted to the generation of ponderomotive squeezed light and to the study of the interaction of non classical quantum states of light and macroscopic objects. The interferometer is a Michelson whose half-meter long arms are constituted by high-finesse cavities, suspended to a seismic isolation chain similar to the Virgo SuperAttenuator. The mass of the suspended cavity mirrors are chosen to be tens of grams: this value is sufficiently high to permit the use of the well-tested Virgo suspension techniques but also sufficiently small to generate the coupling among the two phase quadratures with a limited amount of light in the cavity, of the order of few tens of kW. In this short paper the main features of the interferometer are shown, together with the expected sensitivity and squeezing factor.

  14. Electromagnetic modelling of a space-borne far-infrared interferometer

    Science.gov (United States)

    Donohoe, Anthony; O'Sullivan, Créidhe; Murphy, J. Anthony; Bracken, Colm; Savini, Giorgio; Pascale, Enzo; Ade, Peter; Sudiwala, Rashmi; Hornsby, Amber

    2016-02-01

    In this paper I will describe work done as part of an EU-funded project `Far-infrared space interferometer critical assessment' (FISICA). The aim of the project is to investigate science objectives and technology development required for the next generation THz space interferometer. The THz/FIR is precisely the spectral region where most of the energy from stars, exo-planetary systems and galaxy clusters deep in space is emitted. The atmosphere is almost completely opaque in the wave-band of interest so any observation that requires high quality data must be performed with a space-born instrument. A space-borne far infrared interferometer will be able to answer a variety of crucial astrophysical questions such as how do planets and stars form, what is the energy engine of most galaxies and how common are the molecule building blocks of life. The FISICA team have proposed a novel instrument based on a double Fourier interferometer that is designed to resolve the light from an extended scene, spectrally and spatially. A laboratory prototype spectral-spatial interferometer has been constructed to demonstrate the feasibility of the double-Fourier technique at far infrared wavelengths (0.15 - 1 THz). This demonstrator is being used to investigate and validate important design features and data-processing methods for future instruments. Using electromagnetic modelling techniques several issues related to its operation at long baselines and wavelengths, such as diffraction, have been investigated. These are critical to the design of the concept instrument and the laboratory testbed.

  15. Feedback-stabilized dual-beam laser interferometer for plasma measurements

    International Nuclear Information System (INIS)

    Yasuda, A.; Kanai, Y.; Kusunoki, J.; Kawahata, K.; Takeda, S.

    1980-01-01

    A stabilized laser interferometer is proposed with two beams as the light source. The fringe shift for a 0.63 μm beam of a He--Ne laser is used to stabilize the interferometer against the effect of mechanical vibrations via a feedback controlled speaker coil, while another beam of 3.39 μm, for which consequently the effect of the mechanical vibrations is excluded, is used to measure the plasma density. A stability of approx.1/500 of one fringe for 0.63 μm is obtained during a long period for frequencies lower than a few Hz. The stability for higher frequencies is limited to approx.1/30 of one fringe for 0.63 μm, which correspondes to approx.1/200 of one fringe for 3.39 μm, by the acoustic noise picked up by the speaker coil. Furthermore, the total accuracy is limited by the detector noise to approx.1/60 of one fringe for 3.39 μm, which corresponds to a line electron density of approx.5 x 10 14 cm -2 . The detector noise may be reduced by cooling the detector. The advantage of this technique over the single-laser technique is that the frequency response of the interferometer extends down to zero frequency. The interferometer is tested with the measurement of a plasma in a dynamic magnetic arcjet. Since the effect of the neutral gas background is reduced in the present interferometer, the application has an advantage for the diagnostics of plasmas produced in high pressure gases

  16. Multiphoton- and simultaneous conjugate Ramsey-Borde atom interferometers

    International Nuclear Information System (INIS)

    Mueller, Holger; Chiow, Sheng-wey; Herrmann, Sven; Chu, Steven

    2008-01-01

    We report on our experiment to measure h/M, the ratio of the Planck constant to the mass of Cs atoms, and thereby the fine-structure constant. The target accuracy is 1 part per billion or better. We focus on two recent milestones: (i) The first realization of atom interferometers based on light-pulse beam splitters that transfer the momentum of up to 12 photon pairs, which increases the useful signal (matter wave phase shift) by a factor of 144 compared to the beam splitters used in the best present atom interferometers. Moreover, they lead to a cancellation of important systematic effects. (ii) The first realization of a simultaneous pair of conjugate Ramsey-Borde interferometers. In these, the relative sign of the inertial term is reversed so that it can be cancelled. Simultaneous operation means that this holds for a time-dependent inertial term (vibrations) too, which promises a substantial improvement in the signal to noise ratio

  17. The Virgo gravitational wave interferometer: status and perspectives

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    The first recording of a signal from a binary neutron star system by the Advanced LIGO and Advanced Virgo interferometers, and the observation of its remnants by telescopes in all bands of the electromagnetic spectrum, marked the beginning of multimessenger astronomy with gravitational waves. This followed the detection of gravitational wave signals by the LIGO interferometers in 2015, which started the detailed study of highly curved space time. These achievements come after decades of work spent understanding how to measure the tiny space time strain (h ~ 10-21) carried by gravitational waves. In the future, detectors will able to extract much more precise information from these events, or record signals from fainter sources, providing a new view of the Universe. After a presentation of the Virgo interferometer, the main results obtained from binary black hole and neutron star detection are reviewed. The focus will then shift on the perspective offered by a further reduction of noise in ground based interf...

  18. Integrated fiber Michelson interferometer based on poled hollow twin-core fiber.

    Science.gov (United States)

    Liu, Zhihai; Bo, Fusen; Wang, Lei; Tian, Fengjun; Yuan, Libo

    2011-07-01

    We propose an integrated fiber Michelson interferometer based on a poled hollow twin-core fiber. The Michelson interferometer can be used as an electro-optic modulator by thermal poling one core of the twin-core fiber and introducing second-order nonlinearity in the fiber. The proposed fiber Michelson interferometer is experimentally demonstrated under driving voltages at the frequency range of 149 to 1000 Hz. The half-wave voltage of the poled fiber is 135 V, and the effective second-order nonlinear coefficient χ² is 1.23 pm/V.

  19. Smart photogalvanic running-grating interferometer

    DEFF Research Database (Denmark)

    Kukhtarev, N. V.; Kukhtareva, T.; Edwards, M. E.

    2005-01-01

    Photogalvanic effect produces actuation of periodic motion of macroscopic LiNbO3 crystal. This effect was applied to the development of an all-optical moving-grating interferometer usable for optical trapping and transport of algae chlorella microorganisms diluted in water with a concentration of...

  20. A hybrid Fabry–Perot/Michelson interferometer sensor using a dual asymmetric core microstructured fiber

    International Nuclear Information System (INIS)

    Frazão, O; Silva, S F; Viegas, J; Baptista, J M; Santos, J L; Roy, P

    2010-01-01

    A hybrid Fabry–Perot/Michelson interferometer sensor using a dual asymmetric core microstructured fiber is demonstrated. The hybrid interferometer presents three waves. Two parallel Fabry–Perot cavities with low finesse are formed between the splice region and the end of a dual-core microstructured fiber. A Michelson configuration is obtained by the two small cores of the microstructured fiber. The spectral response of the hybrid interferometer presents two pattern fringes with different frequencies due to the respective optical path interferometers. The hybrid interferometer was characterized in strain and temperature presenting different sensitivity coefficients for each topology. Due to these characteristics, this novel sensing head is able to measure strain and temperature, simultaneously

  1. Detectability of periodic gravitational waves by initial interferometers

    International Nuclear Information System (INIS)

    Owen, Benjamin J

    2006-01-01

    I review three recent theoretical developments in neutron star physics predicting that rotating neutron stars could be very strong emitters of periodic gravitational waves. These imply a small but nonzero chance that ground-based interferometers could detect their first periodic signal in the next few years rather than after advanced upgrades. They also imply that upper limits will become astrophysically interesting before advanced upgrades. I discuss the implications for near-future searches and for the astrophysical payoffs of proposed small upgrades to initial interferometers

  2. Semiconductor laser shearing interferometer

    International Nuclear Information System (INIS)

    Ming Hai; Li Ming; Chen Nong; Xie Jiaping

    1988-03-01

    The application of semiconductor laser on grating shearing interferometry is studied experimentally in the present paper. The method measuring the coherence of semiconductor laser beam by ion etching double frequency grating is proposed. The experimental result of lens aberration with semiconductor laser shearing interferometer is given. Talbot shearing interferometry of semiconductor laser is also described. (author). 2 refs, 9 figs

  3. Reducing tilt-to-length coupling for the LISA test mass interferometer

    Science.gov (United States)

    Tröbs, M.; Schuster, S.; Lieser, M.; Zwetz, M.; Chwalla, M.; Danzmann, K.; Fernández Barránco, G.; Fitzsimons, E. D.; Gerberding, O.; Heinzel, G.; Killow, C. J.; Perreur-Lloyd, M.; Robertson, D. I.; Schwarze, T. S.; Wanner, G.; Ward, H.

    2018-05-01

    Objects sensed by laser interferometers are usually not stable in position or orientation. This angular instability can lead to a coupling of angular tilt to apparent longitudinal displacement—tilt-to-length coupling (TTL). In LISA this is a potential noise source for both the test mass interferometer and the long-arm interferometer. We have experimentally investigated TTL coupling in a setup representative for the LISA test mass interferometer and used this system to characterise two different imaging systems (a two-lens design and a four-lens design) both designed to minimise TTL coupling. We show that both imaging systems meet the LISA requirement of  ±25 μm rad‑1 for interfering beams with relative angles of up to  ±300 μrad. Furthermore, we found a dependency of the TTL coupling on beam properties such as the waist size and location, which we characterised both theoretically and experimentally.

  4. Vibration compensated high-resolution scanning white-light Linnik-interferometer

    Science.gov (United States)

    Tereschenko, Stanislav; Lehmann, Peter; Gollor, Pascal; Kuehnhold, Peter

    2017-06-01

    We present a high-resolution Linnik scanning white-light interferometer (SWLI) with integrated distance measuring interferometer (DMI) for close-to-machine applications in the presence of environmental vibrations. The distance, measured by DMI during the depth-scan, is used for vibration compensation of SWLI signals. The reconstruction of the white-light interference signals takes place after measurement by reordering the captured images in accordance with their real positions obtained by the DMI and subsequent trigonometrical approximation. This system is the further development of our previously presented Michelson-interferometer. We are able to compensate for arbitrary vibrations with frequencies up to several kilohertz and amplitudes in the lower micrometer range. Completely distorted SWLI signals can be reconstructed and the surface topography can be obtained with high accuracy. We demonstrate the feasibility of the method by examples of practical measurements with and without vibrational disturbances.

  5. Design of a Michelson Interferometer for Quantitative Refraction Index Profile Measurements

    NARCIS (Netherlands)

    Nijholt, J.L.M.

    1998-01-01

    This book describes the theoretical design of a three camera Michelson interferometer set-up for quantitative refractive index measuerments. Although a two camera system is easier to align and less expensive, a three camera interferometer is preferred because the expected measuring accuracy is much

  6. Design and fabrication of a high-damage threshold infrared Smattt interferometer

    International Nuclear Information System (INIS)

    Hammond, R.B.; Gibbs, A.J.

    1981-01-01

    It has been shown that a Smartt interferometer may be used as a very precise alignment tool for infrared lasers. This interferometer may also be used effectively to investigate the phase front of a laser pulse. To use this tool for applications to high-power, fast-pulse laser systems such as Helios and Antares; however, it has been necessary to fabricate a structure with the unique optical characteristics of the Smartt interferometer combined with a very high optical-damage threshold. We have been successful in this effort by utilizing the high technology, process control, and unique properties of semiconductor-grade, single-crystal Si

  7. The Design of Phase-Locked-Loop Circuit for Precision Capacitance Micrometer

    Directory of Open Access Journals (Sweden)

    Li Shujie

    2016-01-01

    Full Text Available High precision non-contact micrometer is normally divided into three categories: inductance micrometer, capacitance micrometer and optical interferometer micrometer. The capacitance micrometer is widely used because it has high performance to price ratio. With the improvement of automation level, precision of capacitance micrometer is required higher and higher. Generally, capacitance micrometer consists of the capacitance sensor, capacitance/voltage conversion circuit, and modulation and demodulation circuits. However, due to the existing of resistors, capacitors and other components in the circuit, the phase shift of the carrier signal and the modulated signal might occur. In this case, the specific value of phase shift cannot be determined. Therefore, error caused by the phase shift cannot be eliminated. This will reduce the accuracy of micrometer. In this design, in order to eliminate the impact of the phase shift, the phase-locked-loop (PLL circuit is employed. Through the experiment, the function of tracking the input signal phase and frequency is achieved by the phase-locked-loop circuit. This signal processing method can also be applied to tuber electrical resistance tomography system and other precision measurement circuit.

  8. Does an atom interferometer test the gravitational redshift at the Compton frequency?

    International Nuclear Information System (INIS)

    Wolf, Peter; Borde, Christian J; Blanchet, Luc; Reynaud, Serge; Salomon, Christophe; Cohen-Tannoudji, Claude

    2011-01-01

    Atom interferometers allow the measurement of the acceleration of freely falling atoms with respect to an experimental platform at rest on Earth's surface. Such experiments have been used to test the universality of free fall by comparing the acceleration of the atoms to that of a classical freely falling object. In a recent paper, Mueller et al (2010 Nature 463 926-9) argued that atom interferometers also provide a very accurate test of the gravitational redshift (or universality of clock rates). Considering the atom as a clock operating at the Compton frequency associated with the rest mass, they claimed that the interferometer measures the gravitational redshift between the atom-clocks in the two paths of the interferometer at different values of gravitational potentials. In this paper, we analyze this claim in the frame of general relativity and of different alternative theories. We show that the difference of 'Compton phases' between the two paths of the interferometer is actually zero in a large class of theories, including general relativity, all metric theories of gravity, most non-metric theories and most theoretical frameworks used to interpret the violations of the equivalence principle. Therefore, in most plausible theoretical frameworks, there is no redshift effect and atom interferometers only test the universality of free fall. We also show that frameworks in which atom interferometers would test the redshift pose serious problems, such as (i) violation of the Schiff conjecture, (ii) violation of the Feynman path integral formulation of quantum mechanics and of the principle of least action for matter waves, (iii) violation of energy conservation, and more generally (iv) violation of the particle-wave duality in quantum mechanics. Standard quantum mechanics is no longer valid in such frameworks, so that a consistent interpretation of the experiment would require an alternative formulation of quantum mechanics. As such an alternative has not been

  9. Atomic interferometry: construction, characterisation and optimisation of an interferometer. Application to precision measurements

    International Nuclear Information System (INIS)

    Buechner, Matthias

    2010-01-01

    This manuscript describes my research activity in atom interferometry. As an introduction to this domain, we have first described some atom interferometers and their applications. We then describe the atom interferometer we have developed in Toulouse. This is a Mach-Zehnder atom interferometer; the atom source is a thermal supersonic lithium beam and atom manipulation is based on laser diffraction in the Bragg regime. This two interferometer arms are spatially separated, with a maximum distance near 100 μm. The interferometer performances are excellent, with a fringe visibility as large as 84.5 % and a high output flux, thus providing a phase sensitivity of 15 mrad √(Hz). We have used this interferometer for several experiments, with a perturbation applied on only one interferometer arm. When the perturbation is an electric field, we thus measure the electric polarizability of lithium, with an uncertainty 3 times smaller than the best previous measurement. When the perturbation is a gas at low density, we measure the complex refraction index of this gas for lithium atomic waves. If the perturbation is a nano-grating, we measure the complex amplitude of the diffraction zeroth order and this amplitude is very sensitive to the van der Waals interaction of the lithium atom with the nano-grating surface. An important part of this manuscript concerns further developments of our activity. We discuss several improvements of the measurement of the electric polarizability of lithium atom and we hope to access to a precision comparable to the one of the best ab initio calculations of this quantity. We plan to detect a new topological phase, predicted by theory in 1993 but never observed. Finally, we are starting the construction of a second generation atom interferometer, with a slow and intense lithium beam. This new source will give a larger signal and a longer interaction time, thus enabling the detection of considerably weaker perturbations: a fascinating possibility

  10. Interferometer scanning mechanisms and metrology at ABB: recent developments and future perspectives

    Science.gov (United States)

    Grandmont, Frédéric; Buijs, Henry; Mandar, Julie

    2017-11-01

    Interferometers are devices meant to create an interference pattern between photons emitted from a given target of interest. In most cases, this interference pattern must be scanned over time or space to reveal useful information about the target (ex.: radiance spectra or a star diameter). This scanning is typically achieved by moving mirrors at a precision a few orders of magnitude smaller than the wavelength under study. This sometimes leads to mechanism requirements of especially high dynamic range equivalent to 30 bits or more (ex. Sub-nanometer precision over stoke of tens of cms for spectroscopy or tens of meters for astronomical spatial interferometry). On top of this mechanical challenge, the servo control of the mirror position involves obtaining relative distance measurement between distant optical elements with similar if not better dynamic range. The feedback information for such servo-control loop is usually the optical path difference (OPD) measured with a metrology laser beam injected in the interferometer. Over the years since the establishement of the Fourier Transform Spectrometers (FTS) in the 60's as a standard spectroscopic tools, many different approaches have been used to accomplish this task. When it comes to space however, not all approaches are successful. The design challenge can be viewed as analogous to that of scene scanning modules with the exception that the sensitivity and precision are much finer. These mechanisms must move freely to allow fine corrections while remaining stiff to reject external perturbations with frequencies outside of the servo control system reach. Space also brings the additional challenges of implementing as much redundancy as possible and offering protection during launch for these sub-systems viewed as critical single point failures of the payloads they serve.

  11. Generation of arbitrary vector beams

    Science.gov (United States)

    Perez-Garcia, Benjamin; López-Mariscal, Carlos; Hernandez-Aranda, Raul I.; Gutiérrez-Vega, Julio C.

    2017-08-01

    Optical vector beams arise from point to point spatial variations of the electric component of an electromagnetic field over the transverse plane. In this work, we present a novel experimental technique to generate arbitrary vec- tor beams, and provide sufficient evidence to validate their state of polarization. This technique takes advantage of the capability of a Spatial Light Modulator to simultaneously generate two components of an electromagnetic field by halving the screen of the device and subsequently recombining them in a Sagnac interferometer. Our experimental results show the versatility and robustness of this technique for the generation of vector beams.

  12. Plasma electron density measurement with multichannel microwave interferometer on the HL-1 tokamak device

    International Nuclear Information System (INIS)

    Xu Deming; Zhang Hongyin; Liu Zetian; Ding Xuantong; Li Qirui; Wen Yangxi

    1989-11-01

    A multichannel microwave interferometer which is composed of different microwave interferometers (one 2 mm band, one 4 mm band and two 8 mm band) has been used to measure the plasma electron density on HL-1 tokamak device. The electron density approaching to 5 x 10 13 cm -3 is measured by a 2 mm band microwave interferometer. In the determinable range, the electron density profile in the cross-section on HL-1 device has been measured by this interferometer. A microcomputer data processing system is also developed

  13. Sensitivity of a fibre scattered-light interferometer to external phase perturbations in an optical fibre

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, A E; Potapov, V T [V.A.Kotel' nikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Fryazino Branch, Fryazino, Moscow region (Russian Federation); Gorshkov, B G [OOO ' Petrofaiber' , Russia, Tula region, Novomoskovsk (Russian Federation)

    2015-10-31

    Sensitivity of a fibre scattered-light interferometer to external phase perturbations is studied for the first time. An expression is derived for an average power of a useful signal at the interferometer output under external harmonic perturbations in a signal fibre of the interferometer. It is shown that the maximum sensitivity of the scattered-light interferometer depends on the dispersion of the interferogram intensity. An average signal-to-noise ratio is determined theoretically and experimentally at the output of the interferometer at different amplitudes of external perturbations. Using the measured dependences of the signal-to-noise ratio, the threshold sensitivity of the fibre scattered-light interferometer to external phase perturbations is found. The results obtained can be used to optimise characteristics of optical time-domain reflectometers and to design individual phase-sensitive fibre-optic sensors. (laser applications and other topics in quantum electronics)

  14. Adjustment of a two-block X-ray interferometer and absolute measurement of lattice spacing

    International Nuclear Information System (INIS)

    Nakayama, Kan

    1994-01-01

    X-ray interferometer was invented in 1965 by Bonse and Hart, and it uses the lattice surface of a silicon single crystal as a three-dimensional diffraction lattice. It divides X-ray coherently, changes direction, combines and causes interference. It made for the first time the interference effect of X-ray into the usable form in macroscopic world. As an example of the application of X-ray interferometers to basic science, there is the absolute measurement of lattice spacing. This is the method of simultaneously measuring the same displacement with an X-ray interferometer and a light wave interferometer, and doing the absolute measurement of the lattice spacing of crystals with light wavelength. Avogadro constant is the constant that becomes the foundation of chemistry, and its relation with other basic constants is shown. The principle of X-ray interferometers is explained. As the elementary technologies for the absolute measurement of lattice spacing, the adjustment of X-ray interferometers, parallel movement table and angular adjustment table, light wave interferometer and the prevention of vibration and temperature change are described. The example of the measurement is reported. In order to improve the accuracy, the improvement of the equipment and the measurement in vacuum are prepared at present. (K.I.)

  15. Generation and characterization of erbium-Raman noise-like pulses from a figure-eight fibre laser

    International Nuclear Information System (INIS)

    Santiago-Hernandez, H; Pottiez, O; Paez-Aguirre, R; Ibarra-Villalon, H E; Tenorio-Torres, A; Duran-Sanchez, M; Ibarra-Escamilla, B; Kuzin, E A; Hernandez-Garcia, J C

    2015-01-01

    We report an experimental study of the noise-like pulses generated by a ∼300 m long passively mode-locked erbium-doped figure-eight fibre laser. Non-self-starting mode locking yields the formation of ns scale bunches of sub-ps pulses. Depending on birefringence adjustments, noise-like pulses with a variety of temporal profiles and optical spectra are obtained. In particular, for some adjustments the Raman-enhanced spectrum reaches a 10 dB bandwidth of ∼130 nm. For the first time to our knowledge, we extract information on the inner structure of the noise-like pulses, using a birefringent Sagnac interferometer as a spectral filter and a nonlinear optical loop mirror as an intensity filter. In particular we show that the different spectral components of the bunch are homogeneously distributed within the temporal envelope of the bunch, whereas the amplitude and/or the density of the sub-pulses present substantial variations along the envelope. In some cases, the analysis reveals the existence of an intermediate level of organization in the structure of the noise-like pulse, between the ns bunch and the sub-ps inner pulses, suggesting that these objects may be even more complex than previously recognized. (paper)

  16. Michelson interferometer based interleaver design using classic IIR filter decomposition.

    Science.gov (United States)

    Cheng, Chi-Hao; Tang, Shasha

    2013-12-16

    An elegant method to design a Michelson interferometer based interleaver using a classic infinite impulse response (IIR) filter such as Butterworth, Chebyshev, and elliptic filters as a starting point are presented. The proposed design method allows engineers to design a Michelson interferometer based interleaver from specifications seamlessly. Simulation results are presented to demonstrate the validity of the proposed design method.

  17. Compact all-fiber interferometer system for shock acceleration measurement

    Science.gov (United States)

    Zhao, Jiang; Pi, Shaohua; Hong, Guangwei; Zhao, Dong; Jia, Bo

    2013-08-01

    Acceleration measurement plays an important role in a variety of fields in science and engineering. In particular, the accurate, continuous and non-contact recording of the shock acceleration profiles of the free target surfaces is considered as a critical technique in shock physics. Various kinds of optical interferometers have been developed to monitor the motion of the surfaces of shocked targets since the 1960s, for instance, the velocity interferometer system for any reflector, the fiber optic accelerometer, the photonic Doppler velocimetry system and the displacement interferometer. However, most of such systems rely on the coherent quasi-monochromatic illumination and discrete optic elements, which are costly in setting-up and maintenance. In 1996, L. Levin et al reported an interferometric fiber-optic Doppler velocimeter with high-dynamic range, in which fiber-coupled components were used to replace the discrete optic elements. However, the fringe visibility of the Levin's system is low because of the coupled components, which greatly limits the reliability and accuracy in the shock measurement. In this paper, a compact all-fiber interferometer system for measuring the shock acceleration is developed and tested. The advantage of the system is that not only removes the non-interfering light and enhances the fringe visibility, but also reduces polarization induced signal fading and the polarization induced phase shift. Moreover, it also does not require a source of long coherence length. The system bases entirely on single-mode fiber optics and mainly consists of a polarization beam splitter, a faraday rotator, a depolarizer and a 3×3 single-mode fiber coupler which work at 1310 nm wavelength. The optical systems of the interferometer are described and the experimental results compared with a shock acceleration calibration system with a pneumatic exciter (PneuShockTM Model 9525C by The Modal Shop) are reported. In the shock acceleration test, the

  18. LoopIng: a template-based tool for predicting the structure of protein loops.

    KAUST Repository

    Messih, Mario Abdel

    2015-08-06

    Predicting the structure of protein loops is very challenging, mainly because they are not necessarily subject to strong evolutionary pressure. This implies that, unlike the rest of the protein, standard homology modeling techniques are not very effective in modeling their structure. However, loops are often involved in protein function, hence inferring their structure is important for predicting protein structure as well as function.We describe a method, LoopIng, based on the Random Forest automated learning technique, which, given a target loop, selects a structural template for it from a database of loop candidates. Compared to the most recently available methods, LoopIng is able to achieve similar accuracy for short loops (4-10 residues) and significant enhancements for long loops (11-20 residues). The quality of the predictions is robust to errors that unavoidably affect the stem regions when these are modeled. The method returns a confidence score for the predicted template loops and has the advantage of being very fast (on average: 1 min/loop).www.biocomputing.it/loopinganna.tramontano@uniroma1.itSupplementary data are available at Bioinformatics online.

  19. Mach-Zehnder atom interferometer inside an optical fiber

    Science.gov (United States)

    Xin, Mingjie; Leong, Wuiseng; Chen, Zilong; Lan, Shau-Yu

    2017-04-01

    Precision measurement with light-pulse grating atom interferometry in free space have been used in the study of fundamental physics and applications in inertial sensing. Recent development of photonic band-gap fibers allows light for traveling in hollow region while preserving its fundamental Gaussian mode. The fibers could provide a very promising platform to transfer cold atoms. Optically guided matter waves inside a hollow-core photonic band-gap fiber can mitigate diffraction limit problem and has the potential to bring research in the field of atomic sensing and precision measurement to the next level of compactness and accuracy. Here, we will show our experimental progress towards an atom interferometer in optical fibers. We designed an atom trapping scheme inside a hollow-core photonic band-gap fiber to create an optical guided matter waves system, and studied the coherence properties of Rubidium atoms in this optical guided system. We also demonstrate a Mach-Zehnder atom interferometer in the optical waveguide. This interferometer is promising for precision measurements and designs of mobile atomic sensors.

  20. Potentiality of an orbiting interferometer for space-time experiments

    International Nuclear Information System (INIS)

    Grassi Strini, A.M.; Strini, G.; Tagliaferri, G.

    1979-01-01

    It is suggested that by putting a Michelson interferometer aboard a spacecraft orbiting around the earth, very substantial progress could be made in space-time experiments. It is estimated that in measurements of e.g. some anisotropy of the light velocity, a spacecraft-borne interferometer of quite small size (0.1 m arm-length) would reach a sensitivity greater by a factor of approximately 10 8 than the best achievements to date of ground-based devices. (author)

  1. System analysis of a tilted field-widened Michelson interferometer for high spectral resolution lidar.

    Science.gov (United States)

    Liu, Dong; Hostetler, Chris; Miller, Ian; Cook, Anthony; Hair, Johnathan

    2012-01-16

    High spectral resolution lidars (HSRLs) have shown great value in aircraft aerosol remote sensing application and are planned for future satellite missions. A compact, robust, quasi-monolithic tilted field-widened Michelson interferometer is being developed as the spectral discrimination filter for an second-generation HSRL(HSRL-2) at NASA Langley Research Center. The Michelson interferometer consists of a cubic beam splitter, a solid arm and an air arm. Piezo stacks connect the air arm mirror to the body of the interferometer and can tune the interferometer within a small range. The whole interferometer is tilted so that the standard Michelson output and the reflected complementary output can both be obtained. In this paper, the transmission ratio is proposed to evaluate the performance of the spectral filter for HSRL. The transmission ratios over different types of system imperfections, such as cumulative wavefront error, locking error, reflectance of the beam splitter and anti-reflection coatings, system tilt, and depolarization angle are analyzed. The requirements of each imperfection for good interferometer performance are obtained.

  2. A stellar interferometer on the Moon

    Science.gov (United States)

    Porro, Irene

    The work I present in this document has been divided into two main parts, the first one related to the IOTA project and the second one related to the study on the lunar interferometer, and an introduction section. Each section can be read independently from the other, however they are presented following the logical order in which the research work has been developed. As a guide for the reader here I describe the content of each chapter, which represents the original contribution (except when it is specifically declared) to the research accomplished. This section consists in the Introduction itself, with a presentation of the motivations for this research work, and in the chapter Interferometry from the Earth and from the Moon. The first part of this chapter shows the performances which are expected to be reached by ground-based interferometers (Colavita, 1992) by using adaptive optics systems (Beckers, 1993). The evaluation is made separately for the case of high resolution imaging and for high accuracy astrometric measurements. The most optimistic results expected for ground-based instruments determine the level of the performance that has to be required from a space interferometer (both an orbiting and a lunar instrument). In the second part of the chapter I specifically deal with the case of a lunar interferometer, which allows to put together the advantages o ered by a ground-based instrument (very long baseline, a stable platform) and those offered by the space environment (absence of atmospheric turbulence, long integration times, and wavelength range of observation from the ultraviolet to the far infrared). In order to evaluate the limits of the lunar interferometer, I need to consider three subjects with which I did not explicitly dealt for the study on IOTA: the maximum length of the baseline (Tango and Twiss, 1974), the maximum integration time, and the performances obtainable at the minimum temperature of operation (Ridgway, 1990). The chapter ends with

  3. Plasma measurement by feedback-stabilized dual-beam laser interferometer

    International Nuclear Information System (INIS)

    Yasuda, Akio; Kawahata, Kazuo; Kanai, Yasubumi.

