WorldWideScience

Sample records for cavity mirror undergoing

  1. Cavity QED with atomic mirrors

    Science.gov (United States)

    Chang, D. E.; Jiang, L.; Gorshkov, A. V.; Kimble, H. J.

    2012-06-01

    A promising approach to merge atomic systems with scalable photonics has emerged recently, which consists of trapping cold atoms near tapered nanofibers. Here, we describe a novel technique to achieve strong, coherent coupling between a single atom and photon in such a system. Our approach makes use of collective enhancement effects, which allow a lattice of atoms to form a high-finesse cavity within the fiber. We show that a specially designated ‘impurity’ atom within the cavity can experience strongly enhanced interactions with single photons in the fiber. Under realistic conditions, a ‘strong coupling’ regime can be reached, wherein it becomes feasible to observe vacuum Rabi oscillations between the excited impurity atom and a single cavity quantum. This technique can form the basis for a scalable quantum information network using atom-nanofiber systems.

  2. Entangling movable mirrors in a double cavity system

    DEFF Research Database (Denmark)

    Pinard, Michel; Dantan, Aurelien Romain; Vitali, David

    2005-01-01

    We propose a double-cavity set-up capable of generating a stationary entangled state of two movable mirrors at cryogenic temperatures. The scheme is based on the optimal transfer of squeezing of input optical fields to mechanical vibrational modes of the mirrors, realized by the radiation pressure...

  3. Cavity-mirror degradation in the deep-UV FEL

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, K.; Yamazaki, T.; Sei, N. [Electrotechnical Lab., Ibaraki (Japan)] [and others

    1995-12-31

    It is known that the degradation of dielectric multilayer mirrors used in short wavelength free-electron lasers (FELs) is caused by the carbon contamination on the mirror surface and the defects inside the dielectrics. We reported last year that the degraded dielectric multilayer mirrors can be repaired with both surface treatment by RF-induced oxygen plasma and thermal annealing. However, such a mirror degradation is still one of the most critical issues in the deep ultraviolet (UV) FELs, because the fundamental undulator radiation resonating in the laser cavity, the intensity of which is much higher than that of higher harmonics, can be sufficiently energetic to cause the mirror degradation through photochemical reactions. We are investigating the mirror degradation mainly in the deep UV region down to 240 nm. The experimental results will be shown. The mirror degradation mechanism will be discussed.

  4. ORAL CAVITY: A MIRROR TO HIV MANIFESTATIONS

    OpenAIRE

    Harpreet Singh Grover; Amit Bhardwaj; Prateek Gupta

    2013-01-01

    A multitude of oral lesions have been described in individuals infected with the human immunodeficiency virus. Human immunodeficiency virus infection is a major interest and concern to dentists and other health care workers because of the many varieties of oral lesions often associated with Human immunodeficiency virus infection. Individual’s tested seropositive for Human immunodeficiency virus infections are more susceptible to occurrence of lesions in oral cavity. This review covers the cli...

  5. Nonequilibrium dressing in a cavity with a movable reflecting mirror

    Science.gov (United States)

    Armata, Federico; Kim, M. S.; Butera, Salvatore; Rizzuto, Lucia; Passante, Roberto

    2017-08-01

    We consider a movable mirror coupled to a one-dimensional massless scalar field in a cavity. Both the field and the mirror's mechanical degrees of freedom are described quantum mechanically, and they can interact with each other via the radiation pressure operator. We investigate the dynamical evolution of mirror and field starting from a nonequilibrium initial state, and their local interaction which brings the system to a stationary configuration for long times. This allows us to study the time-dependent dressing process of the movable mirror interacting with the field, and its dynamics leading to a local equilibrium dressed configuration. Also, in order to explore the effect of the radiation pressure on both sides of the movable mirror, we generalize the effective field-mirror Hamiltonian and previous results to the case of two cavities sharing the same mobile boundary. This leads us to address, in the appropriate limit, the dynamical dressing problem of a single mobile wall, bounded by a harmonic potential, in the vacuum space.

  6. Vertical-cavity laser with a novel grating mirror

    DEFF Research Database (Denmark)

    Park, Gyeong Cheol

    Hybrid III-V on silicon (Si) ‘vertical cavity lasers’ (hybrid VCLs), which can emit light laterally into a Si waveguide, are fabricated and investigated. The Si-integrated hybrid VCL consists of a top dielectric Bragg reflector (DBR), a III-V active layer, and a bottom high contrast grating (HCG...... VCLs have been fabricated. The first version of hybrid VCL is designed for demonstrating in-plane emission into a Si waveguide. The in-plane emission is enabled by the bottom HCG abutting the Si waveguide, which not only functions as a highly reflective mirror but also routes the light from...... dispersion has been observed and discussed, which is unique for HCG-based vertical cavities. The second version proves the potential for high-speed operation of hybrid VCL structure. In the hybrid VCL structure, the effective cavity length is substantially reduced by using a dielectric DBR and a TM-HCG...

  7. The ABCD matrix for parabolic reflectors and its application to astigmatism free four-mirror cavities

    Science.gov (United States)

    Dupraz, K.; Cassou, K.; Martens, A.; Zomer, F.

    2015-10-01

    The ABCD matrix for parabolic reflectors is derived for any incident angles. It is used in numerical studies of four-mirror cavities composed of two flat and two parabolic mirrors. Constraints related to laser beam injection efficiency, optical stability, cavity-mode, beam-waist size and high stacking power are satisfied. A dedicated alignment procedure leading to stigmatic cavity-modes is employed to overcome issues related to the optical alignment of parabolic reflectors.

  8. Tunable Resonant-Cavity-Enhanced Photodetector with Double High-Index-Contrast Grating Mirrors

    DEFF Research Database (Denmark)

    Learkthanakhachon, Supannee; Yvind, Kresten; Chung, Il-Sug

    2013-01-01

    In this paper, we propose a broadband-tunable resonant-cavity-enhanced photodetector (RCE-PD) structure with double high-index-contrast grating (HCG) mirrors and numerically investigate its characteristics. The detector is designed to operate at 1550-nm wavelength. The detector structure consists...... of a top InP HCG mirror, a p-i-n photodiode embedding multiple quantum wells, and a Si HCG mirror formed in the Si layer of a silicon-on-insulator wafer. The detection wavelength can be changed by moving the top InP HCG mirror suspended in the air. High reflectivity and small penetration length of HCGs...

  9. Geometrical method for the generalized moore equations of a one-dimensional cavity with two moving mirrors

    CERN Document Server

    Li Li

    2002-01-01

    Extending the approach proposed by Cole and Schieve for a one-dimensional cavity with one moving mirror, the authors develop a geometrical method to solve exactly the generalized Moore (GM) equations for a one-dimensional cavity with two moving mirrors. As examples of applying authors method, the GM equations are solved in detail when the two mirrors oscillate resonantly, and the dependences of the solutions on the frequency and dephasing of the mirror motions are investigated

  10. Tunable mode-locked semiconductor laser with Bragg mirror external cavity

    DEFF Research Database (Denmark)

    Yvind, Kresten; Jørgensen, T.; Birkedal, Dan

    2002-01-01

    We present a simplified design for a wavelength tunable external cavity mode-locked laser by employing a wedged GaAs/AlGaAs Bragg mirror. The device emits 4-6 ps pulses at 10 GHz and is tunable over 15 nm. Although, in the present configuration, tunability is limited to 15 nm, however, we have...

  11. Mirror-smooth surfaces and repair of defects in superconducting RF cavities by mechanical polishing

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, C. A. [Fermilab; Cooley, L. D. [Fermilab

    2012-11-22

    Mechanical techniques for polishing the inside surface of niobium superconducting radio-frequency (SRF) cavities have been systematically explored. By extending known techniques to fine polishing, mirror-like finishes were produced, with <15 nm RMS (root mean square) roughness over 1 mm2 scan area. This is an order of magnitude less than the typical roughness produced by the electropolishing of niobium cavities. The extended mechanical polishing (XMP) process was applied to several SRF cavities which exhibited equator defects that caused quench at <20 MV m-1 and were not improved by further electropolishing. Cavity optical inspection equipment verified the complete removal of these defects, and minor acid processing, which dulled the mirror finish, restored performance of the defective cells to the high gradients and quality factors measured for adjacent cells when tested with other harmonics. This innate repair feature of XMP could be used to increase manufacturing yield. Excellent superconducting properties resulted after initial process optimization, with quality factor Q of 3 × 1010 and accelerating gradient of 43 MV m-1 being attained for a single-cell TESLA cavity, which are both close to practical limits. Several repaired nine-cell cavities also attained Q > 8 × 109 at 35 MV m-1, which is the specification for the International Linear Collider. Future optimization of the process and pathways for eliminating requirements for acid processing are also discussed.

  12. Solar Collector With Image-Forming Mirror Cavity to Irradiate Small Central Volume

    Science.gov (United States)

    Buchele, Don; Castle, Charles; Bonoetti, Joseph A.

    2001-01-01

    A unique solar thermal chamber has been designed and fabricated to produce the maximum concentration of solar energy and higher temperature possible. Its primary purpose was for solar plasma propulsion experiments and related material specimen testing above 3000 K. The design not only maximized solar concentration, but also, minimized infrared heat loss. This paper provides the underlying theory and operation of the chamber and initial optical correlation to the actual fabricated hardware. The chamber is placed at the focal point of an existing primary concentrator with a 2.74 m (9 ft) focal length. A quartz lens focuses a small sun image at the inlet hole of the mirrored cavity. The lens focuses two image planes at prescribed positions; the sun at the cavity's entrance hole and the primary concentrator at the junction plane of two surfaces that form the cavity chamber. The back half is an ellipsoid reflector that produces a 1.27 cm diameter final sun image. The image is "suspended in space," 7.1 cm away from the nearest cavity surface, to minimize thermal and contaminate damage to the mirror surfaces. A hemisphere mirror makes up the front chamber and has its center of curvature at the target image, where rays leaving the target are reflected back upon themselves, minimizing radiation losses.

  13. Nanoparticle-on-mirror cavity modes for huge and/or tunable plasmonic field enhancement

    Science.gov (United States)

    Huang, Yu; Ma, Lingwei; Li, Jianghao; Zhang, Zhengjun

    2017-03-01

    We present a careful numerical study of nanoparticle (NP) faceting, highlighting the great influence of small morphological changes of NP-mirror cavities on near-field enhancement in the nanoparticle-on-mirror (NPOM) system. Using a 3D finite element method (FEM) plasmon mapping method, the active transverse cavity modes can be confirmed. For the dominant mode, we have found that, by increasing the facet width, the resonance can be tuned linearly to the red with little decrease of the peak near-field intensity. It is further demonstrated that by increasing the NP size, the near-field intensity can be strongly enhanced. Understanding of such extreme optics benefits significantly both the optimized design of potential plasmonic devices and the fundamental understanding of nano-optics. Collaborative experimental considerations are expected with the rapid development of nanotechnology.

  14. Mirror design for long-wavelength vertical-cavity surface-emitting lasers

    Science.gov (United States)

    Wang, Jun; Cheng, Zhuo; Hu, Haiyang; Yang, Zeyuan; Bai, Yiming; Duan, Xiaofeng; Huang, Yongqing; Ren, Xiaomin

    2017-12-01

    A kind of bottom mirror, fabricated using a nano-scale epitaxy method, is proposed for long-wavelength InP-based vertical-cavity surface-emitting lasers (VCSELs). The design of the bottom mirror combines the conventional dielectric distributed Bragg reflector structure with a fabrication procedure using nano-scale epitaxial lateral overgrowth (ELO). Hence, this ELO mirror structure can provide both a high reflectivity, to form an optical resonance cavity, and a virtual InP substrate for the growth of high quality active regions in the VCSEL. The dependence of the reflectivity on the epitaxial lateral overgrowth mirror structure parameters is analyzed in detail using numerical methods. The results demonstrate that a stopband at more than 99% reflectivity is achieved in the wavelength range from 1.49 to 2.09 µm, and the threshold optical gain can be as low as 202, 257, and 311 cm‑1 for the internal loss coefficients of 10, 15 and 20 cm‑1.

  15. Sagnac loop mirror and micro-ring based laser cavity for silicon-on-insulator.

    Science.gov (United States)

    Zhang, Yi; Yang, Shuyu; Guan, Hang; Lim, Andy Eu-Jin; Lo, Guo-Qiang; Magill, Peter; Baehr-Jones, Tom; Hochberg, Michael

    2014-07-28

    An integrated laser is a key component in silicon based photonic integrated circuits. Beyond incorporating the gain medium, on-chip cavity design is critical to device performance and yield. Typical recent results involve cavities utilizing distributed Bragg gratings that require ultra-fine feature sizes. We propose to build laser cavity on silicon using a Sagnac loop mirror and a micro-ring wavelength filter for the first time. The Sagnac loop mirror provides broadband reflection, which is simple to fabricate, has an accurately-controlled reflectivity, and negligible excess loss. Single-mode operation is achieved with the intra-cavity micro-ring filter and, using a 248 nm stepper, the laser wavelength can be lithographically controlled within a standard deviation of 3.6 nm. We demonstrate a proof-of-concept device lasing at 1551.7 nm, with 44 dB SMSR, 1.2 MHz linewidth and 4.8 mW on-chip output power.

  16. Design of guided-mode resonance mirrors for short laser cavities.

    Science.gov (United States)

    Kondo, Tomohiro; Ura, Shogo; Magnusson, Robert

    2015-08-01

    A guided-mode resonance mirror (GMRM) consists of a waveguide grating integrated on an optical buffer layer on a high-reflection substrate. An incident free-space wave at the resonance wavelength is once coupled by the grating to a guided mode and coupled again by the same grating back to free space. The reflection characteristics of a GMRM are numerically calculated and theoretically analyzed. It is predicted that notch filtering or flat reflection spectra are obtained depending on the optical buffer layer thickness. Design of short cavities using a GMRM is discussed for potential application in surface-mount packaging of diode lasers onto a photonic circuit board.

  17. Mitigation of radiation-pressure-induced angular instability of a Fabry–Perot cavity consisting of suspended mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Nagano, Koji, E-mail: knagano@icrr.u-tokyo.ac.jp [KAGRA Observatory, Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan); Enomoto, Yutaro; Nakano, Masayuki [KAGRA Observatory, Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan); Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Kawamura, Seiji [KAGRA Observatory, Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan)

    2016-12-01

    To observe radiation pressure noise in optical cavities consisting of suspended mirrors, high laser power is necessary. However, because the radiation pressure on the mirrors could cause an angular anti-spring effect, the high laser power could induce angular instability to the cavity. An angular control system using radiation pressure as an actuator, which was previously invented to reduce the anti-spring effect for the low power case, was applied to the higher power case where the angular instability would occur. As a result the angular instability was mitigated. It was also demonstrated that the cavity was unstable without this control system. - Highlights: • High laser power could cause angular instability to a suspended Fabry–Perot cavity. • To mitigate the instability, the control system using radiation pressure is applied. • Mitigating the radiation-pressure-induced angular instability is demonstrated. • It is also confirmed that the cavity would be unstable without the control system.

  18. Mirroring

    DEFF Research Database (Denmark)

    Wegener, Charlotte; Wegener, Gregers

    2016-01-01

    Most definitions of creativity emphasise originality. The creative product is recognised as distinct from other products and the creative person as someone who stands out from the crowd. What tend to be overlooked are acts of mirroring as a crucial element of the creative process. The human ability...

  19. Influence of thermal deformation in cavity mirrors on beam propagation characteristics of high-power slab lasers

    Science.gov (United States)

    Wang, Zhen; Xiao, Longsheng; Wang, Wei; Wu, Chao; Tang, Xiahui

    2018-01-01

    Owing to their good diffusion cooling and low sensitivity to misalignment, slab-shape negative-branch unstable-waveguide resonators are widely used for high-power lasers in industry. As the output beam of the resonator is astigmatic, an external beam shaping system is required. However, the transverse dimension of the cavity mirrors in the resonator is large. For a long-time operation, the heating of cavity mirrors can be non-uniform. This results in micro-deformation and a change in the radius of curvature of the cavity mirrors, and leads to an output beam of an offset optical axis of the resonator. It was found that a change in the radius of curvature of 0.1% (1 mm) caused by thermal deformation generates a transverse displacement of 1.65 mm at the spatial filter of the external beam shaping system, and an output power loss of more than 80%. This can potentially burn out the spatial filter. In order to analyze the effect of the offset optical axis of the beam on the external optical path, we analyzed the transverse displacement and rotational misalignments of the spatial filter. For instance, if the transverse displacement was 0.3 mm, the loss in the output power was 9.6% and a sidelobe appeared in the unstable direction. If the angle of rotation was 5°, the loss in the output power was 2%, and the poles were in the direction of the waveguide. Based on these results, by adjusting the bending mirror, the deviation angle of the output beam of the resonator cavity was corrected, in order to obtain maximum output power and optimal beam quality. Finally, the propagation characteristics of the corrected output beam were analyzed.

  20. Broadband subwavelength grating mirror and its application to vertical-cavity surface-emitting laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper; Gilet, Philippe

    2008-01-01

    Various high-index-contrast sub-wavelength grating (HCG) mirror designs have been investigated. It reveals that transverse magnetic (TM-) and transverse electric (TE-) HCG reflect the incident fields in quite different ways and that the TM-HCG enables very thin gap below the grating. Based...... on these results, a new HCG VCSEL design with a thin oxide gap has been suggested. The thin oxide gap structure has a number of advantages including easier fabrication, better mechanical stability, and very strong single-mode properties....

  1. Priority of fibular reconstruction in patients with oral cavity cancer undergoing segmental mandibulectomy.

    Directory of Open Access Journals (Sweden)

    Chih-Hung Lin

    Full Text Available BACKGROUND: The fibula osteoseptocutaneous free flap is generally used for segmental mandibular reconstructions following resection of oral cavity squamous cell carcinoma (OSCC. However, less complex reconstructions may be feasible for patients with predicted poor survival. Herein, we sought to identify the main risk factors (RFs associated with poor prognosis in OSCC patients undergoing segmental mandibulectomy to help decide between fibular and non-fibular reconstructions. METHODS: Between 1996 and 2011, we examined the 5-year control, distant metastases, and survival rates in 310 consecutive, previously untreated patients with primary OSCC who underwent segmental mandibulectomy. RESULTS: Margin status was the only independent RF for 5-year local control. Level IV/V metastases, extracapsular spread, and tumor depth ≥15 mm were independent RFs for poor 5-year survival. In the entire study cohort, 23% of the patients had 2 or 3 adverse RFs; such a high-risk group was characterized by a poor prognosis and may be suitable for non-fibular reconstructions. Overall, 70% of the study patients were cT1-4N0, cT1N2, cT2N1, or had tumor depth <15 mm; less than 5% of patients in this subgroup had 2 or 3 adverse RFs and were thus candidates for fibular reconstructions. Among the remaining 30% of patients who showed both advanced clinical stage (cT2N2, cT3-4N1-2 and tumor depth ≥15 mm, 70% exhibited 2 or 3 adverse RFs. CONCLUSIONS: Level IV/V metastases, extracapsular spread, and tumor depth ≥15 mm were independent predictors of poor prognosis in OSCC patients undergoing segmental mandibulectomy. The preoperative or intraoperative identification of adverse RFs may help decide between fibular and non-fibular mandibular reconstruction. High-risk patients bearing 2 or 3 adverse RFs have poor prognosis and should not be considered as candidates for fibular reconstructions.