    1982-03-01

    The plasma density in a dynamic magneto arcjet is measured by a stabilized dual-beam laser interferometer proposed by the authors. The fringe shift for a 0.63 μm beam of He-Ne laser is used to stabilize the interferometer against the effect of mechanical vibration by means of a feedback controlled speaker coil, while the other beam of 3.39 μm, for which the effect of mechanical vibrations is excluded, is used to measure plasma density. Stability of --1/500 of one fringe for 0.63 μm is obtained during a long period for frequencies lower than a few Hertz. Stability for higher frequencies, which determines the accuracy of the present measurement, is limited to --1/30 of one fringe for 0.63 μm, which corresponds to --1/200 of one fringe and a line electron density of --1.5 x 10 14 cm - 2 for 3.39 μm, by acoustic noise picked up by the speaker coil. The advantage of this technique over the single-laser technique is that the frequency response of the interferometer extends down to zero frequency. Since the effect of the neutral gas background is practically reduced to zero, the present interferometer is to be applied advantageously to the diagnostics of the plasma produced in high pressure gases. (author)

  4. Inspection of commercial optical devices for data storage using a three Gaussian beam microscope interferometer

    International Nuclear Information System (INIS)

    Flores, J. Mauricio; Cywiak, Moises; Servin, Manuel; Juarez P, Lorenzo

    2008-01-01

    Recently, an interferometric profilometer based on the heterodyning of three Gaussian beams has been reported. This microscope interferometer, called a three Gaussian beam interferometer, has been used to profile high quality optical surfaces that exhibit constant reflectivity with high vertical resolution and lateral resolution near λ. We report the use of this interferometer to measure the profiles of two commercially available optical surfaces for data storage, namely, the compact disk (CD-R) and the digital versatile disk (DVD-R). We include experimental results from a one-dimensional radial scan of these devices without data marks. The measurements are taken by placing the devices with the polycarbonate surface facing the probe beam of the interferometer. This microscope interferometer is unique when compared with other optical measuring instruments because it uses narrowband detection, filters out undesirable noisy signals, and because the amplitude of the output voltage signal is basically proportional to the local vertical height of the surface under test, thus detecting with high sensitivity. We show that the resulting profiles, measured with this interferometer across the polycarbonate layer, provide valuable information about the track profiles, making this interferometer a suitable tool for quality control of surface storage devices

  5. Design of an optical spatial interferometer with transformation optics

    International Nuclear Information System (INIS)

    Naghibi, Atefeh; Shokooh-Saremi, Mehrdad

    2015-01-01

    In this paper, we apply transformation optics to design an optical spatial interferometer. The transformation equations are described and two-dimensional finite element simulations are presented to numerically confirm the functionality of the device. It is shown that a small change in the refractive index can alter the interference pattern and hence can be detected. The design of the interferometer could expand transformation optics’ applications and make way for introduction of new structures with unique electromagnetic or optical functionalities. (paper)

  6. Power-recycled michelson interferometer with a 50/50 grating beam splitter

    International Nuclear Information System (INIS)

    Friedrich, D; Burmeister, O; Britzger, M; Bunkowski, A; Danzmann, K; Schnabel, R; Clausnitzer, T; Fahr, S; Kley, E-B; Tuennermann, A

    2008-01-01

    We designed and fabricated an all-reflective 50/50 beam splitter based on a dielectric grating. This beam splitter was used to set up a power-recycled Michelson interferometer with a finesse of about F PR ∼ 880. Aspects of the diffractive beam splitter as well as of the interferometer design are discussed

  7. Power-recycled michelson interferometer with a 50/50 grating beam splitter

    OpenAIRE

    Friedrich, Daniel; Burmeister, O.; Britzger, M.; Bunkowski, A.; Clausnitzer, T.; Fahr, S.; Kley, E.B.; Tünnermann, A.; Danzmann, Karsten; Schnabel, Roman

    2008-01-01

    We designed and fabricated an all-reflective 50/50 beam splitter based on a dielectric grating. This beam splitter was used to set up a power-recycled Michelson interferometer with a finesse of about FPR ≈ 880. Aspects of the diffractive beam splitter as well as of the interferometer design are discussed.

  8. Improved density measurement by FIR laser interferometer on EAST tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Jie, E-mail: shenjie1988@ipp.ac.cn; Jie, Yinxian; Liu, Haiqing; Wei, Xuechao; Wang, Zhengxing; Gao, Xiang

    2013-11-15

    Highlights: • In 2012, the water-cooling Mo wall was installed in EAST. • A schottky barrier diode detector is designed and used on EAST for the first time. • The three-channel far-infrared laser interferometer can measure the electron density. • The improved measurement and latest experiment results are reported. • The signal we get in this experiment campaign is much better than we got in 2010. -- Abstract: A three-channel far-infrared (FIR) hydrogen cyanide (HCN) laser interferometer is in operation since 2010 to measure the line averaged electron density on experimental advanced superconducting tokamak (EAST). The HCN laser signal is improved by means of a new schottky barrier diode (SBD) detector. The improved measurement and latest experiment results of the three-channel FIR laser interferometer on EAST tokamak are reported.

  9. Improved density measurement by FIR laser interferometer on EAST tokamak

    International Nuclear Information System (INIS)

    Shen, Jie; Jie, Yinxian; Liu, Haiqing; Wei, Xuechao; Wang, Zhengxing; Gao, Xiang

    2013-01-01

    Highlights: • In 2012, the water-cooling Mo wall was installed in EAST. • A schottky barrier diode detector is designed and used on EAST for the first time. • The three-channel far-infrared laser interferometer can measure the electron density. • The improved measurement and latest experiment results are reported. • The signal we get in this experiment campaign is much better than we got in 2010. -- Abstract: A three-channel far-infrared (FIR) hydrogen cyanide (HCN) laser interferometer is in operation since 2010 to measure the line averaged electron density on experimental advanced superconducting tokamak (EAST). The HCN laser signal is improved by means of a new schottky barrier diode (SBD) detector. The improved measurement and latest experiment results of the three-channel FIR laser interferometer on EAST tokamak are reported

  10. Secondary wavelength stabilization of unbalanced Michelson interferometers for the generation of low-jitter pulse trains.

    Science.gov (United States)

    Shalloo, R J; Corner, L

    2016-09-01

    We present a double unbalanced Michelson interferometer producing up to four output pulses from a single input pulse. The interferometer is stabilized with the Hänsch-Couillaud method using an auxiliary low power continuous wave laser injected into the interferometer, allowing the stabilization of the temporal jitter of the output pulses to 0.02 fs. Such stabilized pulse trains would be suitable for driving multi-pulse laser wakefield accelerators, and the technique could be extended to include amplification in the arms of the interferometer.

  11. Femto-second synchronisation with a waveguide interferometer

    Science.gov (United States)

    Dexter, A. C.; Smith, S. J.; Woolley, B. J.; Grudiev, A.

    2018-03-01

    CERN's compact linear collider CLIC requires crab cavities on opposing linacs to rotate bunches of particles into alignment at the interaction point (IP). These cavities are located approximately 25 metres either side of the IP. The luminosity target requires synchronisation of their RF phases to better than 5 fs r.m.s. This is to be achieved by powering both cavities from one high power RF source, splitting the power and delivering it along two waveguide paths that are controlled to be identical in length to within a micrometre. The waveguide will be operated as an interferometer. A high power phase shifter for adjusting path lengths has been successfully developed and operated in an interferometer. The synchronisation target has been achieved in a low power prototype system.

  12. Two-photon interference of polarization-entangled photons in a Franson interferometer.

    Science.gov (United States)

    Kim, Heonoh; Lee, Sang Min; Kwon, Osung; Moon, Han Seb

    2017-07-18

    We present two-photon interference experiments with polarization-entangled photon pairs in a polarization-based Franson-type interferometer. Although the two photons do not meet at a common beamsplitter, a phase-insensitive Hong-Ou-Mandel type two-photon interference peak and dip fringes are observed, resulting from the two-photon interference effect between two indistinguishable two-photon probability amplitudes leading to a coincidence detection. A spatial quantum beating fringe is also measured for nondegenerate photon pairs in the same interferometer, although the two-photon states have no frequency entanglement. When unentangled polarization-correlated photons are used as an input state, the polarization entanglement is successfully recovered through the interferometer via delayed compensation.

  13. Measurements of Interferometer Parameters at Reception of GLONASS and GPS Signals

    Directory of Open Access Journals (Sweden)

    Nechaeva M.

    2016-10-01

    Full Text Available The present paper deals with the calibration method of interferometers with antennas having a small effective area, on the quasinoise signals of GLONASS and GPS navigation satellites. Algorithms for calculation of antenna coordinates and instrumental delay from the analysis of correlation interferometer response to signals of satellites in the near field of the instrument were reviewed. The method was tested in VLBI experiments on interferometers with medium and large baselines that included radio telescopes of NIRFI and VIRAC. The values of the antenna coordinates and instrumental delay with an error within the limits of one discrete were obtained. The sources of measurement errors and ways to improve the accuracy of results were analysed.

  14. Optical refractometer based on an asymmetrical twin-core fiber Michelson interferometer.

    Science.gov (United States)

    Zhou, Ai; Zhang, Yanhui; Li, Guangping; Yang, Jun; Wang, Yuzhuo; Tian, Fengjun; Yuan, Libo

    2011-08-15

    We report and demonstrate an optical refractometer based on a compact fiber Michelson interferometer. The Michelson interferometer is composed of an asymmetrical twin-core fiber containing a central core and a side core. By chemically etching a segment of the twin-core fiber until the side core is exposed, the effective index of the side core in the etched region is sensitive to the environmental refractive index, which leads to a shift of the transmission spectrum of the Michelson interferometer. The experimental results show that such a device has a refractive index resolution of more than 800 nm/refractive index unit in the range of 1.34-1.37. © 2011 Optical Society of America

  15. A wide-band laser interferometer for the detection of gravitational radiation

    International Nuclear Information System (INIS)

    Billing, H.; Maischberger, K.; Ruediger, A.; Schilling, R.; Schnupp, L.; Winkler, W.

    1979-02-01

    The aim of the current investigations of the model interferometer is to gather quantitative data on different noise effects (some of which were rather unexpected), and to develop methods to cope with them. This knowledge will be the basis for a better design of an interferometer of increased path length. The interferometer, in its present form, is not meant for detecting gravitational waves, and the sensitivity currently obtained does not reach that of resonant bars. If the 1-Watt shot-noise limit could be reached, with 300 reflections in the delay line, this model could, however, be an order of magnitude more sensitive than room-temperature resonant bars. (orig.) 891 WB/orig. 892 MAB

  16. Near-infrared spectral imaging Michelson interferometer for astronomical applications

    Science.gov (United States)

    Wells, C. W.; Potter, A. E.; Morgan, T. H.

    1980-01-01

    The design and operation of an imaging Michelson interferometer-spectrometer used for near-infrared (0.8 micron to 2.5 microns) spectral imaging are reported. The system employs a rapid scan interferometer modified for stable low resolution (250/cm) performance and a 42 element PbS linear detector array. A microcomputer system is described which provides data acquisition, coadding, and Fourier transformation for near real-time presentation of the spectra of all 42 scene elements. The electronic and mechanical designs are discussed and telescope performance data presented.

  17. An active interferometer-stabilization scheme with linear phase control

    DEFF Research Database (Denmark)

    Andresen, Esben Ravn; Krishnamachari, v v; Potma, E O

    2006-01-01

    We report a simple and robust computer-based active interferometer stabilization scheme which does not require modulation of the interfering beams and relies on an error signal which is linearly related to the optical path difference. In this setup, a non-collinearly propagating reference laser...... beam stabilizes the interference output of the laser light propagating collinearly through the interferometer. This stabilization scheme enables adjustable phase control with 20 ms switching times in the range from 0.02π radians to 6π radians at 632.8 nm....

  18. Slow-Light-Enhanced Spectral Interferometers, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We proposoe a research program aimed at developing spectral interferometers with dramatically enhanced performance. A key aspect of our approach is to place a highly...

  19. Naked eye picometer resolution in a Michelson interferometer using conjugated twisted beams.

    Science.gov (United States)

    Emile, Olivier; Emile, Janine

    2017-01-15

    Michelson interferometry is one of the most widely used techniques for accuracy measurements. Its main characteristic feature is to infer a displacement in one of the arms of the interferometer from a phase measurement. Two different twisted beams, also called vortex beams, with opposite twisted rotations in each arm of the interferometer interfere in a daisy flower-like pattern. The number of petals is twice the topological charge. Their position depends on the relative phase of the beams. Naked eye detection of 44 pm displacements is achieved. The sensitivity of such an interferometer together with possible further improvements, and applications are then discussed.

  20. Intensity profiles behind a five-stage neutron interferometer

    International Nuclear Information System (INIS)

    Kischko, U.

    1983-01-01

    By means of the quantitative photography intensity profiles behind a five-stage ideal-crystal neutron interferometer at the thermal channel H25 of the high-flux reactor at the institute Laue-Langevin in Grenoble/France were dermined and compared with theoretical profiles. Contravily to X-rays by neutrons the hole Borrmann range is excited. This leads in the interference picture to superposition of several wave field components. It was shown that the spherical wave theory, as it was developed by W. Bauspiess, U. Bonse, and W. Graeff for the absorption-free neutron interferometer, describes well quantitatively the experimental intensity profiles. Expecially for the t-2t-t geometry the theoretically predicted focusing was confirmed. For the H-beam the intensity profile is symmetric and spatially limited; the O-beam is asymetric with intensities decreasing slowly up to the boundary. Geometrical differences within single stages lead to unique changes in the intensity profile. The pigtail pattern leading in the past to some puzzle guessing could be explained by the influence of geometrical defocusings on the phase shift. Important conclusions for the geometrical tolerances, which have to be regarded in the construction of neutron interferometers, could be obtained. (orig.) [de

  1. Silicon Integrated Dual-Mode Interferometer with Differential Outputs

    Directory of Open Access Journals (Sweden)

    Niklas Hoppe

    2017-09-01

    Full Text Available The dual-mode interferometer (DMI is an attractive alternative to Mach-Zehnder interferometers for sensor purposes, achieving sensitivities to refractive index changes close to state-of-the-art. Modern designs on silicon-on-insulator (SOI platforms offer thermally stable and compact devices with insertion losses of less than 1 dB and high extinction ratios. Compact arrays of multiple DMIs in parallel are easy to fabricate due to the simple structure of the DMI. In this work, the principle of operation of an integrated DMI with differential outputs is presented which allows the unambiguous phase shift detection with a single wavelength measurement, rather than using a wavelength sweep and evaluating the optical output power spectrum. Fluctuating optical input power or varying attenuation due to different analyte concentrations can be compensated by observing the sum of the optical powers at the differential outputs. DMIs with two differential single-mode outputs are fabricated in a 250 nm SOI platform, and corresponding measurements are shown to explain the principle of operation in detail. A comparison of DMIs with the conventional Mach-Zehnder interferometer using the same technology concludes this work.

  2. Interferometer for measuring the dynamic surface topography of a human tear film

    Science.gov (United States)

    Primeau, Brian C.; Greivenkamp, John E.

    2012-03-01

    The anterior refracting surface of the eye is the thin tear film that forms on the surface of the cornea. Following a blink, the tear film quickly smoothes and starts to become irregular after 10 seconds. This irregularity can affect comfort and vision quality. An in vivo method of characterizing dynamic tear films has been designed based upon a near-infrared phase-shifting interferometer. This interferometer continuously measures light reflected from the tear film, allowing sub-micron analysis of the dynamic surface topography. Movies showing the tear film behavior can be generated along with quantitative metrics describing changes in the tear film surface. This tear film measurement allows analysis beyond capabilities of typical fluorescein visual inspection or corneal topography and provides better sensitivity and resolution than shearing interferometry methods. The interferometer design is capable of identifying features in the tear film much less than a micron in height with a spatial resolution of about ten microns over a 6 mm diameter. This paper presents the design of the tear film interferometer along with the considerations that must be taken when designing an interferometer for on-eye diagnostics. Discussions include eye movement, design of null optics for a range of ocular geometries, and laser emission limits for on-eye interferometry.

  3. Increased interference fringe visibility from the post-fabrication heat treatment of a perfect crystal silicon neutron interferometer

    Science.gov (United States)

    Heacock, B.; Arif, M.; Cory, D. G.; Gnaeupel-Herold, T.; Haun, R.; Huber, M. G.; Jamer, M. E.; Nsofini, J.; Pushin, D. A.; Sarenac, D.; Taminiau, I.; Young, A. R.

    2018-02-01

    We find that annealing a previously chemically etched interferometer at 800 °C dramatically increased the interference fringe visibility from 23% to 90%. The Bragg plane misalignments were also measured before and after annealing using neutron rocking curves, showing that Bragg plane alignment was improved across the interferometer after annealing. This suggests that current interferometers with low fringe visibility may be salvageable and that annealing may become an important step in the fabrication process of future neutron interferometers, leading to less need for chemical etching and larger more exotic neutron interferometers.

  4. Analytic models of spectral responses of fiber-grating-based interferometers on FMC theory.

    Science.gov (United States)

    Zeng, Xiangkai; Wei, Lai; Pan, Yingjun; Liu, Shengping; Shi, Xiaohui

    2012-02-13

    In this paper the analytic models (AMs) of the spectral responses of fiber-grating-based interferometers are derived from the Fourier mode coupling (FMC) theory proposed recently. The interferometers include Fabry-Perot cavity, Mach-Zehnder and Michelson interferometers, which are constructed by uniform fiber Bragg gratings and long-period fiber gratings, and also by Gaussian-apodized ones. The calculated spectra based on the analytic models are achieved, and compared with the measured cases and those on the transfer matrix (TM) method. The calculations and comparisons have confirmed that the AM-based spectrum is in excellent agreement with the TM-based one and the measured case, of which the efficiency is improved up to ~2990 times that of the TM method for non-uniform-grating-based in-fiber interferometers.

  5. The three-grating Mach-Zehnder optical interferometer: a tutorial approach using particle optics

    International Nuclear Information System (INIS)

    Miffre, A; Delhuille, R; Viaris Lesegno, B de; Buechner, M; Rizzo, C; Vigue, J

    2002-01-01

    In this paper, we present a tutorial set-up based on an optical three-grating Mach-Zehnder interferometer. As this apparatus is very similar in its principle to the Mach-Zehnder interferometers used with matter waves (neutrons, atoms and molecules), it can be used to familiarize students with particle optics, and in our explanations, we use the complementary points of view of wave optics and particle optics. Finally, we have used this interferometer to measure the index of refraction of BK7 glass for red light at 633 nm, with a technique equivalent to the one used to measure the index of refraction of solid matter for thermal neutrons. The dimensions of this interferometer and its cost make it very interesting for laboratory courses and the experiment described here can be reproduced by students

  6. Characterisation of a resolution enhancing image inversion interferometer.

    Science.gov (United States)

    Wicker, Kai; Sindbert, Simon; Heintzmann, Rainer

    2009-08-31

    Image inversion interferometers have the potential to significantly enhance the lateral resolution and light efficiency of scanning fluorescence microscopes. Self-interference of a point source's coherent point spread function with its inverted copy leads to a reduction in the integrated signal for off-axis sources compared to sources on the inversion axis. This can be used to enhance the resolution in a confocal laser scanning microscope. We present a simple image inversion interferometer relying solely on reflections off planar surfaces. Measurements of the detection point spread function for several types of light sources confirm the predicted performance and suggest its usability for scanning confocal fluorescence microscopy.

  7. Applications of the lateral shearing interferometer in measurement of synchrotron radiation optical elements

    International Nuclear Information System (INIS)

    Liu, Wu-ming; Takacs, P.Z.; Siddons, D.P.

    1987-11-01

    The use of a single plate shearing, or Murty, interferometer for measuring the surface quality of several optical elements is reviewed and several results are given. The principle of the Murty interferometer is also explained

  8. Validation of separated source frequency delivery for a fiber-coupled heterodyne displacement interferometer

    NARCIS (Netherlands)

    Meskers, A.J.H.; Spronck, J.W.; Munnig Schmidt, R.H.

    2014-01-01

    The use of optical fibers presents several advantages with respect to free-space optical transport regarding sourcefrequency delivery to individual heterodyne interferometers. Unfortunately, fiber delivery to individual coaxial heterodyne interferometers leads to an increase of (periodic)

  9. Analysis of the localization of Michelson interferometer fringes using Fourier optics and temporal coherence

    International Nuclear Information System (INIS)

    Narayanamurthy, C S

    2009-01-01

    Fringes formed in a Michelson interferometer never localize in any plane, in the detector plane and in the localization plane. Instead, the fringes are assumed to localize at infinity. Except for some explanation in Principles of Optics by Born and Wolf (1964 (New York: Macmillan)), the fringe localization phenomena of Michelson's interferometer have never been analysed seriously in any book. Because Michelson's interferometer is one of the important and fundamental optical experiments taught at both undergraduate and graduate levels, it would be appropriate to explain the localization of these fringes. In this paper, we analyse the localization of Michelson interferometer fringes using Fourier optics and temporal coherence, and show that they never localize at any plane even at infinity

  10. Mirrors used in the LIGO interferometers for first detection of gravitational waves.

    Science.gov (United States)

    Pinard, L; Michel, C; Sassolas, B; Balzarini, L; Degallaix, J; Dolique, V; Flaminio, R; Forest, D; Granata, M; Lagrange, B; Straniero, N; Teillon, J; Cagnoli, G

    2017-02-01

    For the first time, direct detection of gravitational waves occurred in the Laser Interferometer Gravitational-wave Observatory (LIGO) interferometers. These advanced detectors require large fused silica mirrors with optical and mechanical properties and have never been reached until now. This paper details the main achievements of these ion beam sputtering coatings.

  11. Frequency-tuned microwave photon counter based on a superconductive quantum interferometer

    Science.gov (United States)

    Shnyrkov, V. I.; Yangcao, Wu; Soroka, A. A.; Turutanov, O. G.; Lyakhno, V. Yu.

    2018-03-01

    Various types of single-photon counters operating in infrared, ultraviolet, and optical wavelength ranges are successfully used to study electromagnetic fields, analyze radiation sources, and solve problems in quantum informatics. However, their operating principles become ineffective at millimeter band, S-band, and ultra-high frequency bands of wavelengths due to the decrease in quantum energy by 4-5 orders of magnitude. Josephson circuits with discrete Hamiltonians and qubits are a good foundation for the construction of single-photon counters at these frequencies. This paper presents a frequency-tuned microwave photon counter based on a single-junction superconducting quantum interferometer and flux qutrit. The control pulse converts the interferometer into a two-level system for resonance absorption of photons. Decay of the photon-induced excited state changes the magnetic flux in the interferometer, which is measured by a SQUID magnetometer. Schemes for recording the magnetic flux using a DC SQUID or ideal parametric detector, based on a qutrit with high-frequency excitation, are discussed. It is shown that the counter consisting of an interferometer with a Josephson junction and a parametric detector demonstrates high performance and is capable of detecting single photons in a microwave band.

  12. NEuclid: a long-range tilt-immune homodyne interferometer

    Science.gov (United States)

    Bradshaw, M. J.; Speake, C. C.

    2017-11-01

    The new Easy to Use Compact Laser Interferometric Device (nEUCLID) is a polarisation-based homodyne interferometer with substantially unequal arms that is tolerant to target mirror tilt. The design has no active components, uses standard optical components of 25 mm diameter, has a working distance of 706 mm and a reference arm-length of 21 mm. nEUCLID optics have a footprint of 210 x 190 x 180 mm, and has a tolerance to target mirror tilt of +/- 0.5 degrees, made possible by a novel new retro-reflector design [1]. nEUCLID was built to a set of specifications laid down by Airbus Defence and Space, who required a lowmass, low-power device to measure displacement with nanometre accuracy for space applications. At the University of Birmingham we have previously built a smaller, more compact tilt-insensitive homodyne interferometer - the EUCLID [2, 3, 4] - which has a working distance of 6 mm, a working range of +/- 3 mm, and a tilt range of +/- 1° [2]. We created a new optical design to allow a much larger working distance to be achieved (as discussed in Section II) and used this in a new interferometer - the nEUCLID. Section II describes the interferometer in detail; how nEUCLID is tilt insensitive, and the optical configuration. Section III states the design specifications from Airbus Defence and Space and the components used in the final design. The output interference pattern from nEUCLID, and how it has been corrected with a meniscus lens, is also discussed. In Section IV we discuss the results demonstrating the tilt immunity range, and the sensitivity of the device. Section V describes several potential applications of nEUCLID, and Section VI draws together our conclusions.

  13. Direct reading fast microwave interferometer for EBT

    International Nuclear Information System (INIS)

    Uckan, T.

    1984-10-01

    A simple and inexpensive 4-mm direct reading fast (rise time approx. 100 μs) microwave interferometer is described. The system is particularly useful for density measurements on the ELMO Bumpy Torus (EBT) during pulsed operation

  14. The use of x-ray interferometry to investigate the linearity of the NPL Differential Plane Mirror Optical Interferometer

    Science.gov (United States)

    Yacoot, Andrew; Downs, Michael J.

    2000-08-01

    The x-ray interferometer from the combined optical and x-ray interferometer (COXI) facility at NPL has been used to investigate the performance of the NPL Jamin Differential Plane Mirror Interferometer when it is fitted with stabilized and unstabilized lasers. This Jamin interferometer employs a common path design using a double pass configuration and one fringe is realized by a displacement of 158 nm between its two plane mirror retroreflectors. Displacements over ranges of several optical fringes were measured simultaneously using the COXI x-ray interferometer and the Jamin interferometer and the results were compared. In order to realize the highest measurement accuracy from the Jamin interferometer, the air paths were shielded to prevent effects from air turbulence and electrical signals generated by the photodetectors were analysed and corrected using an optimizing routine in order to subdivide the optical fringes accurately. When an unstabilized laser was used the maximum peak-to-peak difference between the two interferometers was 80 pm, compared with 20 pm when the stabilized laser was used.

  15. Wide-area phase-contrast X-ray imaging using large X-ray interferometers

    Energy Technology Data Exchange (ETDEWEB)

    Momose, Atsushi E-mail: momose@exp.t.u-tokyo.ac.jp; Takeda, Tohoru; Yoneyama, Akio; Koyama, Ichiro; Itai, Yuji

    2001-07-21

    Large X-ray interferometers are developed for phase-contrast X-ray imaging aiming at medical applications. A monolithic X-ray interferometer and a separate one are studied, and currently a 25 mmx20 mm view area can be generated. This paper describes the strategy of our research program and some recent developments.

  16. Wide-area phase-contrast X-ray imaging using large X-ray interferometers

    Science.gov (United States)

    Momose, Atsushi; Takeda, Tohoru; Yoneyama, Akio; Koyama, Ichiro; Itai, Yuji

    2001-07-01

    Large X-ray interferometers are developed for phase-contrast X-ray imaging aiming at medical applications. A monolithic X-ray interferometer and a separate one are studied, and currently a 25 mm×20 mm view area can be generated. This paper describes the strategy of our research program and some recent developments.

  17. Handheld ESPI-speckle interferometer

    DEFF Research Database (Denmark)

    Skov Hansen, René

    2003-01-01

    . The interferometer presented here is a compact version of the set-up, Which is capable of measuring displacements of small objects, having either a specularly reflecting-or a diffusely scattering surface. The small optical set-up together with the use of the popular USB-communication for acquiring the images...... and controlling the phase of the reference wave constitutes a compact "handheld" instrument and eliminates the need for installing extra hardware, such as frame grabber and Digital to Analog converter, in the host computer....

  18. Experimental investigation of a control scheme for a tuned resonant sideband extraction interferometer for next-generation gravitational-wave detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kawazoe, F; Sugamoto, A [Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610 (Japan); Sato, S; Leonhardt, V; Yamazaki, T; Fukushima, M; Kawamura, S [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka-shi, Tokyo 112-8610 (Japan); Miyakawa, O [California Institute of Technology, Pasadena, CA 91125 (United States); Morioka, T [University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Nishizawa, A [Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)], E-mail: kawazoe@gravity.mtk.nao.ac.jp

    2008-07-15

    LCGT plans to use tuned RSE as the optical configuration for its interferometer. A tuned RSE interferometer has five degrees of freedom that need to be controlled in order to operate a gravitational-wave detector, although it is expected to be very challenging because of the complexity of its optical configuration. A new control scheme for a tuned RSE interferometer has been developed and tested with a prototype interferometer to demonstrate successful control of the tuned RSE interferometer. The whole RSE interferometer was successfully locked with the control scheme. Here the control scheme and the current status of the experiment are presented.

  19. Experimental investigation of a control scheme for a tuned resonant sideband extraction interferometer for next-generation gravitational-wave detectors

    International Nuclear Information System (INIS)

    Kawazoe, F; Sugamoto, A; Sato, S; Leonhardt, V; Yamazaki, T; Fukushima, M; Kawamura, S; Miyakawa, O; Morioka, T; Nishizawa, A

    2008-01-01

    LCGT plans to use tuned RSE as the optical configuration for its interferometer. A tuned RSE interferometer has five degrees of freedom that need to be controlled in order to operate a gravitational-wave detector, although it is expected to be very challenging because of the complexity of its optical configuration. A new control scheme for a tuned RSE interferometer has been developed and tested with a prototype interferometer to demonstrate successful control of the tuned RSE interferometer. The whole RSE interferometer was successfully locked with the control scheme. Here the control scheme and the current status of the experiment are presented

  20. Laser-based ultrasonics by dual-probe interferometer detection and narrow-band ultrasound generation

    Science.gov (United States)

    Huang, Jin

    1993-01-01

    Despite the advantages of laser-based ultrasonic (LBU) systems, the overall sensitivity of LBU systems needs to be improved for practical applications. Progress is reported to achieve better LBU detection accuracy and sensitivity for applications with surface waves and Lamb waves. A novel dual-probe laser interferometer has been developed to measure the same signal at two points. The dual-probe interferometer is a modification of a conventional single-probe interferometer in that the reference beam is guided to a second detecting point on the specimen surface to form a differential measurement mode, which measure the difference of the displacements at the two points. This dual-probe interferometer is particularly useful for accurate measurements of the speed and attenuation of surface waves and Lamb waves. The dual-probe interferometer has been applied to obtain accurate measurements of the surface wave speed and attenuation on surfaces of increasing surface roughness. It has also been demonstrated that with an appropriate signal processing method, namely, the power cepstrum method, the dual-probe interferometer is applicable to measure the local surface wave speed even when the probe separation is so small that the two waveforms in the interferometer output signal overlap in the time domain. Narrow-band signal generation and detection improve the sensitivity of LBU systems. It is proposed to use a diffraction grating to form an array of illuminating strips which form a source of narrowband surface and Lamb waves. The line-array of thermoelastic sources generates narrow-band signals whose frequency and bandwidth can be easily controlled. The optimum line-array parameters, such as width, spacing and the number of lines in the array have been derived theoretically and verified experimentally. Narrow-band signal generation with optimum parameters has been demonstrated. The enhanced LBU system with dual-probe detection and narrowband signal generation has been

  1. Quantum mechanical noise in coherent-state and squeezed-state Michelson interferometers

    International Nuclear Information System (INIS)

    Assaf, Ohad; Ben-Aryeh, Yacob

    2002-01-01

    In the present study we extend and generalize previous results for coherent-state and squeezed-state Michelson interferometer quantum mechanical uncertainties (or fluctuations), which are commonly referred to as 'quantum noise'. The calculation of photon counting (PC) fluctuations in the squeezed-state interferometer is extended to fourth-order correlation functions used as the measured signal. We also generalize a 'unified model' for treating both PC and radiation pressure fluctuations in the coherent-state interferometer, by using mathematical methods which apply to Kerr-type interactions. The results are more general than those reported previously in two ways. First, we obtain exact expressions, which lead to previous results under certain approximations. Second, we deal with cases in which the responses of the two mirrors to radiation pressure are not equal

  2. Loop Transfer Matrix and Loop Quantum Mechanics

    International Nuclear Information System (INIS)

    Savvidy, George K.

    2000-01-01

    The gonihedric model of random surfaces on a 3d Euclidean lattice has equivalent representation in terms of transfer matrix K(Q i ,Q f ), which describes the propagation of loops Q. We extend the previous construction of the loop transfer matrix to the case of nonzero self-intersection coupling constant κ. We introduce the loop generalization of Fourier transformation which allows to diagonalize transfer matrices, that depend on symmetric difference of loops only and express all eigenvalues of 3d loop transfer matrix through the correlation functions of the corresponding 2d statistical system. The loop Fourier transformation allows to carry out the analogy with quantum mechanics of point particles, to introduce conjugate loop momentum P and to define loop quantum mechanics. We also consider transfer matrix on 4d lattice which describes propagation of memebranes. This transfer matrix can also be diagonalized by using the generalized Fourier transformation, and all its eigenvalues are equal to the correlation functions of the corresponding 3d statistical system. In particular the free energy of the 4d membrane system is equal to the free energy of 3d gonihedric system of loops and is equal to the free energy of 2d Ising model. (author)

  3. A differential Michelson interferometer with orthogonal single frequency laser for nanometer displacement measurement

    International Nuclear Information System (INIS)

    Yan, Liping; Chen, Benyong; Wang, Bin

    2017-01-01

    A novel differential Michelson laser interferometer is proposed to eliminate the influence of environmental fluctuations for nanometer displacement measurement. This differential interferometer consists of two homodyne interferometers in which two orthogonal single frequency beams share common reference arm and partial measurement arm. By modulating the displacement of the common reference arm with a piezoelectric transducer, the common-mode displacement drift resulting from the environmental disturbances can be well suppressed and the measured displacement as differential-mode displacement signal is achieved. In addition, a phase difference compensation method is proposed for accurately determining the phase difference between interference signals by correcting the time interval according to the average speed in one cycle of interference signal. The nanometer displacement measurement experiments were performed to demonstrate the effectiveness and feasibility of the proposed interferometer and show that precision displacement measurement with standard deviation less than 1 nm has been achieved. (paper)

  4. Measuring correlations in non-separable vector beams using projective measurements

    Science.gov (United States)

    Subramanian, Keerthan; Viswanathan, Nirmal K.

    2017-09-01

    Doubts regarding the completeness of quantum mechanics as raised by Einstein, Podolsky and Rosen(EPR) have predominantly been resolved by resorting to a measurement of correlations between entangled photons which clearly demonstrate violation of Bell's inequality. This article is an attempt to reconcile incompatibility of hidden variable theories with reality by demonstrating experimentally a violation of Bell's inequality in locally correlated systems whose two degrees of freedom, the spin and orbital angular momentum, are maximally correlated. To this end we propose and demonstrate a linear, achromatic modified Sagnac interferometer to project orbital angular momentum states which we combine with spin projections to measure correlations.

  5. Ultrahigh enhancement in absolute and relative rotation sensing using fast and slow light

    International Nuclear Information System (INIS)

    Shahriar, M. S.; Pati, G. S.; Tripathi, R.; Gopal, V.; Messall, M.; Salit, K.

    2007-01-01

    We describe a resonator-based optical gyroscope whose sensitivity for measuring absolute rotation is enhanced via use of the anomalous dispersion characteristic of superluminal light propagation. The enhancement is given by the inverse of the group index, saturating to a bound determined by the group velocity dispersion. We also show how the offsetting effect of the concomitant broadening of the resonator linewidth may be circumvented by using an active cavity. For realistic conditions, the enhancement factor is as high as 10 6 . We also show how normal dispersion used for slow light can enhance relative rotation sensing in a specially designed Sagnac interferometer, with the enhancement given by the slowing factor

  6. Noise sources in the LTP heterodyne interferometer

    International Nuclear Information System (INIS)

    Wand, V; Bogenstahl, J; Braxmaier, C; Danzmann, K; GarcIa, A; Guzman, F; Heinzel, G; Hough, J; Jennrich, O; Killow, C; Robertson, D; Sodnik, Z; Steier, F; Ward, H

    2006-01-01

    The LISA Technology Package uses a heterodyne Mach-Zehnder interferometer to monitor the relative motion of the test masses with picometer accuracy. This paper discusses two classes of noise sources that were identified and investigated during the prototype experiments. Most troublesome are electrically induced sidebands on the light, which give rise to nonlinearities in the interferometer output. Even worse, if the differential pathlength between two optical fibres fluctuates, a noise term of milliradian amplitude appears and completely spoils the performance. We discuss the origin and mitigation of this process. Dissimilar beam shapes of the interfering beams produce another type of noise in conjunction with beam jitter and spatially inhomogeneous photodetectors. To study and minimize this effect, we have built a real-time high-resolution phasefront imaging system that will be used for the production of the flight model

  7. Sun Radio Interferometer Space Experiment (SunRISE)

    Science.gov (United States)

    Kasper, Justin C.; SunRISE Team

    2018-06-01

    The Sun Radio Interferometer Space Experiment (SunRISE) is a NASA Heliophysics Explorer Mission of Opportunity currently in Phase A. SunRISE is a constellation of spacecraft flying in a 10-km diameter formation and operating as the first imaging radio interferometer in space. The purpose of SunRISE is to reveal critical aspects of solar energetic particle (SEP) acceleration at coronal mass ejections (CMEs) and transport into space by making the first spatially resolved observations of coherent Type II and III radio bursts produced by electrons accelerated at CMEs or released from flares. SunRISE will focus on solar Decametric-Hectometric (DH, 0.1 space before major SEP events, but cannot be seen on Earth due to ionospheric absorption. This talk will describe SunRISE objectives and implementation. Presented on behalf of the entire SunRISE team.

  8. Optimum design of a microwave interferometer for plasma density measurement

    International Nuclear Information System (INIS)

    Lindberg, L.; Eriksson, A.

    1980-11-01

    Theoretical and practical problems arising in the application of microwave interferometry to density measurements on transient plasmas are discussed. The conditions for unambiquous measurements in a density range as wide as possible are analyzed. It is shown that the initial zero adjustment of the interferometer bridge recommended in many text books is the worst possible choice of initial condition when the aim is high initial sensitivity at low densities. The analytic expressions needed for unambiquous evaluation of any phase shift from a few degrees to several times π (counting of fringes) are derived. The practical design of the interferometer circuit and its inherent error sources due to reflexions and non-ideal component properties are discussed. The results are applied to an interferometer operating at 80 GHz used on a pulsed plasma experiment. The minimum measurable phase shift is 2deg and the range of linear densities that have been measured is = 1 . 10 16 - 3 . 10 18 m -2

  9. Detection method of nonlinearity errors by statistical signal analysis in heterodyne Michelson interferometer.

    Science.gov (United States)

    Hu, Juju; Hu, Haijiang; Ji, Yinghua

    2010-03-15

    Periodic nonlinearity that ranges from tens of nanometers to a few nanometers in heterodyne interferometer limits its use in high accuracy measurement. A novel method is studied to detect the nonlinearity errors based on the electrical subdivision and the analysis method of statistical signal in heterodyne Michelson interferometer. Under the movement of micropositioning platform with the uniform velocity, the method can detect the nonlinearity errors by using the regression analysis and Jackknife estimation. Based on the analysis of the simulations, the method can estimate the influence of nonlinearity errors and other noises for the dimensions measurement in heterodyne Michelson interferometer.

  10. Eight-chord CO2 interferometer for plasma-density measurements on ZT-40

    International Nuclear Information System (INIS)

    Jacobson, A.R.; Jolin, L.J.

    1981-01-01

    We describe a CO 2 laser interferometer which measures the path-integrated density along eight different chords simultaneously in the ZT-40 reversed-field pinch, a toroidal magnetic confinement experiment at Los Alamos. The interferometer system combines several reliable, commercially available components in a package which provides exceptional measurement resolution as well as ease of operation and maintenance

  11. Compensation of non-ideal beam splitter polarization distortion effect in Michelson interferometer

    Science.gov (United States)

    Liu, Yeng-Cheng; Lo, Yu-Lung; Liao, Chia-Chi

    2016-02-01

    A composite optical structure consisting of two quarter-wave plates and a single half-wave plate is proposed for compensating for the polarization distortion induced by a non-ideal beam splitter in a Michelson interferometer. In the proposed approach, the optimal orientations of the optical components within the polarization compensator are determined using a genetic algorithm (GA) such that the beam splitter can be treated as a free-space medium and modeled using a unit Mueller matrix accordingly. Two implementations of the proposed polarization controller are presented. In the first case, the compensator is placed in the output arm of Michelson interferometer such that the state of polarization of the interfered output light is equal to that of the input light. However, in this configuration, the polarization effects induced by the beam splitter in the two arms of the interferometer structure cannot be separately addressed. Consequently, in the second case, compensator structures are placed in the Michelson interferometer for compensation on both the scanning and reference beams. The practical feasibility of the proposed approach is introduced by considering a Mueller polarization-sensitive (PS) optical coherence tomography (OCT) structure with three polarization controllers in the input, reference and sample arms, respectively. In general, the results presented in this study show that the proposed polarization controller provides an effective and experimentally-straightforward means of compensating for the polarization distortion effects induced by the non-ideal beam splitters in Michelson interferometers and Mueller PS-OCT structures.

  12. Atom Interferometer Technologies in Space for Gravity Mapping and Gravity Science

    Science.gov (United States)

    Williams, Jason; Chiow, Sheng-Wey; Kellogg, James; Kohel, James; Yu, Nan

    2015-05-01

    Atom interferometers utilize the wave-nature of atomic gases for precision measurements of inertial forces, with potential applications ranging from gravity mapping for planetary science to unprecedented tests of fundamental physics with quantum gases. The high stability and sensitivity intrinsic to these devices already place them among the best terrestrial sensors available for measurements of gravitational accelerations, rotations, and gravity gradients, with the promise of several orders of magnitude improvement in their detection sensitivity in microgravity. Consequently, multiple precision atom-interferometer-based projects are under development at the Jet Propulsion Laboratory, including a dual-atomic-species interferometer that is to be integrated into the Cold Atom Laboratory onboard the International Space Station and a highly stable gravity gradiometer in a transportable design relevant for earth science measurements. We will present JPL's activities in the use of precision atom interferometry for gravity mapping and gravitational wave detection in space. Our recent progresses bringing the transportable JPL atom interferometer instrument to be competitive with the state of the art and simulations of the expected capabilities of a proposed flight project will also be discussed. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  13. A Fiber Interferometer for the Magnetized Shock Experiment

    International Nuclear Information System (INIS)

    Yoo, Christian

    2012-01-01

    The Magnetized Shock Experiment (MSX) at Los Alamos National Laboratory requires remote diagnostics of plasma density. Laser interferometry can be used to determine the line-integrated density of the plasma. A multi-chord heterodyne fiber optic Mach-Zehnder interferometer is being assembled and integrated into the experiment. The advantage of the fiber coupling is that many different view chords can be easily obtained by simply moving transmit and receive fiber couplers. Several such fiber sets will be implemented to provide a time history of line-averaged density for several chords at once. The multiple chord data can then be Abel inverted to provide radially resolved spatial profiles of density. We describe the design and execution of this multiple fiber interferometer.

  14. On-chip Mach-Zehnder interferometer for OCT systems

    Science.gov (United States)

    van Leeuwen, Ton G.; Akca, Imran B.; Angelou, Nikolaos; Weiss, Nicolas; Hoekman, Marcel; Leinse, Arne; Heideman, Rene G.

    2018-04-01

    By using integrated optics, it is possible to reduce the size and cost of a bulky optical coherence tomography (OCT) system. One of the OCT components that can be implemented on-chip is the interferometer. In this work, we present the design and characterization of a Mach-Zehnder interferometer consisting of the wavelength-independent splitters and an on-chip reference arm. The Si3N4 was chosen as the material platform as it can provide low losses while keeping the device size small. The device was characterized by using a home-built swept source OCT system. A sensitivity value of 83 dB, an axial resolution of 15.2 μm (in air) and a depth range of 2.5 mm (in air) were all obtained.

  15. Atomic interferometers in an optical lattice

    International Nuclear Information System (INIS)

    Pelle, Bruno

    2013-01-01

    The aim of the ForCa-G project, for Casimir force and short range Gravitation, lies into the measurement of short range forces between atoms and a mirror using atomic interferometry techniques. Particularly, the Casimir-Polder force and the pursuit of short range gravitational tests in the frame of potential deviations of Newton's law are aimed. This experiment is based on the trapping of neutral atoms in a 1D vertical optical lattice, where the energy eigenvalues of the Hamiltonian describing this system is the so-called Wannier-Stark ladder of discrete energy states localized in each lattice well. This work constitutes a demonstration of principle of this project with atoms set far from the mirror. Each energy state is thus separated from the one of the adjacent well by the potential energy increment between those two wells, called the Bloch frequency ν B . Then, atomic interferometers are realized in the lattice using Raman or microwave pulses where the trapped atomic wave functions are placed, and then recombined, in a superposition of states between different energy states localized either in the same well, either in adjacent wells. This work presents the study of different kinds of atomic interferometers in this optical lattice, characterized in terms of sensibility and systematic effects on the Bloch frequency measurement. One of the studied interferometers accessed to a sensitivity on the Bloch frequency of σ δ ν B /ν B =9.0x10 -6 at 1∼s in relative, which integrates until σ δ ν B /ν B =1. 10 -7 in 2800∼s. This corresponds to a state-of-the-art measurement of the gravity acceleration g for a trapped atomic gravimeter. (author)

  16. AMI: Augmented Michelson Interferometer

    Science.gov (United States)

    Furió, David; Hachet, Martin; Guillet, Jean-Paul; Bousquet, Bruno; Fleck, Stéphanie; Reuter, Patrick; Canioni, Lionel

    2015-10-01

    Experiments in optics are essential for learning and understanding physical phenomena. The problem with these experiments is that they are generally time consuming for both their construction and their maintenance, potentially dangerous through the use of laser sources, and often expensive due to high technology optical components. We propose to simulate such experiments by way of hybrid systems that exploit both spatial augmented reality and tangible interaction. In particular, we focus on one of the most popular optical experiments: the Michelson interferometer. In our approach, we target a highly interactive system where students are able to interact in real time with the Augmented Michelson Interferometer (AMI) to observe, test hypotheses and then to enhance their comprehension. Compared to a fully digital simulation, we are investigating an approach that benefits from both physical and virtual elements, and where the students experiment by manipulating 3D-printed physical replicas of optical components (e.g. lenses and mirrors). Our objective is twofold. First, we want to ensure that the students will learn with our simulator the same concepts and skills that they learn with traditional methods. Second, we hypothesis that such a system opens new opportunities to teach optics in a way that was not possible before, by manipulating concepts beyond the limits of observable physical phenomena. To reach this goal, we have built a complementary team composed of experts in the field of optics, human-computer interaction, computer graphics, sensors and actuators, and education science.

  17. An X-ray BBB Michelson interferometer.

    Science.gov (United States)

    Sutter, John P; Ishikawa, Tetsuya; Kuetgens, Ulrich; Materlik, Gerhard; Nishino, Yoshinori; Rostomyan, Armen; Tamasaku, Kenji; Yabashi, Makina

    2004-09-01

    A new X-ray Michelson interferometer based on the BBB interferometer of Bonse and Hart and designed for X-rays of wavelength approximately 1 A was described in a previous paper. Here, a further test carried out at the SPring-8 1 km beamline BL29XUL is reported. One of the BBB's mirrors was displaced by a piezo to introduce the required path-length difference. The resulting variation of intensity with piezo voltage as measured by an avalanche photodiode could be ascribed to the phase variation resulting from the path-length change, with a small additional contribution from the change of the position of the lattice planes of the front mirror relative to the rest of the crystal. This 'Michelson fringe' interpretation is supported by the observed steady movement across the output beam of the interference fringes produced by a refractive wedge when the piezo voltage was ramped. The front-mirror displacement required for one complete fringe at the given wavelength is only 0.675 A; therefore, a quiet environment is vital for operating this device, as previous experiments have shown.

  18. Density Measurement of Compact Toroid with Mach-Zehnder Interferometer

    Science.gov (United States)

    Laufman-Wollitzer, Lauren; Endrizzi, Doug; Brookhart, Matt; Flanagan, Ken; Forest, Cary

    2016-10-01

    Utilizing a magnetized coaxial plasma gun (MCPG) built by Tri Alpha Energy, a dense compact toroid (CT) is created and injected at high speed into the Wisconsin Plasma Astrophysics Laboratory (WiPAL) vessel. A modified Mach-Zehnder interferometer from the Line-Tied Reconnection Experiment (LTRX) provides an absolute measurement of electron density. The interferometer is located such that the beam intersects the plasma across the diameter of the MCPG drift region before the CT enters the vessel. This placement ensures that the measurement is taken before the CT expand. Results presented will be used to further analyze characteristics of the CT. Funding provided by DoE, NSF, and WISE Summer Research.

  19. A reconfigurable optofluidic Michelson interferometer using tunable droplet grating.

    Science.gov (United States)

    Chin, L K; Liu, A Q; Soh, Y C; Lim, C S; Lin, C L

    2010-04-21

    This paper presents a novel optofluidic Michelson interferometer based on droplet microfluidics used to create a droplet grating. The droplet grating is formed by a stream of plugs in the microchannel with constant refractive index variation. It has a real-time tunability in the grating period through varying the flow rates of the liquids and index variation via different combinations of liquids. The optofluidic Michelson interferometer is highly sensitive and is suitable for the measurement of biomedical and biochemical buffer solutions. The experimental results show that it has a sensitivity of 66.7 nm per refractive index unit (RIU) and a detection range of 0.086 RIU.

  20. Analysis of a micropolarizer array-based simultaneous phase-shifting interferometer.

    Science.gov (United States)

    Novak, Matt; Millerd, James; Brock, Neal; North-Morris, Michael; Hayes, John; Wyant, James

    2005-11-10

    Recent technological innovations have enabled the development of a new class of dynamic (vibration-insensitive) interferometer based on a CCD pixel-level phase-shifting approach. We present theoretical and experimental results for an interferometer based on this pixelated phase-shifting technique. Analyses of component errors and instrument functionality are presented. We show that the majority of error sources cause relatively small magnitude peak-to-valley errors in measurement of the order of 0.002-0.005lambda. These errors are largely mitigated by high-rate data acquisition and consequent data averaging.

  1. Herriott Cell Augmentation of a Quadrature Heterodyne Interferometer

    National Research Council Canada - National Science Library

    Antonsen, Erik

    2002-01-01

    A quadrature heterodyne interferometer is augmented with a Herriott Cell multi-pass reflector to increase instrument resolution and enable a separation of the phase shift due to neutral density from room vibrations...

  2. Search for a stochastic background of 100-MHz gravitational waves with laser interferometers.

    Science.gov (United States)

    Akutsu, Tomotada; Kawamura, Seiji; Nishizawa, Atsushi; Arai, Koji; Yamamoto, Kazuhiro; Tatsumi, Daisuke; Nagano, Shigeo; Nishida, Erina; Chiba, Takeshi; Takahashi, Ryuichi; Sugiyama, Naoshi; Fukushima, Mitsuhiro; Yamazaki, Toshitaka; Fujimoto, Masa-Katsu

    2008-09-05

    This Letter reports the results of a search for a stochastic background of gravitational waves (GW) at 100 MHz by laser interferometry. We have developed a GW detector, which is a pair of 75-cm baseline synchronous recycling (resonant recycling) interferometers. Each interferometer has a strain sensitivity of approximately 10;{-16} Hz;{-1/2} at 100 MHz. By cross-correlating the outputs of the two interferometers within 1000 seconds, we found h{100};{2}Omega_{gw}<6 x 10;{25} to be an upper limit on the energy density spectrum of the GW background in a 2-kHz bandwidth around 100 MHz, where a flat spectrum is assumed.

  3. Interferometer for Measuring Fast Changes of Refractive Index and Temperature in Transparent Liquids

    DEFF Research Database (Denmark)

    Miller, Arne; Hussmann, E. K.; McLaughlin, W. L.

    1975-01-01

    A double‐beam interferometer has been designed for detecting changes of refractive index in transparent liquids associated with the absorption of ionizing radiation energy, due to short electron beam pulses from an accelerator. The response time of the interferometer is less than 0.2 μsec......, and refractive index changes of the order of 10−7 can be measured, corresponding to a temperature change of ∼10−3  °C and an absorbed dose in water of ∼350 rad. The interferometer can be used as either a real‐time or integrating radiation dosimeter, if the temperature coefficient of the refractive index (dn...

  4. Broadband squeezing of quantum noise in a Michelson interferometer with Twin-Signal-Recycling.

    Science.gov (United States)

    Thüring, André; Gräf, Christian; Vahlbruch, Henning; Mehmet, Moritz; Danzmann, Karsten; Schnabel, Roman

    2009-03-15

    Twin-Signal-Recycling (TSR) builds on the resonance doublet of two optically coupled cavities and efficiently enhances the sensitivity of an interferometer at a dedicated signal frequency. We report on what we believe to be the first experimental realization of a TSR Michelson interferometer and also its broadband enhancement by squeezed light injection. The complete setup was stably locked, and a broadband quantum noise reduction of the interferometers shot noise by a factor of up to 4 dB was demonstrated. The system was characterized by measuring its quantum noise spectra for several tunings of the TSR cavities. We found good agreement between the experimental results and numerical simulations.

  5. Interferometers as probes of Planckian quantum geometry

    Science.gov (United States)

    Hogan, Craig J.

    2012-03-01

    A theory of position of massive bodies is proposed that results in an observable quantum behavior of geometry at the Planck scale, tP. Departures from classical world lines in flat spacetime are described by Planckian noncommuting operators for position in different directions, as defined by interactions with null waves. The resulting evolution of position wave functions in two dimensions displays a new kind of directionally coherent quantum noise of transverse position. The amplitude of the effect in physical units is predicted with no parameters, by equating the number of degrees of freedom of position wave functions on a 2D space-like surface with the entropy density of a black hole event horizon of the same area. In a region of size L, the effect resembles spatially and directionally coherent random transverse shear deformations on time scale ≈L/c with typical amplitude ≈ctPL. This quantum-geometrical “holographic noise” in position is not describable as fluctuations of a quantized metric, or as any kind of fluctuation, dispersion or propagation effect in quantum fields. In a Michelson interferometer the effect appears as noise that resembles a random Planckian walk of the beam splitter for durations up to the light-crossing time. Signal spectra and correlation functions in interferometers are derived, and predicted to be comparable with the sensitivities of current and planned experiments. It is proposed that nearly colocated Michelson interferometers of laboratory scale, cross-correlated at high frequency, can test the Planckian noise prediction with current technology.

  6. Combined shearing interferometer and hartmann wavefront sensor

    International Nuclear Information System (INIS)

    Hutchin, R. A.

    1985-01-01

    A sensitive wavefront sensor combining attributes of both a Hartmann type of wavefront sensor and an AC shearing interferometer type of wavefront sensor. An incident wavefront, the slope of which is to be detected, is focussed to first and second focal points at which first and second diffraction gratings are positioned to shear and modulate the wavefront, which then diverges therefrom. The diffraction patterns of the first and second gratings are positioned substantially orthogonal to each other to shear the wavefront in two directions to produce two dimensional wavefront slope data for the AC shearing interferometer portion of the wavefront sensor. First and second dividing optical systems are positioned in the two diverging wavefronts to divide the sheared wavefront into an array of subapertures and also to focus the wavefront in each subaperture to a focal point. A quadrant detector is provided for each subaperture to detect the position of the focal point therein, which provides a first indication, in the manner of a Hartmann wavefront sensor, of the local wavefront slope in each subaperture. The total radiation in each subaperture, as modulated by the diffraction grating, is also detected by the quadrant detector which produces a modulated output signal representative thereof, the phase of which relative to modulation by the diffraction grating provides a second indication of the local wavefront slope in each subaperture, in the manner of an AC shearing interferometer wavefront sensor. The data from both types of sensors is then combined by long term averaging thereof to provide an extremely sensitive wavefront sensor

  7. Explosive component acceptance tester using laser interferometer technology

    Science.gov (United States)

    Wickstrom, Richard D.; Tarbell, William W.

    1993-01-01

    Acceptance testing of explosive components requires a reliable and simple to use testing method that can discern less than optimal performance. For hot-wire detonators, traditional techniques use dent blocks or photographic diagnostic methods. More complicated approaches are avoided because of their inherent problems with setup and maintenance. A recently developed tester is based on using a laser interferometer to measure the velocity of flying plates accelerated by explosively actuated detonators. Unlike ordinary interferometers that monitor displacement of the test article, this device measures velocity directly and is commonly used with non-spectral surfaces. Most often referred to as the VISAR technique (Velocity Interferometer System for Any Reflecting Surface), it has become the most widely-accepted choice for accurate measurement of velocity in the range greater than 1 mm/micro-s. Traditional VISAR devices require extensive setup and adjustment and therefore are unacceptable in a production-testing environment. This paper describes a new VISAR approach which requires virtually no adjustments, yet provides data with accuracy comparable to the more complicated systems. The device, termed the Fixed-Cavity VISAR, is currently being developed to serve as a product verification tool for hot-wire detonators and slappers. An extensive data acquisition and analysis computer code was also created to automate the manipulation of raw data into final results.

  8. Erbium-doped fiber ring laser with SMS modal interferometer for hydrogen sensing

    Science.gov (United States)

    Zhang, Ya-nan; Zhang, Lebin; Han, Bo; Peng, Huijie; Zhou, Tianmin; Lv, Ri-qing

    2018-06-01

    A hydrogen sensor based on erbium-doped fiber ring laser with modal interferometer is proposed. A single mode-multimode-single mode (SMS) modal interferometer structure coated with Pd/WO3 film is used as the sensing head, due to that it is easy to be fabricated and low cost. The sensing structure is inserted into an erbium-doped fiber ring laser in order to solve the problem of spectral confusion and improve the detection limit of the hydrogen sensor based on the SMS modal interferometer. The SMS sensing structure is acted as a fiber band-pass filter. When hydrogen concentration around the sensor is changed, it will induce the refractive index and strain variations of the Pd/WO3 film, and then shift the resonant spectrum of the SMS modal interferometer as well as the laser wavelength of the fiber ring laser. Therefore, the hydrogen concentration can be measured by monitoring the wavelength shift of the laser, which has high intensity and narrow full width half maximum. Experimental results demonstrate that the sensor has high sensitivity of 1.23 nm/%, low detection limit of 0.017%, good stability and excellent repeatability.

  9. Background reduction in a young interferometer biosensor

    NARCIS (Netherlands)

    Mulder, H. K P; Subramaniam, V.; Kanger, J. S.

    2014-01-01

    Integrated optical Young interferometer (IOYI) biosensors are among the most sensitive label-free biosensors. Detection limits are in the range of 20 fg/mm2. The applicability of these sensors is however strongly hampered by the large background that originates from both bulk refractive index

  10. Loop kinematics

    International Nuclear Information System (INIS)

    Migdal, A.A.

    1982-01-01

    Basic operators acting in the loop space are introduced. The topology of this space and properties of the Stokes type loop functionals are discussed. The parametrically invariant loop calculus developed here is used in the loop dynamics

  11. Operational experience with synchrotron light interferometers for CEBAF experimental beam lines

    Energy Technology Data Exchange (ETDEWEB)

    Pavel Chevtsov

    2006-10-24

    Beam size and energy spread monitoring systems based on Synchrotron Light Interferometers (SLI) have been in operations at Jefferson Lab for several years. A non-invasive nature and a very high (a few mm) resolution of SLI make these instruments valuable beam diagnostic tools for the CEBAF accelerator. This presentation describes the evolution of the Synchrotron Light Interferometer at Jefferson Lab and highlights our extensive experience in the installation and operation of the SLI for CEBAF experimental beam lines.

  12. Preliminary result of bunch length measurement using a modified Michelson interferometer

    International Nuclear Information System (INIS)

    Lin Xuling; Luo Feng; Bei Hua; Dai Zhimin; Chinese Academy of Sciences, Beijing; Zhang Jianbing; Lu Shanliang; Yu Tiemin

    2009-01-01

    Based on the femtosecond accelerator device which was built at the Shanghai Institute of Applied Physics (SINAP), recently a modified far infrared Michelson interferometer has been developed to measure the length of electron bunches via the optical autocorrelation method. Compared with our former normal Michelson interferometer, we use a hollow retroreflector instead of a flat mirror as the reflective mirror. The experimental setup and results of the bunch length measurement will be described in this paper. (authors)

  13. The Design and Implementation of the Wide-Angle Michelson Interferometer to Observe Thermospheric Winds.

    Science.gov (United States)

    Ward, William Edmund

    The design and implementation of a Wide-Angle Michelson interferometer (WAMI) as a high spectral resolution device for measuring Doppler shifts and temperatures in the thermosphere is discussed in detail. A general theoretical framework is developed to describe the behavior of interferometers and is applied to the WAMI. Notions concerning the optical coupling of various surfaces within an interferometer are developed and used to investigate the effects of misalignments in the WAMI optics. In addition, these notions in combination with ideas on the polarization behavior of interferometers are used to suggest how complex multisurfaced interferometers might be developed, what features affect their behavior most strongly, and how this behavior might be controlled. Those aspects of the Michelson interferometer important to its use as a high resolution spectral device are outlined and expressions relating the physical features of the interferometer and the spectral features of the radiation passing through the instrument, to the form of the observed interference pattern are derived. The sensitivity of the WAMI to misalignments in its optical components is explored, and quantitative estimations of the effects of these misalignments made. A working WAMI with cube corners instead of plane mirrors was constructed and is described. The theoretical notions outlined above are applied to this instrument and found to account for most of its features. A general digital procedure is developed for the analysis of the observed interference fringes which permits an estimation of the amplitude, visibility and phase of the fringes. This instrument was taken to Bird, northern Manitoba as part of the ground based support for the Auroral Rocket and Image Excitation Study (ARIES) rocket campaign. Doppler shifts and linewidth variations in O(^1 D) and O(^1S) emissions in the aurora were observed during several nights and constitute the first synoptic wind measurements taken with a WAMI. The

  14. Crosstalk Cancellation for a Simultaneous Phase Shifting Interferometer

    Science.gov (United States)

    Olczak, Eugene (Inventor)

    2014-01-01

    A method of minimizing fringe print-through in a phase-shifting interferometer, includes the steps of: (a) determining multiple transfer functions of pixels in the phase-shifting interferometer; (b) computing a crosstalk term for each transfer function; and (c) displaying, to a user, a phase-difference map using the crosstalk terms computed in step (b). Determining a transfer function in step (a) includes measuring intensities of a reference beam and a test beam at the pixels, and measuring an optical path difference between the reference beam and the test beam at the pixels. Computing crosstalk terms in step (b) includes computing an N-dimensional vector, where N corresponds to the number of transfer functions, and the N-dimensional vector is obtained by minimizing a variance of a modulation function in phase shifted images.

  15. CAMEX-3 ATMOSPHERIC EMITTED RADIANCE INTERFEROMETER (AERI) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Atmospheric Emitted Radiance Interferometer (AERI) was used to make atmospheric temperature and moisture retrievals. AERI provides absolutely calibrated...