  2. Priority of fibular reconstruction in patients with oral cavity cancer undergoing segmental mandibulectomy.

    Science.gov (United States)

    Lin, Chih-Hung; Kang, Chung-Jan; Tsao, Chung-Kan; Wallace, Christopher Glenn; Lee, Li-Yu; Lin, Chien-Yu; Wang, Hung-Ming; Ng, Shu-Hang; Yen, Tzu-Chen; Liao, Chun-Ta

    2014-01-01

    The fibula osteoseptocutaneous free flap is generally used for segmental mandibular reconstructions following resection of oral cavity squamous cell carcinoma (OSCC). However, less complex reconstructions may be feasible for patients with predicted poor survival. Herein, we sought to identify the main risk factors (RFs) associated with poor prognosis in OSCC patients undergoing segmental mandibulectomy to help decide between fibular and non-fibular reconstructions. Between 1996 and 2011, we examined the 5-year control, distant metastases, and survival rates in 310 consecutive, previously untreated patients with primary OSCC who underwent segmental mandibulectomy. Margin status was the only independent RF for 5-year local control. Level IV/V metastases, extracapsular spread, and tumor depth ≥15 mm were independent RFs for poor 5-year survival. In the entire study cohort, 23% of the patients had 2 or 3 adverse RFs; such a high-risk group was characterized by a poor prognosis and may be suitable for non-fibular reconstructions. Overall, 70% of the study patients were cT1-4N0, cT1N2, cT2N1, or had tumor depth <15 mm; less than 5% of patients in this subgroup had 2 or 3 adverse RFs and were thus candidates for fibular reconstructions. Among the remaining 30% of patients who showed both advanced clinical stage (cT2N2, cT3-4N1-2) and tumor depth ≥15 mm, 70% exhibited 2 or 3 adverse RFs. Level IV/V metastases, extracapsular spread, and tumor depth ≥15 mm were independent predictors of poor prognosis in OSCC patients undergoing segmental mandibulectomy. The preoperative or intraoperative identification of adverse RFs may help decide between fibular and non-fibular mandibular reconstruction. High-risk patients bearing 2 or 3 adverse RFs have poor prognosis and should not be considered as candidates for fibular reconstructions.

  3. Risk Factors for Distant Metastasis in Patients with Oral Cavity Squamous Cell Carcinoma Undergoing Surgical Treatment.

    Science.gov (United States)

    Aires, Felipe Toyama; Lin, Chin Shien; Matos, Leandro Luongo; Kulcsar, Marco Aurélio Vamondes; Cernea, Claudio Roberto

    2018-01-23

    The aim of this study is to investigate the clinical and pathological factors related to distant metastasis in patients with oral cavity squamous cell carcinoma (OCSCC) undergoing surgery. A retrospective data review was conducted on patients who underwent primary surgery for OCSCC at the Instituto do Cancer do Estado de São Paulo (ICESP) between 2009 and 2015. Distant metastasis rates were calculated and predictive factors were determined by the Cox proportional-hazards model. There was a total of 274 patients, including 210 (76.6%) men and 64 (23.4%) women, with a mean age of 59.9 ± 10.9 years. The incidence of distant metastasis was 9.6%, with the lung being the most common site. The mean time interval between surgical treatment and the diagnosis of distant metastasis was 12 months (range 2-40 months). In the multivariate analysis, angiolymphatic invasion (HR = 2,87; p = 0.023), contralateral cervical metastasis (HR = 3.3; p = 0,007), tumor thickness >25 mm (HR = 3.50; p = 0.009), and locoregional recurrence (HR = 6.59; p 25 mm, angiolymphatic invasion, or locoregional recurrence after surgical treatment have a greater risk of developing distant metastasis. © 2018 S. Karger AG, Basel.

  4. Colonization of the oral cavity by yeasts in patients with chronic renal failure undergoing hemodialysis.

    Science.gov (United States)

    Godoy, Janine S R; de Souza Bonfim-Mendonça, Patrícia; Nakamura, Sandra S; Yamada, Sérgio S; Shinobu-Mesquita, Cristiane; Pieralisi, Neli; Fiorini, Adriana; Svidzinski, Terezinha I E

    2013-03-01

    To determine the frequency of yeast in the oral cavity of patients with chronic renal failure, undergoing hemodialysis (PCRFH); identification and antifungal susceptibility profile of yeast and demographic profile of patients. We performed mouthwash in 146 PCRFH; the rinse fluid was collected and cultured, yeasts grown were identified by phenotypic and molecular methods. The antifungal susceptibility profile was determined against nystatin, amphotericin B, fluconazole, voriconazole, and caspofungin based in Clinical and Laboratory Standards Institute (document M27-A3). Positive culture was observed in 39% of patients, of whom 53% were women; the median of dialysis time was 2.9 years. The age of the colonized patients varied between 26 and 84 years, with a median of 52.5 years. PCRFH over 45 years were significantly more colonized (P = 0.0108) as well as denture wearers (84.0%). We isolated 81 yeasts, predominantly Candida albicans (63%) followed by Candida glabrata. In general, yeasts were sensitive to the evaluated antifungal agents, but there was significant variation in the minimum inhibitory concentration, especially among non-C. albicans Candida (NCAC) compared to fluconazole, caspofungin, and amphotericin B. NCAC required significantly higher concentrations of fluconazole (P profile. These results are little known in this group of patients and are important for controlling the risk of developing invasive fungal infections. © 2012 John Wiley & Sons A/S. All rights reserved.

  5. Influences of thermal deformation of cavity mirrors induced by high energy DF laser to beam quality under the simulated real physical circumstances

    Science.gov (United States)

    Deng, Shaoyong; Zhang, Shiqiang; He, Minbo; Zhang, Zheng; Guan, Xiaowei

    2017-05-01

    The positive-branch confocal unstable resonator with inhomogeneous gain medium was studied for the normal used high energy DF laser system. The fast changing process of the resonator's eigenmodes was coupled with the slow changing process of the thermal deformation of cavity mirrors. Influences of the thermal deformation of cavity mirrors to the outcoupled beam quality and transmission loss of high frequency components of high energy laser were computed. The simulations are done through programs compiled by MATLAB and GLAD software and the method of combination of finite elements and Fox-li iteration algorithm was used. Effects of thermal distortion, misaligned of cavity mirrors and inhomogeneous distribution of gain medium were introduced to simulate the real physical circumstances of laser cavity. The wavefront distribution and beam quality (including RMS of wavefront, power in the bucket, Strehl ratio, diffraction limit β, position of the beam spot center, spot size and intensity distribution in far-field ) of the distorted outcoupled beam were studied. The conclusions of the simulation agree with the experimental results. This work would supply references of wavefront correction range to the adaptive optics system of interior alleyway.

  6. Occurrence of yeasts, pseudomonads and enteric bacteria in the oral cavity of patients undergoing head and neck radiotherapy

    OpenAIRE

    Elerson Gaetti-Jardim Júnior; Francisco Isaak Nicolas Ciesielski; Fátima Regina Nunes de Sousa; Francisca Nwaokorie; Christiane Marie Schweitzer; Mario Júlio Avila-Campos

    2011-01-01

    The aim of this study was to evaluate the occurrence of yeasts, pseudomonads and enteric bacteria in the oral cavity of patients undergoing radiotherapy (RT) for treatment of head and neck cancer. Fifty patients receiving RT were examined before, during and 30 days after RT. Saliva, mucosa, and biofilm samples were collected and microorganisms were detected by culture and polymerase chain reaction (PCR). The most prevalent yeasts in patients submitted to RT were Candida albicans, C. tropicali...

  7. Occurrence of yeasts, pseudomonads and enteric bacteria in the oral cavity of patients undergoing head and neck radiotherapy

    Directory of Open Access Journals (Sweden)

    Elerson Gaetti-Jardim Júnior

    2011-09-01

    Full Text Available The aim of this study was to evaluate the occurrence of yeasts, pseudomonads and enteric bacteria in the oral cavity of patients undergoing radiotherapy (RT for treatment of head and neck cancer. Fifty patients receiving RT were examined before, during and 30 days after RT. Saliva, mucosa, and biofilm samples were collected and microorganisms were detected by culture and polymerase chain reaction (PCR. The most prevalent yeasts in patients submitted to RT were Candida albicans, C. tropicalis, C. krusei, C. glabrata and C. parapsilosis. Citrobacter, Enterobacter, Enterococcus, Klebsiella, Proteus, and Pseudomonas were the most frequently cultivated bacteria. Before RT, targeted bacteria were cultivated from 22.2% of edentulous patients and 16.6% of dentate patients; 30 days after RT, these microorganisms were recovered from 77.8% edentulous and 46.8% dentate patients. By PCR, these microorganisms were detected from all edentulous patients, 78.1% of dentate patients. The presence of Gram-negative enteric roads and fungi was particularly frequent in patients presenting mucositis level III or IV. Modifications in the oral environment due to RT treatment seem to facilitate the colonization of oral cavity by members of family Enterobacteriaceae, genera Enterococcus and Candida.

  8. Occurrence of yeasts, pseudomonads and enteric bacteria in the oral cavity of patients undergoing head and neck radiotherapy

    Science.gov (United States)

    Gaetti-Jardim, Elerson; Ciesielski, Francisco Isaak Nicolas; de Sousa, Fátima Regina Nunes; Nwaokorie, Francisca; Schweitzer, Christiane Marie; Avila-Campos, Mario Júlio

    2011-01-01

    The aim of this study was to evaluate the occurrence of yeasts, pseudomonads and enteric bacteria in the oral cavity of patients undergoing radiotherapy (RT) for treatment of head and neck cancer. Fifty patients receiving RT were examined before, during and 30 days after RT. Saliva, mucosa, and biofilm samples were collected and microorganisms were detected by culture and polymerase chain reaction (PCR). The most prevalent yeasts in patients submitted to RT were Candida albicans, C. tropicalis, C. krusei, C. glabrata and C. parapsilosis. Citrobacter, Enterobacter, Enterococcus, Klebsiella, Proteus, and Pseudomonas were the most frequently cultivated bacteria. Before RT, targeted bacteria were cultivated from 22.2% of edentulous patients and 16.6% of dentate patients; 30 days after RT, these microorganisms were recovered from 77.8% edentulous and 46.8% dentate patients. By PCR, these microorganisms were detected from all edentulous patients, 78.1% of dentate patients. The presence of Gram-negative enteric roads and fungi was particularly frequent in patients presenting mucositis level III or IV. Modifications in the oral environment due to RT treatment seem to facilitate the colonization of oral cavity by members of family Enterobacteriaceae, genera Enterococcus and Candida. PMID:24031721

  9. Cavity Shaving plus Lumpectomy versus Lumpectomy Alone for Patients with Breast Cancer Undergoing Breast-Conserving Surgery: A Systematic Review and Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Ke Wang

    Full Text Available The margin status is a well-established prognostic predictor for patients undergoing breast-conserving surgery (BCS. Recent data suggested that cavity shaving in addition to lumpectomy might be a promising approach for improving the clinical outcomes. We aimed to compare the efficacy and safety between cavity shaving plus lumpectomy and lumpectomy alone with a systematic review and meta-analysis. We searched the PubMed, Embase, and Cochrane CENTRAL databases for studies comparing cavity shaving with lumpectomy before June 10, 2016. Both comparative studies and self-control studies were included. A random-effects model was used to estimate the odds ratios (ORs for positive margin rate, reoperation rate, recurrence rate, and weighted mean difference (WMD for excised tissue volume. Twenty-six studies were included in the meta-analysis. The cavity shaving group had a significantly lower positive margin rate than the BCS-alone group (16.4% vs. 31.9%; OR = 0.41, 95% CI 0.32-0.53, P < 0.05. Cavity shaving was associated with a significantly decreased rate of reoperation (OR = 0.42, 95% CI 0.30-0.59, P < 0.05. The overall locoregional rate was low for cavity shaving and BCS-alone (3% vs. 4%. Cavity shaving had no significant effect on the risk of locoregional recurrence (OR = 0.86, 95% CI 0.32-2.35; P = 0.78. The excised tissue volume did not differ substantially between cavity shaving and BCS alone (WMD = -23.88, 95% CI -55.20 to 7.44, P = 0.14. For patients undergoing BCS, additional cavity shaving was an effective method to decrease the positive margin rate and avoid reoperation. The addition of cavity shaving did not appear to have excessive excised tissue volume compared with partial mastectomy alone.

  10. Dosimetric consideration for patients with dental filling materials undergoing irradiation of oral cavity using RapidArc: challenges and solution

    Science.gov (United States)

    Mail, Noor; Albarakati, Y.; Khan, M. Ahmad; Saeedi, F.; Safadi, N.; Al-Ghamdi, S.; Saoudi, A.

    2012-03-01

    In this study, we investigate the effect of dental filling materials (DFM) on RapidArcTM treatment plans and delivery in a patient undergoing radiotherapy treatment. The presence of DFM creates uncertainties in CT number and causes long streaking artifacts in the reconstructed images which greatly affect the dose distribution inside the oral cavity. The influence of extensive dental filling artifacts on dose distribution was performed using a geometrically well defined head and neck IMRT verification phantom (PTW, Freiburg, Germany) together with inserts from DFM (Amalgam, 11.3 g/cm3). The phantom was scanned using Siemens SOMATOM Sensation CT simulator (Siemens AG, Germany) under standard head and neck imaging protocol (120 kV, 120 mAs, voxel size 1×1×2 mm3). Three RapidArcTM plans were created in the Varian Eclipse treatment planning System (TPS) to treat oral cavity using the same CT dataset including; 1) raw CT image, 2) streaking artifacts replaced with a mask of 10 HU and 3) 2 cm thick 6000 HU virtual filter (a volume around the teeth in TPS to mimic extra attenuation). The virtual filter thickness optimization was purely based on measured PDD data acquired with DFM and the calculation in Eclipse Planning System using direct beam. The dose delivery and distribution for the three plans was verified using Gafchromic EBT2 (International Specialty Product, Wayne, NJ, USA) film measurements. The artifact mask and virtual filter around the teeth in the planning was found very useful to reduce the discrepancies between the dose plan and delivery. From clinical point of view, these results can be helpful to understand the increase of mucositis in patient having DFM, and further investigation is underway for clinical solution.

  11. Nuclear light bulb propellant heating simulation using a tungsten/argon aerosol and radiation from a dc arc surrounded by a segmented mirror cavity

    Science.gov (United States)

    Klein, J. F.

    1972-01-01

    Experiments were conducted to simulate radiant heating of the propellant stream of a nuclear light bulb engine to obtain high bulk exit temperatures in the flowing simulated propellant stream by absorption of large fractions of the incident thermal radiation. A high-power, vortex-stabilized dc arc within an uncooled fused silica tube was used as the radiant energy source. It was surrounded by a mirror system to increase the radiation incident on the simulated propellant. The 12.7-cm-long by 2.3-cm-wide, diverging-duct test section had a transparent front wall and a reflecting rear wall. The central stream of seeded gas, a tungsten-particle/argon aerosol, had unseeded argon buffer layers on both sides to prevent coating of the duct walls. Arc operating times were approximately 0.5 sec with power levels up to 780 kW. Bulk exit temperatures were measured using a calorimeter downstream of the duct. The maximum simulated propellant bulk exit temperature obtained was 4515 K, compared with 3860 K in previous tests, 3300 to 3700 K expected in in-reactor tests in the Nuclear Furnace, and 6660 K in the reference nuclear light bulb engine. The maximum temperature in these tests was limited primarily by the amount of radiation incident on the test section (determined by the arc operating characteristics and the effectiveness of the mirror cavity).

  12. ACTOplus Met XR in Treating Patients With Stage I-IV Oral Cavity or Oropharynx Cancer Undergoing Definitive Treatment

    Science.gov (United States)

    2017-08-22

    Oral Cavity Neoplasm; Oropharyngeal Neoplasm; Stage I Oral Cavity Squamous Cell Carcinoma AJCC v6 and v7; Stage I Oropharyngeal Squamous Cell Carcinoma AJCC v6 and v7; Stage II Oral Cavity Squamous Cell Carcinoma AJCC v6 and v7; Stage II Oropharyngeal Squamous Cell Carcinoma AJCC v6 and v7; Stage III Oral Cavity Squamous Cell Carcinoma AJCC v6 and v7; Stage III Oropharyngeal Squamous Cell Carcinoma AJCC v7; Stage IV Oral Cavity Squamous Cell Carcinoma AJCC v6 and v7; Stage IV Oropharyngeal Squamous Cell Carcinoma AJCC v7; Stage IVA Oral Cavity Squamous Cell Carcinoma AJCC v6 and v7; Stage IVA Oropharyngeal Squamous Cell Carcinoma AJCC v7; Stage IVB Oral Cavity Squamous Cell Carcinoma AJCC v6 and v7; Stage IVB Oropharyngeal Squamous Cell Carcinoma AJCC v7; Stage IVC Oral Cavity Squamous Cell Carcinoma AJCC v6 and v7; Stage IVC Oropharyngeal Squamous Cell Carcinoma AJCC v7

  13. Hybrid vertical cavity laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2010-01-01

    A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

  14. Parametric study of cavity length and mirror reflectivity in ultralow threshold quantum well InGaAs/AlGaAs lasers

    OpenAIRE

    Chen, T. R.; Zhao, B.; Eng, L.; Feng, J.; Zhuang, Y. H.; Yariv, A.

    1995-01-01

    Record low CW threshold currents of 16 μA at-room temperature and 21 μA at cryogenic temperature have been demonstrated in buried heterostructure strained layer, single quantum well InGaAs/AlGaAs lasers with a short cavity length and high reflectivity coatings.

  15. Einstein's Mirror

    Science.gov (United States)

    Gjurchinovski, Aleksandar; Skeparovski, Aleksandar

    2008-01-01

    Reflection of light from a plane mirror in uniform rectilinear motion is a century-old problem, intimately related to the foundations of special relativity. The problem was first investigated by Einstein in his famous 1905 paper by using the Lorentz transformations to switch from the mirror's rest frame to the frame where the mirror moves at a…

  16. Hybrid Vertical-Cavity Laser

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention provides a light source (2) for light circuits on a silicon platform (3). A vertical laser cavity is formed by a gain region (101) arranged between a top mirror (4) and a bottom grating-mirror (12) in a grating region (11) in a silicon layer (10) on a substrate. A waveguide...

  17. Mirror symmetry

    CERN Document Server

    Voisin, Claire

    1999-01-01

    This is the English translation of Professor Voisin's book reflecting the discovery of the mirror symmetry phenomenon. The first chapter is devoted to the geometry of Calabi-Yau manifolds, and the second describes, as motivation, the ideas from quantum field theory that led to the discovery of mirror symmetry. The other chapters deal with more specialized aspects of the subject: the work of Candelas, de la Ossa, Greene, and Parkes, based on the fact that under the mirror symmetry hypothesis, the variation of Hodge structure of a Calabi-Yau threefold determines the Gromov-Witten invariants of its mirror; Batyrev's construction, which exhibits the mirror symmetry phenomenon between hypersurfaces of toric Fano varieties, after a combinatorial classification of the latter; the mathematical construction of the Gromov-Witten potential, and the proof of its crucial property (that it satisfies the WDVV equation), which makes it possible to construct a flat connection underlying a variation of Hodge structure in the ...

  18. Early nutritional support in non-metastatic stage IV oral cavity cancer patients undergoing adjuvant concurrent chemoradiotherapy: analysis of treatment tolerance and outcome in an area endemic for betel quid chewing.

    Science.gov (United States)

    Wang, Cheng-Hsu; Wang, Hung-Ming; Pang, Yi-Ping; Yeh, Kun-Yun

    2012-06-01

    Non-metastatic stage IV oral cavity cancer patients undergoing concurrent chemoradiotherapy (CCRT) are at risk of malnutrition because of postoperative eating problems and CCRT-related complications. A high percentage of betel quid use, which is associated with metabolic disorders, is found in oral cavity cancer patients in Taiwan. The aim of this study is to evaluate the effect of an early and intensive nutritional support program, comprising individualized counseling, nasogastric tube feeding, and mandatory hospitalization, throughout the CCRT period for such cases in an area where betel quid use is prevalent. We retrospectively analyzed 35 patients with nutritional support (NI) and 23 patients with no specifically designed nutrition program (NC). The NI group had better maintenance of body weight (p < 0.001) and higher serum albumin levels (p < 0.002) than the NC group. There was no difference in the total dose of radiation completed in the two groups; in contrast, the percentage of NI group patients who had radiation therapy (RT) breaks was lower and who completed planned chemotherapy was higher than in the NC group. Furthermore, more NC group patients suffered from sepsis during the treatment period, and fewer were alive 2 years after treatment. An early and intensive nutrition support may be beneficial to minimizing body weight loss, offering better treatment tolerance and probable survival benefits for patients with non-metastatic stage IV oral cavity cancers undergoing CCRT in endemic betel quid chewing areas.

  19. Dither Cavity Length Controller with Iodine Locking

    Directory of Open Access Journals (Sweden)

    Lawson Marty

    2016-01-01

    Full Text Available A cavity length controller for a seeded Q-switched frequency doubled Nd:YAG laser is constructed. The cavity length controller uses a piezo-mirror dither voltage to find the optimum length for the seeded cavity. The piezo-mirror dither also dithers the optical frequency of the output pulse. [1]. This dither in optical frequency is then used to lock to an Iodine absorption line.