  16. Experimental investigation of a control scheme for a zero-detuning resonant sideband extraction interferometer for next-generation gravitational-wave detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kawazoe, Fumiko; Sugamoto, Akio [Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610 (Japan); Leonhardt, Volker; Sato, Shuichi; Yamazaki, Toshitaka; Fukushima, Mitsuhiro; Kawamura, Seiji [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka-shi, Tokyo 181-8588 (Japan); Miyakawa, Osamu [LIGO Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Somiya, Kentaro [Max-Planck-Institut fuer Gravitationsphysik, Am Muehlenberg 1, 14476 Potsdam (Germany); Morioka, Tomoko [University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Nishizawa, Atsushi [Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501 (Japan)], E-mail: fumiko.kawazoe@aei.mpg.de

    2008-10-07

    Some next-generation gravitational-wave detectors, such as the American Advanced LIGO project and the Japanese LCGT project, plan to use power recycled resonant sideband extraction (RSE) interferometers for their interferometer's optical configuration. A power recycled zero-detuning (PRZD) RSE interferometer, which is the default design for LCGT, has five main length degrees of freedom that need to be controlled in order to operate a gravitational-wave detector. This task is expected to be very challenging because of the complexity of optical configuration. A new control scheme for a PRZD RSE interferometer has been developed and tested with a prototype interferometer. The PRZD RSE interferometer was successfully locked with the control scheme. It is the first experimental demonstration of a PRZD RSE interferometer with suspended test masses. The result serves as an important step for the operation of LCGT.

  17. Experimental investigation of a control scheme for a zero-detuning resonant sideband extraction interferometer for next-generation gravitational-wave detectors

    International Nuclear Information System (INIS)

    Kawazoe, Fumiko; Sugamoto, Akio; Leonhardt, Volker; Sato, Shuichi; Yamazaki, Toshitaka; Fukushima, Mitsuhiro; Kawamura, Seiji; Miyakawa, Osamu; Somiya, Kentaro; Morioka, Tomoko; Nishizawa, Atsushi

    2008-01-01

    Some next-generation gravitational-wave detectors, such as the American Advanced LIGO project and the Japanese LCGT project, plan to use power recycled resonant sideband extraction (RSE) interferometers for their interferometer's optical configuration. A power recycled zero-detuning (PRZD) RSE interferometer, which is the default design for LCGT, has five main length degrees of freedom that need to be controlled in order to operate a gravitational-wave detector. This task is expected to be very challenging because of the complexity of optical configuration. A new control scheme for a PRZD RSE interferometer has been developed and tested with a prototype interferometer. The PRZD RSE interferometer was successfully locked with the control scheme. It is the first experimental demonstration of a PRZD RSE interferometer with suspended test masses. The result serves as an important step for the operation of LCGT

  18. The effect of losses on the quantum-noise cancellation in the SU(1,1) interferometer

    International Nuclear Information System (INIS)

    Xin, Jun; Wang, Hailong; Jing, Jietai

    2016-01-01

    Quantum-noise cancellation (QNC) is an effective method to control the noise of the quantum system, which reduces or even eliminates the noise of the quantum systems by utilizing destructive interference in the quantum system. However, QNC can be extremely dependent on the losses inside the system. In this letter, we experimentally and theoretically study how the losses can affect the QNC in the SU(1,1) interferometer. We find that losses in the different arms inside the SU(1,1) interferometer can have different effects on the QNC in the output fields from the SU(1,1) interferometer. And the QNC in the SU(1,1) interferometer can almost be insensitive to the losses in some cases. Our findings may find its potential applications in the quantum noise control.

  19. The effect of losses on the quantum-noise cancellation in the SU(1,1) interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Xin, Jun; Wang, Hailong [State Key Laboratory of Precision Spectroscopy, School of Physics and Materials Science, East China Normal University, Shanghai 200062 (China); Jing, Jietai, E-mail: jtjing@phy.ecnu.edu.cn [State Key Laboratory of Precision Spectroscopy, School of Physics and Materials Science, East China Normal University, Shanghai 200062 (China); Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006 (China)

    2016-08-01

    Quantum-noise cancellation (QNC) is an effective method to control the noise of the quantum system, which reduces or even eliminates the noise of the quantum systems by utilizing destructive interference in the quantum system. However, QNC can be extremely dependent on the losses inside the system. In this letter, we experimentally and theoretically study how the losses can affect the QNC in the SU(1,1) interferometer. We find that losses in the different arms inside the SU(1,1) interferometer can have different effects on the QNC in the output fields from the SU(1,1) interferometer. And the QNC in the SU(1,1) interferometer can almost be insensitive to the losses in some cases. Our findings may find its potential applications in the quantum noise control.

  20. Development of high resolution Michelson interferometer for stable phase-locked ultrashort pulse pair generation.

    Science.gov (United States)

    Okada, Takumi; Komori, Kazuhiro; Goshima, Keishiro; Yamauchi, Shohgo; Morohashi, Isao; Sugaya, Takeyoshi; Ogura, Mutsuo; Tsurumachi, Noriaki

    2008-10-01

    We developed a high resolution Michelson interferometer with a two-frequency He-Ne laser positioning system in order to stabilize the relative phase of a pulse pair. The control resolution corresponded to a 12 as time resolution or a phase of 1.5 degrees at 900 nm. This high resolution Michelson interferometer can generate a phase-locked pulse pair either with a specific relative phase such as 0 or pi radians or with an arbitrary phase. Coherent control of an InAs self-assembled quantum dot was demonstrated using the high resolution Michelson interferometer with a microspectroscopy system.

  1. Report on the set-up of a holographic interferometer

    International Nuclear Information System (INIS)

    Koster, J.N.

    1977-10-01

    Holographic interferometry is well suited for visualizing temperature, density, pressure and concentration fields in transparent fluids. The holographic real-time interferometer allows a continuous observation of stationary and instationary flow processes. After the explanation of the measuring technique, the problems arising during the interferometer set-up as well as the necessary adjusting operations are described. For heat transfer problems new possibilities for the application of holographic interferometry are revealed. Convection in boxes, temperature fields around heated or cooled bodies, concentration and diffusion processes in two phase-flows, mixtures and solutions as well as melting and freezing processes may be investigated. On the basis of particular examples some applications are presented. (orig.) [de

  2. The Michelson interferometer-how to detect invisible interference patterns

    International Nuclear Information System (INIS)

    Verovnik, Ivo; Likar, Andrej

    2004-01-01

    In a Michelson interferometer, the contrast of the interference pattern fades away due to incoherence of light when the mirrors are not in equidistant positions. We propose an experiment where the distance between the interference fringes can be determined, even when the difference in length of the interferometer arms is far beyond the coherence length of the light, i.e. when the interference pattern disappears completely for the naked eye. We used a semiconductor laser with two photodiodes as sensors, which enabled us to follow the fluctuations of the light intensity on the screen. The distance between invisible interference fringes was determined from periodic changes of the summed fluctuating signal, obtained by changing the distance between the two sensors

  3. Method and apparatus for measuring surface movement of an object using a polarizing interferometer

    Science.gov (United States)

    Schultz, T.J.; Kotidis, P.A.; Woodroffe, J.A.; Rostler, P.S.

    1995-05-09

    A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figs.

  4. The observation of the Aharonov-Bohm effect in suspended semiconductor ring interferometers

    Science.gov (United States)

    Pokhabov, D. A.; Pogosov, A. G.; Shevyrin, A. A.; Zhdanov, E. Yu; Bakarov, A. K.; Shklyaev, A. A.; Ishutkin, S. V.; Stepanenko, M. V.; Shesterikov, E. V.

    2018-02-01

    A suspended semiconductor quantum ring interferometer based on a GaAs/AlGaAs heterostructure with a two-dimensional electron gas (2DEG) is created and experimentally studied. The electron interference in suspended 2DEG is observed. The interference manifests itself as the Aharonov-Bohm oscillations of the interferometer magnetoresistance, clearly observed before as well as after suspension. The amplitude of the oscillations remains almost unchanged after suspension.

  5. Simultaneous measurement of gravity acceleration and gravity gradient with an atom interferometer

    International Nuclear Information System (INIS)

    Sorrentino, F.; Lien, Y.-H.; Rosi, G.; Tino, G. M.; Bertoldi, A.; Bodart, Q.; Cacciapuoti, L.; Angelis, M. de; Prevedelli, M.

    2012-01-01

    We demonstrate a method to measure the gravitational acceleration with a dual cloud atom interferometer; the use of simultaneous atom interferometers reduces the effect of seismic noise on the gravity measurement. At the same time, the apparatus is capable of accurate measurements of the vertical gravity gradient. The ability to determine the gravity acceleration and gravity gradient simultaneously and with the same instrument opens interesting perspectives in geophysical applications.

  6. The TEXT upgrade vertical interferometer

    International Nuclear Information System (INIS)

    Hallock, G.A.; Gartman, M.L.; Li, W.; Chiang, K.; Shin, S.; Castles, R.L.; Chatterjee, R.; Rahman, A.S.

    1992-01-01

    A far-infrared interferometer has been installed on TEXT upgrade to obtain electron density profiles. The primary system views the plasma vertically through a set of large (60-cm radialx7.62-cm toroidal) diagnostic ports. A 1-cm channel spacing (59 channels total) and fast electronic time response is used, to provide high resolution for radial profiles and perturbation experiments. Initial operation of the vertical system was obtained late in 1991, with six operating channels

  7. A microwave interferometer for density measurement and stabilization in process plasmas

    International Nuclear Information System (INIS)

    Pearson, D.I.C.; Campbell, G.A.; Domier, C.W.

    1988-01-01

    A low-cost heterodyne microwave interferometer system capable of measuring and/or controlling the plasma density over a dynamic range covering two orders of magnitude is demonstrated. The microwave frequency is chosen to match the size and density of plasma to be monitored. Large amplitude, high frequency fluctuations can be quantitatively followed and the longer-time-scale density can be held constant over hours of operation, for example during an inline production process to maintain uniformity and stoichiometry of films. A linear relationship is shown between plasma density and discharge current in a specific plasma device. This simple relationship makes control of the plasma straightforward using the interferometer as a density monitor. Other plasma processes could equally well benefit from such density control capability. By combining the interferometer measurement with diagnostics such as probes or optical spectroscopy, the total density profile and the constituent proportions of the various species in the plasma could be determined

  8. Stable mounting of beamsplitters for an interferometer

    NARCIS (Netherlands)

    Veggel, van A.A.; Nijmeijer, H.

    2008-01-01

    The Basic Angle Monitoring (BAM) system for satellite GAIA (2012–2018) will measure variation on the angle between the lines-of-sight between two telescopes with 2.5 prad uncertainty. It is a laser-interferometer system consisting of two optical benches with a number of mirrors and beamsplitters.

  9. Near-Infrared Keck Interferometer and IOTA Closure Phase Observations of Wolf-Rayet stars

    Science.gov (United States)

    Rajagopal, J.; Wallace, D.; Barry, R.; Richardson, L. J.; Traub, W.; Danchi, W. C.

    We present first results from observations of a small sample of IR-bright Wolf-Rayet stars with the Keck Interferometer in the near-infrared, and with the IONIC beam three-telescope beam combiner at the Infrared and Optical Telescope Array (IOTA) observatory. The former results were obtained as part of shared-risk observations in commissioning the Keck Interferometer and form a subset of a high-resolution study of dust around Wolf-Rayet stars using multiple interferometers in progress in our group. The latter results are the first closure phase observations of these stars in the near-infrared in a separated telescope interferometer. Earlier aperture-masking observations with the Keck-I telescope provide strong evidence that dust-formation in late-type WC stars are a result of wind-wind collision in short-period binaries.Our program with the Keck interferometer seeks to further examine this paradigm at much higher resolution. We have spatially resolved the binary in the prototypical dusty WC type star WR 140. WR 137, another episodic dust-producing star, has been partially resolved for the first time, providing the first direct clue to its possible binary nature.We also include WN stars in our sample to investigate circumstellar dust in this other main sub-type of WRs. We have been unable to resolve any of these, indicating a lack of extended dust.Complementary observations using the MIDI instrument on the VLTI in the mid-infrared are presented in another contribution to this workshop.

  10. Non-destructive evaluation of fiber-reinforced composites with a fast 2D fiber-optic laser-ultrasound scanner

    Science.gov (United States)

    Pelivanov, Ivan; Buma, Takashi; Xia, Jinjun; Wei, Chen-Wei; Shtokolov, Alex; O'Donnell, Matthew

    2015-03-01

    Laser ultrasonic (LU) inspection represents an attractive, non-contact method to evaluate composite materials. Current non-contact systems, however, have relatively low sensitivity compared to contact piezoelectric detection. They are also difficult to adjust, very expensive, and strongly influenced by environmental noise. Here, we demonstrate that most of these drawbacks can be eliminated by combining a new generation of compact, inexpensive fiber lasers with new developments in fiber telecommunication optics and an optimally designed balanced probe scheme. In particular, a new type of a balanced fiber-optic Sagnac interferometer is presented as part of an all-optical LU pump-probe system for high speed non-destructive testing and evaluation (NDT&E) of aircraft composites. The performance of the LU system is demonstrated on a composite sample typically used in the aircraft industry. Wide-band ultrasound probe signals are generated directly at the sample surface with a pulsed diode-pumped laser delivering nanosecond laser pulses at a 1 kHz repetition rate with a pulse energy of 2 mJ. A balanced fiber-optic Sagnac interferometer is employed to detect pressure signals in a 1-10 MHz frequency range at the same point (an 8 μm focal spot) on the composite surface. A fast (up to 100 mm/s) 2D translation system is employed to move the sample during scanning and produce a complete B-scan consisting of one thousand A-scans in less than a second. The sensitivity of this system, in terms of the noise equivalent pressure, is found to be only 10 dB above the Nyquist thermal noise limit. To our knowledge, this is the best reported sensitivity for a non-contact ultrasonic detector of this dimension.

  11. Analysis of a quantum nondemolition speed-meter interferometer

    International Nuclear Information System (INIS)

    Purdue, Patricia

    2002-01-01

    In the quest to develop viable designs for third-generation optical interferometric gravitational-wave detectors (e.g. LIGO-III and EURO), one strategy is to monitor the relative momentum or speed of the test-mass mirrors rather than monitoring their relative position. This paper describes and analyzes the most straightforward design for a speed meter interferometer that accomplishes this--a design (due to Braginsky, Gorodetsky, Khalili and Thorne) that is analogous to a microwave-cavity speed meter conceived by Braginsky and Khalili. A mathematical mapping between the microwave speed meter and the optical interferometric speed meter is developed and is used to show [in accord with the speed being a quantum nondemolition observable] that in principle the interferometric speed meter can beat the gravitational-wave standard quantum limit (SQL) by an arbitrarily large amount, over an arbitrarily wide range of frequencies, and can do so without the use of squeezed vacuum or any auxiliary filter cavities at the interferometer's input or output. However, in practice, to reach or beat the SQL, this specific speed meter requires exorbitantly high input light power. The physical reason for this is explored, along with other issues such as constraints on performance due to optical dissipation. This analysis forms a foundation for ongoing attempts to develop a more practical variant of an interferometric speed meter and to combine the speed meter concept with other ideas to yield a promising LIGO-III/EURO interferometer design that entails low laser power

  12. Adaptive DFT-Based Interferometer Fringe Tracking

    Science.gov (United States)

    Wilson, Edward; Pedretti, Ettore; Bregman, Jesse; Mah, Robert W.; Traub, Wesley A.

    2005-12-01

    An automatic interferometer fringe tracking system has been developed, implemented, and tested at the Infrared Optical Telescope Array (IOTA) Observatory at Mount Hopkins, Arizona. The system can minimize the optical path differences (OPDs) for all three baselines of the Michelson stellar interferometer at IOTA. Based on sliding window discrete Fourier-transform (DFT) calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on offline data. Implemented in ANSI C on the 266 MHz PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately [InlineEquation not available: see fulltext.] milliseconds per scan (including all three interferograms), using the science camera and piezo scanners to measure and correct the OPDs. The adaptive DFT-based tracking algorithm should be applicable to other systems where there is a need to detect or track a signal with an approximately constant-frequency carrier pulse. One example of such an application might be to the field of thin-film measurement by ellipsometry, using a broadband light source and a Fourier-transform spectrometer to detect the resulting fringe patterns.

  13. Adaptive DFT-Based Interferometer Fringe Tracking

    Directory of Open Access Journals (Sweden)

    Wesley A. Traub

    2005-09-01

    Full Text Available An automatic interferometer fringe tracking system has been developed, implemented, and tested at the Infrared Optical Telescope Array (IOTA Observatory at Mount Hopkins, Arizona. The system can minimize the optical path differences (OPDs for all three baselines of the Michelson stellar interferometer at IOTA. Based on sliding window discrete Fourier-transform (DFT calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on offline data. Implemented in ANSI C on the 266 MHz PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately 2.0 milliseconds per scan (including all three interferograms, using the science camera and piezo scanners to measure and correct the OPDs. The adaptive DFT-based tracking algorithm should be applicable to other systems where there is a need to detect or track a signal with an approximately constant-frequency carrier pulse. One example of such an application might be to the field of thin-film measurement by ellipsometry, using a broadband light source and a Fourier-transform spectrometer to detect the resulting fringe patterns.

  14. A prototype imaging second harmonic interferometer

    International Nuclear Information System (INIS)

    Jobes, F.C.; Bretz, N.L.

    1997-01-01

    We have built a prototype imaging second harmonic interferometer, which is intended to test critical elements of a design for a tangential array interferometer on C-Mod 6 . The prototype uses a pulsed, 35 mJ, 10 Hz multimode, Nd:YAG laser, LiB 3 O 5 doublers, a fan beam created by a cylindrical lens, four retroreflector elements, and a CCD camera as a detector. The prototype also uses a polarization scheme in which the interference information is eventually carried by two second harmonic beams with crossed polarization. These are vector summed and differenced, and separated, by a Wollaston prism, to give two spots on the CCD. There is a pair of these spots for each retroreflector used. The phase information is directly available as the ratio of the difference to sum the intensities of the two spots. We have tested a single channel configuration of this prototype, varying the phase by changing the pressure in an air cell, and we have obtained a 5:1 light to dark ratio, and a clear sinusoidal variation of the ratio as a function of pressure change. copyright 1997 American Institute of Physics

  15. Optofluidic in-fiber interferometer based on hollow optical fiber with two cores.

    Science.gov (United States)

    Yuan, Tingting; Yang, Xinghua; Liu, Zhihai; Yang, Jun; Li, Song; Kong, Depeng; Qi, Xiuxiu; Yu, Wenting; Long, Qunlong; Yuan, Libo

    2017-07-24

    We demonstrate a novel integrated optical fiber interferometer for in-fiber optofluidic detection. It is composed of a specially designed hollow optical fiber with a micro-channel and two cores. One core on the inner surface of the micro-channel is served as sensing arm and the other core in the annular cladding is served as reference arm. Fusion-and-tapering method is employed to couple light from a single mode fiber to the hollow optical fiber in this device. Sampling is realized by side opening a microhole on the surface of the hollow optical fiber. Under differential pressure between the end of the hollow fiber and the microhole, the liquids can form steady microflows in the micro-channel. Simultaneously, the interference spectrum of the interferometer device shifts with the variation of the concentration of the microfluid in the channel. The optofluidic in-fiber interferometer has a sensitivity of refractive index around 2508 nm/RIU for NaCl. For medicine concentration detection, its sensitivity is 0.076 nm/mmolL -1 for ascorbic acid. Significantly, this work presents a compact microfluidic in-fiber interferometer with a micro-channel which can be integrated with chip devices without spatial optical coupling and without complex manufacturing procedure of the waveguide on the chips.

  16. Fast and low power Michelson interferometer thermo-optical switch on SOI.

    Science.gov (United States)

    Song, Junfeng; Fang, Q; Tao, S H; Liow, T Y; Yu, M B; Lo, G Q; Kwong, D L

    2008-09-29

    We designed and fabricated silicon-on-insulator based Michelson interferometer (MI) thermo-optical switches with deep etched trenches for heat-isolation. Switch power was reduced approximately 20% for the switch with deep etched trenches, and the MI saved approximately 50% power than that of the Mach-Zehnder interferometer. 10.6 mW switch power, approximately 42 micros switch time for the MI with deep trenches, 13.14 mW switch power and approximately 34 micros switch time for the MI without deep trenches were achieved.

  17. Development of measurement system for gauge block interferometer

    Science.gov (United States)

    Chomkokard, S.; Jinuntuya, N.; Wongkokua, W.

    2017-09-01

    We developed a measurement system for collecting and analyzing the fringe pattern images from a gauge block interferometer. The system was based on Raspberry Pi which is an open source system with python programming and opencv image manipulation library. The images were recorded by the Raspberry Pi camera with five-megapixel capacity. The noise of images was suppressed for the best result in analyses. The low noise images were processed to find the edge of fringe patterns using the contour technique for the phase shift analyses. We tested our system with the phase shift patterns between a gauge block and a reference plate. The phase shift patterns were measured by a Twyman-Green type of interferometer using the He-Ne laser with the temperature controlled at 20.0 °C. The results of the measurement will be presented and discussed.

  18. A fiber-coupled displacement measuring interferometer for determination of the posture of a reflective surface

    International Nuclear Information System (INIS)

    Mao, Shuai; Hu, Peng-Cheng; Ding, Xue-Mei; Tan, Jiu-Bin

    2016-01-01

    A fiber-coupled displacement measuring interferometer capable of determining of the posture of a reflective surface of a measuring mirror is proposed. The newly constructed instrument combines fiber-coupled displacement and angular measurement technologies. The proposed interferometer has advantages of both the fiber-coupled and the spatially beam-separated interferometer. A portable dual-position sensitive detector (PSD)-based unit within this proposed interferometer measures the parallelism of the two source beams to guide the fiber-coupling adjustment. The portable dual PSD-based unit measures not only the pitch and yaw of the retro-reflector but also measures the posture of the reflective surface. The experimental results of displacement calibration show that the deviations between the proposed interferometer and a reference one, Agilent 5530, at two different common beam directions are both less than ±35 nm, thus verifying the effectiveness of the beam parallelism measurement. The experimental results of angular calibration show that deviations of pitch and yaw with the auto-collimator (as a reference) are less than ±2 arc sec, thus proving the proposed interferometer’s effectiveness for determination of the posture of a reflective surface.

  19. Polymer/silica hybrid waveguide temperature sensor based on asymmetric Mach-Zehnder interferometer

    Science.gov (United States)

    Niu, Donghai; Wang, Xibin; Sun, Shiqi; Jiang, Minghui; Xu, Qiang; Wang, Fei; Wu, Yuanda; Zhang, Daming

    2018-04-01

    A highly sensitive waveguide temperature sensor based on asymmetric Mach-Zehnder interferometer was designed and experimentally demonstrated. The interferometer is based on the polymer/silica hybrid waveguide structure, and Norland Optical Adhesive 73 (NOA 73) was employed as the waveguide core to enhance the temperature sensitivity. The influence of the different length differences between the two interferometer arms on the sensitivity of the sensor was systemically studied. It is shown that the maximum temperature sensitivity of -431 pm °C-1 can be obtained in the range of 25 °C-75 °C, while the length difference is 92 μm. Moreover, the temperature sensitivity contributions from different core materials were also investigated experimentally. It is shown that the waveguide material and microstructure of the device have significant influences on the sensitivity of the waveguide temperature sensor.

  20. Development of control and data processing system for CO2 laser interferometer

    International Nuclear Information System (INIS)

    Chiba, Shinichi; Kawano, Yasunori; Tsuchiya, Katsuhiko; Inoue, Akira

    2001-11-01

    CO 2 laser interferometer diagnostic has been operating to measure the central electron density in JT-60U plasmas. We have developed a control and data processing system for the CO 2 laser interferometer with flexible functions of data acquisition, data processing and data transfer in accordance with the sequence of JT-60U discharges. This system is mainly composed of two UNIX workstations and CAMAC clusters, in which the high reliability was obtained by sharing the data process functions to the each workstations. Consequently, the control and data processing system becomes to be able to provide electron density data immediately after a JT-60U discharge, routinely. The realtime feedback control of electron density in JT-60U also becomes to be available by using a reference density signal from the CO 2 laser interferometer. (author)

  1. Generation of Optical Vortex Arrays Using Single-Element Reversed-Wavefront Folding Interferometer

    Directory of Open Access Journals (Sweden)

    Brijesh Kumar Singh

    2012-01-01

    Full Text Available Optical vortex arrays have been generated using simple, novel, and stable reversed-wavefront folding interferometer. Two new interferometric configurations were used for generating a variety of optical vortex lattices. In the first interferometric configuration one cube beam splitter (CBS was used in one arm of Mach-Zehnder interferometer for splitting and combining the collimated beam, and one mirror of another arm is replaced by second CBS. At the output of interferometer, three-beam interference gives rise to optical vortex arrays. In second interferometric configuration, a divergent wavefront was made incident on a single CBS which splits and combines wavefronts leading to the generation of vortex arrays due to four-beam interference. It was found that the orientation and structure of the optical vortices can be stably controlled by means of changing the rotation angle of CBS.

  2. Two-loop polygon Wilson loops in N = 4 SYM

    International Nuclear Information System (INIS)

    Anastasiou, C.; Brandhuber, A.; Heslop, P.; Spence, B.; Travaglini, G.; Khoze, V.V.

    2009-01-01

    We compute for the first time the two-loop corrections to arbitrary n-gon lightlike Wilson loops in N = 4 supersymmetric Yang-Mills theory, using efficient numerical methods. The calculation is motivated by the remarkable agreement between the finite part of planar six-point MHV amplitudes and hexagon Wilson loops which has been observed at two loops. At n = 6 we confirm that the ABDK/BDS ansatz must be corrected by adding a remainder function, which depends only on conformally invariant ratios of kinematic variables. We numerically compute remainder functions for n = 7,8 and verify dual conformal invariance. Furthermore, we study simple and multiple collinear limits of the Wilson loop remainder functions and demonstrate that they have precisely the form required by the collinear factorisation of the corresponding two-loop n-point amplitudes. The number of distinct diagram topologies contributing to the n-gon Wilson loops does not increase with n, and there is a fixed number of 'master integrals', which we have computed. Thus we have essentially computed general polygon Wilson loops, and if the correspondence with amplitudes continues to hold, all planar n-point two-loop MHV amplitudes in the N = 4 theory.

  3. Strongly coupled chameleon fields: Possible test with a neutron Lloyd's mirror interferometer

    International Nuclear Information System (INIS)

    Pokotilovski, Yu.N.

    2013-01-01

    The consideration of possible neutron Lloyd's mirror interferometer experiment to search for strongly coupled chameleon fields is presented. The chameleon scalar fields were proposed to explain the acceleration of expansion of the Universe. The presence of a chameleon field results in a change of a particle's potential energy in vicinity of a massive body. This interaction causes a phase shift of neutron waves in the interferometer. The sensitivity of the method is estimated

  4. Quantum light in coupled interferometers for quantum gravity tests.

    Science.gov (United States)

    Ruo Berchera, I; Degiovanni, I P; Olivares, S; Genovese, M

    2013-05-24

    In recent years quantum correlations have received a lot of attention as a key ingredient in advanced quantum metrology protocols. In this Letter we show that they provide even larger advantages when considering multiple-interferometer setups. In particular, we demonstrate that the use of quantum correlated light beams in coupled interferometers leads to substantial advantages with respect to classical light, up to a noise-free scenario for the ideal lossless case. On the one hand, our results prompt the possibility of testing quantum gravity in experimental configurations affordable in current quantum optics laboratories and strongly improve the precision in "larger size experiments" such as the Fermilab holometer; on the other hand, they pave the way for future applications to high precision measurements and quantum metrology.

  5. Optical-fiber interferometer for velocity measurements with picosecond resolution

    International Nuclear Information System (INIS)

    Weng Jidong; Tan Hua; Wang Xiang; Ma Yun; Hu Shaolou; Wang Xiaosong

    2006-01-01

    The conventional Doppler laser-interference velocimeters are made up of traditional optical elements such as lenses and mirrors and will generally restrict its applications in multipoint velocity measurements. By transfering the light from multimode optical fiber to single-mode optical fiber and using the currently available conventional telecommunications elements, the authors have constructed a velocimeter called all-fiber displacement interferometer system for any reflector. The unique interferometer system is only made up of fibers or fiber-coupled components. The viability of this technique is demonstrated by measuring the velocity of an interface moving at velocity of 2133 m/s with 50 ps time resolution. In addition, the concept of optical-fiber mode conversion would provide a way to develop various optical-fiber sensors

  6. Parametric Instability in Advanced Laser Interferometer Gravitational Wave Detectors

    International Nuclear Information System (INIS)

    Ju, L; Grass, S; Zhao, C; Degallaix, J; Blair, D G

    2006-01-01

    High frequency parametric instabilities in optical cavities are radiation pressure induced interactions between test mass mechanical modes and cavity optical modes. The parametric gain depends on the cavity power and the quality factor of the test mass internal modes (usually in ultrasonic frequency range), as well as the overlap integral for the mechanical and optical modes. In advanced laser interferometers which require high optical power and very low acoustic loss test masses, parametric instabilities could prevent interferometer operation if not suppressed. Here we review the problem of parametric instabilities in advanced detector configurations for different combinations of sapphire and fused silica test masses, and compare three methods for control or suppression of parametric instabilities-thermal tuning, surface damping and active feedback

  7. Alternative loop rings

    CERN Document Server

    Goodaire, EG; Polcino Milies, C

    1996-01-01

    For the past ten years, alternative loop rings have intrigued mathematicians from a wide cross-section of modern algebra. As a consequence, the theory of alternative loop rings has grown tremendously. One of the main developments is the complete characterization of loops which have an alternative but not associative, loop ring. Furthermore, there is a very close relationship between the algebraic structures of loop rings and of group rings over 2-groups. Another major topic of research is the study of the unit loop of the integral loop ring. Here the interaction between loop rings and group ri

  8. Feasibility evaluation of a neutron grating interferometer with an analyzer grating based on a structured scintillator

    Science.gov (United States)

    Kim, Youngju; Kim, Jongyul; Kim, Daeseung; Hussey, Daniel. S.; Lee, Seung Wook

    2018-03-01

    We introduce an analyzer grating based on a structured scintillator fabricated by a gadolinium oxysulfide powder filling method for a symmetric Talbot-Lau neutron grating interferometer. This is an alternative way to analyze the Talbot self-image of a grating interferometer without using an absorption grating to block neutrons. Since the structured scintillator analyzer grating itself generates the signal for neutron detection, we do not need an additional scintillator screen as an absorption analyzer grating. We have developed and tested an analyzer grating based on a structured scintillator in our symmetric Talbot-Lau neutron grating interferometer to produce high fidelity absorption, differential phase, and dark-field contrast images. The acquired images have been compared to results of a grating interferometer utilizing a typical absorption analyzer grating with two commercial scintillation screens. The analyzer grating based on the structured scintillator enhances interference fringe visibility and shows a great potential for economical fabrication, compact system design, and so on. We report the performance of the analyzer grating based on a structured scintillator and evaluate its feasibility for the neutron grating interferometer.

  9. Non-coaxial superposition of vector vortex beams.

    Science.gov (United States)

    Aadhi, A; Vaity, Pravin; Chithrabhanu, P; Reddy, Salla Gangi; Prabakar, Shashi; Singh, R P

    2016-02-10

    Vector vortex beams are classified into four types depending upon spatial variation in their polarization vector. We have generated all four of these types of vector vortex beams by using a modified polarization Sagnac interferometer with a vortex lens. Further, we have studied the non-coaxial superposition of two vector vortex beams. It is observed that the superposition of two vector vortex beams with same polarization singularity leads to a beam with another kind of polarization singularity in their interaction region. The results may be of importance in ultrahigh security of the polarization-encrypted data that utilizes vector vortex beams and multiple optical trapping with non-coaxial superposition of vector vortex beams. We verified our experimental results with theory.