  20. 130-nm tunable grating-mirror VCSEL

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2014-01-01

    We have reported that a combination of the high-index-contrast grating (HCG) mirror as movable mirror and the extended cavity configuration with an antireflection layer can provide a tuning wavelength range of 100 nm for tunable VCSELs. Here, we report that using the air-coupled cavity configurat......We have reported that a combination of the high-index-contrast grating (HCG) mirror as movable mirror and the extended cavity configuration with an antireflection layer can provide a tuning wavelength range of 100 nm for tunable VCSELs. Here, we report that using the air-coupled cavity...... configuration instead of the extended cavity configuration can bring 130-nm tuning range around 1330-nm wavelength. The air-coupled cavity is known to reduce the quantum confinement factor in VCSELs, increasing threshold. In our air-coupled cavity HCG VCSEL case, the very short power penetration length...... in the HCG minimizes this reduction of the quantum confinement factor, not as significant as in the air-coupled cavity DBR VCSEL....

  1. Mirror, mirror on the wall

    CERN Multimedia

    2005-01-01

    RICH 2, one of the two Ring Imaging Cherenkov detectors of the LHCb experiment, is being prepared to join the other detector elements ready for the first proton-proton collisions at LHC. The mirrors of the RICH2 detector are meticulously assembled in a clean room.In a large dark room, men in white move around an immense structure some 7 metres high, 10 metres wide and nearly 2.5 metres deep. Apparently effortlessly, they are installing the two large high-precision spherical mirrors. These mirrors will focus Cherenkov light, created by the charged particles that will traverse this detector, onto the photon detectors. Each spherical mirror wall is made up of facets like a fly's eye. Twenty-eight individual thin glass mirrors will all point to the same point in space to within a few micro-radians. The development of these mirrors has been technically demanding : Ideally they should be massless, sturdy, precise and have high reflectivity. In practice, though not massless, they are made from a mere 6 mm thin gl...

  2. Reflectivity-modulated grating-mirror

    DEFF Research Database (Denmark)

    2012-01-01

    The invention relates to vertical cavity lasers (VCL) incorporating a reflectivity-modulated grating mirror (1) for modulating the laser output. A cavity is formed by a bottom mirror (4), an active region (3), and an outcoupling top grating mirror (1) formed by a periodic refractive index grating...... region in a layer structure comprising a p- and a n-doped semiconductor layer with an electrooptic material layer (12) arranged there between. The grating region comprises a grating structure formed by periodic perforations to change the refractive index periodically in directions normal...... to the oscillation axis. A modulated voltage (91) is applied in reverse bias between the n- and p-doped layers to modulate the refractive index of the electrooptic material layer (12) and thereby the reflectivity spectrum of the grating mirror (1). The reflectivity of the grating mirror (1) can be modulated between...

  3. What do mirror neurons mirror?

    NARCIS (Netherlands)

    Uithol, S.; Rooij, I.J.E.I. van; Bekkering, H.; Haselager, W.F.G.

    2011-01-01

    Single cell recordings in monkeys provide strong evidence for an important role of the motor system in action understanding. This evidence is backed up by data from studies of the (human) mirror neuron system using neuroimaging or TMS techniques, and behavioral experiments. Although the data

  4. Speed enhancement in VCSELs employing grating mirrors

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2013-01-01

    In recent years, various approaches to improve the speed of directly modulated vertical-cavity surface-emitting lasers (VCSELs) have been reported and demonstrated good improvement. In this paper, we propose and numerically investigate a new possibility of using high-index-contrast grating (HCG......) as mirror for VCSELs. By changing the grating design, one can control the reflection delay of the grating mirror, enabling the control of cavity photon lifetime. On the other hand, short energy penetration depth of the HCG results in smaller modal volume, compared to DBR VCSELs. An example structure shows...... that the HCG VCSEL has a 30-% higher 3-dB bandwidth than the DBR VCSEL....

  5. Chinese "Magic" Mirrors.

    Science.gov (United States)

    Swinson, Derek B.

    1992-01-01

    Chinese "magic" mirrors are made from bronze with the front side a mirror and the reverse side a molded image. When light is reflected from the mirror,the image on the reverse side appears. Discusses reflections of conventional mirrors, possible explanations for the magic mirror phenomenon, and applications of the phenomenon to…

  6. Althusser's Mirror

    Directory of Open Access Journals (Sweden)

    Carsten Strathausen

    1994-01-01

    Full Text Available Jacques Lacan significantly influenced Althusser's accounts of ideology and the subject. Althusser's belief that science is a discourse without a subject parallels Lacan's belief that in the Symbolic Order the Subject and the Other are alienated. Althusser's account of interpellation, which explains how ideology recognizes individuals as subjects, takes for granted Lacan's notion of the mirror stage. Althusser repudiates the plenitude of the subject, whose interpellation conceals its lack; Lacan shows that the subject's failure to express itself in language makes the subject a void. However, Althusser, whose subject is too much like Lacan's ego, fails to distinguish between the "I" of the split subject and the "ego" of the subject's imaginary self-identity. What is more, Althusser rejects the self-consciousness implied by the subject's lack of plenitude and its suturing interpellation.

  7. Single Atoms in Nearly Concentric Cavity

    Science.gov (United States)

    Utama, Adrian Nugraha; Nguyen, Chi Huan; Lewty, Nick; Kurtsiefer, Christian; Quantum Optics Group Team

    2017-04-01

    Strong interaction between photons and neutral single atoms are usually observed in cavity quantum electrodynamics (CQED) systems with high finesse mirrors and small physical volume. We demonstrate another approach that employs a near concentric cavity with relatively low finesse mirrors ( 100) and large physical separation between mirrors ( 10 mm). The transmission spectrum of our CQED system with trapped single atoms is observed to exhibit two resolved normal mode peaks, in which the single atom cooperativity is estimated to be around 0.4. The cooperativity of the system can be improved further by increasing the finesse of the mirrors or moving the cavity closer to the concentric point. The successful realization of concentric CQED systems will open opportunities for scaling up with applications in quantum computing. This work is supported by the National Research Foundation and Ministry of Education, Singapore.

  8. Double arch mirror study

    Science.gov (United States)

    Vukobratovich, D.; Hillman, D.

    1983-01-01

    The development of a method of mounting light weight glass mirrors for astronomical telescopes compatible with the goals of the Shuttle Infrared Telescope Facility (SIRTF) was investigated. A 20 in. diameter double arch lightweight mirror previously fabricated was modified to use a new mount configuration. This mount concept was developed and fabricated. The mounting concept of the double mounting mirror is outlined. The modifications made to the mirror, fabrication of the mirror mount, and room temperature testing of the mirror and mount and the extension of the mirror and mount concept to a full size (40 in. diameter) primary mirror for SIRTF are discussed.

  9. Dewetting Transitions in Protein Cavities *

    Science.gov (United States)

    Young, Tom; Hua, Lan; Huang, Xuhui; Abel, Robert; Friesner, Richard; Berne, B. J.

    2010-01-01

    In a previous analysis of the solvation of protein active sites, a drying transition was observed in the narrow hydrophobic binding cavity of Cox-2. With the use of a crude metric that often seems able to discriminate those protein cavities that dry from those that do not, we made an extensive search of the pdb, and identified five other proteins that, in molecular dynamics simulations, undergo drying transitions in their active sites. Because such cavities need not desolvate before binding hydrophobic ligands they often exhibit very large binding affinities. This paper gives evidence that drying in protein cavities is not unique to Cox-2. PMID:20225258

  10. Mirror Neurons and Mirror-Touch Synesthesia.

    Science.gov (United States)

    Linkovski, Omer; Katzin, Naama; Salti, Moti

    2016-05-30

    Since mirror neurons were introduced to the neuroscientific community more than 20 years ago, they have become an elegant and intuitive account for different cognitive mechanisms (e.g., empathy, goal understanding) and conditions (e.g., autism spectrum disorders). Recently, mirror neurons were suggested to be the mechanism underlying a specific type of synesthesia. Mirror-touch synesthesia is a phenomenon in which individuals experience somatosensory sensations when seeing someone else being touched. Appealing as it is, careful delineation is required when applying this mechanism. Using the mirror-touch synesthesia case, we put forward theoretical and methodological issues that should be addressed before relying on the mirror-neurons account. © The Author(s) 2016.

  11. Coeliac cavity ultrasonic diagnosis apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Ando, O.; Suwaki, T.

    1983-07-05

    A coeliac cavity ultrasonic diagnosis apparatus is disclosed which includes an ultrasonic transducer or scanner portion adapted to be inserted into a coeliac cavity to effect a sector scan of an ultrasonic beam to produce an ultrasonic image of internal tissues and in which the ultrasonic oscillator on the one hand and an ultrasonic reflecting mirror and rotary disc on the other hand are relatively rotated so as to effect the sector scan of the ultrasonic beam and the rotary angle of the rotary disc is detected so as to obtain a deflecting angle of the ultrasonic beam and a display on a cathode ray tube of a precise ultrasonic picture image.

  12. Durable solar mirror films

    Science.gov (United States)

    O'Neill, Mark B.; Henderson, Andrew J.; Hebrink, Timothy J.; Katare, Rajesh K.; Jing, Naiyong; North, Diane; Peterson, Eric M.

    2017-02-14

    The present disclosure generally relates to durable solar mirror films, methods of making durable solar mirror films, and constructions including durable solar mirror films. In one embodiment, the present disclosure relates to a solar mirror film comprising: a multilayer optical film layer including having a coefficient of hygroscopic expansion of less than about 30 ppm per percent relative humidity; and a reflective layer having a coefficient of hygroscopic expansion.

  13. accelerating cavity

    CERN Multimedia

    On the inside of the cavity there is a layer of niobium. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment.

  14. Polarisation dynamics of a birefringent Fabry-Perot cavity

    Science.gov (United States)

    Ejlli, A.; Della Valle, F.; Zavattini, G.

    2018-02-01

    Optical Fabry-Perot cavities always show a non-degeneracy of two orthogonal polarisation states. This is due to the unavoidable birefringence of dielectric mirrors whose effects are extremely important in Fabry-Perot-based high-accuracy polarimeters: in birefringent cavities, ellipticities and rotations mix. We have developed and present here a theory of the polarisation state dynamics in a birefringent Fabry-Perot resonator, and we validate it through measurements performed with the polarimeter of the PVLAS experiment. The measurements are performed while a laser is frequency-locked to the cavity, and provide values for the phase difference between the two orthogonal polarisation components introduced by the combination of the two cavity mirrors (equivalent wave-plate) and for the finesse of the cavity. The theoretical formulas and the experimental data agree well showing that the consequences of the mirror birefringence must be taken into account in this and in any other similar experiment.

  15. radiofrequency cavity

    CERN Multimedia

    1988-01-01

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  16. Micro-Cavity Fluidic Dye Laser

    DEFF Research Database (Denmark)

    Helbo, Bjarne; Kristensen, Anders; Menon, Aric Kumaran

    2003-01-01

    We have successfully designed, fabricated and characterized a micro-cavity fluidic dye laser with metallic mirrors, which can be integrated with polymer based lab-on-a-chip microsystems without further processing steps. A simple rate-equation model is used to predict the average pumping power...

  17. Castable Amorphous Metal Mirrors and Mirror Assemblies

    Science.gov (United States)

    Hofmann, Douglas C.; Davis, Gregory L.; Agnes, Gregory S.; Shapiro, Andrew A.

    2013-01-01

    A revolutionary way to produce a mirror and mirror assembly is to cast the entire part at once from a metal alloy that combines all of the desired features into the final part: optical smoothness, curvature, flexures, tabs, isogrids, low CTE, and toughness. In this work, it has been demonstrated that castable mirrors are possible using bulk metallic glasses (BMGs, also called amorphous metals) and BMG matrix composites (BMGMCs). These novel alloys have all of the desired mechanical and thermal properties to fabricate an entire mirror assembly without machining, bonding, brazing, welding, or epoxy. BMGs are multi-component metal alloys that have been cooled in such a manner as to avoid crystallization leading to an amorphous (non-crystalline) microstructure. This lack of crystal structure and the fact that these alloys are glasses, leads to a wide assortment of mechanical and thermal properties that are unlike those observed in crystalline metals. Among these are high yield strength, carbide-like hardness, low melting temperatures (making them castable like aluminum), a thermoplastic processing region (for improving smoothness), low stiffness, high strength-to-weight ratios, relatively low CTE, density similar to titanium alloys, high elasticity and ultra-smooth cast parts (as low as 0.2-nm surface roughness has been demonstrated in cast BMGs). BMGMCs are composite alloys that consist of a BMG matrix with crystalline dendrites embedded throughout. BMGMCs are used to overcome the typically brittle failure observed in monolithic BMGs by adding a soft phase that arrests the formation of cracks in the BMG matrix. In some cases, BMGMCs offer superior castability, toughness, and fatigue resistance, if not as good a surface finish as BMGs. This work has demonstrated that BMGs and BMGMCs can be cast into prototype mirrors and mirror assemblies without difficulty.

  18. Dependence of mis-alignment sensitivity of ring laser gyro cavity on cavity parameters

    Energy Technology Data Exchange (ETDEWEB)

    Sun Feng; Zhang Xi; Zhang Hongbo; Yang Changcheng, E-mail: sunok1234@sohu.com [Huazhong Institute of Electro-Optics - Wuhan National Lab for Optoelectronics, Wuhan, Hubei (China)

    2011-02-01

    The ring laser gyroscope (RLG), as a rotation sensor, has been widely used for navigation and guidance on vehicles and missiles. The environment of strong random-vibration and large acceleration may deteriorate the performance of the RLG due to the vibration-induced tilting of the mirrors. In this paper the RLG performance is theoretically analyzed and the parameters such as the beam diameter at the aperture, cavity mirror alignment sensitivities and power loss due to the mirror tilting are calculated. It is concluded that by carefully choosing the parameters, the significant loss in laser power can be avoided.

  19. Geometrically induced surface polaritons in planar nanostructured metallic cavities

    Energy Technology Data Exchange (ETDEWEB)

    Davids, P. S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Intravia, F [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dalvit, Diego A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-01-14

    We examine the modal structure and dispersion of periodically nanostructured planar metallic cavities within the scattering matrix formulation. By nanostructuring a metallic grating in a planar cavity, artificial surface excitations or spoof plasmon modes are induced with dispersion determined by the periodicity and geometric characteristics of the grating. These spoof surface plasmon modes are shown to give rise to new cavity polaritonic modes at short mirror separations that modify the density of modes in nanostructured cavities. The increased modal density of states form cavity polarirons have a large impact on the fluctuation induced electromagnetic forces and enhanced hear transfer at short separations.

  20. Advanced Mirror Technology Development

    Science.gov (United States)

    Stahl, H. Philip

    2017-01-01

    The Advanced Mirror Technology Development (AMTD) project matures critical technologies required to enable ultra-stable 4-m-or-larger monolithic or segmented ultraviolet, optical, and infrared (UVOIR) space telescope primary-mirror assemblies for general astrophysics and ultra-high-contrast observations of exoplanets.

  1. Bronze rainbow hologram mirrors

    Science.gov (United States)

    Dawson, P.

    2006-02-01

    This project draws on holographic embossing techniques, ancient artistic conventions of bronze mirror design and modelling and casting processes to accomplish portraiture of reflection. Laser scanning, 3D computer graphics and holographic imaging are employed to enable a permanent 3D static holographic image to appear integrated with the real-time moving reflection of a viewer's face in a polished bronze disc. The disc and the figure which holds it (caryatid) are cast in bronze from a lost wax model, a technique which has been used for millennia to make personal mirrors. The Caryatid form of bronze mirror which went through many permutations in ancient Egyptian, Greece and Rome shows a plethora of expressive figure poses ranging from sleek nudes to highly embellished multifigure arrangements. The prototype of this series was made for Australian choreographer Graeme Murphy, Artistic Director of the Sydney Dance Company. Each subsequent mirror will be unique in figure and holographic imagery as arranged between artist and subject. Conceptually this project references both the modern experience of viewing mirrors retrieved from ancient tombs, which due to deterioration of the surface no longer reflect, and the functioning of Chinese Magic mirrors, which have the ability to project a predetermined image. Inspired by the metaphorical potential of these mirrors, which do not reflect the immediate reality of the viewer, this bronze hologram mirror series enables each viewer to reflect upon himself or herself observing simultaneously the holographic image and their own partially obliterated reflection.

  2. COI NMSD Hybrid Mirror

    Science.gov (United States)

    Mehle, Greg; Stahl, Phil (Technical Monitor)

    2002-01-01

    This presentation provides an overview of the development of the 1.6 meter hybrid mirror demonstrator for the NGST Mirror System Demonstrator (NMSD) program. The COI design approach for the NGST program combines the optical performance of glass, with the high specific stiffness capabilities of composite materials The foundation technologies being exploited in the development of the hybrid mirror focus upon precision Composite Materials for cryogenic operation, and non-contact optical processing (ion figuring) of the lightweight mirror surface. The NGST Mirror System Demonstrator (NMSD) has been designed and built by Composite Optics, Inc. (COI) with optical processing performed by SAGEM (REOSC). The sponsors of these efforts are the NASA Marshall and Goddard Space Flight Centers.

  3. Vertical external cavity surface emitting semiconductor lasers

    CERN Document Server

    Holm, M

    2001-01-01

    Active stabilisation showed a relative locked linewidth of approx 3 kHz. Coarse tuning over 7 nm was achieved using a 3-plate birefingent filter plate while fine-tuning using cavity length change allowed tuning over 250 MHz. Vertical external cavity semiconductor lasers have emerged as an interesting technology based on current vertical cavity semiconductor laser knowledge. High power output into a single transverse mode has attracted companies requiring good fibre coupling for telecommunications systems. The structure comprises of a grown semiconductor Bragg reflector topped with a multiple quantum well gain region. This is then included in an external cavity. This device is then optically pumped to promote laser action. Theoretical modelling of AIGaAs based VECSEL structures was undertaken, showing the effect of device design on laser characteristics. A simple 3-mirror cavity was constructed to assess the static characteristics of the structure. Up to 153 mW of output power was achieved in a single transver...

  4. Adaptive metal mirror for high-power CO2 lasers

    Science.gov (United States)

    Jarosch, Uwe-Klaus

    1996-08-01

    Spherical mirrors with a variable radius of curvature are used inside laser resonators as well as in the beam path between the laser and the workpiece. Commercially-available systems use piezoelectric actuators, or the pressure of the coolant, to deform the mirror surface. In both cases, the actuator and the cooling system influence each other. This interaction is avoided through the integration of the cooling system with the flexible mirror membrane. A multi- channel design leads to an optimized cooling effect, which is necessary for high power applications. The contour of the variable metal mirror depends on the mounting between the membrane and the mirror body and on the distribution of forces. Four cases of deformation can be distinguished for a circular elastic membrane. The realization of an adaptive metal mirror requires a technical compromise to be made. A mechanical construction is presented which combines an elastic hinge with the inlet and outlet of the coolant. For the deformation of the mirror membranes two actuators with different character of deformation are used. The superposition of the two deformations results in smaller deviations from the spherical surface shape than can be achieved using a single actuator. DC proportional magnets have been introduced as cheap and rigid actuators. The use of this adaptive mirror, either in a low pressure atmosphere of a gas laser resonator, or in an extra-cavity beam path is made possible through the use of a ventilation system.

  5. White-Light Phase-Conjugate Mirrors as Distortion Correctors

    Science.gov (United States)

    Frazier, Donald; Smith, W. Scott; Abdeldayem, Hossin; Banerjee, Partha

    2010-01-01

    White-light phase-conjugate mirrors would be incorporated into some optical systems, according to a proposal, as means of correcting for wavefront distortions caused by imperfections in large optical components. The proposal was given impetus by a recent demonstration that white, incoherent light can be made to undergo phase conjugation, whereas previously, only coherent light was known to undergo phase conjugation. This proposal, which is potentially applicable to almost any optical system, was motivated by a need to correct optical aberrations of the primary mirror of the Hubble Space telescope. It is difficult to fabricate large optical components like the Hubble primary mirror and to ensure the high precision typically required of such components. In most cases, despite best efforts, the components as fabricated have small imperfections that introduce optical aberrations that adversely affect imaging quality. Correcting for such aberrations is difficult and costly. The proposed use of white-light phase conjugate mirrors offers a relatively simple and inexpensive solution of the aberration-correction problem. Indeed, it should be possible to simplify the entire approach to making large optical components because there would be no need to fabricate those components with extremely high precision in the first place: A white-light phase-conjugate mirror could correct for all the distortions and aberrations in an optical system. The use of white-light phase-conjugate mirrors would be essential for ensuring high performance in optical systems containing lightweight membrane mirrors, which are highly deformable. As used here, "phase-conjugate mirror" signifies, more specifically, an optical component in which incident light undergoes time-reversal phase conjugation. In practice, a phase-conjugate mirror would typically be implemented by use of a suitably positioned and oriented photorefractive crystal. In the case of a telescope comprising a primary and secondary

  6. The obsidian mirror The obsidian mirror

    Directory of Open Access Journals (Sweden)

    Maria do Socorro Reis Amorin

    2008-04-01

    Full Text Available The author James Norman is an American who has always lived in Mexico during the summer. He seems to love Mexican - Indian traditions and he is well acquainted with the pre-historic culture as it is shown in his book: "The Obsidian Mirror". "The Obsidian Mirror" is a mysterious story about an archeologist: Quigley that lives in a small village in Mexico-San Marcos. He is searching for antiques that belong to some tribes of pre-historic Indians in order to find out their mysteries. Quigley becomes so engaged in his work that his mind has reached a stage that is impossible to separate between Quigley the archeologist, and Quigley as an ancient Indian. The culture, the myth, the sensation of Omen - characteristics of the Indians are within himself. As a result, Quigley acts sometimes as a real Indian. The author James Norman is an American who has always lived in Mexico during the summer. He seems to love Mexican - Indian traditions and he is well acquainted with the pre-historic culture as it is shown in his book: "The Obsidian Mirror". "The Obsidian Mirror" is a mysterious story about an archeologist: Quigley that lives in a small village in Mexico-San Marcos. He is searching for antiques that belong to some tribes of pre-historic Indians in order to find out their mysteries. Quigley becomes so engaged in his work that his mind has reached a stage that is impossible to separate between Quigley the archeologist, and Quigley as an ancient Indian. The culture, the myth, the sensation of Omen - characteristics of the Indians are within himself. As a result, Quigley acts sometimes as a real Indian.

  7. Mirror reactor surface study

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, A. L.; Damm, C. C.; Futch, A. H.; Hiskes, J. R.; Meisenheimer, R. G.; Moir, R. W.; Simonen, T. C.; Stallard, B. W.; Taylor, C. E.

    1976-09-01

    A general survey is presented of surface-related phenomena associated with the following mirror reactor elements: plasma first wall, ion sources, neutral beams, director converters, vacuum systems, and plasma diagnostics. A discussion of surface phenomena in possible abnormal reactor operation is included. Several studies which appear to merit immediate attention and which are essential to the development of mirror reactors are abstracted from the list of recommended areas for surface work. The appendix contains a discussion of the fundamentals of particle/surface interactions. The interactions surveyed are backscattering, thermal desorption, sputtering, diffusion, particle ranges in solids, and surface spectroscopic methods. A bibliography lists references in a number of categories pertinent to mirror reactors. Several complete published and unpublished reports on surface aspects of current mirror plasma experiments and reactor developments are also included.

  8. The Athena Mirror

    Science.gov (United States)

    Wille, Eric

    2016-07-01

    The Athena mission (Advanced Telescope for High Energy Astrophysics) requires lightweight X-ray Wolter optics with a high angular resolution and large effective area. For achieving an effective area of 2 m^2 (at 1 keV) and an angular resolution of below 5 arcsec, the Silicon Pore Optics technology was developed by ESA together with a consortium of European industry. Silicon Pore Optics are made of commercial Si wafers using process technology adapted from the semiconductor industry. We present the current design of the Athena mirror concentrating on the technology development status of the Silicon Pore Optics, ranging from the manufacturing of single mirror plates towards complete focusing mirror modules and their integration into the mirror structure.

  9. Manufacturing parabolic mirrors

    CERN Multimedia

    CERN PhotoLab

    1975-01-01

    The photo shows the construction of a vertical centrifuge mounted on an air cushion, with a precision of 1/10000 during rotation, used for the manufacture of very high=precision parabolic mirrors. (See Annual Report 1974.)

  10. Cavity Enhanced Absorption Spectroscopy using a Prism Cavity and Supercontinuum Source

    Science.gov (United States)

    Lehmann, Kevin K.; Johnston, Paul S.

    2010-03-01

    The multiplex advantage of current cavity enhanced spectrometers is limited by the limited high reflectivity bandwidth of the dielectric mirrors used to construct the high finesse cavity. We report on our development of a spectrometer that uses Brewster's angle retroreflectors that is excited with supercontinuum radiation generated by a 1.06 μm pumped photonic crystal fiber, which covers the 500-1800 nm spectral range. Recent progress will be discussed including modeling of the prism cavity losses, alternative prism materials for use in the UV and mid-IR, and a new higher power source pumped by a mode-locked laser.

  11. A micropillar for cavity optomechanics

    Science.gov (United States)

    Kuhn, Aurélien; Neuhaus, Leonhard; Van Brackel, Emmanuel; Chartier, Claude; Ducloux, Olivier; Le Traon, Olivier; Michel, Christophe; Pinard, Laurent; Flaminio, Raffaele; Deléglise, Samuel; Briant, Tristan; Cohadon, Pierre-François; Heidmann, Antoine

    2014-12-01

    Demonstrating the quantum ground state of a macroscopic mechanical object is a major experimental challenge in physics, at the origin of the rapid emergence of cavity optomechanics. We have developed a new generation of optomechanical devices, based on a microgram quartz micropillar with a very high mechanical quality factor. The structure is used as end mirror in a Fabry-Perot cavity with a high optical finesse, leading to ultra-sensitive interferometric measurement of the resonator displacement. We expect to reach the ground state of this optomechanical resonator by combining cryogenic cooling in a dilution fridge at 30 mK and radiation-pressure cooling. We have already carried out a quantum-limited measurement of the micropillar thermal noise at low temperature.

  12. A micropillar for cavity optomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, Aurélien; Neuhaus, Leonhard; Deléglise, Samuel; Briant, Tristan; Cohadon, Pierre-François; Heidmann, Antoine [Laboratoire Kastler Brossel, UPMC-ENS-CNRS, Paris (France); Van Brackel, Emmanuel [Département de Physique, ENS, Paris (France); Chartier, Claude; Ducloux, Olivier; Le Traon, Olivier [Département Mesures Physiques, ONERA, Châtillon (France); Michel, Christophe; Pinard, Laurent; Flaminio, Raffaele [Laboratoire des Matériaux Avancés, IN2P3-CNRS, Lyon (France)

    2014-12-04

    Demonstrating the quantum ground state of a macroscopic mechanical object is a major experimental challenge in physics, at the origin of the rapid emergence of cavity optomechanics. We have developed a new generation of optomechanical devices, based on a microgram quartz micropillar with a very high mechanical quality factor. The structure is used as end mirror in a Fabry-Perot cavity with a high optical finesse, leading to ultra-sensitive interferometric measurement of the resonator displacement. We expect to reach the ground state of this optomechanical resonator by combining cryogenic cooling in a dilution fridge at 30 mK and radiation-pressure cooling. We have already carried out a quantum-limited measurement of the micropillar thermal noise at low temperature.

  13. New method to measure the angular antispring effect in a Fabry–Perot cavity with remote excitation using radiation pressure

    Energy Technology Data Exchange (ETDEWEB)

    Nagano, Koji, E-mail: knagano@icrr.u-tokyo.ac.jp [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan); Enomoto, Yutaro; Nakano, Masayuki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan); Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Kawamura, Seiji [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan)

    2016-03-06

    In experiments with Fabry–Perot cavities consisting of suspended mirrors, an angular antispring effect on the mirror of the cavity is caused by radiation pressure from resonant light in the cavity. A new method was invented to measure the effect precisely with remote excitation on the mirror using the radiation pressure. This method was found to be available for the suspended 23 mg mirror and improved the measurement accuracy by a factor of two, compared with the previous method. This result leads to stable control systems to eliminate the angular instability of the mirror caused by the effect. - Highlights: • A method to measure an angular antispring effect on a suspended mirror was proposed. • Remote excitation on the mirror with radiation pressure of resonant light is used. • This method provides better measurement accuracy compared with the previous method.

  14. Cavity nano-optomechanics: a nanomechanical system in a high finesse optical cavity

    CERN Document Server

    Stapfner, Sebastian; Hunger, David; Paulitschke, Philipp; Reichel, Jakob; Karrai, Khaled; Weig, Eva M; 10.1117/12.705901

    2011-01-01

    The coupling of mechanical oscillators with light has seen a recent surge of interest, as recent reviews report.[1, 2] This coupling is enhanced when confining light in an optical cavity where the mechanical oscillator is integrated as back- mirror or movable wall. At the nano-scale, the optomechanical coupling increases further thanks to a smaller optomechanical interaction volume and reduced mass of the mechanical oscillator. In view of realizing such cavity nano- optomechanics experiments, a scheme was proposed where a sub-wavelength sized nanomechanical oscillator is coupled to a high finesse optical microcavity.[3] Here we present such an experiment involving a single nanomechanical rod precisely positioned into the confined mode of a miniature Fabry-P\\'erot cavity.[4] We describe the employed stabilized cavity set-up and related finesse measurements. We proceed characterizing the nanorod vibration properties using ultrasonic piezo-actuation methods. Using the optical cavity as a transducer of nanomechan...

  15. Cavity-enhanced spectroscopy and sensing

    CERN Document Server

    Loock, Hans-Peter

    2014-01-01

    The book reviews the dramatic recent advances in the use of optical resonators for high sensitivity and high resolution molecular spectroscopy as well as for chemical, mechanical and physical sensing.  It encompasses a variety of cavities including those made of two or more mirrors, optical fiber loops, fiber gratings and spherical cavities. The book focuses on novel techniques and their applications. Each chapter is written by an expert and/or pioneer in the field. These experts also provide the theoretical background in optics and molecular physics where needed. Examples of recent breakthroughs include the use of frequency combs (Nobel prize 2005) for cavity enhanced sensing and spectroscopy, the use of novel cavity materials and geometries, the development of optical heterodyne detection techniques combined to active frequency-locking schemes. These methods allow the use and interrogation of optical resonators with a variety of coherent light sources for trace gas detection and sensing of strain, temperat...

  16. Spectral line absorption measurement using optical cavities.

    Science.gov (United States)

    Blanaru, D. L.

    1973-01-01

    A simple technique using a conventional gas laser with spherical mirrors having identical radii of curvature in the nonoscillating regime for spectral line absorption measurements is described and applications for laser work are suggested. The theory of the measurement carried out in the geometrical optical approach for Doppler-broadened lines was checked experimentally and conditions are specified for which measurement inaccuracies of the order of 1% for the peak value of the line absorption coefficient can be obtained. Since the device provides a fine adjustment of the cavity losses, formation of the diffraction modes could be observed in the preoscillating regime of the optical cavity.

  17. Piezoelectric deformable mirror for intra-cavity laser adaptive optics.

    CSIR Research Space (South Africa)

    Long, CS

    2008-03-01

    Full Text Available -constant Zernike polynomials are reported in the comparison, even though 6 polynomials were extracted. Table 1 presents the coefficients of the first three non-constant Zernike polynomials, extracted from the experimental results and the finite element model...OC, then reverse propagating the field to the DOE yields [6]: rdrrf ikrL ik L rkJruL ikikLLkiLu nOCnDOE ⎟⎟⎠ ⎞ ⎜⎜⎝ ⎛−⎟⎠ ⎞⎜⎝ ⎛⎟⎠ ⎞⎜⎝ ⎛⎟⎠ ⎞⎜⎝ ⎛−= ∫∞+ 22 0 21 2 exp 2 exp)( 2 exp)exp()/(),( ρρρ (1) where we have assumed that the resonator...

  18. Dirac quantum time mirror

    Science.gov (United States)

    Reck, Phillipp; Gorini, Cosimo; Goussev, Arseni; Krueckl, Viktor; Fink, Mathias; Richter, Klaus

    2017-04-01

    Both metaphysical and practical considerations related to time inversion have intrigued scientists for generations. Physicists have strived to devise and implement time-inversion protocols, in particular different forms of "time mirrors" for classical waves. Here we propose an instantaneous time mirror for quantum systems, i.e., a controlled time discontinuity generating wave function echoes with high fidelities. This concept exploits coherent particle-hole oscillations in a Dirac spectrum in order to achieve population reversal, and can be implemented in systems such as (real or artificial) graphene.

  19. Surface micromachined scanning mirrors

    DEFF Research Database (Denmark)

    Mattsson, Kent Erik

    1992-01-01

    Both aluminum cantilever and torsional scanning mirrors have been fabricated and their static and dynamic properties are studied experimentally and theoretically. The experiments showed resonance frequencies in the range of 163 k-Hz - 632 kHz for cantilever beams with Q values between 5 and 11....... Torsional mirrors showed resonance frequencies in the range of 410 kHz - 667 kHz with Q values of 10 - 17. All measurements performed at atmospheric pressure. Both types of mechanical structures were deflected electrostatically at large angles (± 5°) more than 1011 times without breaking and without any...

  20. Unification with mirror fermions

    Directory of Open Access Journals (Sweden)

    Triantaphyllou George

    2014-04-01

    Full Text Available We present a new framework unifying interactions in nature by introducing mirror fermions, explaining the hierarchy between the weak scale and the coupling unification scale, which is found to lie close to Planck energies. A novel process leading to the emergence of symmetry is proposed, which not only reduces the arbitrariness of the scenario proposed but is also followed by significant cosmological implications. Phenomenology includes the probability of detection of mirror fermions via the corresponding composite bosonic states and the relevant quantum corrections at the LHC.

  1. Frequency splitting of polarization eigenmodes in microscopic Fabry-Perot cavities

    CERN Document Server

    Uphoff, Manuel; Rempe, Gerhard; Ritter, Stephan

    2014-01-01

    We study the frequency splitting of the polarization eigenmodes of the fundamental transverse mode in CO2 laser-machined, high-finesse optical Fabry-Perot cavities and investigate the influence of the geometry of the cavity mirrors. Their highly reflective surfaces are typically not rotationally symmetric, but have slightly different radii of curvature along two principal axes. We observe that the eccentricity of such elliptical mirrors lifts the degeneracy of the polarization eigenmodes. The impact of the eccentricity increases for smaller radii of curvature. A model derived from corrections to the paraxial resonator theory is in excellent agreement with measurements, showing that geometric effects are the main source of the frequency splitting of polarization modes for the studied type of microscopic cavity. By rotation of one of the mirrors around the cavity axis, the splitting can be tuned. In the case of an identical differential phase shift per mirror it can even be eliminated, despite a nonvanishing ec...

  2. VCSELs and silicon light sources exploiting SOI grating mirrors

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2012-01-01

    grating works as a highly-reflective mirror as well as routes light into a Si in-plane output waveguide connected to the grating. In the vertical-cavity surface-emitting laser (VCSEL) version, there is no in-plane output waveguide connected to the grating. Thus, light is vertically emitted through...... the Bragg reflector. Numerical simulations show that both the silicon light source and the VCSEL exploiting SOI grating mirrors have superior performances, compared to existing silicon light sources and long wavelength VCSELs. These devices are highly adequate for chip-level optical interconnects as well...

  3. Subwavelength grating-mirror VCSEL with a thin oxide gap

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper; Gilet, Philippe

    2008-01-01

    A new vertical-cavity surface-emitting laser (VCSEL) structure based on a subwavelength grating mirror and a thin oxide gap is suggested and numerically investigated. The structure is shown to exhibit similar threshold gain, suppression of higher order transverse modes, and polarization stability...... as a grating-mirror VCSEL reported in the literature based on a thick air gap. The thin oxide gap structure has a number of advantages including easier fabrication, better mechanical stability, and very strong single-mode properties....

  4. Rearview Mirror Dimming Function

    Science.gov (United States)

    Layton, William

    2011-01-01

    Students are often unaware of the little tab on a rear-view mirror that is used to dim headlights from the rear. Those who know about this tab are usually interested in knowing how it works. Explanations of the optics involved can be found in Serway and Jewett and Jones and Edge. An alternate explanation is given.

  5. Optical cavity cooling of mechanical modes of a semiconductor nanomembrane

    DEFF Research Database (Denmark)

    Usami, Koji; Naesby, A.; Bagci, Tolga

    2012-01-01

    Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metal–semiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high...... an alternative cooling mechanism that is a result of electronic stress via the deformation potential, and outline future directions for cavity optomechanics with optically active semiconductors.......-quality-factor and optically active semiconductor nanomembrane. The cooling is a result of electron–hole generation by cavity photons. Consequently, the cooling factor depends on the optical wavelength, varies drastically in the vicinity of the semiconductor bandgap, and follows the excitonic absorption behaviour...

  6. Cosmology with liquid mirror telescopes

    Science.gov (United States)

    Hogg, David W.; Gibson, Brad K.; Hickson, Paul

    1993-01-01

    Liquid mirrors provide an exciting means to obtain large optical telescopes for substantially lower costs than conventional technologies. The liquid mirror concept has been demonstrated in the lab with the construction of a diffraction limited 1.5 m mirror. The mirror surface, using liquid mercury, forms a perfect parabolic shape when the mirror cell is rotated at a uniform velocity. A liquid mirror must be able to support a heavy mercury load with minimal flexure and have a fundamental resonant frequency that is as high as possible, to suppress the amplitude of surface waves caused by small vibrations transmitted to the mirror. To minimize the transmission of vibrations to the liquid surface, the entire mirror rests on an air bearing. This necessitates the mirror cell being lightweight, due to the limited load capabilities of the air bearing. The mirror components must also have physical characteristics which minimize the effects of thermal expansion with ambient temperature fluctuations in the observatory. In addition, the 2.7 m mirror construction is designed so that the techniques used may be readily extended to the construction of large mirrors. To attain the goals of a lightweight, rigid mirror, a composite laminant construction was used. The mirror consists of a foam core cut to the desired parabolic shape, with an accuracy of a few mm. An aluminum hub serves as an anchor for the foam and skin, and allows precise centering of the mirror on the air bearing and drive system. Several plys of Kevlar, covered in an epoxy matrix, are then applied to the foam. A final layer of pure epoxy is formed by spin casting. This final layer is parabolic to within a fraction of a mm. An aluminum ring bonded to the circumference of the mirror retains the mercury, and incorporates stainless-steel hard-points for the attachment of balance weights.

  7. Optimization of VCSELs incorporating monolithic subwavelength high-refractive-index contrast surface grating mirrors

    Science.gov (United States)

    Gebski, Marcin; Marciniak, Magdalena; Dems, Maciej; Czyszanowski, Tomasz; Lott, James A.

    2017-02-01

    We present results of computer simulations of vertical cavity surface emitting lasers (VCSELs) using novel, highreflectivity monolithic high refractive-index contrast grating (MHCG) mirrors and their more advanced version, partially covered by a thin metal layer - metallic MHCG (mMHCG) mirrors. The first experimental realization of this new class of mirrors is presented and discussed. We show that the metal layer does not deteriorate the high reflectivity of an mMHCG mirror, but in contrary, is a crucial element which allows high reflectivity and additionally opens a way for a more efficient electrical pumping of a VCSEL. Comparison of results of thermal-electrical-carrier-gain self-consistent simulations of both MHCG- and mMHCG-based VCSELs is presented and discussed. It is shown that using mHCG mirror as a top mirror of a VCSEL improves electrical characteristics and greatly decreases the differential resistance of the device.