  10. Prototype development and field measurements of high etendue spatial heterodyne imaging spectrometer

    Science.gov (United States)

    Cai, Qisheng; Xiangli, Bin; Huang, Min; Han, Wei; Pei, Linlin; Bu, Meixia

    2018-03-01

    High etendue spatial heterodyne imaging spectrometer (HESHIS) is a new pushbroom Fourier transform hyperspectral imager with no moving parts. It is based on a Sagnac interferometer combined with a pair of parallel gratings. In this paper, the basic principle of HESHIS is reviewed and the first prototype of HESHIS is designed and developed. The spectral band of this prototype is designed at O2-A band (757 nm to 777 nm) and the average spectral resolution is 0.04 nm. Using the prototype, the pushbroom imaging experiments are carried out and the original interference images are obtained. The spectral data cube is generated using spectrum reconstruction method and high-resolution spectra are achieved.

  11. Quantum computation with classical light: The Deutsch Algorithm

    International Nuclear Information System (INIS)

    Perez-Garcia, Benjamin; Francis, Jason; McLaren, Melanie; Hernandez-Aranda, Raul I.; Forbes, Andrew; Konrad, Thomas

    2015-01-01

    We present an implementation of the Deutsch Algorithm using linear optical elements and laser light. We encoded two quantum bits in form of superpositions of electromagnetic fields in two degrees of freedom of the beam: its polarisation and orbital angular momentum. Our approach, based on a Sagnac interferometer, offers outstanding stability and demonstrates that optical quantum computation is possible using classical states of light. - Highlights: • We implement the Deutsh Algorithm using linear optical elements and classical light. • Our qubits are encoded in the polarisation and orbital angular momentum of the beam. • We show that it is possible to achieve quantum computation with two qubits in the classical domain of light

  12. Quantum computation with classical light: The Deutsch Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Garcia, Benjamin [Photonics and Mathematical Optics Group, Tecnológico de Monterrey, Monterrey 64849 (Mexico); University of the Witwatersrand, Private Bag 3, Johannesburg 2050 (South Africa); Francis, Jason [School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000 (South Africa); McLaren, Melanie [University of the Witwatersrand, Private Bag 3, Johannesburg 2050 (South Africa); Hernandez-Aranda, Raul I. [Photonics and Mathematical Optics Group, Tecnológico de Monterrey, Monterrey 64849 (Mexico); Forbes, Andrew [University of the Witwatersrand, Private Bag 3, Johannesburg 2050 (South Africa); Konrad, Thomas, E-mail: konradt@ukzn.ac.za [School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000 (South Africa); National Institute of Theoretical Physics, Durban Node, Private Bag X54001, Durban 4000 (South Africa)

    2015-08-28

    We present an implementation of the Deutsch Algorithm using linear optical elements and laser light. We encoded two quantum bits in form of superpositions of electromagnetic fields in two degrees of freedom of the beam: its polarisation and orbital angular momentum. Our approach, based on a Sagnac interferometer, offers outstanding stability and demonstrates that optical quantum computation is possible using classical states of light. - Highlights: • We implement the Deutsh Algorithm using linear optical elements and classical light. • Our qubits are encoded in the polarisation and orbital angular momentum of the beam. • We show that it is possible to achieve quantum computation with two qubits in the classical domain of light.

  13. X-ray wavefront characterization using a rotating shearing interferometer technique.

    Science.gov (United States)

    Wang, Hongchang; Sawhney, Kawal; Berujon, Sébastien; Ziegler, Eric; Rutishauser, Simon; David, Christian

    2011-08-15

    A fast and accurate method to characterize the X-ray wavefront by rotating one of the two gratings of an X-ray shearing interferometer is described and investigated step by step. Such a shearing interferometer consists of a phase grating mounted on a rotation stage, and an absorption grating used as a transmission mask. The mathematical relations for X-ray Moiré fringe analysis when using this device are derived and discussed in the context of the previous literature assumptions. X-ray beam wavefronts without and after X-ray reflective optical elements have been characterized at beamline B16 at Diamond Light Source (DLS) using the presented X-ray rotating shearing interferometer (RSI) technique. It has been demonstrated that this improved method allows accurate calculation of the wavefront radius of curvature and the wavefront distortion, even when one has no previous information on the grating projection pattern period, magnification ratio and the initial grating orientation. As the RSI technique does not require any a priori knowledge of the beam features, it is suitable for routine characterization of wavefronts of a wide range of radii of curvature. © 2011 Optical Society of America

  14. Laser frequency stabilization using a transfer interferometer

    Science.gov (United States)

    Jackson, Shira; Sawaoka, Hiromitsu; Bhatt, Nishant; Potnis, Shreyas; Vutha, Amar C.

    2018-03-01

    We present a laser frequency stabilization system that uses a transfer interferometer to stabilize slave lasers to a reference laser. Our implementation uses off-the-shelf optical components along with microcontroller-based digital feedback, and offers a simple, flexible, and robust way to stabilize multiple laser frequencies to better than 1 MHz.

  15. Atom Michelson interferometer on a chip using a Bose-Einstein condensate.

    Science.gov (United States)

    Wang, Ying-Ju; Anderson, Dana Z; Bright, Victor M; Cornell, Eric A; Diot, Quentin; Kishimoto, Tetsuo; Prentiss, Mara; Saravanan, R A; Segal, Stephen R; Wu, Saijun

    2005-03-11

    An atom Michelson interferometer is implemented on an "atom chip." The chip uses lithographically patterned conductors and external magnetic fields to produce and guide a Bose-Einstein condensate. Splitting, reflecting, and recombining of condensate atoms are achieved by a standing-wave light field having a wave vector aligned along the atom waveguide. A differential phase shift between the two arms of the interferometer is introduced by either a magnetic-field gradient or with an initial condensate velocity. Interference contrast is still observable at 20% with an atom propagation time of 10 ms.

  16. Atom Michelson interferometer on a chip using a Bose-Einstein condensate

    International Nuclear Information System (INIS)

    Wang Yingju; Anderson, Dana Z.; Cornell, Eric A.; Diot, Quentin; Kishimoto, Tetsuo; Segal, Stephen R.; Bright, Victor M.; Saravanan, R.A.; Prentiss, Mara; Wu Saijun

    2005-01-01

    An atom Michelson interferometer is implemented on an 'atom chip'. The chip uses lithographically patterned conductors and external magnetic fields to produce and guide a Bose-Einstein condensate. Splitting, reflecting, and recombining of condensate atoms are achieved by a standing-wave light field having a wave vector aligned along the atom waveguide. A differential phase shift between the two arms of the interferometer is introduced by either a magnetic-field gradient or with an initial condensate velocity. Interference contrast is still observable at 20% with an atom propagation time of 10 ms

  17. X-ray film interferometer as an instrument for semiconductor heterostructure investigation

    CERN Document Server

    Vasilenko, A P; Nikitenko, S G; Fedorov, A A; Sokolov, L V; Nikiforov, A I; Trukhanov, E M

    2001-01-01

    Translation Moire pictures were first observed in interference topographs obtained using Synchrotron radiation. A film interferometer was prepared on the base of the GeSi heterosystem. Another film interferometer, which presents the heterosystem of epitaxial Si/ porous Si/ substrate Si, permitted us to observe a decrease in the bending of the film atomic planes at annealing of the heterosystem. This bend smoothing was calculated with the sensitivity better than 1 A with the use of X-ray interference topographs. Contrast peculiarities in Moire pictures are discussed for nondiffracting layers and crystal quantum wells.

  18. Collinear interferometer with variable delay for carrier-envelope offset frequency measurement

    Energy Technology Data Exchange (ETDEWEB)

    Pawlowska, Monika; Ozimek, Filip; Fita, Piotr; Radzewicz, Czeslaw [Institute of Experimental Physics, University of Warsaw, ul. Hoza 69, 00-681 Warsaw (Poland)

    2009-08-15

    We demonstrate a novel scheme for measuring the carrier-envelope offset frequency in a femtosecond optical frequency comb. Our method is based on a common-path interferometer with a calcite Babinet-Soleil compensator employed to control the delay between the two interfering beams of pulses. The large delay range (up to 8 ps) of our device is sufficient for systems that rely on spectral broadening in microstructured fibers. We show an experimental proof that the stability of a common-path arrangement is superior to that of the standard interferometers.

  19. Collinear interferometer with variable delay for carrier-envelope offset frequency measurement

    Science.gov (United States)

    Pawłowska, Monika; Ozimek, Filip; Fita, Piotr; Radzewicz, Czesław

    2009-08-01

    We demonstrate a novel scheme for measuring the carrier-envelope offset frequency in a femtosecond optical frequency comb. Our method is based on a common-path interferometer with a calcite Babinet-Soleil compensator employed to control the delay between the two interfering beams of pulses. The large delay range (up to 8 ps) of our device is sufficient for systems that rely on spectral broadening in microstructured fibers. We show an experimental proof that the stability of a common-path arrangement is superior to that of the standard interferometers.

  20. Collinear interferometer with variable delay for carrier-envelope offset frequency measurement

    International Nuclear Information System (INIS)

    Pawlowska, Monika; Ozimek, Filip; Fita, Piotr; Radzewicz, Czeslaw

    2009-01-01

    We demonstrate a novel scheme for measuring the carrier-envelope offset frequency in a femtosecond optical frequency comb. Our method is based on a common-path interferometer with a calcite Babinet-Soleil compensator employed to control the delay between the two interfering beams of pulses. The large delay range (up to 8 ps) of our device is sufficient for systems that rely on spectral broadening in microstructured fibers. We show an experimental proof that the stability of a common-path arrangement is superior to that of the standard interferometers.

  1. Rational choices for the wavelengths of a two color interferometer

    International Nuclear Information System (INIS)

    Jobes, F.C.

    1995-07-01

    If in a two color interferometer for plasma density measurements, the two wavelengths are chosen to have a ratio that is a rational number, and if the signals from each of the wavelengths are multiplied in frequency by the appropriate integer of the rational number and then heterodyned together, the resultant signal will have all effects of component motion nulled out. A phase measurement of this signal will have only plasma density information in it. With CO 2 lasers, it is possible to find suitable wavelength pairs which are close enough to rational numbers to produce an improvement of about 100 in density resolution, compared to standard two color interferometers

  2. Development of Neutron Interferometer with Wide-Gapped ''BSE''s for Precision Measurements

    International Nuclear Information System (INIS)

    Seki, Y.; Kitaguchi, M.; Hino, M.; Funahashi, H.; Taketani, K.; Otake, Y.; Shimizu, H. M.

    2007-01-01

    We are developing large-dimensional cold-neutron interferometers with multilayer mirrors in order to investigate small interactions. In particular Jamin type interferometers composed of wide-gapped 'BSE's, which divide the beam completely, can realize the precision measurement of topological Aharonov-Casher effect. We have made a prototype with 200 μm gapped BSEs and confirmed the spatial separation of its two paths at monochromatic cold-neutron beamline MINE2 on JRR-3M reactor in JAEA

  3. Experimental Demonstration of a Suspended Dual Recycling Interferometer for Gravitational Wave Detection

    OpenAIRE

    Heinzel, G.; Strain, K.; Mizuno, J.; Skeldon, K.; Willke, B.; Winkler, W.; Schilling, R.; Rüdiger, A.; Danzmann, K.

    1998-01-01

    The advanced scheme of “signal recycling” is to be used in the British-German GEO 600 project, in addition to “power recycling” (which has become standard for all laser-interferometer gravitational wave detector projects). This combination, “dual recycling,” has been demonstrated for the first time on a fully suspended interferometer, the Garching prototype with 30 m arm length. Signal enhancement and power buildup were as predicted; operation was reliable, and a significant contrast enhancem...

  4. An interferometer for high-resolution optical surveillance from GEO - internal metrology breadboard

    Science.gov (United States)

    Bonino, L.; Bresciani, F.; Piasini, G.; Pisani, M.; Cabral, A.; Rebordão, J.; Musso, F.

    2017-11-01

    This paper describes the internal metrology breadboard development activities performed in the frame of the EUCLID CEPA 9 RTP 9.9 "High Resolution Optical Satellite Sensor" project of the WEAO Research Cell by AAS-I and INETI. The Michelson Interferometer Testbed demonstrates the possibility of achieving a cophasing condition between two arms of the optical interferometer starting from a large initial white light Optical Path Difference (OPD) unbalance and of maintaining the fringe pattern stabilized in presence of disturbances.

  5. Sub-atomic dimensional metrology: developments in the control of x-ray interferometers

    Science.gov (United States)

    Yacoot, Andrew; Kuetgens, Ulrich

    2012-07-01

    Within the European Metrology Research Programme funded project NANOTRACE, the nonlinearity of the next generation of optical interferometers has been measured using x-ray interferometry. The x-ray interferometer can be regarded as a ruler or translation stage whose graduations or displacement steps are based on the lattice spacing of the crystallographic planes from which the x-rays are diffracted: in this case the graduations are every 192 pm corresponding to the spacing between the (2 2 0) planes in silicon. Precise displacement of the x-ray interferometer's monolithic translation stage in steps corresponding to discrete numbers of x-ray fringes requires servo positioning capability at the picometre level. To achieve this very fine control, a digital control system has been developed which has opened up the potential for advances in metrology using x-ray interferometry that include quadrature counting of x-ray fringes.

  6. Sub-atomic dimensional metrology: developments in the control of x-ray interferometers

    International Nuclear Information System (INIS)

    Yacoot, Andrew; Kuetgens, Ulrich

    2012-01-01

    Within the European Metrology Research Programme funded project NANOTRACE, the nonlinearity of the next generation of optical interferometers has been measured using x-ray interferometry. The x-ray interferometer can be regarded as a ruler or translation stage whose graduations or displacement steps are based on the lattice spacing of the crystallographic planes from which the x-rays are diffracted: in this case the graduations are every 192 pm corresponding to the spacing between the (2 2 0) planes in silicon. Precise displacement of the x-ray interferometer's monolithic translation stage in steps corresponding to discrete numbers of x-ray fringes requires servo positioning capability at the picometre level. To achieve this very fine control, a digital control system has been developed which has opened up the potential for advances in metrology using x-ray interferometry that include quadrature counting of x-ray fringes. (paper)

  7. A differential optical interferometer for measuring short pulses of surface acoustic waves.

    Science.gov (United States)

    Shaw, Anurupa; Teyssieux, Damien; Laude, Vincent

    2017-09-01

    The measurement of the displacements caused by the propagation of a short pulse of surface acoustic waves on a solid substrate is investigated. A stabilized time-domain differential interferometer is proposed, with the surface acoustic wave (SAW) sample placed outside the interferometer. Experiments are conducted with surface acoustic waves excited by a chirped interdigital transducer on a piezoelectric lithium niobate substrate having an operational bandwidth covering the 200-400MHz frequency range and producing 10-ns pulses with 36nm maximum out-of-plane displacement. The interferometric response is compared with a direct electrical measurement obtained with a receiving wide bandwidth interdigital transducer and good correspondence is observed. The effects of varying the path difference of the interferometer and the measurement position on the surface are discussed. Pulse compression along the chirped interdigital transducer is observed experimentally. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Correlation functions formed by a femtosecond pulse interferometer

    NARCIS (Netherlands)

    Cui, M.; Bhattacharya, N.; Urbach, H.P.; Van den berg, S.A.

    2008-01-01

    We experimentally demonstrate that a stabilized femtosecond frequency comb can be applied as a tool for distance measurement. The scheme is based on optical interference between individual pulses in a Michelson type interferometer. The cross-correlation functions between individual pulses with a

  9. A fiber-optic interferometer with subpicometer resolution for dc and low-frequency displacement measurement

    International Nuclear Information System (INIS)

    Smith, D. T.; Pratt, J. R.; Howard, L. P.

    2009-01-01

    We have developed a fiber-optic interferometer optimized for best performance in the frequency range from dc to 1 kHz, with displacement linearity of 1% over a range of ± 25 nm, and noise-limited resolution of 2 pm. The interferometer uses a tunable infrared laser source (nominal 1550 nm wavelength) with high amplitude and wavelength stability, low spontaneous self-emission noise, high sideband suppression, and a coherence control feature that broadens the laser linewidth and dramatically lowers the low-frequency noise in the system. The amplitude stability of the source, combined with the use of specially manufactured ''bend-insensitive'' fiber and all-spliced fiber construction, results in a robust homodyne interferometer system, which achieves resolution of 40 fm Hz -1/2 above 20 Hz and approaches the shot-noise-limit of 20 fm Hz -1/2 at 1 kHz for an optical power of 10 μW, without the need for differential detection. Here we describe the design and construction of the interferometer, as well as modes of operation, and demonstrate its performance.

  10. X-ray speckle correlation interferometer

    International Nuclear Information System (INIS)

    Eisenhower, Rachel; Materlik, Gerhard

    2000-01-01

    Speckle Pattern Correlation Interferometry (SPCI) is a well-established technique in the visible-light regime for observing surface disturbances. Although not a direct imaging technique, SPCI gives full-field, high-resolution information about an object's motion. Since x-ray synchrotron radiation beamlines with high coherent flux have allowed the observation of x-ray speckle, x-ray SPCI could provide a means to measure strains and other quasi-static motions in disordered systems. This paper therefore examines the feasibility of an x-ray speckle correlation interferometer

  11. Measurement of Microvibration by Using Dual-Cavity Fiber Fabry-Perot Interferometer for Structural Health Monitoring

    Directory of Open Access Journals (Sweden)

    Dae-Hyun Kim

    2014-01-01

    Full Text Available Extensive researches have recently been performed to study structural integrity using structural vibration data measured by in-structure sensors. A fiber optic sensor is one of candidates for the in-structure sensors because it is low in cost, light in weight, small in size, resistant to EM interference, long in service life, and so forth. Especially, an interferometric fiber optic sensor is very useful to measure vibrations with high resolution and accuracy. In this paper, a dual-cavity fiber Fabry-Perot interferometer was proposed with a phase-compensating algorithm for measuring micro-vibration. The interferometer has structurally two arbitrary cavities; therefore the initial phase difference between two sinusoidal signals induced from the interferometer was also arbitrary. In order to do signal processing including an arc-tangent method, a random value of the initial phase difference is automatically adjusted to the exact 90 degrees in the phase-compensating algorithm part. For the verification of the performance of the interferometer, a simple vibration-test was performed to measure micro-vibration caused by piezoelectric transducer (PZT. As an experimental result, the interferometer attached on the PZT successfully measured the 50 Hz-vibration of which the absolute displacement oscillated between −424 nm and +424 nm.

  12. High-accuracy self-mixing interferometer based on single high-order orthogonally polarized feedback effects.

    Science.gov (United States)

    Zeng, Zhaoli; Qu, Xueming; Tan, Yidong; Tan, Runtao; Zhang, Shulian

    2015-06-29

    A simple and high-accuracy self-mixing interferometer based on single high-order orthogonally polarized feedback effects is presented. The single high-order feedback effect is realized when dual-frequency laser reflects numerous times in a Fabry-Perot cavity and then goes back to the laser resonator along the same route. In this case, two orthogonally polarized feedback fringes with nanoscale resolution are obtained. This self-mixing interferometer has the advantages of higher sensitivity to weak signal than that of conventional interferometer. In addition, two orthogonally polarized fringes are useful for discriminating the moving direction of measured object. The experiment of measuring 2.5nm step is conducted, which shows a great potential in nanometrology.

  13. Random walk loop soups and conformal loop ensembles

    NARCIS (Netherlands)

    van de Brug, T.; Camia, F.; Lis, M.

    2016-01-01

    The random walk loop soup is a Poissonian ensemble of lattice loops; it has been extensively studied because of its connections to the discrete Gaussian free field, but was originally introduced by Lawler and Trujillo Ferreras as a discrete version of the Brownian loop soup of Lawler and Werner, a

  14. Snapshot imaging Fraunhofer line discriminator for detection of plant fluorescence

    Science.gov (United States)

    Gupta Roy, S.; Kudenov, M. W.

    2015-05-01

    Non-invasive quantification of plant health is traditionally accomplished using reflectance based metrics, such as the normalized difference vegetative index (NDVI). However, measuring plant fluorescence (both active and passive) to determine photochemistry of plants has gained importance. Due to better cost efficiency, lower power requirements, and simpler scanning synchronization, detecting passive fluorescence is preferred over active fluorescence. In this paper, we propose a high speed imaging approach for measuring passive plant fluorescence, within the hydrogen alpha Fraunhofer line at ~656 nm, using a Snapshot Imaging Fraunhofer Line Discriminator (SIFOLD). For the first time, the advantage of snapshot imaging for high throughput Fraunhofer Line Discrimination (FLD) is cultivated by our system, which is based on a multiple-image Fourier transform spectrometer and a spatial heterodyne interferometer (SHI). The SHI is a Sagnac interferometer, which is dispersion compensated using blazed diffraction gratings. We present data and techniques for calibrating the SIFOLD to any particular wavelength. This technique can be applied to quantify plant fluorescence at low cost and reduced complexity of data collection.

  15. Measurement of Refractive Index Using a Michelson Interferometer.

    Science.gov (United States)

    Fendley, J. J.

    1982-01-01

    Describes a novel and simple method of measuring the refractive index of transparent plates using a Michelson interferometer. Since it is necessary to use a computer program when determining the refractive index, undergraduates could be given the opportunity of writing their own programs. (Author/JN)

  16. Electrically switchable holographic liquid crystal/polymer Fresnel lens using a Michelson interferometer.

    Science.gov (United States)

    Jashnsaz, Hossein; Mohajerani, Ezeddin; Nemati, Hossein; Razavi, Seyed Hossein; Alidokht, Isa Ahmad

    2011-06-10

    A holographic technique for fabricating an electrically switchable liquid crystal/polymer composite Fresnel lens is reported. A Michelson interferometer is used to produce the required Fresnel pattern, by placing a convex lens into one path of the interferometer. Simplicity of the method and the possibility of fabricating different focal length lenses in a single arrangement are advantages of the method. The performance of the fabricated lens was demonstrated and its electro-optical properties were investigated for its primary focal length.

  17. Enhancement of fiber-optic low-coherence Fabry-Pérot interferometer with ZnO ALD films

    Science.gov (United States)

    Hirsch, Marzena; Listewnik, Paulina; Jedrzejewska-Szczerska, Małgorzata

    2018-04-01

    In this paper investigation of the enhanced fiber-optic low coherence Fabry-Pérot interferometer with zinc oxide (ZnO) film deposited by atomic layer deposition (ALD) was presented. Model of the interferometer, which was constructed of single-mode optical fiber with applied ZnO ALD films, was built. The interferometer was also examined by means of experiment. Measurements were performed for both reflective and transmission modes, using wavelengths of 1300 nm and 1500 nm. The measurements with the air cavity showed the best performance in terms of a visibility of the interference signal can be achieved for small cavity lengths ( 50μm) in both configurations. Combined with the enhancement of reflectance of the interferometer mirrors due to the ALD film, proposed construction could be successfully applied in refractive index (RI) sensor that can operate with improved visibility of the signal even in 1.3-1.5 RI range as well as with small volume samples, as shown by the modeling.

  18. Renormalization of loop functions for all loops

    International Nuclear Information System (INIS)

    Brandt, R.A.; Neri, F.; Sato, M.

    1981-01-01

    It is shown that the vacuum expectation values W(C 1 ,xxx, C/sub n/) of products of the traces of the path-ordered phase factors P exp[igcontour-integral/sub C/iA/sub μ/(x)dx/sup μ/] are multiplicatively renormalizable in all orders of perturbation theory. Here A/sub μ/(x) are the vector gauge field matrices in the non-Abelian gauge theory with gauge group U(N) or SU(N), and C/sub i/ are loops (closed paths). When the loops are smooth (i.e., differentiable) and simple (i.e., non-self-intersecting), it has been shown that the generally divergent loop functions W become finite functions W when expressed in terms of the renormalized coupling constant and multiplied by the factors e/sup -K/L(C/sub i/), where K is linearly divergent and L(C/sub i/) is the length of C/sub i/. It is proved here that the loop functions remain multiplicatively renormalizable even if the curves have any finite number of cusps (points of nondifferentiability) or cross points (points of self-intersection). If C/sub γ/ is a loop which is smooth and simple except for a single cusp of angle γ, then W/sub R/(C/sub γ/) = Z(γ)W(C/sub γ/) is finite for a suitable renormalization factor Z(γ) which depends on γ but on no other characteristic of C/sub γ/. This statement is made precise by introducing a regularization, or via a loop-integrand subtraction scheme specified by a normalization condition W/sub R/(C-bar/sub γ/) = 1 for an arbitrary but fixed loop C-bar/sub γ/. Next, if C/sub β/ is a loop which is smooth and simple except for a cross point of angles β, then W(C/sub β/) must be renormalized together with the loop functions of associated sets S/sup i//sub β/ = ]C/sup i/ 1 ,xxx, C/sup i//sub p/i] (i = 2,xxx,I) of loops C/sup i//sub q/ which coincide with certain parts of C/sub β/equivalentC 1 1 . Then W/sub R/(S/sup i//sub β/) = Z/sup i/j(β)W(S/sup j//sub β/) is finite for a suitable matrix Z/sup i/j

  19. Frequency-domain interferometer simulation with higher-order spatial modes

    International Nuclear Information System (INIS)

    Freise, A; Heinzel, G; Lueck, H; Schilling, R; Willke, B; Danzmann, K

    2004-01-01

    FINESSE is a software simulation allowing one to compute the optical properties of laser interferometers used by interferometric gravitational-wave detectors today. This fast and versatile tool has already proven to be useful in the design and commissioning of gravitational-wave detectors. The basic algorithm of FINESSE numerically computes the light amplitudes inside an interferometer using Hermite-Gauss modes in the frequency domain. In addition, FINESSE provides a number of commands for easily generating and plotting the most common signals including power enhancement, error and control signals, transfer functions and shot-noise-limited sensitivities. Among the various simulation tools available to the gravitational wave community today, FINESSE provides an advanced and versatile optical simulation based on a general analysis of user-defined optical setups and is quick to install and easy to use

  20. Length sensing and control of a Michelson interferometer with power recycling and twin signal recycling cavities.

    Science.gov (United States)

    Gräf, Christian; Thüring, André; Vahlbruch, Henning; Danzmann, Karsten; Schnabel, Roman

    2013-03-11

    The techniques of power recycling and signal recycling have proven as key concepts to increase the sensitivity of large-scale gravitational wave detectors by independent resonant enhancement of light power and signal sidebands within the interferometer. Developing the latter concept further, twin signal recycling was proposed as an alternative to conventional detuned signal recycling. Twin signal recycling features the narrow-band sensitivity gain of conventional detuned signal recycling but furthermore facilitates the injection of squeezed states of light, increases the detector sensitivity over a wide frequency band and requires a less complex detection scheme for optimal signal readout. These benefits come at the expense of an additional recycling mirror, thus increasing the number of degrees of freedom in the interferometer which need to be controlled.In this article we describe the development of a length sensing and control scheme and its successful application to a tabletop-scale power recycled Michelson interferometer with twin signal recycling. We were able to lock the interferometer in all relevant longitudinal degrees of freedom and thus laid the foundation for further investigations of this interferometer configuration to evaluate its viability for the application in gravitational wave detectors.

  1. Analysis and compensation of synchronous measurement error for multi-channel laser interferometer

    International Nuclear Information System (INIS)

    Du, Shengwu; Hu, Jinchun; Zhu, Yu; Hu, Chuxiong

    2017-01-01

    Dual-frequency laser interferometer has been widely used in precision motion system as a displacement sensor, to achieve nanoscale positioning or synchronization accuracy. In a multi-channel laser interferometer synchronous measurement system, signal delays are different in the different channels, which will cause asynchronous measurement, and then lead to measurement error, synchronous measurement error (SME). Based on signal delay analysis of the measurement system, this paper presents a multi-channel SME framework for synchronous measurement, and establishes the model between SME and motion velocity. Further, a real-time compensation method for SME is proposed. This method has been verified in a self-developed laser interferometer signal processing board (SPB). The experiment result showed that, using this compensation method, at a motion velocity 0.89 m s −1 , the max SME between two measuring channels in the SPB is 1.1 nm. This method is more easily implemented and applied to engineering than the method of directly testing smaller signal delay. (paper)

  2. Electron density measurement of non-equilibrium atmospheric pressure plasma using dispersion interferometer

    Science.gov (United States)

    Yoshimura, Shinji; Kasahara, Hiroshi; Akiyama, Tsuyoshi

    2017-10-01

    Medical applications of non-equilibrium atmospheric plasmas have recently been attracting a great deal of attention, where many types of plasma sources have been developed to meet the purposes. For example, plasma-activated medium (PAM), which is now being studied for cancer treatment, has been produced by irradiating non-equilibrium atmospheric pressure plasma with ultrahigh electron density to a culture medium. Meanwhile, in order to measure electron density in magnetic confinement plasmas, a CO2 laser dispersion interferometer has been developed and installed on the Large Helical Device (LHD) at the National Institute for Fusion Science, Japan. The dispersion interferometer has advantages that the measurement is insensitive to mechanical vibrations and changes in neutral gas density. Taking advantage of these properties, we applied the dispersion interferometer to electron density diagnostics of atmospheric pressure plasmas produced by the NU-Global HUMAP-WSAP-50 device, which is used for producing PAM. This study was supported by the Grant of Joint Research by the National Institutes of Natural Sciences (NINS).

  3. Development of the measurement system with interferometers for ultraprecise X-ray mirror

    CERN Document Server

    Yamauchi, K; Mimura, H

    2003-01-01

    A figure measurement system with a stitching method has been developed for evaluation and fabrication of the ultraprecise hard X-ray mirror optics. This system was constructed by two interferometers. One is the Michelson-type microscopic interferometer which is improved to keep the focus distance within 0.1 mu m. Another is the Fizeau's interferometer employed to compensate stitching error in the long spatial wavelength range. To estimate the absolute accuracy in this figure measurement system, the reflection X-ray intensity distributions of flat and aspherical mirrors, which are fabricated by us, were predicted by wave-optical simulation based on measured profile an compared with actually observed distributions. As the result, they are in good agreements. These agreements prove that the developed system has sub-nanometer absolute accuracy in all the spatial wavelength range longer than 0.5mm, because sub-nanometer figure error in those spatial wavelength ranges are known to affect reflection X-ray intensity ...

  4. Optical-feedback semiconductor laser Michelson interferometer for displacement measurements with directional discrimination

    International Nuclear Information System (INIS)

    Rodrigo, Peter John; Lim, May; Saloma, Caesar

    2001-01-01

    An optical-feedback semiconductor laser Michelson interferometer (OSMI) is presented for measuring microscopic linear displacements without ambiguity in the direction of motion. The two waves from the interferometer arms, one from the reference mirror and the other from the reflecting moving target, are fed back into the lasing medium (λ=830 nm), causing variations in the laser output power. We model the OSMI into an equivalent Fabry-Perot resonator and derive the dependence of the output power (and the junction voltage) on the path difference between the two interferometer arms. Numerical and experimental results consistently show that the laser output power varies periodically (period, λ/2) with path difference. The output power variation exhibits an asymmetric behavior with the direction of motion, which is used to measure, at subwavelength resolution, the displacement vector (both amplitude and direction) of the moving sample. Two samples are considered in the experiments: (i) a piezoelectric transducer and (ii) an audio speaker

  5. Analysis and compensation of synchronous measurement error for multi-channel laser interferometer

    Science.gov (United States)

    Du, Shengwu; Hu, Jinchun; Zhu, Yu; Hu, Chuxiong

    2017-05-01

    Dual-frequency laser interferometer has been widely used in precision motion system as a displacement sensor, to achieve nanoscale positioning or synchronization accuracy. In a multi-channel laser interferometer synchronous measurement system, signal delays are different in the different channels, which will cause asynchronous measurement, and then lead to measurement error, synchronous measurement error (SME). Based on signal delay analysis of the measurement system, this paper presents a multi-channel SME framework for synchronous measurement, and establishes the model between SME and motion velocity. Further, a real-time compensation method for SME is proposed. This method has been verified in a self-developed laser interferometer signal processing board (SPB). The experiment result showed that, using this compensation method, at a motion velocity 0.89 m s-1, the max SME between two measuring channels in the SPB is 1.1 nm. This method is more easily implemented and applied to engineering than the method of directly testing smaller signal delay.