  8. Mirror image agnosia.

    Science.gov (United States)

    Chandra, Sadanandavalli Retnaswami; Issac, Thomas Gregor

    2014-10-01

    Gnosis is a modality-specific ability to access semantic knowledge of an object or stimulus in the presence of normal perception. Failure of this is agnosia or disorder of recognition. It can be highly selective within a mode. self-images are different from others as none has seen one's own image except in reflection. Failure to recognize this image can be labeled as mirror image agnosia or Prosopagnosia for reflected self-image. Whereas mirror agnosia is a well-recognized situation where the person while looking at reflected images of other objects in the mirror he imagines that the objects are in fact inside the mirror and not outside. Five patients, four females, and one male presented with failure to recognize reflected self-image, resulting in patients conversing with the image as a friend, fighting because the person in mirror is wearing her nose stud, suspecting the reflected self-image to be an intruder; but did not have prosopagnosia for others faces, non living objects on self and also apraxias except dressing apraxia in one patient. This phenomena is new to our knowledge. Mirror image agnosia is an unique phenomena which is seen in patients with parietal lobe atrophy without specificity to a category of dementing illness and seems to disappear as disease advances. Reflected self-images probably have a specific neural substrate that gets affected very early in posterior dementias specially the ones which predominantly affect the right side. At that phase most patients are mistaken as suffering from psychiatric disorder as cognition is moderately preserved. As disease becomes more widespread this symptom becomes masked. A high degree of suspicion and proper assessment might help physicians to recognize the organic cause of the symptom so that early therapeutic interventions can be initiated. Further assessment of the symptom with FMRI and PET scan is likely to solve the mystery of how brain handles reflected self-images. A new observation involving failure

  9. BN-350 "Mirror System".

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, A. L. (Angela L.); Halbig, J. K. (James K.)

    2004-01-01

    The BN-350 Unattended Monitoring System plays an important role for the Safeguards Department of the International Atomic Energy Agency (IAEA). In 1998, the Los Alamos National Laboratory, in conjunction with the IAEA and sponsored by the US Department of Energy, designed and installed an integrated multi-instrument safeguards system at the BN-350 reactor in Aktau, Kazakhstan, to monitor spent-fuel and blanket assembly conditioning and canning activities. The purpose of the system was to provide effective safeguards at this facility while reducing the manpower load on the IAEA. The system is composed of many individual nondestructive analysis and surveillance components, each having a unique function and working together to provide fully unattended measurement of spent-fuel assemblies. The BN-350 ''Mirror System'' was built to provide a similar system with like components at the IAEA Headquarters in Vienna to facilitate analysis and/or simulation of problems that might occur in the field and for training inspectors and other technical staff in preparation for their work in the field. In addition, the system is used to test new equipment and qualify new or modified software. This paper describes the main components of the Mirror System, how the components are integrated, and how the Mirror System has benefited the IAEA.

  10. Segmented trapped vortex cavity

    Science.gov (United States)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  11. Mirror perception in mice: Preference for and stress reduction by mirrors and stress reduction by mirror

    OpenAIRE

    Watanabe, Shigeru

    2016-01-01

    I measured the amount of time mice spent in a compartment with either a mirror or an opaque screen and found that mice stayed longer in the compartment with the mirror. This finding suggests that mice prefer mirrors. They also showed a preference for the mirror over unfamiliar live mice but did not show a differential preference for the mirror over a familiar live mouse (cage mate). Restraint stress caused hyperthermia (known as stress-induced hyperthermia) in the mice. When cage mates receiv...

  12. Crab Cavity Development

    CERN Document Server

    Calaga, R; Burt, G; Ratti, A

    2015-01-01

    The HL-LHC upgrade will use deflecting (or crab) cavities to compensate for geometric luminosity loss at low β* and non-zero crossing angle. A local scheme with crab cavity pairs across the IPs is used employing compact crab cavities at 400 MHz. Design of the cavities, the cryomodules and the RF system is well advanced. The LHC crab cavities will be validated initially with proton beam in the SPS.

  13. Mid-Infrared Tunable Resonant Cavity Enhanced Detectors

    Directory of Open Access Journals (Sweden)

    Hans Zogg

    2008-09-01

    Full Text Available Mid-infrared detectors that are sensitive only in a tunable narrow spectral band are presented. They are based on the Resonant Cavity Enhanced Detector (RCED principle and employing a thin active region using IV-VI narrow gap semiconductor layers. A Fabry-Pérot cavity is formed by two mirrors. The active layer is grown onto one mirror, while the second mirror can be displaced. This changes the cavity length thus shifting the resonances where the detector is sensitive. Using electrostatically actuated MEMS micromirrors, a very compact tunable detector system has been fabricated. Mirror movements of more than 3 μm at 30V are obtained. With these mirrors, detectors with a wavelength tuning range of about 0.7 μm have been realized. Single detectors can be used in mid-infrared micro spectrometers, while a detector arrangement in an array makes it possible to realize Adaptive Focal Plane Arrays (AFPA.

  14. Adenoid size assessment: a comparison of palpation, nasendoscopy and mirror examination.

    Science.gov (United States)

    Chisholm, E J; Lew-Gor, S; Hajioff, D; Caulfield, H

    2005-02-01

    To compare the digital, mirror and nasendoscopic assessment of adenoid size and posterior choanal obstruction in patients undergoing adenoidectomy. Prospective, blinded study. Otorhinolaryngology department at a London teaching hospital. Twenty-eight consecutive patients undergoing adenoidectomy in conjunction with tonsillectomy or myringotomy under general anaesthesia, aged 17 months to 16 years. Adenoid size and postnasal space obstruction as assessed by digital examination, nasendoscopy and trans-oral mirror visualization. These examination methods were each compared with each other. Nasendoscopy and mirror examination correlated well (Spearman's R(S) = 0.71, P palpation (R(S) = 0.26, P = 0.17) and only a moderate correlation between mirror examination and palpation (R(S) = 0.46, P = 0.014). If nasendoscopy is considered the gold standard, then palpation is a poor measure of adenoid hypertrophy and mirror examination consistently underestimates choanal occlusion.

  15. Mode-locked Pr3+-doped silica fiber laser with an external cavity

    DEFF Research Database (Denmark)

    Shi, Yuan; Poulsen, Christian; Sejka, Milan

    1994-01-01

    We present a Pr3+-doped silica-based fiber laser mode-locked by using a linear external cavity with a vibrating mirror. Stable laser pulses with a FWHM of less than 44 ps, peak power greater than 9 W, and repetition rate up to 100 MHz are obtained. The pulse width versus cavity mismatch ΔL and pump...

  16. Digital control of laser modes with an intra-cavity spatial light modulator

    CSIR Research Space (South Africa)

    Ngcobo, S

    2014-02-01

    Full Text Available In this paper we outline a simple laser cavity which produces customised on-demand digitally controlled laser modes by replacing the end-mirror of the cavity with an electrically addressed reflective phase-only spatial light modulator as a digital...

  17. Intra-cavity metamorphosis of a Gaussian beam to flat-top distribution

    CSIR Research Space (South Africa)

    Naidoo, Darryl

    2014-02-01

    Full Text Available We explore an intra-cavity beam shaping approach to generate a Gaussian distribution by the metamorphosis of a Gaussian beam into a flat-top distribution on opposing mirrors. The concept is tested external to the cavity through the use of two...

  18. SXI prototype mirror mount

    Science.gov (United States)

    1995-04-01

    The purpose of this contract was to provide optomechanical engineering and fabrication support to the Solar X-ray Imager (SXI) program in the areas of mirror, optical bench and camera assemblies of the telescope. The Center for Applied Optics (CAO) worked closely with the Optics and S&E technical staff of MSFC to develop and investigate the most viable and economical options for the design and fabrication of a number of parts for the various telescope assemblies. All the tasks under this delivery order have been successfully completed within budget and schedule. A number of development hardware parts have been designed and fabricated jointly by MSFC and UAH for the engineering model of SXI. The major parts include a nickel electroformed mirror and a mirror mount, plating and coating of the ceramic spacers, and gold plating of the contact rings and fingers for the camera assembly. An aluminum model of the high accuracy sun sensor (HASS) was also designed and fabricated. A number of fiber optic tapers for the camera assembly were also coated with indium tin oxide and phosphor for testing and evaluation by MSFC. A large number of the SXI optical bench parts were also redesigned and simplified for a prototype telescope. These parts include the forward and rear support flanges, front aperture plate, the graphite epoxy optical bench and a test fixture for the prototype telescope. More than fifty (50) drawings were generated for various components of the prototype telescope. Some of these parts were subsequently fabricated at UAH machine shop or at MSFC or by the outside contractors. UAH also provide technical support to MSFC staff for a number of preliminary and critical design reviews. These design reviews included PDR and CDR for the mirror assembly by United Technologies Optical Systems (UTOS), and the program quarterly reviews, and SXI PDR and CDR. UAH staff also regularly attended the monthly status reviews, and made a significant number of suggestions to improve

  19. SXI prototype mirror mount

    Science.gov (United States)

    1995-01-01

    The purpose of this contract was to provide optomechanical engineering and fabrication support to the Solar X-ray Imager (SXI) program in the areas of mirror, optical bench and camera assemblies of the telescope. The Center for Applied Optics (CAO) worked closely with the Optics and S&E technical staff of MSFC to develop and investigate the most viable and economical options for the design and fabrication of a number of parts for the various telescope assemblies. All the tasks under this delivery order have been successfully completed within budget and schedule. A number of development hardware parts have been designed and fabricated jointly by MSFC and UAH for the engineering model of SXI. The major parts include a nickel electroformed mirror and a mirror mount, plating and coating of the ceramic spacers, and gold plating of the contact rings and fingers for the camera assembly. An aluminum model of the high accuracy sun sensor (HASS) was also designed and fabricated. A number of fiber optic tapers for the camera assembly were also coated with indium tin oxide and phosphor for testing and evaluation by MSFC. A large number of the SXI optical bench parts were also redesigned and simplified for a prototype telescope. These parts include the forward and rear support flanges, front aperture plate, the graphite epoxy optical bench and a test fixture for the prototype telescope. More than fifty (50) drawings were generated for various components of the prototype telescope. Some of these parts were subsequently fabricated at UAH machine shop or at MSFC or by the outside contractors. UAH also provide technical support to MSFC staff for a number of preliminary and critical design reviews. These design reviews included PDR and CDR for the mirror assembly by United Technologies Optical Systems (UTOS), and the program quarterly reviews, and SXI PDR and CDR. UAH staff also regularly attended the monthly status reviews, and made a significant number of suggestions to improve

  20. SXI Prototype mirror mount

    Science.gov (United States)

    1995-01-01

    This final report describes the work performed from June 1993 to January 1995. The purpose of this contract was to provide optomechanical engineering and fabrication support to the Solar X-ray Imager (SXI) program in the areas of mirror, optical bench and camera assemblies of the telescope. The Center for Applied Optics (CAO) worked closely with the Optics and S&E technical staff of MSFC to develop and investigate the most viable and economical options for the design and fabrication of a number of parts for the various telescope assemblies. All the tasks under this delivery order have been successfully completed within budget and schedule.

  1. Mirror symmetry II

    CERN Document Server

    Greene, Brian R

    1997-01-01

    Mirror symmetry has undergone dramatic progress during the last five years. Tremendous insight has been gained on a number of key issues. This volume surveys these results. Some of the contributions in this work have appeared elsewhere, while others were written specifically for this collection. The areas covered are organized into 4 sections, and each presents papers by both physicists and mathematicians. This volume collects the most important developments that have taken place in mathematical physics since 1991. It is an essential reference tool for both mathematics and physics libraries and for students of physics and mathematics.

  2. Robust double Z-type cavity mode locked Yb:KYW ultrafast laser

    Science.gov (United States)

    Wang, Sha; Han, Jing-hua; Wang, Yan-biao; Feng, Guo-ying; Zhou, Shou-huan

    2015-12-01

    Semiconductor saturable absorber mirror (SESAM) mode locked Yb doped ultrafast lasers have been widely used in industrial applications. High laser stability against environment change and delivery process are required for industrial laser systems. A double Z-type ultrafast laser cavity was demonstrated experimentally and theoretically. Compared with the conventional Z-type cavity, this double Z-type cavity SESAM mode locked laser is less sensitive to misalignment and can tolerate more arm length changes while still staying cw mode locking.

  3. JWST Primary Mirror Technology Development

    Science.gov (United States)

    Stahl, H. Philip

    2010-01-01

    Mirror Technology was identified as a (if not the) critical capability necessary to achieve the Level 1 science goals. A never before demonstrated space telescope capability was required: 6 to 8 meter class pri mary mirror, diffraction limited at 2 micrometers and operates at temperatures below 50K. Launch vehicle constraints placed significant architectural constraints: deployed/segmented primary mirror (4.5 meter fairing diameter) 20 kg/m2 areal density (PM 1000 kg mass) Such mirror technology had never been demonstrated - and did not exist

  4. Scanning mirror for infrared sensors

    Science.gov (United States)

    Anderson, R. H.; Bernstein, S. B.

    1972-01-01

    A high resolution, long life angle-encoded scanning mirror, built for application in an infrared attitude sensor, is described. The mirror uses a Moire' fringe type optical encoder and unique torsion bar suspension together with a magnetic drive to meet stringent operational and environmental requirements at a minimum weight and with minimum power consumption. Details of the specifications, design, and construction are presented with an analysis of the mirror suspension that allows accurate prediction of performance. The emphasis is on mechanical design considerations, and brief discussions are included on the encoder and magnetic drive to provide a complete view of the mirror system and its capabilities.

  5. Electrotunable nanoplasmonic liquid mirror

    Science.gov (United States)

    Montelongo, Yunuen; Sikdar, Debabrata; Ma, Ye; McIntosh, Alastair J. S.; Velleman, Leonora; Kucernak, Anthony R.; Edel, Joshua B.; Kornyshev, Alexei A.

    2017-11-01

    Recently, there has been a drive to design and develop fully tunable metamaterials for applications ranging from new classes of sensors to superlenses among others. Although advances have been made, tuning and modulating the optical properties in real time remains a challenge. We report on the first realization of a reversible electrotunable liquid mirror based on voltage-controlled self-assembly/disassembly of 16 nm plasmonic nanoparticles at the interface between two immiscible electrolyte solutions. We show that optical properties such as reflectivity and spectral position of the absorption band can be varied in situ within +/-0.5 V. This observed effect is in excellent agreement with theoretical calculations corresponding to the change in average interparticle spacing. This electrochemical fully tunable nanoplasmonic platform can be switched from a highly reflective `mirror' to a transmissive `window' and back again. This study opens a route towards realization of such platforms in future micro/nanoscale electrochemical cells, enabling the creation of tunable plasmonic metamaterials.

  6. Decreased oscillation threshold of a continuous-wave OPO using a semiconductor gain mirror.

    Science.gov (United States)

    Siltanen, Mikael; Leinonen, Tomi; Halonen, Lauri

    2011-09-26

    We have constructed a singly resonant, continuous-wave optical parametric oscillator, where the signal beam resonates and is amplified by a semiconductor gain mirror. The gain mirror can significantly decrease the oscillation threshold compared to an identical system with conventional mirrors. The largest idler beam tuning range reached by changing the pump laser wavelength alone is from 3.6 to 4.7 µm. The single mode output power is limited but can be continuously scanned for at least 220 GHz by adding optical components in the oscillator cavity for increased stability. © 2011 Optical Society of America

  7. Relaxation oscillations in real laser cavity

    Science.gov (United States)

    Szczepanski, Pawel; Malinowski, Michal; Wolski, Radoslaw

    1990-07-01

    An approximate analysis of the relaxation oscillations in Fabry Perot laser cavities is presented. A linear smallsignal perturbation solution of the coupled laser rate equations is generalized by including transverse1 as well longitudinal field dependence2. By the threshold field approximation3 we obtain an expression relating the frequency 0 and damping rate X of the relaxation oscillations to the laser parameters such as steadystate output power P0/Pq normaliezed to the saturation power P distributed losses a L'' poin losses at the mirrors a1 and a arbitrary relectivities o the mirrors r1 and r2 spontaneous liftime ''r of the active medium and geometry o the resonator. 2. THEORY The couppled laser rate equations for single mode can be written in the following form dN I(r) N N dQ I(r) N Q --- ---- (1) dt I ''r #r dt I -r 5 S Q where N denotes the inversion density I (r) describes the total intensity of the nmth laser mode in the cavity I is the saturation in tensity p is the exatation rate Q denotes the number of the photons in the nmth laser mode and ''r is the cavity lifetime. An approximate expressions for the spatial dependence of the electric fields for the forward and backward amplitudes of the nmth laser mode in our approach can be written as R AUR(t) f(x e''TZ S A(r) f(x

  8. Cavity Enhanced Absorption Spectroscopy Using a Broadband Prism Cavity and a Supercontinuum Source

    Science.gov (United States)

    Johnston, Paul S.; Lehmann, Kevin K.

    2009-06-01

    The multiplex advantage of current cavity enhanced spectrometers is limited by the high reflectivity bandwidth of the mirrors used to construct the high finesse cavity. Previously, we reported the design and construction of a new spectrometer that circumvents this limitation by utilizing Brewster^{,}s angle prism retroreflectors. The prisms, made from fused silica and combined with a supercontinuum source generated by pumping a highly nonlinear photonic crystal fiber, yields a spectral window ranging from 500 nm to 1750 nm. Recent progress in the instruments development will be discussed, including work on modeling the prism cavity losses, alternative prism material for use in the UV and mid-IR spectral regions, and a new high power supercontinuum source based on mode-locked picosecond laser.

  9. Laser frequency stabilization and control of optical cavities with suspended mirrors for the VIRGO interferometric detector of gravitational waves; Stabilisation en frequence du laser et controle de cavites optiques a miroirs suspendus pour le detecteur interferometrique d'ondes gravitationnelles VIRGO

    Energy Technology Data Exchange (ETDEWEB)

    Barsuglia, Matteo [Paris-11 Univ., 91 Orsay (France)

    1999-05-17

    The VIRGO detector is an interferometer with 3 km Fabry-Perot cavities in the arms. It is aimed at the detection of gravitational radiation emitted by astrophysical sources. This thesis comprises two independent parts. The first part is devoted to the laser frequency stabilization. In the second one we present a study of a suspended cavity. We determine the impact of laser frequency fluctuations on the overall VIRGO sensitivity. We study the frequency stabilization of the interferometer considered as an ultra-stable standard and we evaluate the noise pertaining to different signals taken into consideration. A strategy of control is discussed. We then study the VIRGO mode-cleaner prototype, a 30 m suspended triangular cavity, for which we have developed a control in order to keep it locked. Finally, we characterize this cavity in terms of mode spectra, finesse and mechanical transfer functions. (author)

  10. Prototype LHC RF cavity

    CERN Multimedia

    A radiofrequency (RF) cavity is a metallic chamber that contains an electromagnetic field. Its primary purpose is to accelerate charged particles. RF cavities can be structured like beads on a string, where the beads are the cavities and the string is the beam pipe of a particle accelerator, through which particles travel in a vacuum.

  11. Demonstration of an optical enhancement cavity with 10 micron wavelength

    Science.gov (United States)

    Sakaue, K.; Washio, M.; Endo, A.

    2015-05-01

    We have been developing a pulsed-laser optical enhancement cavity for laser-Compton scattering (LCS). LCS can produce high brightness X-ray through the collision between relativistic electrons generated from the accelerator and high power laser photons with a compact facility. In order to increase the number of collisions/sec, high repetition rate accelerator and laser are required. For the laser system, an optical enhancement cavity is the most powerful tool for LCS, thus we have been developing the cavity for storing 1 micron laser pulse. On the other hand, the resulting X-ray energy can be changed by the collision laser wavelength. If we have another optical cavity with different wavelength, the multicolor, quasi-monochromatic, high brightness and compact X-ray source can be realized. Therefore, we started to develop an optical cavity at 10 micron wavelength with CO2 laser. At this wavelength region, the absorption loss is dominant compared with scattering loss. Thus we carefully chose the optical mirrors for enhancement cavity. We demonstrated a more than 200 enhancement factor with 795 finesse optical cavity at 10 micron CO2 laser. Moreover, 2.3 kW storage in the optical cavity was successfully demonstrated. The design of optical cavity, first experimental results and future prospects will be presented at the conference.

  12. Heliostat mirror survey and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lind, M.A.; Buckwalter, C.Q.; Daniel, J.L.; Hartman, J.S.; Thomas, M.T.; Pederson, L.R.