  6. Dynamic frequency-domain interferometer for absolute distance measurements with high resolution

    International Nuclear Information System (INIS)

    Weng, Jidong; Liu, Shenggang; Ma, Heli; Tao, Tianjiong; Wang, Xiang; Liu, Cangli; Tan, Hua

    2014-01-01

    A unique dynamic frequency-domain interferometer for absolute distance measurement has been developed recently. This paper presents the working principle of the new interferometric system, which uses a photonic crystal fiber to transmit the wide-spectrum light beams and a high-speed streak camera or frame camera to record the interference stripes. Preliminary measurements of harmonic vibrations of a speaker, driven by a radio, and the changes in the tip clearance of a rotating gear wheel show that this new type of interferometer has the ability to perform absolute distance measurements both with high time- and distance-resolution

  7. Dynamic frequency-domain interferometer for absolute distance measurements with high resolution

    Science.gov (United States)

    Weng, Jidong; Liu, Shenggang; Ma, Heli; Tao, Tianjiong; Wang, Xiang; Liu, Cangli; Tan, Hua

    2014-11-01

    A unique dynamic frequency-domain interferometer for absolute distance measurement has been developed recently. This paper presents the working principle of the new interferometric system, which uses a photonic crystal fiber to transmit the wide-spectrum light beams and a high-speed streak camera or frame camera to record the interference stripes. Preliminary measurements of harmonic vibrations of a speaker, driven by a radio, and the changes in the tip clearance of a rotating gear wheel show that this new type of interferometer has the ability to perform absolute distance measurements both with high time- and distance-resolution.

  8. A compact, large-range interferometer for precision measurement and inertial sensing

    Science.gov (United States)

    Cooper, S. J.; Collins, C. J.; Green, A. C.; Hoyland, D.; Speake, C. C.; Freise, A.; Mow-Lowry, C. M.

    2018-05-01

    We present a compact, fibre-coupled interferometer with high sensitivity and a large working range. We propose to use this interferometer as a readout mechanism for future inertial sensors, removing a major limiting noise source, and in precision positioning systems. The interferometer’s peak sensitivity is 2 × 10-{14} m \\sqrt{Hz-1} at 70 Hz and 7 × 10-{11} m \\sqrt{Hz-1} at 10 mHz. If deployed on a GS-13 geophone, the resulting inertial sensing output will be limited by the suspension thermal noise of the reference mass from 10 mHz to 2 Hz.

  9. Feedback-stabilized fractional fringe laser interferometer for plasma density measurements

    International Nuclear Information System (INIS)

    Schneider, J.; Robertson, S.

    1979-01-01

    A feedback stabilization technique is described for a fractional fringe interferometer measuring plasma electron densities. Using this technique, a CO 2 laser Michelson interferometer with a pyroelectric detector exhibited a sensitivity of 3.4 x 10 -4 fringe on a 1-ms time scale and, due to acoustic pickup, 1.8 x 10 -2 fringe on a 10-ms time scale. The rise time is 45 μs. Stabilization against slow drifts in mirror distances is achieved by an electromechanically translated mirror driven by a servo system having a 0.2-s response time. A mechanical chopper in one of the two beam paths generates the signal which drives the servo system

  10. Crustal Strain Observation Using a Two-Color Interferometer with Accurate Correction of Refractive Index of Air

    Directory of Open Access Journals (Sweden)

    Souichi Telada

    2014-07-01

    Full Text Available A highly accurate two-color interferometer with automatic correction of the refractive index of air was developed for crustal strain observation. The two-color interferometer, which can measure a geometrical distance of approximately 70 m, with a relative resolution of 2 × 10−9, clearly detected a change in strain due to earth tides in spite of optical measurement in air. Moreover, a large strain quake due to an earthquake could be observed without disturbing the measurement. We demonstrated the advantages of the two-color interferometer in air for geodetic observation.

  11. Virgo: a laser interferometer to detect gravitational waves

    NARCIS (Netherlands)

    Accadia, T.; van den Brand, J.F.J.; Bulten, H.J.; Ketel, T.J.; van der Voet, H.; Mul, F.A.; Rabeling, D.S.

    2012-01-01

    This paper presents a complete description of Virgo, the French-Italian gravitational wave detector. The detector, built at Cascina, near Pisa (Italy), is a very large Michelson interferometer, with 3 km-long arms. In this paper, following a presentation of the physics requirements, leading to the

  12. Aerosol absorption measurement with a sinusoidal phase modulating fiber optic photo thermal interferometer

    Science.gov (United States)

    Li, Shuwang; Shao, Shiyong; Mei, Haiping; Rao, Ruizhong

    2016-10-01

    Aerosol light absorption plays an important role in the earth's atmosphere direct and semi-direct radiate forcing, simultaneously, it also has a huge influence on the visibility impairment and laser engineering application. Although various methods have been developed for measuring aerosol light absorption, huge challenge still remains in precision, accuracy and temporal resolution. The main reason is that, as a part of aerosol light extinction, aerosol light absorption always generates synchronously with aerosol light scattering, and unfortunately aerosol light scattering is much stronger in most cases. Here, a novel photo-thermal interferometry is proposed only for aerosol absorption measurement without disturbance from aerosol scattering. The photo-thermal interferometry consists of a sinusoidal phase-modulating single mode fiber-optic interferometer. The thermal dissipation, caused by aerosol energy from photo-thermal conversion when irritated by pump laser through interferometer, is detected. This approach is completely insensitive to aerosol scattering, and the single mode fiber-optic interferometer is compact, low-cost and insensitive to the polarization shading. The theory of this technique is illustrated, followed by the basic structure of the sinusoidal phase-modulating fiber-optic interferometer and demodulation algorithms. Qualitative and quantitative analysis results show that the new photo-thermal interference is a potential approach for aerosol absorption detection and environmental pollution detection.

  13. Development of control and data processing system for CO{sub 2} laser interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, Shinichi; Kawano, Yasunori; Tsuchiya, Katsuhiko; Inoue, Akira [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2001-11-01

    CO{sub 2} laser interferometer diagnostic has been operating to measure the central electron density in JT-60U plasmas. We have developed a control and data processing system for the CO{sub 2} laser interferometer with flexible functions of data acquisition, data processing and data transfer in accordance with the sequence of JT-60U discharges. This system is mainly composed of two UNIX workstations and CAMAC clusters, in which the high reliability was obtained by sharing the data process functions to the each workstations. Consequently, the control and data processing system becomes to be able to provide electron density data immediately after a JT-60U discharge, routinely. The realtime feedback control of electron density in JT-60U also becomes to be available by using a reference density signal from the CO{sub 2} laser interferometer. (author)

  14. Frequency locking of a field-widened Michelson interferometer based on optimal multi-harmonics heterodyning.

    Science.gov (United States)

    Cheng, Zhongtao; Liu, Dong; Zhou, Yudi; Yang, Yongying; Luo, Jing; Zhang, Yupeng; Shen, Yibing; Liu, Chong; Bai, Jian; Wang, Kaiwei; Su, Lin; Yang, Liming

    2016-09-01

    A general resonant frequency locking scheme for a field-widened Michelson interferometer (FWMI), which is intended as a spectral discriminator in a high-spectral-resolution lidar, is proposed based on optimal multi-harmonics heterodyning. By transferring the energy of a reference laser to multi-harmonics of different orders generated by optimal electro-optic phase modulation, the heterodyne signal of these multi-harmonics through the FWMI can reveal the resonant frequency drift of the interferometer very sensitively within a large frequency range. This approach can overcome the locking difficulty induced by the low finesse of the FWMI, thus contributing to excellent locking accuracy and lock acquisition range without any constraint on the interferometer itself. The theoretical and experimental results are presented to verify the performance of this scheme.

  15. Effect of telescope antenna diagram on the data acquisition in a stellar interferometer

    Science.gov (United States)

    Longueteau, Emmanuel; Delage, Laurent; Reynaud, François

    2017-11-01

    This paper deals with the effect of the telescope size on accuracy of the data acquisition in a optical fibre linked stellar interferometer. In this context we introduce the concept of antenna diagram commonly used for microwaves antennae. This concept is essential to explain the contrasts and the phaseclosure acquisitions corruption in a stellar interferometer. The telescope pointing errors induces additional effects that are superimposed with the field limitation and could become critical.

  16. Plasma flow velocity measurements using a modulated Michelson interferometer

    International Nuclear Information System (INIS)

    Howard, J.

    1997-01-01

    This paper discusses the possibility of flow velocity reconstruction using passive spectroscopic techniques. We report some preliminary measurements of the toroidal flow velocity of hydrogen atoms in the RTP tokamak using a phase modulated Michelson interferometer. (orig.)

  17. Quantitative Phase Determination by Using a Michelson Interferometer

    Science.gov (United States)

    Pomarico, Juan A.; Molina, Pablo F.; D'Angelo, Cristian

    2007-01-01

    The Michelson interferometer is one of the best established tools for quantitative interferometric measurements. It has been, and is still successfully used, not only for scientific purposes, but it is also introduced in undergraduate courses for qualitative demonstrations as well as for quantitative determination of several properties such as…

  18. Thermoluminescence spectra measured with a Michelson interferometer

    International Nuclear Information System (INIS)

    Haschberger, P.

    1991-01-01

    A Michelson interferometer was redesigned to prove its capabilities in the measurement of short-lived, low-intensity thermoluminescence spectra. Interferograms are collected during heating up the thermoluminescent probe in a heater plate. A personal computer controls the data acquisition and processes the Fourier transform. As the results show, even a comparatively simple and limited setup leads to relevant and reproducible spectra. (author)

  19. The design of a second harmonic tangential array interferometer for C-Mod

    International Nuclear Information System (INIS)

    Bretz, N.; Jobes, F.; Irby, J.

    1997-01-01

    A design for a tangential array interferometer for C-Mod operating at 1.06 and 0.53 μm is presented. This is a special type of two color interferometer in which a Nd:YAG laser is frequency doubled in a nonlinear crystal. Because the doubling efficiency is imperfect, two frequencies propagate collinearly through the plasma after which the 1.06 μm ray is doubled again mixing in the optical domain with the undoubled ray. The resulting interference is insensitive to path length but is affected by plasma dispersion in the usual way. A typical central fringe shift in C-Mod is expected to be 0.1 endash 1.0, but the absolute and relative accuracy in n e l measurements can be as high as in a conventional interferometer. This design uses a repetitively pulsed laser which is converted to a fan beam crossing the horizontal midplane. The chordal array is defined by internal retroreflectors on the C-Mod midplane which return the beam to the second doubler and a detector array. This interferometer design has beam diameters of a few millimeters and element spacings of a few centimeters, uses a repetitively pulsed, TEM 00 Nd:YAG laser, fiber optic beam transport, commercial components, and a compact optical design which minimizes port space requirements. An optical system design is presented which is based on the performance of a tabletop prototype at Princeton Plasma Physics Laboratory. copyright 1997 American Institute of Physics

  20. Guided magnonic Michelson interferometer.

    Science.gov (United States)

    Ahmed, Muhammad H; Jeske, Jan; Greentree, Andrew D

    2017-01-30

    Magnonics is an emerging field with potential applications in classical and quantum information processing. Freely propagating magnons in two-dimensional media are subject to dispersion, which limits their effective range and utility as information carriers. We show the design of a confining magnonic waveguide created by two surface current carrying wires placed above a spin-sheet, which can be used as a primitive for reconfigurable magnonic circuitry. We theoretically demonstrate the ability of such guides to counter the transverse dispersion of the magnon in a spin-sheet, thus extending the range of the magnon. A design of a magnonic directional coupler and controllable Michelson interferometer is shown, demonstrating its utility for information processing tasks.

  1. Validation experiment of a numerically processed millimeter-wave interferometer in a laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kogi, Y., E-mail: kogi@fit.ac.jp; Higashi, T.; Matsukawa, S. [Department of Information Electronics, Fukuoka Institute of Technology, Fukuoka 811-0295 (Japan); Mase, A. [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga, Fukuoka 816-0811 (Japan); Kohagura, J.; Yoshikawa, M. [Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Nagayama, Y.; Kawahata, K. [National Institute for Fusion Science, Toki, Gifu 509-5202 (Japan); Kuwahara, D. [Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

    2014-11-15

    We propose a new interferometer system for density profile measurements. This system produces multiple measurement chords by a leaky-wave antenna driven by multiple frequency inputs. The proposed system was validated in laboratory evaluation experiments. We confirmed that the interferometer generates a clear image of a Teflon plate as well as the phase shift corresponding to the plate thickness. In another experiment, we confirmed that quasi-optical mirrors can produce multiple measurement chords; however, the finite spot size of the probe beam degrades the sharpness of the resulting image.

  2. Free diffusion of translation of macromolecules in solution with the rayleigh interferometer

    International Nuclear Information System (INIS)

    Leger, J.J.

    1969-01-01

    The aim of this study is to develop a rapid and accurate measurement, with the Rayleigh interferometer, of the free diffusion coefficient of translation of macromolecules in solution. After having explained the choice of a diffusion cell with laminar lateral flow, and explained the principle of the Rayleigh interferometer, a semi-automatic technique of free diffusion are then introduced. Solutions are proposed for systems composed of two or three components, such as biopolymers. The paper ends by drafting the possible treatment of recorded experimental data by means of electronic computer. (author) [fr

  3. Study on the wide-angle Michelson interferometer with large air gap.

    Science.gov (United States)

    Gao, Haiyang; Tang, Yuanhe; Hua, Dengxin; Liu, Hanchen

    2011-10-10

    A wide-angle Michelson interferometer with large air gap is proposed to effectively reduce the size of the glass arms and constraint on material. It provides a novel and practical instrument for ground based wind measurement of the upper atmosphere. The field widening conditions for the large air gap are calculated in theory. For the five spectral lines of 557.7 nm, 630.0 nm, 732.0 nm, 834.6 nm, and 865.7 nm, the optimal results under ideal condition are obtained with air gaps of 1.0 cm, 1.5 cm, and 2.0 cm, respectively. With the fixed optical path difference (OPD) of 7.495 cm, three pairs of glass arms are optimized. The pair with length of 1.5 cm for air gap, 5.765 cm for H-ZF12, and 2.956 cm for H-ZLaF54, has better effect of field widening than the other two pairs and its OPD variation is only within 0.30 wavelengths at incident angle of 3°. For developing a more practical wide-angle Michelson interferometer, the H-K9L glass with size of 4.445 cm is employed as the arm material of solid interferometer. The experiment for field of view of 3° is designed and the data processing and analysis for 60 images show the agreement between experimental results and theoretical simulation. The OPD variations are only within 0.27 wavelengths for image edge. The feasibility and practicality of the wide-angle Michelson interferometer with large air gap is proved by means of theory and experiment. © 2011 Optical Society of America

  4. Analysis on optical heterodyne frequency error of full-field heterodyne interferometer

    Science.gov (United States)

    Li, Yang; Zhang, Wenxi; Wu, Zhou; Lv, Xiaoyu; Kong, Xinxin; Guo, Xiaoli

    2017-06-01

    The full-field heterodyne interferometric measurement technology is beginning better applied by employing low frequency heterodyne acousto-optical modulators instead of complex electro-mechanical scanning devices. The optical element surface could be directly acquired by synchronously detecting the received signal phases of each pixel, because standard matrix detector as CCD and CMOS cameras could be used in heterodyne interferometer. Instead of the traditional four-step phase shifting phase calculating, Fourier spectral analysis method is used for phase extracting which brings lower sensitivity to sources of uncertainty and higher measurement accuracy. In this paper, two types of full-field heterodyne interferometer are described whose advantages and disadvantages are also specified. Heterodyne interferometer has to combine two different frequency beams to produce interference, which brings a variety of optical heterodyne frequency errors. Frequency mixing error and beat frequency error are two different kinds of inescapable heterodyne frequency errors. In this paper, the effects of frequency mixing error to surface measurement are derived. The relationship between the phase extraction accuracy and the errors are calculated. :: The tolerance of the extinction ratio of polarization splitting prism and the signal-to-noise ratio of stray light is given. The error of phase extraction by Fourier analysis that caused by beat frequency shifting is derived and calculated. We also propose an improved phase extraction method based on spectrum correction. An amplitude ratio spectrum correction algorithm with using Hanning window is used to correct the heterodyne signal phase extraction. The simulation results show that this method can effectively suppress the degradation of phase extracting caused by beat frequency error and reduce the measurement uncertainty of full-field heterodyne interferometer.

  5. Experiments on the Porch Swing Bearing of Michelson Interferometer for Low Resolution FTIR

    OpenAIRE

    Tuomas Välikylä; Jyrki Kauppinen

    2013-01-01

    Porch swing bearing for the linear motion of the mirror in Michelson interferometer for mid-infrared low resolution Fourier transform spectrometer was studied experimentally using the modulation depth of the collimated laser beam. The mirror tilting was measured to be lower than 5 μrad over 3 mm mirror travel using two different bearings assemblies. Additionally, the manufacturing tolerances of the bearing type were proved to be loose enough not to limit the interferometer application. These ...

  6. Digital atom interferometer with single particle control on a discretized space-time geometry.

    Science.gov (United States)

    Steffen, Andreas; Alberti, Andrea; Alt, Wolfgang; Belmechri, Noomen; Hild, Sebastian; Karski, Michał; Widera, Artur; Meschede, Dieter

    2012-06-19

    Engineering quantum particle systems, such as quantum simulators and quantum cellular automata, relies on full coherent control of quantum paths at the single particle level. Here we present an atom interferometer operating with single trapped atoms, where single particle wave packets are controlled through spin-dependent potentials. The interferometer is constructed from a sequence of discrete operations based on a set of elementary building blocks, which permit composing arbitrary interferometer geometries in a digital manner. We use this modularity to devise a space-time analogue of the well-known spin echo technique, yielding insight into decoherence mechanisms. We also demonstrate mesoscopic delocalization of single atoms with a separation-to-localization ratio exceeding 500; this result suggests their utilization beyond quantum logic applications as nano-resolution quantum probes in precision measurements, being able to measure potential gradients with precision 5 x 10(-4) in units of gravitational acceleration g.

  7. Comparison Study of Lightning observations from VHF interferometer and Geostationary Lightning Mapper

    Science.gov (United States)

    Kudo, A.; Stock, M.; Ushio, T.

    2017-12-01

    We compared the optical observation from Geostationary Lightning Mapper (GLM) which is mounted on the geostationary meteorological satellite GOES-16 launched last year, and the radio observations from the ground-based VHF broad band interferometer. GLM detects 777.4 nm wavelength infrared optical signals from thunderstorm cells which are illuminated by the heated path during lightning discharge, and was developed mainly for the purpose of increasing the lead time for warning of severe weather and clarifying the discharge mechanism. Its detection has 2 ms frame rate, and 8 km square of space resolution at nadir. The VHF broad band interferometer is able to capture the electromagnetic waves from 20 MHz to 75 MHz and estimate the direction of arrival of the radiation sources using the interferometry technique. This system also has capability of observing the fast discharge process which cannot be captured by other systems, so it is expected to able to make detailed comparison. The recording duration of the system is 1 second. We installed the VHF broad band interferometer which consists of three VHF antenna and one fast antenna at Huntsville, Alabama from April 22nd to May 15th and in this total observation period, 720 triggers of data were observed by the interferometer. For comparison, we adopted the data from April 27th , April 30th. Most April 27th data has GLM "event" detection which is coincident time period. In time-elevation plot comparison, we found GLM detection timing was well coincide with interferometer during K-changes or return strokes and few detection during breakdown process. On the other hand, no GLM detection near the site for all data in April 30th and we are triyng to figure out the reason. We would like to thank University of Alabama Huntsville, New Mexico Institute of Mining and Technology, and RAIRAN Pte. Ltd for the help during the campaign.

  8. A novel scanning interferometer for two-dimensional plasma density measurements

    International Nuclear Information System (INIS)

    Howard, J.

    1989-01-01

    A novel multichannel scanning interferometer designed for tomographically inferring contours of electron density in magnetically confined plasmas is described. The scanning element is a multi-sectored blazed rotating grating. The diffracted beam emerges at a different angle from each sector giving rise to a fan array of discrete beams for each rotation of the grating. Signals from the probing chords are multiplexed in time enabling the use of a single detecting element for the extraction of many channels of line integrated density information. An air turbine driven grating wheel assembly has been fabricated and initial tests performed. The proposed interferometer is to be installed on the H-1 helical axis stellarator currently under construction at the Australian National University. 16 refs., 12 figs

  9. Phase-measuring laser holographic interferometer for use in high speed flows

    Science.gov (United States)

    Yanta, William J.; Spring, W. Charles, III; Gross, Kimberly Uhrich; McArthur, J. Craig

    Phase-measurement techniques have been applied to a dual-plate laser holographic interferometer (LHI). This interferometer has been used to determine the flowfield densities in a variety of two-dimensional and axisymmetric flows. In particular, LHI has been applied in three different experiments: flowfield measurements inside a two-dimensional scramjet inlet, flow over a blunt cone, and flow over an indented nose shape. Comparisons of experimentally determined densities with computational results indicate that, when phase-measurement techniques are used in conjunction with state-of-the-art image-processing instrumentation, holographic interferometry can be a diagnostic tool with high resolution, high accuracy, and rapid data retrieval.

  10. Special features of Newton-type fringe formation in a diffraction interferometer

    Science.gov (United States)

    Koronkevich, Voldemar P.; Lenkova, Galina A.; Matochkin, Aleksey E.

    2006-01-01

    An interferometer with a Fresnel zone plate located in the center of curvature of a concave mirror was studied. Attention was paid to the unique features of the interference field, which has a special point at which the path difference is equal to zero, thereby allowing for the observation of Newton-type fringes in white and quasi-monochromatic light. The conditions necessary for reducing the instrumental error to values less than lambda/20 were determined. Methods for suppressing noise and destructive interference patterns were also found. Metrological tests were carried out, and they proved the possibility of using this interferometer for industrial testing of spherical and parabolic mirrors.

  11. Far-infrared tangential interferometer/polarimeter design and installation for NSTX-U

    Energy Technology Data Exchange (ETDEWEB)

    Scott, E. R., E-mail: evrscott@ucdavis.edu [Department of Mechanical and Aerospace Engineering, University of California, Davis, California 95616 (United States); Barchfeld, R. [Department of Applied Science, University of California, Davis, California 95616 (United States); Riemenschneider, P.; Domier, C. W.; Sohrabi, M.; Luhmann, N. C. [Department of Electrical and Computer Engineering, University of California, Davis, California 95616 (United States); Muscatello, C. M. [General Atomics, San Diego, California 92121 (United States); Kaita, R.; Ren, Y. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States)

    2016-11-15

    The Far-infrared Tangential Interferometer/Polarimeter (FIReTIP) system has been refurbished and is being reinstalled on the National Spherical Torus Experiment—Upgrade (NSTX-U) to supply real-time line-integrated core electron density measurements for use in the NSTX-U plasma control system (PCS) to facilitate real-time density feedback control of the NSTX-U plasma. Inclusion of a visible light heterodyne interferometer in the FIReTIP system allows for real-time vibration compensation due to movement of an internally mounted retroreflector and the FIReTIP front-end optics. Real-time signal correction is achieved through use of a National Instruments CompactRIO field-programmable gate array.

  12. Size constraints on a Majorana beam-splitter interferometer: Majorana coupling and surface-bulk scattering

    Science.gov (United States)

    Røising, Henrik Schou; Simon, Steven H.

    2018-03-01

    Topological insulator surfaces in proximity to superconductors have been proposed as a way to produce Majorana fermions in condensed matter physics. One of the simplest proposed experiments with such a system is Majorana interferometry. Here we consider two possibly conflicting constraints on the size of such an interferometer. Coupling of a Majorana mode from the edge (the arms) of the interferometer to vortices in the center of the device sets a lower bound on the size of the device. On the other hand, scattering to the usually imperfectly insulating bulk sets an upper bound. From estimates of experimental parameters, we find that typical samples may have no size window in which the Majorana interferometer can operate, implying that a new generation of more highly insulating samples must be explored.

  13. Electron cyclotron emission measurements on JET: Michelson interferometer, new absolute calibration, and determination of electron temperature

    NARCIS (Netherlands)

    Schmuck, S.; Fessey, J.; Gerbaud, T.; Alper, B.; Beurskens, M. N. A.; de la Luna, E.; Sirinelli, A.; Zerbini, M.

    2012-01-01

    At the fusion experiment JET, a Michelson interferometer is used to measure the spectrum of the electron cyclotron emission in the spectral range 70-500 GHz. The interferometer is absolutely calibrated using the hot/cold technique and, in consequence, the spatial profile of the plasma electron

  14. Two-loop hard-thermal-loop thermodynamics with quarks

    International Nuclear Information System (INIS)

    Andersen, Jens O.; Petitgirard, Emmanuel; Strickland, Michael

    2004-01-01

    We calculate the quark contribution to the free energy of a hot quark-gluon plasma to two-loop order using hard-thermal-loop (HTL) perturbation theory. All ultraviolet divergences can be absorbed into renormalizations of the vacuum energy and the HTL quark and gluon mass parameters. The quark and gluon HTL mass parameters are determined self-consistently by a variational prescription. Combining the quark contribution with the two-loop HTL perturbation theory free energy for pure glue we obtain the total two-loop QCD free energy. Comparisons are made with lattice estimates of the free energy for N f =2 and with exact numerical results obtained in the large-N f limit

  15. Long axial imaging range using conventional swept source lasers in optical coherence tomography via re-circulation loops

    Science.gov (United States)

    Bradu, Adrian; Jackson, David A.; Podoleanu, Adrian

    2018-03-01

    Typically, swept source optical coherence tomography (SS-OCT) imaging instruments are capable of a longer axial range than their camera based (CB) counterpart. However, there are still various applications that would take advantage for an extended axial range. In this paper, we propose an interferometer configuration that can be used to extend the axial range of the OCT instruments equipped with conventional swept-source lasers up to a few cm. In this configuration, the two arms of the interferometer are equipped with adjustable optical path length rings. The use of semiconductor optical amplifiers in the two rings allows for compensating optical losses hence, multiple paths depth reflectivity profiles (Ascans) can be combined axially. In this way, extremely long overall axial ranges are possible. The use of the recirculation loops produces an effect equivalent to that of extending the coherence length of the swept source laser. Using this approach, the achievable axial imaging range in SS-OCT can reach values well beyond the limit imposed by the coherence length of the laser, to exceed in principle many centimeters. In the present work, we demonstrate axial ranges exceeding 4 cm using a commercial swept source laser and reaching 6 cm using an "in-house" swept source laser. When used in a conventional set-up alone, both these lasers can provide less than a few mm axial range.

  16. First Colombian Solar Radio Interferometer: current stage

    Science.gov (United States)

    Guevara Gómez, J. C.; Martínez Oliveros, J. C.; Calvo-Mozo, B.

    2017-10-01

    Solar radio astronomy is a fast developing research field in Colombia. Here, we present the scientific goals, specifications and current state of the First Colombian Solar Radio Interferometer consisting of two log-periodic antennas covering a frequency bandwidth op to 800 MHz. We describe the importance and benefits of its development to the radioastronomy in Latin America and its impact on the scientific community and general public.

  17. Last technology and results from the IOTA interferometer

    Science.gov (United States)

    Pedretti, Ettore; Traub, Wesley A.; Monnier, John D.; Schuller, Peter A.; Ragland, Sam; Berger, Jean–Philippe; Millan-Gabet, Rafael; Wallace, Gary; Burke, Michael; Lacasse, Marc G.; Thureau, Nathalie D.; Carleton, Nathaniel

    2008-07-01

    The infrared optical telescope array (IOTA), one of the most productive interferometers in term of science and new technologies was decommissioned in summer 2006. We discuss the testing of a low-resolution spectrograph coupled with the IOTA-3T integrated-optics beam combiner and some of the scientific results obtained from this instrument.

  18. Photonic crystal fiber modal interferometer based on thin-core-fiber mode exciter.

    Science.gov (United States)

    Miao, Yinping; Ma, Xixi; Wu, Jixuan; Song, Binbin; Zhang, Hao; Liu, Bo; Yao, Jianquan

    2015-11-10

    A thin-core-fiber excited photonic crystal fiber modal interferometer has been proposed and experimentally demonstrated. By employing a thin-core fiber as the mode exciter, both of the core and cladding modes propagate in the photonic crystal fiber and interfere with each other. The experimental results show that the transmission dips corresponding to different-order modes have various strain responses with opposite shift directions. The strain sensitivity could be improved to 58.57  pm/με for the applied strain from 0 to 491 με by utilizing the wavelength interval between the dips with opposite shift directions. Moreover, due to the pure silica property of the employed photonic crystal fiber, the proposed fiber modal interferometer exhibits a low-temperature sensitivity of about 0.56  pm/°C within a temperature range from 26.4°C (room temperature) to 70°C. Additionally, the proposed fiber modal interferometer has several advantages, such as good stability, compact structure, and simple fabrication. Therefore, it is more applicable for strain measurement with reducing temperature cross-sensitivity.

  19. LoopIng: a template-based tool for predicting the structure of protein loops.

    KAUST Repository

    Messih, Mario Abdel; Lepore, Rosalba; Tramontano, Anna

    2015-01-01

    ) and significant enhancements for long loops (11-20 residues). The quality of the predictions is robust to errors that unavoidably affect the stem regions when these are modeled. The method returns a confidence score for the predicted template loops and has

  20. Reduction of quantum noise in the Michelson interferometer by use of squeezed vacuum states

    International Nuclear Information System (INIS)

    Assaf, Ohad; Ben-Aryeh, Yacob

    2002-01-01

    We develop further the unified model for treating photon-counting and radiation-pressure fluctuations in the Michelson interferometer with input of squeezed vacuum state. The dependence of the quantum fluctuations on the phase of the input light is calculated. The analysis is restricted to a single-mode interferometer, but generalized in a way that includes both harmonic-oscillator and floating mirrors. We compare our results with those of other authors

  1. Refractometric sensor based on all-fiber coaxial Michelson and Mach-Zehnder interferometers for ethanol detection in fuel

    International Nuclear Information System (INIS)

    Mosquera, L; Osorio, Jonas H; Hayashi, Juliano G; Cordeiro, Cristiano M B

    2011-01-01

    A refractometric sensor based on mechanically induced interferometers formed with long period gratings is reported. It is also shown two different setups based on a Michelson and Mach-Zehnder interferometer and its application to measure ethanol concentration in gasoline.

  2. Plasma flow velocity measurements using a modulated Michelson interferometer

    NARCIS (Netherlands)

    Howard, J.; Meijer, F. G.