    1979-09-01

    The mirrors used on concentrating solar systems must be able to withstand severe and sustained environmental stresses for long periods of time if they are to be economically acceptable. Little is known about how commercially produced wet process silvered second surface mirrors will withstand the test of time in solar applications. Field experience in existing systems has shown that the performance of the reflective surface varies greatly with time and is influenced to a large extent by the construction details of the mirror module. Degradation of the reflective layer has been seen that ranges from non-observable to severe. The exact mechanisms involved in the degradation process are not well understood from either the phenomenological or microanalytical points of view and are thus subject to much debate. The three chapters of this report summarize the work recently performed in three general areas that are key to understanding and ultimately controlling the degradation phenomena. These areas are: a survey of the present commercial mirroring industry, the microanalytical examination of numerous degraded and nondegraded mirrors, and an investigation of several novel techniques that might be used to extend the life of heliostat mirrors. Appendices include: (a) list of mirror manufacturers and (b) recommended specifications for second surface silvered mirrors for central receiver heliostat applications. (WHK)

  13. TCV mirrors cleaned by plasma

    Directory of Open Access Journals (Sweden)

    L. Marot

    2017-08-01

    Full Text Available Metallic mirrors exposed in TCV tokamak were cleaned by plasma in laboratory. A gold (Au mirror was deposited with 185–285nm of amorphous carbon (aC:D film coming from the carbon tiles of TCV. Another molybdenum (Mo mirror had a thicker deposit due to a different location within the tokamak. The thickness measurements were carried out using ellipsometry and the reflectivity measurements performed by spectrophotometry revealed a decrease of the specular reflectivity in the entire range (250–2500nm for the Mo mirror and specifically in the visible spectrum for the Au. Comparison of the simulated reflectivity using a refractive index of 1.5 and a Cauchy model for the aC:D gives good confidence on the estimated film thickness. Plasma cleaning using radio frequency directly applied to a metallic plate where the mirrors were fixed demonstrated the ability to remove the carbon deposits. A mixture of 50% hydrogen and 50% helium was used with a −200V self-bias. Due to the low sputtering yield of He and the low chemical erosion of hydrogen leading to volatile molecules, 20h of cleaning were needed for Au mirror and more than 60h for Mo mirror. Recovery of the reflectivity was not complete for the Au mirror most likely due to damage of the surface during tokamak exposure (breakdown phenomena.

  14. Orientifolds and Mirror Symmetry

    CERN Document Server

    Brunner, I; Brunner, Ilka; Hori, Kentaro

    2004-01-01

    We study parity symmetries and crosscap states in classes of N=2 supersymmetric quantum field theories in 1+1 dimensions, including non-linear sigma models, gauged WZW models, Landau-Ginzburg models, and linear sigma models. The parity anomaly and its cancellation play important roles in many of them. The case of the N=2 minimal model are studied in complete detail, from all three realizations -- gauged WZW model, abstract RCFT, and LG models. We also identify mirror pairs of orientifolds, extending the correspondence between symplectic geometry and algebraic geometry by including unorientable worldsheets. Through the analysis in various models and comparison in the overlapping regimes, we obtain a global picture of orientifolds and D-branes.

  15. Introduction: Mirrors of Passing

    DEFF Research Database (Denmark)

    Seebach, Sophie Hooge; Willerslev, Rane

    How is death, time, and materiality interconnected? How to approach an understanding of the world of the dead? In this introduction, we seek to understand how the experience of material decay, of the death of those around us, makes us aware of the passing of time. Through the literary lens of Neil...... Gaiman’s The Graveyard Book, we explore how the world of the dead and the world of the living can intersect; how time and materiality shifts and changes depending on who experiences it. These revelations, based on fiction, provide a mirror through which the reader can experience the varied chapters...... of the book, which each presents a different perspective on death, materiality, and time....

  16. Beam cavity interaction

    CERN Document Server

    Gamp, A

    2011-01-01

    We begin by giving a description of the rf generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, rf feedback, and feed-forward are described. Examples of digital rf phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  17. Optical re-injection in cavity-enhanced absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Leen, J. Brian, E-mail: b.leen@lgrinc.com; O’Keefe, Anthony [Los Gatos Research, 67 E. Evelyn Avenue, Suite 3, Mountain View, California 94041 (United States)

    2014-09-15

    Non-mode-matched cavity-enhanced absorption spectrometry (e.g., cavity ringdown spectroscopy and integrated cavity output spectroscopy) is commonly used for the ultrasensitive detection of trace gases. These techniques are attractive for their simplicity and robustness, but their performance may be limited by the reflection of light from the front mirror and the resulting low optical transmission. Although this low transmitted power can sometimes be overcome with higher power lasers and lower noise detectors (e.g., in the near-infrared), many regimes exist where the available light intensity or photodetector sensitivity limits instrument performance (e.g., in the mid-infrared). In this article, we describe a method of repeatedly re-injecting light reflected off the front mirror of the optical cavity to boost the cavity's circulating power and deliver more light to the photodetector and thus increase the signal-to-noise ratio of the absorption measurement. We model and experimentally demonstrate the method's performance using off-axis cavity ringdown spectroscopy (OA-CRDS) with a broadly tunable external cavity quantum cascade laser. The power coupled through the cavity to the detector is increased by a factor of 22.5. The cavity loss is measured with a precision of 2 × 10{sup −10} cm{sup −1}/√(Hz;) an increase of 12 times over the standard off-axis configuration without reinjection and comparable to the best reported sensitivities in the mid-infrared. Finally, the re-injected CRDS system is used to measure the spectrum of several volatile organic compounds, demonstrating the improved ability to resolve weakly absorbing spectroscopic features.

  18. Fast response cavity enhanced ozone monitor

    Directory of Open Access Journals (Sweden)

    A. L. Gomez

    2013-02-01

    Full Text Available Ozone is an important atmospheric gas due to its role in air quality and radiative forcing. A new method for sensitive, rapid monitoring of ambient ozone has been developed using a compact platform and relatively inexpensive components. Based on incoherent broadband cavity enhanced absorption spectroscopy (IBB-CEAS, the device utilizes an optical cavity of just 14.5 cm and 99.3% reflective mirrors. Performance of the instrument has been validated against direct absorption measurements in a single-pass measurement cell. Currently, the IBB-CEAS ozone instrument can achieve ∼1 ppb sensitivities at 0.1 s integration time with a dynamic range over four orders of magnitude, accessing relevant ozone concentrations in both the stratosphere and troposphere. This new device offers improved sensitivity and time response for mapping ozone aboard airborne platforms.

  19. Advanced Mirror & Modelling Technology Development

    Science.gov (United States)

    Effinger, Michael; Stahl, H. Philip; Abplanalp, Laura; Maffett, Steven; Egerman, Robert; Eng, Ron; Arnold, William; Mosier, Gary; Blaurock, Carl

    2014-01-01

    The 2020 Decadal technology survey is starting in 2018. Technology on the shelf at that time will help guide selection to future low risk and low cost missions. The Advanced Mirror Technology Development (AMTD) team has identified development priorities based on science goals and engineering requirements for Ultraviolet Optical near-Infrared (UVOIR) missions in order to contribute to the selection process. One key development identified was lightweight mirror fabrication and testing. A monolithic, stacked, deep core mirror was fused and replicated twice to achieve the desired radius of curvature. It was subsequently successfully polished and tested. A recently awarded second phase to the AMTD project will develop larger mirrors to demonstrate the lateral scaling of the deep core mirror technology. Another key development was rapid modeling for the mirror. One model focused on generating optical and structural model results in minutes instead of months. Many variables could be accounted for regarding the core, face plate and back structure details. A portion of a spacecraft model was also developed. The spacecraft model incorporated direct integration to transform optical path difference to Point Spread Function (PSF) and between PSF to modulation transfer function. The second phase to the project will take the results of the rapid mirror modeler and integrate them into the rapid spacecraft modeler.

  20. Survey of mirror machine reactors

    Energy Technology Data Exchange (ETDEWEB)

    Condit, W.C.

    1978-08-11

    The Magnetic Mirror Fusion Program is one of the two main-line fusion efforts in the United States. Starting from the simple axisymmetric mirror concept in the 1950's, the program has successfully overcome gross flute-type instabilities (using minimum-B magnetic fields), and the most serious of the micro-instabilities which plagued it (the drift-cyclotron loss-cone mode). Dense plasmas approaching the temperature range of interest for fusion have been created (n/sub p/ = 10/sup 14//cc at 10 to 12 keV). At the same time, rather extensive conceptual design studies of possible mirror configurations have led to three principle designs of interest: the standard mirror fission-fusion hybrid, tandem mirror, and the field-reversed mirror. The lectures will discuss these three concepts in turn. There will be no discussion of diagnostics for the mirror machine in these lectures, but typical plasma parameters will be given for each type of machine, and the diagnostic requirements will be apparent. In a working fusion reactor, diagnostics will be required for operational control, and remarks will be made on this subject.

  1. Edificio Daily Mirror

    Directory of Open Access Journals (Sweden)

    Williams, Owen

    1963-07-01

    Full Text Available The building has 18 levels. The Press occupies the 4 basement floors. The ground floor is taken up with the entrance hall, and an indoor carriage way. A snack bar and the telephone operators are situated on the second floor. The production department and the medical services are located on the third storey, whilst the fourth is occupied by the offices and library. The fifth floor is the beginning of the higher section of the building. This floor and up to including the 11th floor are devoted to office space, except for the 10th storey, which contains the office apartments of the directors and the Council Chamber. Equipment related to various services of the building is housed on the 12th storey. Finally, this tall building constitutes a fine landmark in the London skyline. The Daily Mirror building is outstanding for the appropriate nature, the completeness and the quality of its installations, which thus provide the most widely read paper in the world with outstandingly efficient offices.Este edificio consta de 18 plantas. El cuerpo de Prensa se aloja en los cuatro sótanos; los vestíbulos de entrada y una calzada interior para vehículos se hallan en la planta baja; la primera alberga un snack-bar y centralita telefónica; la segunda, el departamento de producción y centro de asistencia médica, y la tercera, las oficinas y biblioteca principales. La cuarta planta señala el comienzo del bloque alto; esta planta, junto con las quinta, sexta, séptima, octava y décima, están dedicadas a oficinas. La novena contiene las oficinas-apartamentos de los directores y salas de Consejo, y la undécima, la maquinaria para las diversas instalaciones del edificio. La elevada torre constituye un grandioso hito de referencia en esta zona de Londres. El «Daily Mirror» se distingue por el acierto, número y perfección de sus instalaciones, que proporcionan, al periódico de mayor actualidad mundial, las más adecuadas y amplias oficinas modernas.

  2. Tandem mirror and field-reversed mirror experiments

    Energy Technology Data Exchange (ETDEWEB)

    Coensgen, F.H.; Simonen, T.C.; Turner, W.C.

    1979-08-21

    This paper is largely devoted to tandem mirror and field-reversed mirror experiments at the Lawrence Livermore Laboratory (LLL), and briefly summarizes results of experiments in which field-reversal has been achieved. In the tandem experiment, high-energy, high-density plasmas (nearly identical to 2XIIB plasmas) are located at each end of a solenoid where plasma ions are electrostatically confined by the high positive poentials arising in the end plug plasma. End plug ions are magnetically confined, and electrons are electrostatically confined by the overall positive potential of the system. The field-reversed mirror reactor consists of several small field-reversed mirror plasmas linked together for economic reasons. In the LLL Beta II experiment, generation of a field-reversed plasma ring will be investigated using a high-energy plasma gun with a transverse radial magnetic field. This plasma will be further heated and sustained by injection of intense, high-energy neutral beams.

  3. Stable linear SESAM femtosecond fiber laser by use of faraday rotator mirrors

    Science.gov (United States)

    Hekmat, M. J.; Gholami, A.; Omoomi, M.; Taheri, A.; Kanani, M.; Malek Mohammadi, S.; Shahriari, N.; Abdollahi, M.; Noormohammadi, H.

    2016-11-01

    We present a linear cavity type of Erbium-Doped fiber oscillator designed for high stability femtosecond pulse production. Commercial Semiconductor Saturable Absorber Mirrors (SESAM) is applied. To avoid environment unstable effects which affects on polarization state of fiber, standard faraday rotator is used in this cavity. Also the experimental study of ring femtosecond fiber laser is compared with linear once. The linear cavity is more stable than ring configuration. With addition of Erbium-Doped fiber amplifier, the output power 100mW with 910 fs and 45.5 MHz repetition rate is acquired without any pulse compressing.

  4. Mirroring patients – or not

    DEFF Research Database (Denmark)

    Davidsen, Annette Sofie; Fosgerau, Christina Fogtmann

    2015-01-01

    For mentalization theorists, implicit mentalization is a key component of all forms of therapy. However, it has been difficult to grasp and to describe precisely how implicit mentalization works. It is said to take place partly by mirroring others in posture, facial expression and vocal tone. Based...... and acoustic features of speech. GPs mirrored their patients more than psychiatrists in all modalities and were more flexible in their interactional behaviour. Psychiatrists seemed more static, regardless of the emotionality displayed by patients. Implicitly mirroring and attuning to patients could signify...

  5. Metamaterial saturable absorber mirror.

    Science.gov (United States)

    Dayal, Govind; Ramakrishna, S Anantha

    2013-02-01

    We propose a metamaterial saturable absorber mirror at midinfrared wavelengths that can show a saturation of absorption with intensity of incident light and switch to a reflecting state. The design consists of an array of circular metallic disks separated by a thin film of vanadium dioxide (VO(2)) from a continuous metallic film. The heating due to the absorption in the absorptive state causes the VO(2) to transit to a metallic phase from the low temperature insulating phase. The metamaterial switches from an absorptive state (R≃0.1%) to a reflective state (R>95%) for a specific threshold intensity of the incident radiation corresponding to the phase transition of VO(2), resulting in the saturation of absorption in the metamaterial. The computer simulations show over 99.9% peak absorbance, a resonant bandwidth of about 0.8 μm at 10.22 μm wavelengths, and saturation intensity of 140 mW cm(-2) for undoped VO(2) at room temperature. We also carried out numerical simulations to investigate the effects of localized heating and temperature distribution by solving the heat diffusion problem.

  6. The LHC superconducting cavities

    CERN Document Server

    Boussard, Daniel; Häbel, E; Kindermann, H P; Losito, R; Marque, S; Rödel, V; Stirbet, M

    1999-01-01

    The LHC RF system, which must handle high intensity (0.5 A d.c.) beams, makes use of superconducting single-cell cavities, best suited to minimizing the effects of periodic transient beam loading. There will be eight cavities per beam, each capable of delivering 2 MV (5 MV/m accelerating field) at 400 MHz. The cavities themselves are now being manufactured by industry, using niobium-on-copper technology which gives full satisfaction at LEP. A cavity unit includes a helium tank (4.5 K operating temperature) built around a cavity cell, RF and HOM couplers and a mechanical tuner, all housed in a modular cryostat. Four-unit modules are ultimately foreseen for the LHC (two per beam), while at present a prototype version with two complete units is being extensively tested. In addition to a detailed description of the cavity and its ancillary equipment, the first test results of the prototype will be reported.

  7. Myopericytoma in nasal cavity

    Directory of Open Access Journals (Sweden)

    Zimmermann, Elise

    2009-06-01

    Full Text Available Introduction: The myopericytomas represent about 1% of the vascular tumors, is relatively common in the region of head and neck, 25% of the cases, and uncommon in the nasal and paranasal cavities. Objective: To describe one case of myopericytoma in nasal cavity. Case Report: We present a case of an adult patient, of the female sex, with complaints of nasal obstruction, pain in the nasal cavities region and eventual epistaxis in the right nasal cavity, which present an angiomatous and easily bleeding, non-pulsatile mass occupying all the right nasal cavity. Final Considerations: The myopericytomas are uncommon vascular tumors, rarely located in the nasal cavity and in the paranasal sinuses. They must be included in the differential diagnosis of the well delimited, vascular and slow growth masses upon computed tomography.

  8. Fast Picometer Mirror Mount Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a 6DOF controllable mirror mount with high dynamic range and fast tip/tilt capability for space based applications. It will enable the...

  9. Advanced Mirror Material System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Peregrine will bring together recent laboratory developments and mature the technology so that complete mirror and telescope assemblies can be reliably and robustly...

  10. Bessel-Gauss beam enhancement cavities for high-intensity applications.

    Science.gov (United States)

    Putnam, William P; Schimpf, Damian N; Abram, Gilberto; Kärtner, Franz X

    2012-10-22

    We introduce Bessel-Gauss beam enhancement cavities that may circumvent the major obstacles to more efficient cavity-enhanced high-field physics such as high-harmonic generation. The basic properties of Bessel-Gauss beams are reviewed and their transformation properties through simple optical systems (consisting of spherical and conical elements) are presented. A general Bessel-Gauss cavity design strategy is outlined, and a particular geometry, the confocal Bessel-Gauss cavity, is analyzed in detail. We numerically simulate the confocal Bessel-Gauss cavity and present an example cavity with 300 MHz repetition rate supporting an effective waist of 33 μm at the focus and an intensity ratio from the focus to the cavity mirror surfaces of 1.5 × 10(4).

  11. Optically measuring interior cavities

    Science.gov (United States)

    Stone, Gary Franklin

    2008-12-21

    A method of measuring the three-dimensional volume or perimeter shape of an interior cavity includes the steps of collecting a first optical slice of data that represents a partial volume or perimeter shape of the interior cavity, collecting additional optical slices of data that represents a partial volume or perimeter shape of the interior cavity, and combining the first optical slice of data and the additional optical slices of data to calculate of the three-dimensional volume or perimeter shape of the interior cavity.

  12. Advances in telescope mirror cleaning

    Science.gov (United States)

    Blanken, Maarten F.; Chopping, Alan K.; Dee, Kevin M.

    2004-09-01

    Metrology and cleaning techniques for telescope mirrors are generally well established. CO2 cleaning and water washing are mainly used. Water washing has proven to be the best method of removing oil and water stains and restoring the aluminium to nearly fresh values. The risk of water getting to unwanted places such as electronics or other optics prevents this method from being employed more often. Recently the Isaac Newton Group introduced a new cleaning technique for their telescope mirrors, which reduces the risks discussed above. This technique uses water vapour instead of water to wash the mirror. The advantage of this method is that the amount of water needed is drastically reduced. In addition the pressure of the vapour will blow away any large dust particles on the mirror and the temperature shock between the vapour and the mirror will help to de-bond the dust particles. Adding a soapy solution will help to clean oil and watermarks of the mirror. This paper describes the vapour cleaning method, tests that have been done and the overall findings.

  13. Issues facing the U. S. mirror program

    Energy Technology Data Exchange (ETDEWEB)

    George, T.V.

    1978-07-01

    Some of the current issues associated with the U.S. Magnetic Mirror Program are analyzed. They are presented as five separate papers entitled: (1) Relevant Issues Broughtup by the Mirror Reactor Design Studies. (2) An Assessment of the Design Study of the 1 MeV Neutral Beam Injector Required for a Tandem Mirror Reactor. (3) The Significance of the Radial Plasma Size Measured in Units of Ion Gyroradii in Tandem Mirrors and Field Reversed Mirrors. (4) Producing Field Reversed Mirror Plasmas by Methods used in Field Reversed Theta Pinch. (5) RF Stoppering of Mirror Confined Plasma.

  14. Wavelength-Agile External-Cavity Diode Laser for DWDM

    Science.gov (United States)

    Pilgrim, Jeffrey S.; Bomse, David S.

    2006-01-01

    A prototype external-cavity diode laser (ECDL) has been developed for communication systems utilizing dense wavelength- division multiplexing (DWDM). This ECDL is an updated version of the ECDL reported in Wavelength-Agile External- Cavity Diode Laser (LEW-17090), NASA Tech Briefs, Vol. 25, No. 11 (November 2001), page 14a. To recapitulate: The wavelength-agile ECDL combines the stability of an external-cavity laser with the wavelength agility of a diode laser. Wavelength is modulated by modulating the injection current of the diode-laser gain element. The external cavity is a Littman-Metcalf resonator, in which the zeroth-order output from a diffraction grating is used as the laser output and the first-order-diffracted light is retro-reflected by a cavity feedback mirror, which establishes one end of the resonator. The other end of the resonator is the output surface of a Fabry-Perot resonator that constitutes the diode-laser gain element. Wavelength is selected by choosing the angle of the diffracted return beam, as determined by position of the feedback mirror. The present wavelength-agile ECDL is distinguished by design details that enable coverage of all 60 channels, separated by 100-GHz frequency intervals, that are specified in DWDM standards.