    1997-01-01

    This paper discusses the possibility of flow velocity reconstruction using passive spectroscopic techniques. We report some preliminary measurements of the toroidal flow velocity of hydrogen atoms in the RTP tokamak using a phase modulated Michelson interferometer. (C) 1997 Elsevier Science S.A.

  3. Progress in gravitational wave detection: Interferometers

    International Nuclear Information System (INIS)

    Kuroda, Kazuaki

    2002-01-01

    A gravitational wave (GW) is a physical entity of space-time derived from Einstein's theory of general relativity. Challenging projects to observe gravitational waves are being conducted throughout the world. A Japanese project involving a 300 m baseline laser interferometer, TAMA, achieved 1000 hr of continuous observation with the best sensitivity in the world during the summer of 2001. After achieving promising results, the realization of LCGT (Large-scale Cryogenic Gravitational wave Telescope) will become possible in the near future

  4. Preliminary measurement performance evaluation of a new white light interferometer for cylindrical surfaces

    International Nuclear Information System (INIS)

    Albertazzi, Armando Jr; Pont, Alex Dal

    2005-01-01

    This paper introduces a new design of a white light interferometer, suitable for measurement of cylindrical or quasi-cylindrical parts. A high precision 45 deg. conical mirror is used to direct collimated light radially, making it possible to measure in true cylindrical coordinates. The image of the measurand, distorted by the conical mirror, is projected in a high resolution digital camera. A mapping algorithm is used to reconstruct the cylindrical geometry from the distorted image. The rest of the interferometer is quite similar to a conventional white light interferometer: A flat reference mirror is scanned through the measurement range while an algorithm is searching for the maximum contrast position of the interference pattern. The performance evaluation of a configuration suitable for measurement of external cylindrical surfaces is also presented in this paper. A master cylinder was used as reference. Uncertainties of about 1.0 μm were found at the present stage of development

  5. High speed FPGA-based Phasemeter for the far-infrared laser interferometers on EAST

    Science.gov (United States)

    Yao, Y.; Liu, H.; Zou, Z.; Li, W.; Lian, H.; Jie, Y.

    2017-12-01

    The far-infrared laser-based HCN interferometer and POlarimeter/INTerferometer\\break (POINT) system are important diagnostics for plasma density measurement on EAST tokamak. Both HCN and POINT provide high spatial and temporal resolution of electron density measurement and used for plasma density feedback control. The density is calculated by measuring the real-time phase difference between the reference beams and the probe beams. For long-pulse operations on EAST, the calculation of density has to meet the requirements of Real-Time and high precision. In this paper, a Phasemeter for far-infrared laser-based interferometers will be introduced. The FPGA-based Phasemeter leverages fast ADCs to obtain the three-frequency signals from VDI planar-diode Mixers, and realizes digital filters and an FFT algorithm in FPGA to provide real-time, high precision electron density output. Implementation of the Phasemeter will be helpful for the future plasma real-time feedback control in long-pulse discharge.

  6. Investigation of propagation dynamics of truncated vector vortex beams.

    Science.gov (United States)

    Srinivas, P; Perumangatt, C; Lal, Nijil; Singh, R P; Srinivasan, B

    2018-06-01

    In this Letter, we experimentally investigate the propagation dynamics of truncated vector vortex beams generated using a Sagnac interferometer. Upon focusing, the truncated vector vortex beam is found to regain its original intensity structure within the Rayleigh range. In order to explain such behavior, the propagation dynamics of a truncated vector vortex beam is simulated by decomposing it into the sum of integral charge beams with associated complex weights. We also show that the polarization of the truncated composite vector vortex beam is preserved all along the propagation axis. The experimental observations are consistent with theoretical predictions based on previous literature and are in good agreement with our simulation results. The results hold importance as vector vortex modes are eigenmodes of the optical fiber.

  7. Generation of vector beams using a double-wedge depolarizer: Non-quantum entanglement

    Science.gov (United States)

    Samlan, C. T.; Viswanathan, Nirmal K.

    2016-07-01

    Propagation of horizontally polarized Gaussian beam through a double-wedge depolarizer generates vector beams with spatially varying state of polarization. Jones calculus is used to show that such beams are maximally nonseparable on the basis of even (Gaussian)-odd (Hermite-Gaussian) mode parity and horizontal-vertical polarization state. The maximum nonseparability in the two degrees of freedom of the vector beam at the double wedge depolarizer output is verified experimentally using a modified Sagnac interferometer and linear analyser projected interferograms to measure the concurrence 0.94±0.002 and violation of Clauser-Horne-Shimony-Holt form of Bell-like inequality 2.704±0.024. The investigation is carried out in the context of the use of vector beams for metrological applications.

  8. Enlarging the angle of view in Michelson-interferometer-based shearography by embedding a 4f system.

    Science.gov (United States)

    Wu, Sijin; He, Xiaoyuan; Yang, Lianxiang

    2011-07-20

    Digital shearography based on Michelson interferometers suffers from the disadvantage of a small angle of view due to the structure. We demonstrate a novel digital shearography system with a large angle of view. In the optical arrangement, the imaging lens is in front of the Michelson interferometer rather than behind it as in traditional digital shearography. Thus, the angle of view is no longer limited by the Michelson interferometer. The images transmitting between the separate lens and camera are accomplished by a 4f system in the new style of shearography. The influences of the 4f system on shearography are also discussed. © 2011 Optical Society of America

  9. Iodine-frequency-stabilized laser diode and displacement-measuring interferometer based on sinusoidal phase modulation

    Science.gov (United States)

    Duong, Quang Anh; Vu, Thanh Tung; Higuchi, Masato; Wei, Dong; Aketagawa, Masato

    2018-06-01

    We propose a sinusoidal phase modulation method to achieve both the frequency stabilization of an external-cavity laser diode (ECLD) to an 127I2 saturated absorption transition near 633 nm and displacement measurement using a Mach–Zehnder interferometer. First, the frequency of the ECLD is stabilized to the b 21 hyperfine component of the P(33) 6-3 transition of 127I2 by combining sinusoidal phase modulation by an electro-optic modulator and frequency modulation spectroscopy by chopping the pump beam using an acousto-optic modulator. Even though a small modulation index of m  =  3.768 rad is utilized, a relative frequency stability of 10‑11 order is obtained over a sampling time of 400 s. Secondly, the frequency-stabilized ECLD is applied as a light source to a Mach–Zehnder interferometer. From the two consecutive modulation harmonics (second and third orders) involved in the interferometer signal, the displacement of the moving mirror is determined for four optical path differences (L 0  =  100, 200, 500, and 1000 mm). The measured modulation indexes for the four optical path differences coincide with the designated value (3.768 rad) within 0.5%. Compared with the sinusoidal frequency modulation Michelson interferometer (Vu et al 2016 Meas. Sci. Technol. 27 105201) which was demonstrated by some of the same authors of this paper, the phase modulation Mach–Zhender interferometer could fix the modulation index to a constant value for the four optical path differences. In this report, we discuss the measurement principle, experimental system, and results.

  10. Michelson interferometer vibrometer using self-correcting synthetic-heterodyne demodulation.

    Science.gov (United States)

    Connelly, Michael J; Galeti, José Henrique; Kitano, Cláudio

    2015-06-20

    Synthetic-heterodyne demodulation is a useful technique for dynamic displacement and velocity detection in interferometric sensors, as it can provide an output signal that is immune to interferometric drift. With the advent of cost-effective, high-speed real-time signal-processing systems and software, processing of the complex signals encountered in interferometry has become more feasible. In synthetic heterodyne, to obtain the actual dynamic displacement or vibration of the object under test requires knowledge of the interferometer visibility and also the argument of two Bessel functions. In this paper, a method is described for determining the former and setting the Bessel function argument to a set value, which ensures maximum sensitivity. Conventional synthetic-heterodyne demodulation requires the use of two in-phase local oscillators; however, the relative phase of these oscillators relative to the interferometric signal is unknown. It is shown that, by using two additional quadrature local oscillators, a demodulated signal can be obtained that is independent of this phase difference. The experimental interferometer is a Michelson configuration using a visible single-mode laser, whose current is sinusoidally modulated at a frequency of 20 kHz. The detected interferometer output is acquired using a 250 kHz analog-to-digital converter and processed in real time. The system is used to measure the displacement sensitivity frequency response and linearity of a piezoelectric mirror shifter over a range of 500 Hz to 10 kHz. The experimental results show good agreement with two data-obtained independent techniques: the signal coincidence and denominated n-commuted Pernick method.

  11. Optical Coupling Structures of Fiber-Optic Mach-Zehnder Interferometers Using CO2 Laser Irradiation

    Directory of Open Access Journals (Sweden)

    Chien-Hsing Chen

    2014-01-01

    Full Text Available The Mach-Zehnder interferometer (MZI can be used to test changes in the refractive index of sucrose solutions at different concentrations. However, the popularity of this measurement tool is limited by its substantial size and portability. Therefore, the MZI was integrated with a small fiber-optic waveguide component to develop an interferometer with fiber-optic characteristics, specifically a fiber-optic Mach-Zehnder interferometer (FO-MZI. Optical fiber must be processed to fabricate two optical coupling structures. The two optical coupling structures are a duplicate of the beam splitter, an optical component of the interferometer. Therefore, when the sensor length and the two optical coupling structures vary, the time or path for optical transmission in the sensor changes, thereby influencing the back-end interference signals. The researchers successfully developed an asymmetrical FO-MZI with sensing abilities. The spacing value between the troughs of the sensor length and interference signal exhibited an inverse relationship. In addition, image analysis was employed to examine the size-matching relationship between various sensor lengths and the coupling and decoupling structure. Furthermore, the spectral wavelength shift results measured using a refractive index sensor indicate that FO-MZIs with a sensor length of 38 mm exhibited excellent sensitivity, measuring 59.7 nm/RIU.

  12. Digital holographic amplification of interferograms in the Michelson interferometer using the phase-only LCOS modulator

    Science.gov (United States)

    Balbekin, Nikolay; Petrov, Nikolay; Pul'kin, Sergey; Shoev, Vladislav; Sevryugin, Alexander; Tursunov, Ibrohim; Venediktov, Dmitrii; Venediktov, Vladimir

    2017-10-01

    The method of amplification of hologram was applied to the so-called Rozhdestvenskiy hooks, that were obtained in the Rozhdestvenskiy interferometer (Michelson interferometer, combined with a grating spectrograph). In such a device the absorption lines reveal themselves as specific "hooks", whose curvature provides the information about the atomic oscillator force. The holographic amplification "smoothes" the hooks and thus makes their analysis much simpler.

  13. Demonstration of a robust magnonic spin wave interferometer.

    Science.gov (United States)

    Kanazawa, Naoki; Goto, Taichi; Sekiguchi, Koji; Granovsky, Alexander B; Ross, Caroline A; Takagi, Hiroyuki; Nakamura, Yuichi; Inoue, Mitsuteru

    2016-07-22

    Magnonics is an emerging field dealing with ultralow power consumption logic circuits, in which the flow of spin waves, rather than electric charges, transmits and processes information. Waves, including spin waves, excel at encoding information via their phase using interference. This enables a number of inputs to be processed in one device, which offers the promise of multi-input multi-output logic gates. To realize such an integrated device, it is essential to demonstrate spin wave interferometers using spatially isotropic spin waves with high operational stability. However, spin wave reflection at the waveguide edge has previously limited the stability of interfering waves, precluding the use of isotropic spin waves, i.e., forward volume waves. Here, a spin wave absorber is demonstrated comprising a yttrium iron garnet waveguide partially covered by gold. This device is shown experimentally to be a robust spin wave interferometer using the forward volume mode, with a large ON/OFF isolation value of 13.7 dB even in magnetic fields over 30 Oe.

  14. Prospects for Observing Ultracompact Binaries with Space-Based Gravitational Wave Interferometers and Optical Telescopes

    Science.gov (United States)

    Littenberg, T. B.; Larson, S. L.; Nelemans, G.; Cornish, N. J.

    2012-01-01

    Space-based gravitational wave interferometers are sensitive to the galactic population of ultracompact binaries. An important subset of the ultracompact binary population are those stars that can be individually resolved by both gravitational wave interferometers and electromagnetic telescopes. The aim of this paper is to quantify the multimessenger potential of space-based interferometers with arm-lengths between 1 and 5 Gm. The Fisher information matrix is used to estimate the number of binaries from a model of the Milky Way which are localized on the sky by the gravitational wave detector to within 1 and 10 deg(exp 2) and bright enough to be detected by a magnitude-limited survey.We find, depending on the choice ofGW detector characteristics, limiting magnitude and observing strategy, that up to several hundred gravitational wave sources could be detected in electromagnetic follow-up observations.

  15. Registering upper atmosphere parameters in East Siberia with Fabry—Perot Interferometer KEO Scientific "Arinae"

    Science.gov (United States)

    Vasilyev, Roman; Artamonov, Maksim; Beletsky, Aleksandr; Zherebtsov, Geliy; Medvedeva, Irina; Mikhalev, Aleksandr; Syrenova, Tatyana

    2017-09-01

    We describe the Fabry–Perot interferometer designed to study Earth’s upper atmosphere. We propose a modification of the existing data processing method for determining the Doppler shift and Doppler widening and also for separating the observed line intensity and the background intensity. The temperature and wind velocity derived from these parameters are compared with physical characteristics obtained from modeling (NRLMSISE-00, HWM14). We demonstrate that the temperature is determined from the oxygen 630 nm line irrespective of the hydroxyl signal existing in interference patterns. We show that the interferometer can obtain temperature from the oxygen 557.7 nm line in case of additional calibration of the device. The observed wind velocity mainly agrees with model data. Night variations in the red and green oxygen lines quite well coincide with those in intensities obtained by devices installed nearby the interferometer.

  16. Improved path imbalance measurement of a fiber-optic interferometer based on frequency scanning interferometry

    International Nuclear Information System (INIS)

    Hou, C B; Wang, J G; Yang, J; Li, H Y; Peng, F; Yuan, L B; Yuan, Y G

    2017-01-01

    We developed a path imbalance measuring system using a reference interferometer with alterable optical path difference (OPD), aiming to eliminate the uncertainties due to synthetic wavelength measurement and remove the requirement of a known and stable reference OPD in frequency scanning interferometry. The path imbalance can be solved by using the phase ratios between the two interferometers produced before and after altering the OPD in the reference interferometer. The results have shown that the measurement uncertainty and the path imbalance are linearly related and a combined relative uncertainty of 4.9  ×  10 −6 (1 σ ) in path imbalance measurement over a range from 0.5 m to 50 m is achieved. Besides, we analyzed the contributions to the uncertainty that limit the performance of the system, and we discussed how to obtain a better measurement uncertainty. (paper)

  17. Potential of the neutron lloyd's mirror interferometer for the search for new interactions

    Energy Technology Data Exchange (ETDEWEB)

    Pokotilovski, Yu. N., E-mail: pokot@nf.jinr.ru [Joint Institute for Nuclear Research (Russian Federation)

    2013-04-15

    We discuss the potential of the neutron Lloyd's mirror interferometer in a search for new interactions at small scales. We consider three hypothetical interactions that may be tested using the interferometer. The chameleon scalar field proposed to solve the enigma of accelerating expansion of the Universe produces interaction between particles and matter. The axion-like spin-dependent coupling between a neutron and nuclei or/and electrons may result in a P- and T-noninvariant interaction with matter. Hypothetical non-Newtonian gravitational interactions mediates an additional short-range potential between neutrons and bulk matter. These interactions between the neutron and the mirror of a Lloyd-type neutron interferometer cause a phase shift of neutron waves. We estimate the sensitivity and systematic effects of possible experiments.

  18. Optics Alignment of a Balloon-Borne Far-Infrared Interferometer BETTII

    Science.gov (United States)

    Dhabal, Arnab; Rinehart, Stephen A.; Rizzo, Maxime J.; Mundy, Lee; Sampler, Henry; Juanola Parramon, Roser; Veach, Todd; Fixsen, Dale; Vila Hernandez De Lorenzo, Jor; Silverberg, Robert F.

    2017-01-01

    The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-m baseline far-infrared (FIR: 30 90 micrometer) interferometer providing spatially resolved spectroscopy. The initial scientific focus of BETTII is on clustered star formation, but this capability likely has a much broader scientific application.One critical step in developing an interferometer, such as BETTII, is the optical alignment of the system. We discuss how we determine alignment sensitivities of different optical elements on the interferogram outputs. Accordingly, an alignment plan is executed that makes use of a laser tracker and theodolites for precise optical metrology of both the large external optics and the small optics inside the cryostat. We test our alignment on the ground by pointing BETTII to bright near-infrared sources and obtaining their images in the tracking detectors.

  19. Design of compact dispersion interferometer with a high efficiency nonlinear crystal and a low power CO2 laser

    Science.gov (United States)

    Akiyama, T.; Yoshimura, S.; Tomita, K.; Shirai, N.; Murakami, T.; Urabe, K.

    2017-12-01

    When the electron density of a plasma generated in high pressure environment is measured by a conventional interferometer, the phase shifts due to changes of the neutral gas density cause significant measurement errors. A dispersion interferometer, which measures the phase shift that arises from dispersion of medium between the fundamental and the second harmonic wavelengths of laser light, can suppress the measured phase shift due to the variations of neutral gas density. In recent years, the CO2 laser dispersion interferometer has been applied to the atmospheric pressure plasmas and its feasibility has been demonstrated. By combining a low power laser and a high efficiency nonlinear crystal for the second harmonic component generation, a compact dispersion interferometer can be designed. The optical design and preliminary experiments are conducted.

  20. Behavior of a hollow core photonic crystal fiber under high radial pressure for downhole application

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, J., E-mail: j-sadeghi@sbu.ac.ir; Chenari, Z.; Ziaee, F. [Laser and Plasma Research Institute, Shahid Beheshti University, 1983963113 Tehran (Iran, Islamic Republic of); Latifi, H., E-mail: latifi@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, 1983963113 Tehran (Iran, Islamic Republic of); Department of Physics, Shahid Beheshti University, Evin, 1983963113 Tehran (Iran, Islamic Republic of); Santos, J. L., E-mail: josantos@fc.up.pt [INESC Porto—Instituto de Engenharia de Sistemas e Computadores do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Departamento de Física, da Faculdade de Ciências, da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal)

    2014-02-17

    Pressure fiber sensors play an important role in downhole high pressure measurements to withstand long term operation. The purpose of this paper is to present an application of hollow core photonic crystal fiber (HC-PCF) as a high pressure sensor head for downhole application based on dispersion variation. We used a high pressure stainless steel unit to exert pressure on the sensor. The experimental results show that different wavelengths based on sagnac loop interferometer have additive sensitivities from 5 × 10{sup −5} nm/psi at 1480 nm to 1.3 × 10{sup −3} nm/psi at 1680 nm. We developed a simulation to understand the reason for difference in sensitivity of wavelengths and also the relationship between deformation of HC-PCF and dispersion variation under pressure. For this purpose, by using the finite element method, we investigated the effect of structural variation of HC-PCF on spectral transformation of two linear polarizations under 1000 psi pressure. The simulation and experimental results show exponential decay behavior of dispersion variation from −3.4 × 10{sup −6} 1/psi to −1.3 × 10{sup −6} 1/psi and from −5 × 10{sup −6} 1/psi to −1.8 × 10{sup −6} 1/psi, respectively, which were in a good accordance with each other.

  1. Neocortical electrical stimulation for epilepsy : Closed-loop versus open-loop

    NARCIS (Netherlands)

    Vassileva, Albena; van Blooijs, Dorien; Leijten, Frans; Huiskamp, Geertjan

    2018-01-01

    The aim of this review is to evaluate whether open-loop or closed-loop neocortical electrical stimulation should be the preferred approach to manage seizures in intractable epilepsy. Twenty cases of open-loop neocortical stimulation with an implanted device have been reported, in 5 case studies.

  2. galario: Gpu Accelerated Library for Analyzing Radio Interferometer Observations

    Science.gov (United States)

    Tazzari, Marco; Beaujean, Frederik; Testi, Leonardo

    2017-10-01

    The galario library exploits the computing power of modern graphic cards (GPUs) to accelerate the comparison of model predictions to radio interferometer observations. It speeds up the computation of the synthetic visibilities given a model image (or an axisymmetric brightness profile) and their comparison to the observations.

  3. Realization of an optical interferometer based on holographic optics ...

    Indian Academy of Sciences (India)

    The paper describes a simple and cost effective method for the realization of an optical interferometer based on holographic optics, which use minimal bulk optical components. The optical arrangement in the proposed method involves a very simple alignment procedure and inexpensive holographic recording material is ...

  4. Measurement of Local Gravity via a Cold Atom Interferometer

    International Nuclear Information System (INIS)

    Zhou Lin; Xiong Zong-Yuan; Yang Wei; Tang Biao; Peng Wen-Cui; Wang Yi-Bo; Xu Peng; Wang Jin; Zhan Ming-Sheng

    2011-01-01

    We demonstrate a precision measurement of local gravity acceleration g in Wuhan by a compact cold atom interferometer. The atom interferometer is in vertical Mach—Zehnder configuration realized using a π/2 - π - π/2 Raman pulse sequence. Cold atoms were prepared in a magneto-optical trap, launched upward to form an atom fountain, and then coherently manipulated to interfere by stimulated Raman transition. Population signal vs Raman laser phase was recorded as interference fringes, and the local gravity was deduced from the interference signal. We have obtained a resolution of 7 × 10 −9 g after an integration time of 236s under the best vibrational environment conditions. The absolute g value was derived from the chirp rate with a difference of 1.5 × 10 −7 g compared to the gravity reference value. The tidal phenomenon was observed by continuously monitoring the local gravity over 123 h. (atomic and molecular physics)

  5. Achieving resonance in the Advanced LIGO gravitational-wave interferometer

    International Nuclear Information System (INIS)

    Staley, A; Martynov, D; Abbott, R; Adhikari, R X; Arai, K; Brooks, A F; Ballmer, S; Barsotti, L; Evans, M; Fritschel, P; DeRosa, R T; Effler, A; Dwyer, S; Gray, C; Izumi, K; Frolov, V V; Guido, C J; Heintze, M; Gustafson, R; Hoak, D

    2014-01-01

    Interferometric gravitational-wave detectors are complex instruments comprised of a Michelson interferometer enhanced by multiple coupled cavities. Active feedback control is required to operate these instruments and keep the cavities locked on resonance. The optical response is highly nonlinear until a good operating point is reached. The linear operating range is between 0.01% and 1% of a fringe for each degree of freedom. The resonance lock has to be achieved in all five degrees of freedom simultaneously, making the acquisition difficult. Furthermore, the cavity linewidth seen by the laser is only ∼1 Hz, which is four orders of magnitude smaller than the linewidth of the free running laser. The arm length stabilization system is a new technique used for arm cavity locking in Advanced LIGO. Together with a modulation technique utilizing third harmonics to lock the central Michelson interferometer, the Advanced LIGO detector has been successfully locked and brought to an operating point where detecting gravitational-waves becomes feasible. (paper)

  6. Experimental demonstration of a variable reflectivity signal recycled Michelson interferometer for gravitational wave detection

    International Nuclear Information System (INIS)

    De Vine, G.; Shaddock, D.; McClelland, D.

    2002-01-01

    Full text: One technique of improving the sensitivity of interferometric gravitational wave detectors is to implement a signal mirror. This involves placing a mirror at the output of the Michelson interferometer. The gravitational wave signal is then 'recycled' back into the interferometer where it can coherently add with the gravitational wave signal still being produced. The frequency of the improved sensitivity is dependent on the position of the signal mirror, while the peak height and bandwidth are dependent on the reflectivity of the signal mirror. This is because the signal mirror forms a cavity with the Michelson interferometer and this cavity has a resonant frequency dependent on its length and a bandwidth dependent on its finesse, which are a function of signal mirror position and reflectivity, respectively. Due to the varying and/or unknown nature of the gravitational wave frequencies and wave-forms, it is desirable to be able to control both the peak frequency and bandwidth of the detector. The peak frequency can be easily adjusted by altering the signal mirror position. The bandwidth, however, is fixed with the signal mirror reflectivity. In a long base-line gravitational wave detector it is impractical to swap the signal mirror with one of different reflectivity for a number of reasons, for example, the detector's high vacuum would have to be broken, realignment performed and locking re-acquired. This is addressed by the proposal of two different forms of variable reflectivity signal mirror (VRSM): a Fabry-Perot cavity and a Michelson interferometer. These are analysed and the reasons for choosing to investigate the Michelson VRSM are given. The reasons include the potential for easier control and the smooth variation in reflectivity with arm length difference. The experiment is discussed and the results of the first demonstration of variable reflectivity signal recycling are presented in the form of frequency responses obtained by injecting a second

  7. Determination of refractive indices of biconvex lenses by use of a Michelson interferometer.

    Science.gov (United States)

    Chhaniwal, Vani K; Anand, Arun; Narayanamurthy, C S

    2006-06-10

    Measurements of lens parameters such as focal length, radius of curvature, and refractive index are important. We describe a measurement method that utilizes a Michelson interferometer to determine parameters of thin, convex lenses. The real fringe system formed by a Michelson interferometer is used to determine the focal lengths and the radii of curvature of the lenses. The refractive index of the lens material is determined from the thin-lens formula. We were able to determine the refractive indices to an accuracy as great as 99.97%. A detailed theoretical and experimental analysis is given.

  8. Improvement on a Michelson interferometer for bunch length measurement of a femtosecond accelerator

    International Nuclear Information System (INIS)

    Lin Xuling; Bei Hua; Zhang Jianbing; Dai Zhimin

    2009-01-01

    Based on the femtosecond accelerator facility at Shanghai Institute of Applied Physics (SINAP), a conventional far-infrared Michelson interferometer was built to measure the bunch length by means of optical autocorrelation. However, according to the preliminary experiment result, the resolution of interferometer is not good enough, because the mirror-driving mechanism makes the moving mirror tend to tilt or wobble as it retards. Considering of the allowable errors, we calculate the maximum allowable titling angle of the moving mirror, and discuss the alignment plan in this paper. (authors)

  9. Strongly coupled chameleon fields: Possible test with a neutron Lloyd's mirror interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Pokotilovski, Yu.N., E-mail: pokot@nf.jinr.ru [Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region (Russian Federation)

    2013-02-26

    The consideration of possible neutron Lloyd's mirror interferometer experiment to search for strongly coupled chameleon fields is presented. The chameleon scalar fields were proposed to explain the acceleration of expansion of the Universe. The presence of a chameleon field results in a change of a particle's potential energy in vicinity of a massive body. This interaction causes a phase shift of neutron waves in the interferometer. The sensitivity of the method is estimated.

  10. A real time 155 GHz millimeter wave interferometer module for electron density measurement in large plasma devices

    International Nuclear Information System (INIS)

    Huettemann, P.W.; Waidmann, G.

    1982-09-01

    A homodyne, real time 155 GHz interferometer channel is described which is one module of a multichannel system for use on TEXTOR tokamak. A standing sine wave is generated in a phase bridge by transmitting a frequency modulated millimeter wave down two unequal interferometer branches. The presence of plasma produces a phase slip of the sine wave with respect to a reference signal. The phase shift is linear proportional to plasma density for expected TEXTOR plasmas. Long plasma paths give multiradian phase shifts which are recorded by a digital fringe counting system. The accuracy of phase measurement is ΔPHI = 2π/16. Phase changes of 7π/8 are accepted per modulation period. The microwave in the measurement branch of the interferometer is transmitted using a quasioptical technique. Components and technical details are described. The interferometer was tested in a simulation set-up and in two different plasma experiments. Experimental results are presented. (orig.)

  11. Resolving fringe ambiguities of a wide-field Michelson interferometer using visibility measurements of a noncollimated laser beam.

    Science.gov (United States)

    Wan, Xiaoke; Wang, Ji; Ge, Jian

    2009-09-10

    An actively stabilized interferometer with a constant optical path difference is a key element in long-term astronomical observation, and resolving interference fringe ambiguities is important to produce high-precision results for the long term. We report a simple and reliable method of resolving fringe ambiguities of a wide-field Michelson interferometer by measuring the interference visibility of a noncollimated single-frequency laser beam. Theoretical analysis shows that the interference visibility is sensitive to a subfringe phase shift, and a wide range of beam arrangements is suitable for real implementation. In an experimental demonstration, a Michelson interferometer has an optical path difference of 7 mm and a converging monitoring beam has a numerical aperture of 0.045 with an incidental angle of 17 degrees. The resolution of visibility measurements corresponds to approximately 1/16 fringe in the interferometer phase shift. The fringe ambiguity-free region is extended over a range of approximately 100 fringes.

  12. A multiple-pass ring oscillator based dual-loop phase-locked loop

    International Nuclear Information System (INIS)

    Chen Danfeng; Ren Junyan; Deng Jingjing; Li Wei; Li Ning

    2009-01-01

    A dual-loop phase-locked loop (PLL) for wideband operation is proposed. The dual-loop architecture combines a coarse-tuning loop with a fine-tuning one, enabling a wide tuning range and low voltage-controlled oscillator (VCO) gain without poisoning phase noise and reference spur suppression performance. An analysis of the phase noise and reference spur of the dual-loop PLL is emphasized. A novel multiple-pass ring VCO is designed for the dual-loop application. It utilizes both voltage-control and current-control simultaneously in the delay cell. The PLL is fabricated in Jazz 0.18-μm RF CMOS technology. The measured tuning range is from 4.2 to 5.9 GHz. It achieves a low phase noise of -99 dBc/Hz - 1 MHz offset from a 5.5 GHz carrier.

  13. A multiple-pass ring oscillator based dual-loop phase-locked loop

    Energy Technology Data Exchange (ETDEWEB)

    Chen Danfeng; Ren Junyan; Deng Jingjing; Li Wei; Li Ning, E-mail: dfchen@fudan.edu.c [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

    2009-10-15

    A dual-loop phase-locked loop (PLL) for wideband operation is proposed. The dual-loop architecture combines a coarse-tuning loop with a fine-tuning one, enabling a wide tuning range and low voltage-controlled oscillator (VCO) gain without poisoning phase noise and reference spur suppression performance. An analysis of the phase noise and reference spur of the dual-loop PLL is emphasized. A novel multiple-pass ring VCO is designed for the dual-loop application. It utilizes both voltage-control and current-control simultaneously in the delay cell. The PLL is fabricated in Jazz 0.18-{mu}m RF CMOS technology. The measured tuning range is from 4.2 to 5.9 GHz. It achieves a low phase noise of -99 dBc/Hz - 1 MHz offset from a 5.5 GHz carrier.

  14. Feedback stabilized tandem Fabry-Perot interferometer

    International Nuclear Information System (INIS)

    Fukushima, Hiroyuki; Ito, Mikio; Shirasu, Hiroshi.

    1986-01-01

    A new system for measuring the isotopic ratio of uranium, in which two plane-type Fabry-Perot interferometers (tandem FP) are connected in series. The parallelism between the two FPs is achieved automatically by a feedback control mechanism based on laser interference fringe monitoring. The structure of the tandem FP, feedback control system, automatic parallelism adjustment mechanism and wavelength synchronization mechanism are described in detail. For experiments, a hollow cathode discharge tube of a pulse discharge type is employed. Measurements are made to determine the effects of pulse width on the 238 U peak height of 502.7 nm line, recorder traces of 235 U and 238 U lines, half width for 238 U component of the 502.7 nm line, SN ratio, reproducibility of the 235 U/ 238 U peak height ratio and 235 U/ 238 U intensity ratio. Considerations are made on the spectral line width, contrast, transmission factor, and stability of automatic parallelism control and wavelength synchronization. Results obtained indicates that a single-type interferometer would serve adequately for measuring the 235 U/ 238 U ratio if the automatic parallelism control developed here is used. The ultimate object of the tandem system is to make measurement of 236 U. Satisfactory results have not obtained as yet, but most likely the present system would make it possible if a light source of a higher intensity and advanced photometric techniques are developed. (Nogami, K.)

  15. The first educational interferometer in Mexico (FEYMANS): A novel project

    Science.gov (United States)

    Villicana Pedraza, Ilhuiyolitzin; Guesten, Rolf; Saucedo Morales, Julio Cesar; Carreto, Francisco; Valdes Estrada, Erik; Wendolyn Blanco Cardenas, Monica; Rodríguez Garza, Carolina B.; Pech Castillo, Gerardo A.; Ángel Vaquerizo, Juan

    2016-07-01

    An interferometer is composed of several radio telescopes (dishes) separated by a defined distance and used in synchrony. This kind of array produces a superior angular resolution, better than the resolution achieved by a single dish of the same combined area. In this work we propose the First Educational Youth Mexican Array North South, FEYMANS. It consists of an educational interferometer with initially four dishes. This array harvests Mexico's geography by locating each dish at the periphery of the country; creating new scientific links of provincial populations with the capital. The FEYMANS project focus in high school students and their projects on physics, chemistry and astronomy as a final project. Also, it can be used for bachelor theses. The initial and central dish-node is planed to be in Mexico City. After its construction, the efforts will focus to build subsequent nodes, on the Northwest region, Northeast, or Southeast. Region Northwest will give service to Baja California, Sonora and Chihuahua states. Region Northeast will cover Coahuila, Nuevo Leon and Tamaulipas. Finally, region Southeast will give access to Yucatan, Quintana Roo, Campeche, Tabasco and Chiapas. This project has been conceived by young professional astronomers and Mexican experts that will operate each node. Also, we have the technical support of the "Max Planck Institute fuer Radioastronomy in Bonn Germany" and the educational model of the "PARTNeR" project in Spain. This interferometer will be financed by Mexico's Federal Congress and by Mexico City's Legislative Assembly (ALDF).

  16. Sequence-structure relationships in RNA loops: establishing the basis for loop homology modeling.

    Science.gov (United States)

    Schudoma, Christian; May, Patrick; Nikiforova, Viktoria; Walther, Dirk

    2010-01-01

    The specific function of RNA molecules frequently resides in their seemingly unstructured loop regions. We performed a systematic analysis of RNA loops extracted from experimentally determined three-dimensional structures of RNA molecules. A comprehensive loop-structure data set was created and organized into distinct clusters based on structural and sequence similarity. We detected clear evidence of the hallmark of homology present in the sequence-structure relationships in loops. Loops differing by structures. Thus, our results support the application of homology modeling for RNA loop model building. We established a threshold that may guide the sequence divergence-based selection of template structures for RNA loop homology modeling. Of all possible sequences that are, under the assumption of isosteric relationships, theoretically compatible with actual sequences observed in RNA structures, only a small fraction is contained in the Rfam database of RNA sequences and classes implying that the actual RNA loop space may consist of a limited number of unique loop structures and conserved sequences. The loop-structure data sets are made available via an online database, RLooM. RLooM also offers functionalities for the modeling of RNA loop structures in support of RNA engineering and design efforts.

  17. The CryoSat Interferometer after 6 years in orbit: calibration and achievable performance

    Science.gov (United States)

    Scagliola, Michele; Fornari, Marco; De Bartolomei, Maurizio; Bouffard, Jerome; Parrinello, Tommaso

    2016-04-01

    The main payload of CryoSat is a Ku-band pulse width limited radar altimeter, called SIRAL (Synthetic interferometric radar altimeter). When commanded in SARIn (synthetic aperture radar interferometry) mode, through coherent along-track processing of the returns received from two antennas, the interferometric phase related to the first arrival of the echo is used to retrieve the angle of arrival of the scattering in the across-track direction. In fact, the across-track echo direction can be derived by exploiting the precise knowledge of the baseline vector (i.e. the vector between the two antennas centers of phase) and simple geometry. The end-to-end calibration strategy for the CryoSat interferometer consists on in-orbit calibration campaigns following the approach described in [1]. From the beginning of the CryoSat mission, about once a year the interferometer calibration campaigns have been periodically performed by rolling left and right the spacecraft of about ±0.4 deg. This abstract is aimed at presenting our analysis of the calibration parameters and of the achievable performance of the CryoSat interferometer over the 6 years of mission. Additionally, some further studies have been performed to assess the accuracy of the roll angle computed on ground as function of the aberration (the apparent displacement of a celestial object from its true position, caused by the relative motion of the observer and the object) correction applied to the attitude quaternions, provided by the Star Tracker mounted on-board. In fact, being the roll information crucial to obtain an accurate estimate of the angle of arrival, the data from interferometer calibration campaigns have been used to verify how the application of the aberration correction affects the roll information and, in turns, the measured angle of arrival. [1] Galin, N.; Wingham, D.J.; Cullen, R.; Fornari, M.; Smith, W.H.F.; Abdalla, S., "Calibration of the CryoSat-2 Interferometer and Measurement of Across

  18. Quantum non-locality in a two-slit interferometer for short-lived particles

    International Nuclear Information System (INIS)

    Klein, Spencer R.; Nystrand, Joakim

    2001-01-01

    We describe a new test of quantum nonlocality, using an interferometer for short-lived particles. The separation is large compared with the particle lifetimes. This interferometer is realized by vector meson production in distant heavy ion collisions. The mesons decay before waves from the two sources (ions) can overlap, so interference is only possible among the decay products. The post-decay wave function must retain amplitudes for all possible decays. The decay products are spatially separated, necessitating a non-local wave function. The interference is measurable by summing the product momenta. Alternately, the products positions could be observed, allowing new tests of the EPR paradox

  19. Investigation into the limitations of straightness interferometers using a multisensor-based error separation method

    Science.gov (United States)

    Weichert, Christoph; Köchert, Paul; Schötka, Eugen; Flügge, Jens; Manske, Eberhard

    2018-06-01

    The uncertainty of a straightness interferometer is independent of the component used to introduce the divergence angle between the two probing beams, and is limited by three main error sources, which are linked to each other: their resolution, the influence of refractive index gradients and the topography of the straightness reflector. To identify the configuration with minimal uncertainties under laboratory conditions, a fully fibre-coupled heterodyne interferometer was successively equipped with three different wedge prisms, resulting in three different divergence angles (4°, 8° and 20°). To separate the error sources an independent reference with a smaller reproducibility is needed. Therefore, the straightness measurement capability of the Nanometer Comparator, based on a multisensor error separation method, was improved to provide measurements with a reproducibility of 0.2 nm. The comparison results revealed that the influence of the refractive index gradients of air did not increase with interspaces between the probing beams of more than 11.3 mm. Therefore, over a movement range of 220 mm, the lowest uncertainty was achieved with the largest divergence angle. The dominant uncertainty contribution arose from the mirror topography, which was additionally determined with a Fizeau interferometer. The measured topography agreed within  ±1.3 nm with the systematic deviations revealed in the straightness comparison, resulting in an uncertainty contribution of 2.6 nm for the straightness interferometer.

  20. High-efficiency interaction-free measurement with an unbalanced Mach–Zehnder interferometer

    Science.gov (United States)

    Chao, Liu; Jinhong, Liu; Junxiang, Zhang; Shiyao, Zhu

    2018-06-01

    The presence of an object can be detected without the absorption of photons in an interaction-free measurement (IFM) system based on the Zeno effect in chained Mach–Zehnder interferometers (MZIs). In this paper, we propose a scheme with an unbalanced MZI to perform the transmission of two frequency components of input light simultaneously. The two components are separated at two output ports of the MZI, achieving a high probability of asserting the absence of the object. The two final outputs of the MZI can also be extended to perform special information processing via IFM. As a result, this proposal contributes to the improvement of efficiency in interaction-free measurements with a very small number of interferometers for potential practical implementations of quantum information technology.

  1. Electrical Double Layer-Induced Ion Surface Accumulation for Ultrasensitive Refractive Index Sensing with Nanostructured Porous Silicon Interferometers.

    Science.gov (United States)

    Mariani, Stefano; Strambini, Lucanos Marsilio; Barillaro, Giuseppe

    2018-03-23

    Herein, we provide the first experimental evidence on the use of electrical double layer (EDL)-induced accumulation of charged ions (using both Na + and K + ions in water as the model) onto a negatively charged nanostructured surface (e.g., thermally growth SiO 2 )-Ion Surface Accumulation, ISA-as a means of improving performance of nanostructured porous silicon (PSi) interferometers for optical refractometric applications. Nanostructured PSi interferometers are very promising optical platforms for refractive index sensing due to PSi huge specific surface (hundreds of m 2 per gram) and low preparation cost (less than $0.01 per 8 in. silicon wafer), though they have shown poor resolution ( R) and detection limit (DL) (on the order of 10 -4 -10 -5 RIU) compared to other plasmonic and photonic platforms ( R and DL on the order of 10 -7 -10 -8 RIU). This can be ascribed to both low sensitivity and high noise floor of PSi interferometers when bulk refractive index variation of the solution infiltrating the nanopores either approaches or is below 10 -4 RIU. Electrical double layer-induced ion surface accumulation (EDL-ISA) on oxidized PSi interferometers allows the interferometer output signal (spectral interferogram) to be impressively amplified at bulk refractive index variation below 10 -4 RIU, increasing, in turn, sensitivity up to 2 orders of magnitude and allowing reliable measurement of refractive index variations to be carried out with both DL and R of 10 -7 RIU. This represents a 250-fold-improvement (at least) with respect to the state-of-the-art literature on PSi refractometers and pushes PSi interferometer performance to that of state-of-the-art ultrasensitive photonics/plasmonics refractive index platforms.

  2. The recent development of an X-ray grating interferometer at Shanghai Synchrotron Radiation Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sun Haohua; Kou Bingquan; Xi Yan; Qi Juncheng; Sun Jianqi; Mohr, Juergen; Boerner, Martin; Zhao Jun; Xu, Lisa X.; Xiao Tiqiao; Wang Yujie [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China) and Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200040 (China); Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Karlsruhe Institute of Technology (KIT), Institute for Microstructure Technology (IMT), Hermannvon-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2012-07-31

    An X-ray grating interferometer has been installed at Shanghai Synchrotron Radiation Facility (SSRF). Three sets of phase gratings were designed to cover the wide X-ray energy range needed for biological and soft material imaging capabilities. The performance of the grating interferometer has been evaluated by a tomography study of a PMMA particle packing and a new born mouse chest. In the mouse chest study, the carotid artery and carotid vein inside the mouse can be identified in situ without contrast agents.

  3. The recent development of an X-ray grating interferometer at Shanghai Synchrotron Radiation Facility

    International Nuclear Information System (INIS)

    Sun Haohua; Kou Bingquan; Xi Yan; Qi Juncheng; Sun Jianqi; Mohr, Jürgen; Börner, Martin; Zhao Jun; Xu, Lisa X.; Xiao Tiqiao; Wang Yujie

    2012-01-01

    An X-ray grating interferometer has been installed at Shanghai Synchrotron Radiation Facility (SSRF). Three sets of phase gratings were designed to cover the wide X-ray energy range needed for biological and soft material imaging capabilities. The performance of the grating interferometer has been evaluated by a tomography study of a PMMA particle packing and a new born mouse chest. In the mouse chest study, the carotid artery and carotid vein inside the mouse can be identified in situ without contrast agents.

  4. Studies on a double-interferometer and mesospheric temperature measurements with a sodium-LIDAR-instrument

    International Nuclear Information System (INIS)

    Serwazi, M.

    1989-07-01

    The first part of this report describes the integration and alignment of a second Fabry-Perot-Interferometer into the optical bench of the sodium LIDAR experiment in Northern Norway. The spectral efficiency of this double interferometer was instrumentally and theoretically examined. The second part of the report presents results of temperature measurements in March 1989, which were made jointly with a Rayleigh LIDAR from the Max Planck Institute for Aeronomy. Measured temperatures and Na densities of three nights are presented. (orig.)

  5. Structural-Thermal-Optical-Performance (STOP) Model Development and Analysis of a Field-widened Michelson Interferometer

    Science.gov (United States)

    Scola, Salvatore J.; Osmundsen, James F.; Murchison, Luke S.; Davis, Warren T.; Fody, Joshua M.; Boyer, Charles M.; Cook, Anthony L.; Hostetler, Chris A.; Seaman, Shane T.; Miller, Ian J.; hide

    2014-01-01

    An integrated Structural-Thermal-Optical-Performance (STOP) model was developed for a field-widened Michelson interferometer which is being built and tested for the High Spectral Resolution Lidar (HSRL) project at NASA Langley Research Center (LaRC). The performance of the interferometer is highly sensitive to thermal expansion, changes in refractive index with temperature, temperature gradients, and deformation due to mounting stresses. Hand calculations can only predict system performance for uniform temperature changes, under the assumption that coefficient of thermal expansion (CTE) mismatch effects are negligible. An integrated STOP model was developed to investigate the effects of design modifications on the performance of the interferometer in detail, including CTE mismatch, and other three- dimensional effects. The model will be used to improve the design for a future spaceflight version of the interferometer. The STOP model was developed using the Comet SimApp'TM' Authoring Workspace which performs automated integration between Pro-Engineer®, Thermal Desktop®, MSC Nastran'TM', SigFit'TM', Code V'TM', and MATLAB®. This is the first flight project for which LaRC has utilized Comet, and it allows a larger trade space to be studied in a shorter time than would be possible in a traditional STOP analysis. This paper describes the development of the STOP model, presents a comparison of STOP results for simple cases with hand calculations, and presents results of the correlation effort to bench-top testing of the interferometer. A trade study conducted with the STOP model which demonstrates a few simple design changes that can improve the performance seen in the lab is also presented.

  6. Applications of phase-contrast x-ray imaging to medicine using an x-ray interferometer

    Science.gov (United States)

    Momose, Atsushi; Yoneyama, Akio; Takeda, Tohoru; Itai, Yuji; Tu, Jinhong; Hirano, Keiichi

    1999-10-01

    We are investigating possible medical applications of phase- contrast X-ray imaging using an X-ray interferometer. This paper introduces the strategy of the research project and the present status. The main subject is to broaden the observation area to enable in vivo observation. For this purpose, large X-ray interferometers were developed, and 2.5 cm X 1.5 cm interference patterns were generated using synchrotron X-rays. An improvement of the spatial resolution is also included in the project, and an X-ray interferometer designed for high-resolution phase-contrast X-ray imaging was fabricated and tested. In parallel with the instrumental developments, various soft tissues are observed by phase- contrast X-ray CT to find correspondence between the generated contrast and our histological knowledge. The observation done so far suggests that cancerous tissues are differentiated from normal tissues and that blood can produce phase contrast. Furthermore, this project includes exploring materials that modulate phase contrast for selective imaging.

  7. Twin-Core Fiber-Based Mach Zehnder Interferometer for Simultaneous Measurement of Strain and Temperature

    Science.gov (United States)

    Kowal, Dominik; Urbanczyk, Waclaw; Mergo, Pawel

    2018-01-01

    In this paper we present an all-fiber interferometric sensor for the simultaneous measurement of strain and temperature. It is composed of a specially fabricated twin-core fiber spliced between two pieces of a single-mode fiber. Due to the refractive index difference between the two cores in a twin-core fiber, a differential interference pattern is produced at the sensor output. The phase response of the interferometer to strain and temperature is measured in the 850–1250 nm spectral range, showing zero sensitivity to strain at 1000 nm. Due to the significant difference in sensitivities to both parameters, our interferometer is suitable for two-parameter sensing. The simultaneous response of the interferometer to strain and temperature was studied using the two-wavelength interrogation method and a novel approach based on the spectral fitting of the differential phase response. As the latter technique uses all the gathered spectral information, it is more reliable and yields the results with better accuracy. PMID:29558386

  8. Neutron spin quantum precession using multilayer spin splitters and a phase-spin echo interferometer

    International Nuclear Information System (INIS)

    Ebisawa, Toru; Tasaki, Seiji; Kawai, Takeshi; Hino, Masahiro; Akiyoshi, Tsunekazu; Achiwa, Norio; Otake, Yoshie; Funahashi, Haruhiko.

    1996-01-01

    Neutron spin quantum precession by multilayer spin splitter has been demonstrated using a new spin interferometer. The multilayer spin splitter consists of a magnetic multilayer mirror on top, followed by a gap layer and a non magnetic multilayer mirror which are evaporated on a silicon substrate. Using the multilayer spin splitter, a polarized neutron wave in a magnetic field perpendicular to the polarization is split into two spin eigenstates with a phase shift in the direction of the magnetic field. The spin quantum precession is equal to the phase shift, which depends on the effective thickness of the gap layer. The demonstration experiments verify the multilayer spin splitter as a neutron spin precession device as well as the coherent superposition principle of the two spin eigenstates. We have developed a new phase-spin echo interferometer using the multilayer spin splitters. We present successful performance tests of the multilayer spin splitter and the phase-spin echo interferometer. (author)

  9. Measurement facilities and accuracy limits of sampling digital interferometers. Meresi lehetoesegek es hibaanalizis digitalis mintavetelezoe interferometeren

    Energy Technology Data Exchange (ETDEWEB)

    Czitrovszky, A.; Jani, P.; Szoter, L.

    1990-12-15

    We discuss the measurement facilities of a recently development sampling digital interferometer for machine tool testing. As opposed to conventional interferometers the present device provides possibilities for the digital storage up to 4 kHz of the complete information of the motion so that displacement, velocity, acceleration and power density spectrum measurement can be performed. An estimation is given for the truncation, round-off, jitter and frequency-aliasing sources of error of the reconstructed motion parameters. On the basis of the Shannon sampling theory optimal conditions of measurement parameters are defined for the case when the accuracy of the reconstructed part of motion and vibration is equal to the resolution of the conventional interferometer. 7 refs., 3 figs., 1 tab.

  10. LOOP CALCULUS AND BELIEF PROPAGATION FOR Q-ARY ALPHABET: LOOP TOWER

    Energy Technology Data Exchange (ETDEWEB)

    CHERTKOV, MICHAEL [Los Alamos National Laboratory; CHERNYAK, VLADIMIR [Los Alamos National Laboratory

    2007-01-10

    Loop calculus introduced in [1], [2] constitutes a new theoretical tool that explicitly expresses symbol Maximum-A-Posteriori (MAP) solution of a general statistical inference problem via a solution of the Belief Propagation (BP) equations. This finding brought a new significance to the BP concept, which in the past was thought of as just a loop-free approximation. In this paper they continue a discussion of the Loop Calculus, partitioning the results into three Sections. In Section 1 they introduce a new formulation of the Loop Calculus in terms of a set of transformations (gauges) that keeping the partition function of the problem invariant. The full expression contains two terms referred to as the 'ground state' and 'excited states' contributions. The BP equations are interpreted as a special (BP) gauge fixing condition that emerges as a special orthogonality constraint between the ground state and excited states, which also selects loop contributions as the only surviving ones among the excited states. In Section 2 they demonstrate how the invariant interpretation of the Loop Calculus, introduced in Section 1, allows a natural extension to the case of a general q-ary alphabet, this is achieved via a loop tower sequential construction. The ground level in the tower is exactly equivalent to assigning one color (out of q available) to the 'ground state' and considering all 'excited' states colored in the remaining (q-1) colors, according to the loop calculus rule. Sequentially, the second level in the tower corresponds to selecting a loop from the previous step, colored in (q-1) colors, and repeating the same ground vs excited states splitting procedure into one and (q-2) colors respectively. The construction proceeds till the full (q-1)-levels deep loop tower (and the corresponding contributions to the partition function) are established. In Section 3 they discuss an ultimate relation between the loop calculus and the Bethe

  11. [Research on lateral shearing interferometer for field monitoring of natural gas pipeline leak].

    Science.gov (United States)

    Zhang, Xue-Feng; Gao, Yu-Bin

    2012-09-01

    Aimed at the mechanical scanning spectroscopy equipment with poor anti-interference and anti-jamming ability, which affects the accuracy of its natural gas pipeline leak detection in the wild, a new type of lateral shearing interferometer system was designed. The system uses a beam splitter to get optical path difference by a mechanical scanning part, and it cancel the introduction of external vibration interference through the linkage between the two beam splitterw. The interference intensity of interference fringes produced was calculated, and analysis of a rotating beam splitter corresponds to the angle of the optical path difference function, solving for the maximum angle of the forward rotation and reverse rotation, which is the maximum optical path range. Experiments using the gas tank deflated simulated natural gas pipeline leak process, in the interference conditions, and the test data of the type WQF530 spectrometer and the new type of lateral shearing interferometer system were comparedt. The experimental results show that the relative error of both systems is about 1% in indoor conditions without interference. However, in interference environment, the error of WQF530 type spectrometer becomes larger, more than 10%, but the error of the new type of lateral shearing interferometer system is still below 5%. The detection accuracy of the type WQF530 spectrometer decreased significantly due to the environment. Therefore, the seismic design of the system can effectively offset power deviation and half-width increases of center wavelength caused by external interference, and compared to conventional mechanical scanning interferometer devices the new system is more suitable for field detection.

  12. Design of interferometer system for Keda Torus eXperiment using terahertz solid-state diode sources

    International Nuclear Information System (INIS)

    Xie, Jinlin; Wang, Haibo; Li, Hong; Lan, Tao; Liu, Adi; Liu, Wandong; Yu, Changxuan; Ding, Weixing

    2014-01-01

    A solid-state source based terahertz (THz) interferometer diagnostic system has been designed and characterized for the Keda Torus eXperiment (KTX). The THz interferometer utilizes the planar diodes based frequency multiplier (X48) to provide the probing beam at fixed frequency 0.650 THz, and local oscillator is provided by an independent solid-state diode source with tunable frequency (0.650 THz +/− 10 MHz). Both solid-state sources have approximately 1 mW power. The planar-diode mixers optimized for high sensitivity, ∼750 mV/mW, are used in the heterodyne detection system, which permits multichannel interferometer on KTX with a low phase noise. A sensitivity of e l> min = 4.5 × 10 16 m −2 and a temporal resolution of 0.2 μs have been achieved during the initial bench test

  13. Quantitative phase determination by using a Michelson interferometer

    International Nuclear Information System (INIS)

    Pomarico, Juan A; Molina, Pablo F; Angelo, Cristian D'

    2007-01-01

    The Michelson interferometer is one of the best established tools for quantitative interferometric measurements. It has been, and is still successfully used, not only for scientific purposes, but it is also introduced in undergraduate courses for qualitative demonstrations as well as for quantitative determination of several properties such as refractive index, wavelength, optical thickness, etc. Generally speaking, most of the measurements are carried out by determining phase distortions through the changes in the location and/or shape of the interference fringes. However, the extreme sensitivity of this tool, for which minimum deviations of the conditions of its branches can cause very large modifications in the fringe pattern, makes phase changes difficult to follow and measure. The purpose of this communication is to show that, under certain conditions, the sensitivity of the Michelson interferometer can be 'turned down' allowing the quantitative measurement of phase changes with relative ease. As an example we present how the angle (or, optionally, the refractive index) of a transparent standard optical wedge can be determined. Experimental results are shown and compared with the data provided by the manufacturer showing very good agreement

  14. Tracking Solar Type II Bursts with Space Based Radio Interferometers

    Science.gov (United States)

    Hegedus, Alexander M.; Kasper, Justin C.; Manchester, Ward B.

    2018-06-01

    The Earth’s Ionosphere limits radio measurements on its surface, blocking out any radiation below 10 MHz. Valuable insight into many astrophysical processes could be gained by having a radio interferometer in space to image the low frequency window for the first time. One application is observing type II bursts tracking solar energetic particle acceleration in Coronal Mass Ejections (CMEs). In this work we create a simulated data processing pipeline for several space based radio interferometer (SBRI) concepts and evaluate their performance in the task of localizing these type II bursts.Traditional radio astronomy software is hard coded to assume an Earth based array. To circumvent this, we manually calculate the antenna separations and insert them along with the simulated visibilities into a CASA MS file for analysis. To create the realest possible virtual input data, we take a 2-temperature MHD simulation of a CME event, superimpose realistic radio emission models from the CME-driven shock front, and propagate the signal through simulated SBRIs. We consider both probabilistic emission models derived from plasma parameters correlated with type II bursts, and analytical emission models using plasma emission wave interaction theory.One proposed SBRI is the pathfinder mission SunRISE, a 6 CubeSat interferometer to circle the Earth in a GEO graveyard orbit. We test simulated trajectories of SunRISE and image what the array recovers, comparing it to the virtual input. An interferometer on the lunar surface would be a stable alternative that avoids noise sources that affect orbiting arrays, namely the phase noise from positional uncertainty and atmospheric 10s-100s kHz noise. Using Digital Elevation Models from laser altimeter data, we test different sets of locations on the lunar surface to find near optimal configurations for tracking type II bursts far from the sun. Custom software is used to model the response of different array configurations over the lunar year

  15. Practical speed meter designs for quantum nondemolition gravitational-wave interferometers

    International Nuclear Information System (INIS)

    Purdue, Patricia; Chen Yanbei

    2002-01-01

    In the quest to develop viable designs for third-generation optical interferometric gravitational-wave detectors (e.g., LIGO-III and EURO), one strategy is to monitor the relative momentum or speed of the test-mass mirrors, rather than monitoring their relative position. A previous paper analyzed a straightforward but impractical design for a speed-meter interferometer that accomplishes this. This paper describes some practical variants of speed-meter interferometers. Like the original interferometric speed meter, these designs in principle can beat the gravitational-wave standard quantum limit (SQL) by an arbitrarily large amount, over an arbitrarily wide range of frequencies. These variants essentially consist of a Michelson interferometer plus an extra 'sloshing' cavity that sends the signal back into the interferometer with opposite phase shift, thereby cancelling the position information and leaving a net phase shift proportional to the relative velocity. In practice, the sensitivity of these variants will be limited by the maximum light power W circ circulating in the arm cavities that the mirrors can support and by the leakage of vacuum into the optical train at dissipation points. In the absence of dissipation and with squeezed vacuum (power squeeze factor e -2R ≅0.1) inserted into the output port so as to keep the circulating power down, the SQL can be beat by h/h SQL ∼√(W circ SQL e -2R /W circ ) at all frequencies below some chosen f opt ≅100 Hz. Here W circ SQL ≅800 kW(f opt /100 Hz) 3 is the power required to reach the SQL in the absence of squeezing. (However, as the power increases in this expression, the speed meter becomes more narrow band; additional power and reoptimization of some parameters are required to maintain the wide band. See Sec. III B.) Estimates are given of the amount by which vacuum leakage at dissipation points will debilitate this sensitivity; these losses are 10% or less over most of the frequency range of interest (f

  16. Optical path difference measurements with a two-step parallel phase shifting interferometer based on a modified Michelson configuration

    Science.gov (United States)

    Toto-Arellano, Noel Ivan; Serrano-Garcia, David I.; Rodriguez-Zurita, Gustavo

    2017-09-01

    We report an optical implementation of a parallel phase-shifting quasi-common path interferometer using two modified Michelson interferometers to generate two interferograms. By using a displaceable polarizer's array, placed on the image plane, we can obtain four phase-shifted interferograms in two captures. The system operates as a quasi-common path interferometer generating four beams, which are to interfere with alignment procedures on the mirrors of the Michelson configurations. The optical phase data are retrieved using the well-known four-step algorithms. To present the capabilities of the system, experimental results obtained from transparent structures are presented.

  17. Temporal characterization of short-pulse third-harmonic generation in an atomic gas by a transmission-grating Michelson interferometer.

    Science.gov (United States)

    Papadogiannis, N A; Nersisyan, G; Goulielmakis, E; Rakitzis, T P; Hertz, E; Charalambidis, D; Tsakiris, G D; Witte, K

    2002-09-01

    By use of a transmission-grating-based Michelson interferometer, second-order interferometric as well as intensity autocorrelation traces of the third harmonic of a Ti:sapphire 50-fs laser beam produced in Ar have been measured. The duration of the harmonic is found to be that expected from lowest-order perturbation theory. At this wavelength, the performance of the interferometer with respect to pulse-front distortion and dispersion is found to be satisfactory. This result is a first step toward the use of the interferometer for the temporal characterization of higher harmonics or harmonic superposition forming attosecond pulse trains.

  18. Cantilever biosensor reader using a common-path, holographic optical interferometer

    DEFF Research Database (Denmark)

    Pedersen, Henrik Chresten; Jakobsen, Michael Linde; Hanson, Steen Grüner

    2010-01-01

    We demonstrate an optical reader principle aimed at monitoring biologically induced deflections of microcantilevers often used in biosensor systems. The principle is based on a so-called common-path optical interferometer in which the two interfering optical beams are copropagating,which makes...

  19. Non magnetic neutron spin quantum precession using multilayer spin splitter and a phase-spin echo interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Ebisawa, T.; Tasaki, S.; Kawai, T.; Akiyoshi, T. [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.; Achiwa, N.; Hino, M.; Otake, Y.; Funahashi, H.

    1996-08-01

    The authors have developed cold neutron optics and interferometry using multilayer mirrors. The advantages of the multilayer mirrors are their applicability to long wavelength neutrons and a great variety of the mirror performance. The idea of the present spin interferometry is based on nonmagnetic neutron spin quantum precession using multilayer spin splitters. The equation for polarized neutrons means that the polarized neutrons are equivalent to the coherent superposition of two parallel spin eigenstates. The structure and principle of a multilayer spin splitter are explained, and the nonmagnetic gap layer of the multilayer spin splitter gives rise to neutron spin quantum precession. The performance test of the multilayer spin splitter were made with a new spin interferometer, which is analogous optically to a spin echo system with vertical precession field. The spin interferometers were installed at Kyoto University research reactor and the JRR-3. The testing method and the results are reported. The performance tests on a new phase-spin echo interferometer are described, and its applications to the development of a high resolution spin echo system and a Jamin type cold neutron interferometer are proposed. (K.I.)

  20. Electron cyclotron emission measurements on JET: Michelson interferometer, new absolute calibration, and determination of electron temperature.

    Science.gov (United States)

    Schmuck, S; Fessey, J; Gerbaud, T; Alper, B; Beurskens, M N A; de la Luna, E; Sirinelli, A; Zerbini, M

    2012-12-01

    At the fusion experiment JET, a Michelson interferometer is used to measure the spectrum of the electron cyclotron emission in the spectral range 70-500 GHz. The interferometer is absolutely calibrated using the hot/cold technique and, in consequence, the spatial profile of the plasma electron temperature is determined from the measurements. The current state of the interferometer hardware, the calibration setup, and the analysis technique for calibration and plasma operation are described. A new, full-system, absolute calibration employing continuous data acquisition has been performed recently and the calibration method and results are presented. The noise level in the measurement is very low and as a result the electron cyclotron emission spectrum and thus the spatial profile of the electron temperature are determined to within ±5% and in the most relevant region to within ±2%. The new calibration shows that the absolute response of the system has decreased by about 15% compared to that measured previously and possible reasons for this change are presented. Temperature profiles measured with the Michelson interferometer are compared with profiles measured independently using Thomson scattering diagnostics, which have also been recently refurbished and recalibrated, and agreement within experimental uncertainties is obtained.