  15. Free-space cavity optomechanics in a cryogenic environment

    Science.gov (United States)

    Kuhn, A. G.; Teissier, J.; Neuhaus, L.; Zerkani, S.; van Brackel, E.; Deléglise, S.; Briant, T.; Cohadon, P.-F.; Heidmann, A.; Michel, C.; Pinard, L.; Dolique, V.; Flaminio, R.; Taïbi, R.; Chartier, C.; Le Traon, O.

    2014-01-01

    We present a free-space optomechanical system operating in the 1-K range. The device is made of a high mechanical quality factor micropillar with a high-reflectivity optical coating atop, combined with an ultra-small radius-of-curvature coupling mirror to form a high-finesse Fabry-Perot cavity embedded in a dilution refrigerator. The cavity environment as well as the cryostat have been designed to ensure low vibrations and to preserve micron-level alignment from room temperature down to 100 mK.

  16. Vertical-cavity surface-emitting lasers for medical diagnosis

    DEFF Research Database (Denmark)

    Ansbæk, Thor

    -Pérot filters with dissimilar mirrors and the design of such Fabry-Pérot cavities for VCSELs. Fabrication of InGaAs multiple quantum wells with GaAsP strain balancing layers is covered together with the growth and wet chemical etching of InAlP. The fabrication of the proposed Fabry-Pérot filters and VCSELs......This thesis deals with the design and fabrication of tunable Vertical-Cavity Surface-Emitting Lasers (VCSELs). The focus has been the application of tunable VCSELs in medical diagnostics, specifically OCT. VCSELs are candidates as light sources for swept-source OCT where their high sweep rate, wide...

  17. EUV-mirror, optical system with EUV-mirror and associated operating method

    NARCIS (Netherlands)

    Dinger, U.; Bijkerk, Frederik; Bayraktar, Muharrem; Dier, O.

    2016-01-01

    An EUV mirror (1000) has a mirror element which forms a mirror surface of the mirror. The mirror element has a substrate (1020) and a multilayer arrangement (1030) applied on the substrate and having a reflective effect with respect to radiation from the extreme ultraviolet range (EUV). The

  18. Parametric generation of radiation in a dynamic cavity with frequency dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Rosanov, N N; Fedorov, E G; Matskovsky, A A [Federal State Unitary Enterprise ' Scientific and Industrial Corporation ' Vavilov State Optical Institute' , St. Petersburg (Russian Federation)

    2016-01-31

    A numerical simulation of the parametric generation of electromagnetic radiation in a cavity with periodically oscillating mirrors and Lorentz-type frequency dispersion has been performed. It is shown that initially weak seed radiation can be transformed into intense short pulses, the shape of which under steady-state conditions changes periodically when reflecting from mirrors and, depending on the dispersion characteristics, corresponds to uni- or bipolar pulses. (letters)

  19. Microwave Cavity for Anapole Moment Measurement in Francium

    Science.gov (United States)

    Zhang, Jiehang; Sheng, Dong; Orozco, Luis

    2011-05-01

    We present a study of the Polka-Dot microwave plano-spherical mirror for a Fabry-Perot resonator. The microwave resonator is an essential element of the apparatus to measure the anapole moment in francium. A crucial requirement for the cavity is the mode-matching into the fundamental Gaussian TEM00 mode. We investigate new coupling mechanisms of the radiation into the cavity to suppress unwanted higher order modes. We are exploring the method of printing two dimensional array of holes and feeding in through horn antennas. According to a HFSS simulation, this method should improve significantly the mode purity in contrast to conventional antenna. We fabricate the mirrors on standard optical blank using standard film deposition techniques with lithographic method to print the pattern. Preliminary tests show resonances, with potential improvements of the Q factors. Work supported by DOE and NSF

  20. Superconducting cavities for LEP

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Above: a 350 MHz superconducting accelerating cavity in niobium of the type envisaged for accelerating electrons and positrons in later phases of LEP. Below: a small 1 GHz cavity used for investigating the surface problems of superconducting niobium. Albert Insomby stays on the right. See Annual Report 1983 p. 51.

  1. Superconducting RF cavities

    CERN Document Server

    Bernard, Philippe

    1999-01-01

    It was 20 years ago when the research and development programme for LEP superconducting cavities was initiated. It lasted about 10 years. Today, my aim is not to tell you in great detail about the many innovations made thanks to our research, but I would like to point out some milestones in the development of superconducting cavities where Emilio's influence was particularly important.

  2. SPS accelerating cavity

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    One of the SPS acceleration cavities (200 MHz, travelling wave structure). On the ceiling one sees the coaxial transmission line which feeds the power from the amplifier, located in a surface building above, to the upstream end of the cavity. See 7603195 for more details, 7411032 for the travelling wave structure, and also 8104138, 8302397.

  3. SPS accelerating cavity

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    One of the SPS accelerating cavities (200 MHz, travelling wave structure). The power that is fed into the upstream end of the cavity is extracted at the downstream end and sent into a dump load. See 7603195 for more details, 7411032 for the travelling wave structure, and also 8011289, 8302397.

  4. Cavity Attenuated Phase Shift (CAPS) Monitor Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, Arthur J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-04-01

    The CAPS PMex monitor is a cavity attenuated phase shift extinction instrument. It operates as an optical extinction spectrometer, using a visible-light-emitting diode (LED) as the light source, a sample cell incorporating two high-reflectivity mirrors centered at the wavelength of the LED, and a vacuum photodiode detector. Its efficacy is based on the fact that aerosols are broadband scatterers and absorbers of light.

  5. Position sensors for segmented mirror

    Science.gov (United States)

    Rozière, Didier; Buous, Sébastien; Courteville, Alain

    2004-09-01

    There are currently several projects for giant telescopes with segmented mirrors under way. These future telescopes will have their primary mirror made of several thousand segments. The main advantage of segmentation is that it enables the active control of the whole mirror, so as to suppress the deformations of the support structure due to the wind, gravity, thermal inhomogeneities etc. ..., thus getting the best possible stigmatism. However, providing active control of segmented mirrors requires numerous accurate edges sensors. It is acknowledged that capacitance-based technology nowadays offers the best metrological performances-to-cost ratio. As the leader in capacitive technology, FOGALE nanotech offers an original concept which reduces the cost of instrumentation, sensors and electronics, while keeping a very high level of performances with a manufacturing process completely industrialised. We present here the sensors developed for the Segment Alignment Measurement System (SAMS) of the Southern African Large Telescope (SALT). This patented solution represents an important improvement in terms of cost, to market the Position Sensors for Segmented Mirrors of ELTs, whilst maintaining a very high performance level. We present here the concept, the laboratory qualification, and the first trials on the 7 central segments of SALT. The laboratory results are good, and we are now working on the on-site implementation to improve the immunity of the sensors to environment.

  6. Metamaterial mirrors in optoelectronic devices

    KAUST Repository

    Esfandyarpour, Majid

    2014-06-22

    The phase reversal that occurs when light is reflected from a metallic mirror produces a standing wave with reduced intensity near the reflective surface. This effect is highly undesirable in optoelectronic devices that use metal films as both electrical contacts and optical mirrors, because it dictates a minimum spacing between the metal and the underlying active semiconductor layers, therefore posing a fundamental limit to the overall thickness of the device. Here, we show that this challenge can be circumvented by using a metamaterial mirror whose reflection phase is tunable from that of a perfect electric mirror († = €) to that of a perfect magnetic mirror († = 0). This tunability in reflection phase can also be exploited to optimize the standing wave profile in planar devices to maximize light-matter interaction. Specifically, we show that light absorption and photocurrent generation in a sub-100 nm active semiconductor layer of a model solar cell can be enhanced by ∼20% over a broad spectral band. © 2014 Macmillan Publishers Limited.

  7. The Construction of Mirror Symmetry

    CERN Document Server

    Schimmrigk, R

    1992-01-01

    The construction of mirror symmetry in the heterotic string is reviewed in the context of Calabi-Yau and Landau-Ginzburg compactifications. This framework has the virtue of providing a large subspace of the configuration space of the heterotic string, probing its structure far beyond the present reaches of solvable models. The construction proceeds in two stages: First all singularities/catastrophes which lead to ground states of the heterotic string are found. It is then shown that not all ground states described in this way are independent but that certain classes of these LG/CY string vacua can be related to other, simpler, theories via a process involving fractional transformations of the order parameters as well as orbifolding. This construction has far reaching consequences. Firstly it allows for a systematic identification of mirror pairs that appear abundantly in this class of string vacua, thereby showing that the emerging mirror symmetry is not accidental. This is important because models with mirro...

  8. Metrology of IXO Mirror Segments

    Science.gov (United States)

    Chan, Kai-Wing

    2011-01-01

    For future x-ray astrophysics mission that demands optics with large throughput and excellent angular resolution, many telescope concepts build around assembling thin mirror segments in a Wolter I geometry, such as that originally proposed for the International X-ray Observatory. The arc-second resolution requirement posts unique challenges not just for fabrication, mounting but also for metrology of these mirror segments. In this paper, we shall discuss the metrology of these segments using normal incidence metrological method with interferometers and null lenses. We present results of the calibration of the metrology systems we are currently using, discuss their accuracy and address the precision in measuring near-cylindrical mirror segments and the stability of the measurements.

  9. SPS RF Accelerating Cavity

    CERN Multimedia

    1979-01-01

    This picture shows one of the 2 new cavities installed in 1978-1979. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X

  10. SPS RF Cavity

    CERN Multimedia

    1975-01-01

    The picture shows one of the two initially installed cavities. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also gradually increased: by end 1980 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412017X, 7411048X, 7505074.

  11. Superconducting TESLA cavities

    Science.gov (United States)

    Aune, B.; Bandelmann, R.; Bloess, D.; Bonin, B.; Bosotti, A.; Champion, M.; Crawford, C.; Deppe, G.; Dwersteg, B.; Edwards, D. A.; Edwards, H. T.; Ferrario, M.; Fouaidy, M.; Gall, P.-D.; Gamp, A.; Gössel, A.; Graber, J.; Hubert, D.; Hüning, M.; Juillard, M.; Junquera, T.; Kaiser, H.; Kreps, G.; Kuchnir, M.; Lange, R.; Leenen, M.; Liepe, M.; Lilje, L.; Matheisen, A.; Möller, W.-D.; Mosnier, A.; Padamsee, H.; Pagani, C.; Pekeler, M.; Peters, H.-B.; Peters, O.; Proch, D.; Rehlich, K.; Reschke, D.; Safa, H.; Schilcher, T.; Schmüser, P.; Sekutowicz, J.; Simrock, S.; Singer, W.; Tigner, M.; Trines, D.; Twarowski, K.; Weichert, G.; Weisend, J.; Wojtkiewicz, J.; Wolff, S.; Zapfe, K.

    2000-09-01

    The conceptional design of the proposed linear electron-positron collider TESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with an accelerating gradient of Eacc>=25 MV/m at a quality factor Q0>=5×109. The design goal for the cavities of the TESLA Test Facility (TTF) linac was set to the more moderate value of Eacc>=15 MV/m. In a first series of 27 industrially produced TTF cavities the average gradient at Q0 = 5×109 was measured to be 20.1+/-6.2 MV/m, excluding a few cavities suffering from serious fabrication or material defects. In the second production of 24 TTF cavities, additional quality control measures were introduced, in particular, an eddy-current scan to eliminate niobium sheets with foreign material inclusions and stringent prescriptions for carrying out the electron-beam welds. The average gradient of these cavities at Q0 = 5×109 amounts to 25.0+/-3.2 MV/m with the exception of one cavity suffering from a weld defect. Hence only a moderate improvement in production and preparation techniques will be needed to meet the ambitious TESLA goal with an adequate safety margin. In this paper we present a detailed description of the design, fabrication, and preparation of the TESLA Test Facility cavities and their associated components and report on cavity performance in test cryostats and with electron beam in the TTF linac. The ongoing research and development towards higher gradients is briefly addressed.

  12. Dirichlet branes and mirror symmetry

    CERN Document Server

    2009-01-01

    This is the second of two books that provide the scientific record of the school. The first book, Strings and Geometry, edited by Michael R. Douglas et al., was a proceedings volume and largely focused on the topics of manifolds holonomy and supergravity. The present volume, intended to be a monograph, covers mirror symmetry from the homological and torus fibration points of view. We hope that this volume is a natural sequel to Mirror Symmetry, written by Hoi, Katz, Klemm, Pandharipande, Thomas, Vafa, Vakil and Zaslow, which was a product of the first Clay School in the spring of 2000.

  13. Hydroforming of elliptical cavities

    Directory of Open Access Journals (Sweden)

    W. Singer

    2015-02-01

    Full Text Available Activities of the past several years in developing the technique of forming seamless (weldless cavity cells by hydroforming are summarized. An overview of the technique developed at DESY for the fabrication of single cells and multicells of the TESLA cavity shape is given and the major rf results are presented. The forming is performed by expanding a seamless tube with internal water pressure while simultaneously swaging it axially. Prior to the expansion the tube is necked at the iris area and at the ends. Tube radii and axial displacements are computer controlled during the forming process in accordance with results of finite element method simulations for necking and expansion using the experimentally obtained strain-stress relationship of tube material. In cooperation with industry different methods of niobium seamless tube production have been explored. The most appropriate and successful method is a combination of spinning or deep drawing with flow forming. Several single-cell niobium cavities of the 1.3 GHz TESLA shape were produced by hydroforming. They reached accelerating gradients E_{acc} up to 35  MV/m after buffered chemical polishing (BCP and up to 42  MV/m after electropolishing (EP. More recent work concentrated on fabrication and testing of multicell and nine-cell cavities. Several seamless two- and three-cell units were explored. Accelerating gradients E_{acc} of 30–35  MV/m were measured after BCP and E_{acc} up to 40  MV/m were reached after EP. Nine-cell niobium cavities combining three three-cell units were completed at the company E. Zanon. These cavities reached accelerating gradients of E_{acc}=30–35  MV/m. One cavity is successfully integrated in an XFEL cryomodule and is used in the operation of the FLASH linear accelerator at DESY. Additionally the fabrication of bimetallic single-cell and multicell NbCu cavities by hydroforming was successfully developed. Several NbCu clad single-cell and

  14. SPS RF cavity

    CERN Multimedia

    1974-01-01

    The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. A power of up to 790 kW can be supplied to each giving a total accelerating voltage of about 8 MV. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities.

  15. Cavity-enhanced spectroscopies

    CERN Document Server

    van Zee, Roger

    2003-01-01

    ""Cavity-Enhanced Spectroscopy"" discusses the use of optical resonators and lasers to make sensitive spectroscopic measurements. This volume is written by the researcchers who pioneered these methods. The book reviews both the theory and practice behind these spectroscopic tools and discusses the scientific discoveries uncovered by these techniques. It begins with a chapter on the use of optical resonators for frequency stabilization of lasers, which is followed by in-depth chapters discussing cavity ring-down spectroscopy, frequency-modulated, cavity-enhanced spectroscopy, intracavity spectr

  16. Composite single crystal silicon scan mirror substrates Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Single crystal silicon is a desirable mirror substrate for scan mirrors in space telescopes. As diameters of mirrors become larger, existing manufacturing...

  17. Dental Sealants Prevent Cavities

    Science.gov (United States)

    ... RSS VitalSigns RSS Error processing SSI file Dental Sealants Prevent Cavities Effective protection for children Language: English ( ... Problem About 7 million low-income children need sealants. What are sealants? Sealants are thin coatings painted ...

  18. accelerating cavity from LEP

    CERN Multimedia

    This is an accelerating cavity from LEP, with a layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities are now used in LEP to double the energy of the particle beams.

  19. SPS accelerating cavity

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    View towards the downstream end of one of the SPS accelerating cavities (200 MHz, travelling wave structure). See 7603195 and 8011289 for more details, 7411032 for the travelling wave structure, and also 8104138.

  20. SPS accelerating cavity

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    The SPS started up with 2 accelerating cavities (each consisting of 5 tank sections) in LSS3. They have a 200 MHz travelling wave structure (see 7411032 and 7802190) and 750 kW of power is fed to each of the cavities from a 1 MW tetrode power amplifier, located in a surface building above, via a coaxial transmission line. Clemens Zettler, builder of the SPS RF system, is standing at the side of one of the cavities. In 1978 and 1979 another 2 cavities were added and entered service in 1980. These were part of the intensity improvement programme and served well for the new role of the SPS as proton-antiproton collider. See also 7411032, 8011289, 8104138, 8302397.

  1. Melatonin and Oral Cavity

    National Research Council Canada - National Science Library

    Cengiz, Murat İnanç; Cengiz, Seda; Wang, Hom-Lay

    2012-01-01

      While initially the oral cavity was considered to be mainly a source of various bacteria, their toxins and antigens, recent studies showed that it may also be a location of oxidative stress and periodontal inflammation...

  2. Novel laser machining of optical fibers for long cavities with low birefringence.

    Science.gov (United States)

    Takahashi, Hiroki; Morphew, Jack; Oručević, Fedja; Noguchi, Atsushi; Kassa, Ezra; Keller, Matthias

    2014-12-15

    We present a novel method of machining optical fiber surfaces with a CO₂ laser for use in Fiber-based Fabry-Perot Cavities (FFPCs). Previously FFPCs were prone to large birefringence and limited to relatively short cavity lengths (≤ 200 μm). These characteristics hinder their use in some applications such as cavity quantum electrodynamics with trapped ions. We optimized the laser machining process to produce large, uniform surface structures. This enables the cavities to achieve high finesse even for long cavity lengths. By rotating the fibers around their axis during the laser machining process the asymmetry resulting from the laser's transverse mode profile is eliminated. Consequently we are able to fabricate fiber mirrors with a high degree of rotational symmetry, leading to remarkably low birefringence. Through measurements of the cavity finesse over a range of cavity lengths and the polarization dependence of the cavity linewidth, we confirmed the quality of the produced fiber mirrors for use in low-birefringence FFPCs.

  3. On four dimensional mirror symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Losev, A. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Nekrasov, N.; Shatashvili, S.

    2000-07-01

    A conjecture relating instanton calculus in four dimensional supersymmetric theories and the deformation theory of Lagrangian submanifolds in C{sup 2r} invariant under a (subgroup of) Sp(2r,Z) is formulated. This is a four dimensional counterpart of the mirror symmetry of topological strings (relating Gromov-Witten invariants and generalized variations of Hodge structure). (orig.)

  4. The Superconducting TESLA Cavities

    CERN Document Server

    Aune, B.; Bloess, D.; Bonin, B.; Bosotti, A.; Champion, M.; Crawford, C.; Deppe, G.; Dwersteg, B.; Edwards, D.A.; Edwards, H.T.; Ferrario, M.; Fouaidy, M.; Gall, P-D.; Gamp, A.; Gössel, A.; Graber, J.; Hubert, D.; Hüning, M.; Juillard, M.; Junquera, T.; Kaiser, H.; Kreps, G.; Kuchnir, M.; Lange, R.; Leenen, M.; Liepe, M.; Lilje, L.; Matheisen, A.; Möller, W-D.; Mosnier, A.; Padamsee, H.; Pagani, C.; Pekeler, M.; Peters, H-B.; Peters, O.; Proch, D.; Rehlich, K.; Reschke, D.; Safa, H.; Schilcher, T.; Schmüser, P.; Sekutowicz, J.; Simrock, S.; Singer, W.; Tigner, M.; Trines, D.; Twarowski, K.; Weichert, G.; Weisend, J.; Wojtkiewicz, J.; Wolff, S.; Zapfe, K.

    2000-01-01

    The conceptional design of the proposed linear electron-positron colliderTESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with anaccelerating gradient of Eacc >= 25 MV/m at a quality factor Q0 > 5E+9. Thedesign goal for the cavities of the TESLA Test Facility (TTF) linac was set tothe more moderate value of Eacc >= 15 MV/m. In a first series of 27industrially produced TTF cavities the average gradient at Q0 = 5E+9 wasmeasured to be 20.1 +- 6.2 MV/m, excluding a few cavities suffering fromserious fabrication or material defects. In the second production of 24 TTFcavities additional quality control measures were introduced, in particular aneddy-current scan to eliminate niobium sheets with foreign material inclusionsand stringent prescriptions for carrying out the electron-beam welds. Theaverage gradient of these cavities at Q0 = 5E+9 amounts to 25.0 +- 3.2 MV/mwith the exception of one cavity suffering from a weld defect. Hence only amoderate improvement in production and preparation technique...

  5. Surface explosion cavities

    CERN Document Server

    Benusiglio, Adrien; Clanet, Christophe

    2012-01-01

    We present a fluid dynamics video on cavities created by explosions of firecrackers at the water free surface. We use three types of firecrackers containing 1, 1.3 and 5 g of flash powder. The firecrackers are held with their center at the surface of water in a cubic meter pool. The movies are recorded from the side with a high-speed video camera. Without confinement the explosion produces an hemispherical cavity. Right after the explosion this cavity grows isotropically, the bottom then stops while the sides continue to expand. In the next phase the bottom of the cavity accelerates backwards to the surface. During this phase the convergence of the flow creates a central jet that rises above the free surface. In the last part of the video the explosion is confined in a vertical open tube made of glass and of centimetric diameter. The explosion creates a cylindrical cavity that develops towards the free end of the tube. Depending on the charge, the cavity can either stop inside the tube or at its exit, but nev...

  6. The Axisymmetric Tandem Mirror: A Magnetic Mirror Concept Game Changer Magnet Mirror Status Study Group

    Energy Technology Data Exchange (ETDEWEB)

    Simonen, T; Cohen, R; Correll, D; Fowler, K; Post, D; Berk, H; Horton, W; Hooper, E B; Fisch, N; Hassam, A; Baldwin, D; Pearlstein, D; Logan, G; Turner, B; Moir, R; Molvik, A; Ryutov, D; Ivanov, A A; Kesner, J; Cohen, B; McLean, H; Tamano, T; Tang, X Z; Imai, T

    2008-10-24

    Experimental results, theory and innovative ideas now point with increased confidence to the possibility of a Gas Dynamic Trap (GDT) neutron source which would be on the path to an attractively simple Axisymmetric Tandem Mirror (ATM) power plant. Although magnetic mirror research was terminated in the US 20 years ago, experiments continued in Japan (Gamma 10) and Russia (GDT), with a very small US effort. This research has now yielded data, increased understanding, and generated ideas resulting in the new concepts described here. Early mirror research was carried out with circular axisymmetric magnets. These plasmas were MHD unstable due to the unfavorable magnetic curvature near the mid-plane. Then the minimum-B concept emerged in which the field line curvature was everywhere favorable and the plasma was situated in a MHD stable magnetic well (70% average beta in 2XII-B). The Ioffe-bar or baseball-coil became the standard for over 40 years. In the 1980's, driven by success with minimum-B stabilization and the control of ion cyclotron instabilities in PR6 and 2XII-B, mirrors were viewed as a potentially attractive concept with near-term advantages as a lower Q neutron source for applications such as a hybrid fission fuel factory or toxic waste burner. However there are down sides to the minimum-B geometry: coil construction is complex; restraining magnetic forces limit field strength and mirror ratios. Furthermore, the magnetic field lines have geodesic curvature which introduces resonant and neoclassical radial transport as observed in early tandem mirror experiments. So what now leads us to think that simple axisymmetric mirror plasmas can be stable? The Russian GDT experiment achieves on-axis 60% beta by peaking of the kinetic plasma pressure near the mirror throat (where the curvature is favorable) to counter-balance the average unfavorable mid-plane curvature. Then a modest augmentation of plasma pressure in the expander results in stability. The GDT

  7. Secrets of the Chinese magic mirror replica

    Science.gov (United States)

    Mak, Se-yuen; Yip, Din-yan

    2001-03-01

    We examine the structure of five Chinese magic mirror replicas using a special imaging technique developed by the authors. All mirrors are found to have a two-layered structure. The reflecting surface that gives rise to a projected magic pattern on the screen is hidden under a polished half-reflecting top layer. An alternative method of making the magic mirror using ancient technology has been proposed. Finally, we suggest a simple method of reconstructing a mirror replica in the laboratory.

  8. Mounting and Alignment of IXO Mirror Segments

    Science.gov (United States)

    Chan, Kai-Wing; Zhang, William; Evans, Tyler; McClelland, Ryan; Hong, Melinda; Mazzarella, James; Saha, Timo; Jalota, Lalit; Olsen, Lawrence; Byron, Glenn

    2010-01-01

    A suspension-mounting scheme is developed for the IXO (International X-ray Observatory) mirror segments in which the figure of the mirror segment is preserved in each stage of mounting. The mirror, first fixed on a thermally compatible strongback, is subsequently transported, aligned and transferred onto its mirror housing. In this paper, we shall outline the requirement, approaches, and recent progress of the suspension mount processes.

  9. Aprotinin administration in the pericardial cavity does not prevent platelet activation

    NARCIS (Netherlands)

    Maquelin, K. N.; Nieuwland, R.; Lentjes, E. G.; Böing, A. N.; Mochtar, B.; Eijsman, L.; Sturk, A.

    2000-01-01

    Aprotinin is frequently administered systemically to patients undergoing cardiopulmonary bypass to inhibit activation of platelets and plasma protein systems and thus reduce postoperative blood loss. Two reports on local aprotinin administration, that is, into the pericardial cavity, also indicated

  10. The mirror neuron system : New frontiers

    NARCIS (Netherlands)

    Keysers, Christian; Fadiga, Luciano

    2008-01-01

    Since the discovery of mirror neurons, much effort has been invested into Studying their location and properties in the human brain. Here we review these original findings and introduce the Main topics of this special issue of Social Neuroscience. What does the mirror system code? How is the mirror

  11. Through the looking-glass: mirror reading.

    Science.gov (United States)

    Duñabeitia, Jon Andoni; Molinaro, Nicola; Carreiras, Manuel

    2011-02-14

    At early stages of object identification we process correctly oriented and mirrored versions of an object similarly. However, in letter and word perception, such tolerance to mirror reversals is harmful for efficient reading. Do readers successfully develop blindness mechanisms for mirror-letters and words? We conducted two masked priming experiments while recording participants' electrophysiological brain responses to briefly presented primes including mirror-letters (Experiment 1) or to shortly presented mirror-words (Experiment 2). Results showed that the human visual word recognition system is not totally blind to mirror-letters and mirror-words, since the early stages of processing mirror-letters and mirror-words produced effects on target word recognition that were highly similar to the effects produced by identical primes (N250 component). In a posterior stage of processing (N400 epoch), the effect of mirror-letters and mirror-words was different from the effect of identical primes, even though reversed primes still elicited N400 priming effects different from unrelated primes. These results demonstrate that readers perceive mirror-letters and words as correct at initial stages of word recognition, and that the visual word recognition system's neural representation is grounded on basic principles that govern object perception. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. Light Weight Silicon Mirrors for Space Instrumentation

    Science.gov (United States)

    Bly, Vincent T.; Hill, Peter C.; Hagopian, John G.; Strojay, Carl R.; Miller, Timothy

    2012-01-01

    Each mirror is a monolithic structure from a single crystal of silicon. The mirrors are light weighted after the optical surface is ground and polished. Mirrors made during the initial phase of this work were typically 1/50 lambda or better (RMS at 633 n m)

  13. EUV multilayer mirror, optical system including a multilayer mirror and method of manufacturing a multilayer mirror

    NARCIS (Netherlands)

    Huang, Qiushi; Louis, Eric; Bijkerk, Frederik; de Boer, Meint J.; von Blanckenhagen, G.

    2016-01-01

    A multilayer mirror (M) reflecting extreme ultraviolet (EUV) radiation from a first wave-length range in a EUV spectral region comprises a substrate (SUB) and a stack of layers (SL) on the substrate, the stack of layers comprising layers comprising a low index material and a high index material, the

  14. 313 MHz repetition rate mode-locked Yb:fiber laser with phase-biased nonlinear amplifying loop mirror

    Science.gov (United States)

    Liu, Guanyu; Jiang, Xinghe; Wang, Bo; Jiang, Tongxiao; Wang, Aimin; Zhang, Zhigang

    2017-08-01

    We demonstrate a self-starting 313 MHz repetition rate, 77 fs Yb:fiber laser incorporated with a phase-biased nonlinear amplifying loop mirror and intra-cavity dispersion compensation. Although all of the fibers are non-polarization-maintaining, the mode locking is environmentally stable.

  15. Cavity-enhanced absorption spectroscopy of methane at 1.73 μm

    Science.gov (United States)

    Barry, H. R.; Corner, L.; Hancock, G.; Peverall, R.; Ritchie, G. A. D.

    2001-01-01

    The integrated cavity output spectroscopy technique has been applied to the study of methane near 1.73 μm using a tunable diode laser. We have shown that this simple approach produces accurate high resolution spectra and have achieved a detection sensitivity of 1.8×10 -7 cm -1 for mirror reflectivities of 99.84%.

  16. Cavity ring-down technique for measurement of reflectivity of high ...

    Indian Academy of Sciences (India)

    Abstract. A simple, accurate and reliable method for measuring the reflectivity of laser- grade mirrors (R > 99.5%) based on cavity ring-down (CRD) technique has been success- fully demonstrated in our laboratory using a pulsed Nd:YAG laser. A fast photomultiplier tube with an oscilloscope was used to detect and analyse ...

  17. Bloch-wave engineering of quantum dot-micropillars for cavity quantum electrodynamics experiments

    DEFF Research Database (Denmark)

    Lermer, Matthias; Gregersen, Niels; Dunzer, Florian

    2012-01-01

    We have employed Bloch-wave engineering to realize submicron diameter ultra-high quality factor GaAs/AlAs micropillars (MPs). The design features a tapered cavity in which the fundamental Bloch mode is subject to an adiabatic transition to match the Bragg mirror Bloch mode. The resulting reduced...

  18. Cavity ring-down technique for measurement of reflectivity of high ...

    Indian Academy of Sciences (India)

    grade mirrors ( > 99.5 %) based on cavity ring-down (CRD) technique has been success-fully demonstrated in our laboratory using a pulsed Nd:YAG laser. A fast photomultiplier tube with an oscilloscope was used to detect and analyse the CRD ...

  19. Photothermal optomechanics in superfluid helium coupled to a fiber-based cavity

    CERN Document Server

    Kashkanova, A D; Brown, C D; Flowers-Jacobs, N E; Childress, L; Hoch, S W; Hohmann, L; Ott, K; Reichel, J; Harris, J G E

    2016-01-01

    Presented in this paper are measurements of an optomechanical device in which various acoustic modes of a sample of superfluid helium couple to a fiber-based optical cavity. In contrast with recent work on the paraxial acoustic mode confined by the cavity mirrors, we focus specifically on the acoustic modes associated with the helium surrounding the cavity. This paper provides a framework for understanding how the acoustic modes depend on device geometry. The acoustic modes are observed using the technique of optomechanically induced transparency/amplification. The optomechanical coupling to these modes is found to be predominantly photothermal.

  20. Selecting detection wavelength of resonant cavity-enhanced photodetectors by guided-mode resonance reflectors.

    Science.gov (United States)

    Lai, Kuo-Wei; Lee, Yi-Shan; Fu, Ying-Jhe; Lin, Sheng-Di

    2012-02-13

    We propose and demonstrate a novel device structure of resonant cavity-enhanced photodetector (RCE-PD). The new RCE-PD structure consists of a bottom distributed Bragg reflector (DBR), a cavity with InGaAs multiple quantum wells (MQWs) for light absorption and a top mirror of sub-wavelength grating. By changing the fill factor of the 2-D grating, the effective cavity length of RCE-PDs can be varied so the resonant wavelength can be selected post growth. Accordingly, we can fabricate an array of PDs on a single chip, on which every PD aims for a specific wavelength.

  1. OPTICAL PARAMETRIC OSCILLATORS: Optimal feedback in efficient single-cavity optical parametric oscillators

    Science.gov (United States)

    Petnikova, V. M.; Shuvalov, Vladimir V.

    2010-09-01

    An approach based on the description of competition of quadratic processes of merging and decomposition of quanta resulting in the formation of cnoidal waves on an effective cascade cubic Kerr-type nonlinearity is used to optimise the scheme of a single-cavity optical parametric oscillator. It is shown that the use of a feedback circuit (cavity) decreases the period of cnoidal waves produced in a nonlinear crystal, while the optimisation procedure of the transfer constant of this circuit (reflectivity of the output mirror of the cavity) is reduced to matching this period with the nonlinear crystal length.

  2. Harmonic Distortion in CMOS Current Mirrors

    DEFF Research Database (Denmark)

    Bruun, Erik

    1998-01-01

    One of the origins of harmonic distortion in CMOS current mirrors is the inevitable mismatch between the MOS transistors involved. In this paper we examine both single current mirrors and complementary class AB current mirrors and develop an analytical model for the mismatch induced harmonic...... distortion. This analytical model is verified through simulations and is used for a discussion of the impact of mismatch on harmonic distortion properties of CMOS current mirrors. It is found that distortion levels somewhat below 1% can be attained by carefully matching the mirror transistors but ultra low...

  3. Development of ATHENA mirror modules

    Science.gov (United States)

    Collon, Maximilien J.; Vacanti, Giuseppe; Barrière, Nicolas M.; Landgraf, Boris; Günther, Ramses; Vervest, Mark; van der Hoeven, Roy; Dekker, Danielle; Chatbi, Abdel; Girou, David; Sforzini, Jessica; Beijersbergen, Marco W.; Bavdaz, Marcos; Wille, Eric; Fransen, Sebastiaan; Shortt, Brian; Haneveld, Jeroen; Koelewijn, Arenda; Booysen, Karin; Wijnperle, Maurice; van Baren, Coen; Eigenraam, Alexander; Müller, Peter; Krumrey, Michael; Burwitz, Vadim; Pareschi, Giovanni; Massahi, Sonny; Christensen, Finn E.; Della Monica Ferreira, Desirée.; Valsecchi, Giuseppe; Oliver, Paul; Checquer, Ian; Ball, Kevin; Zuknik, Karl-Heinz

    2017-08-01

    Silicon Pore Optics (SPO), developed at cosine with the European Space Agency (ESA) and several academic and industrial partners, provides lightweight, yet stiff, high-resolution x-ray optics. This technology enables ATHENA to reach an unprecedentedly large effective area in the 0.2 - 12 keV band with an angular resolution better than 5''. After developing the technology for 50 m and 20 m focal length, this year has witnessed the first 12 m focal length mirror modules being produced. The technology development is also gaining momentum with three different radii under study: mirror modules for the inner radii (Rmin = 250 mm), outer radii (Rmax = 1500 mm) and middle radii (Rmid = 737 mm) are being developed in parallel.

  4. Nine toes; Mirror Foot Deformity

    Directory of Open Access Journals (Sweden)

    Aleksandar M Vlahovic

    2015-01-01

    Full Text Available Mirror foot is a very rare congenital anomaly, with only a few papers presenting definitive treatment for this entity. There are limited management recommendations. Most cases are treated before walking age. In our case, there were no associated developmental defects of the leg. The child underwent complex rays resection with medial foot reconstruction. After 7.5 years of followup, definitive surgical treatment was performed with satisfactory cosmetic and functional outcome.

  5. Dynamics of a broad-area diode laser with lateral-mode-selected long-cavity feedback

    DEFF Research Database (Denmark)

    Chi, Mingjun; Petersen, Paul Michael

    2014-01-01

    The temporal dynamics of a broad-area diode laser with lateral-mode-selected long-cavity feedback is studied experimentally. Different dynamics are observed when different lateral modes are selected. When the feedback mirror is aligned perfectly and high-order modes are selected, in most of the c......The temporal dynamics of a broad-area diode laser with lateral-mode-selected long-cavity feedback is studied experimentally. Different dynamics are observed when different lateral modes are selected. When the feedback mirror is aligned perfectly and high-order modes are selected, in most....... When the feedback mirror is aligned non-perfectly, pulse-package oscillation is observed, for the first time to our knowledge, in a diode laser with long-cavity feedback....

  6. Experimental investigation of cavity flows

    Energy Technology Data Exchange (ETDEWEB)

    Loeland, Tore

    1998-12-31

    This thesis uses LDV (Laser Doppler Velocimetry), PIV (Particle Image Velocimetry) and Laser Sheet flow Visualisation to study flow inside three different cavity configurations. For sloping cavities, the vortex structure inside the cavities is found to depend upon the flow direction past the cavity. The shape of the downstream corner is a key factor in destroying the boundary layer flow entering the cavity. The experimental results agree well with numerical simulations of the same geometrical configurations. The results of the investigations are used to find the influence of the cavity flow on the accuracy of the ultrasonic flowmeter. A method to compensate for the cavity velocities is suggested. It is found that the relative deviation caused by the cavity velocities depend linearly on the pipe flow. It appears that the flow inside the cavities should not be neglected as done in the draft for the ISO technical report on ultrasonic flowmeters. 58 refs., 147 figs., 2 tabs.

  7. Practical Considerations on the Multi-layer Mirrors for Superluminal Ring Laser Gyroscopes

    Science.gov (United States)

    Wang, Zhiguo; Yuan, Baolun

    2015-07-01

    We have created a simple model to analyze the restrictions on superluminal ring laser gyroscopes arising from the absorption of coating materials. For a ring laser gyroscope with a cavity length of 15 cm, the scale factor enhancement is nearly impossible due to absorption from the high dispersion mirror. In order to obtain a practical superluminal ring laser gyroscope, the extinction coefficient of coating materials should be less than 1E-10, which is a challenge at present.

  8. Mirror agnosia and the mirrored-self misidentification delusion: a hypnotic analogue.

    Science.gov (United States)

    Connors, Michael H; Cox, Rochelle E; Barnier, Amanda J; Langdon, Robyn; Coltheart, Max

    2012-05-01

    Mirrored-self misidentification is the delusional belief that one's reflection in the mirror is a stranger. Current theories suggest that one pathway to the delusion is mirror agnosia (a deficit in which patients are unable to use mirror knowledge when interacting with mirrors). This study examined whether a hypnotic suggestion for mirror agnosia can recreate features of the delusion. Ten high hypnotisable participants were given either a suggestion to not understand mirrors or to see the mirror as a window. Participants were asked to look into a mirror and describe what they saw. Participants were tested on their understanding of mirrors and received a series of challenges. Participants then received a detailed postexperimental inquiry. Three of five participants given the suggestion to not understand mirrors reported seeing a stranger and maintained this belief when challenged. These participants also showed signs of mirror agnosia. No participants given the suggestion to see a window reported seeing a stranger. Results indicate that a hypnotic suggestion for mirror agnosia can be used to recreate the mirrored-self misidentification delusion. Factors influencing the effectiveness of hypnotic analogues of psychopathology, such as participants' expectations and interpretations, are discussed.

  9. Alice Munro's "Runaway" in the Mirror of Sigmund Freud

    Directory of Open Access Journals (Sweden)

    Raheleh Bahador

    2015-03-01

    Full Text Available Mirroring the complexities of the human psyche, literature has received new comprehension through a psychoanalytic lens.  Alice Munro's "Runaway" (2003 is character-based and has the psychological analysis potential but it had never received such kind of study. The objective of the present paper is to read Munro's "Runaway" in the mirror of Sigmund Freud to detect the psychological aspects of its fictional characters. The characters are driven by the Freudian mental agencies and undergo phases of psychic disorder.  In the present paper, Munro's short fiction has been discussed based on Sigmund Freud's theory of the Unconscious and its connection with the interpretation of dreams as well as the symbolization of three main characters based on tripartite agencies of the id, ego and superego. Clarifying the latent and manifest levels of characters and the world of dreams indicates the artistic creation of Alice Munro in handling complex characterization. The unconscious and its connection with the female character's dreams have been discussed. The unconscious of the female character is reflected in her dreams in result of repression and asocial drives and desires. Unconscious through dreams is the mirror of the repressed psyche of the female character. Scrutinizing the three main characters in terms of Freudian psychic trilogy, they prove to fit their psychological Freudian terms.

  10. Continuously tunable pulsed Ti:Sa laser self-seeded by an extended grating cavity

    CERN Document Server

    Li, Ruohong; Rothe, Sebastian; Teigelhöfer, Andrea; Mostamand, Maryam

    2016-01-01

    A continuously tunable titanium:sapphire (Ti:Sa) laser self-seeded by an extended grating cavity was demonstrated and characterized. By inserting a partially reflecting mirror inside the cavity of a classic single-cavity grating laser, two oscillators are created: a broadband power oscillator, and a narrowband oscillator with a prism beam expander and a diffraction grating in Littrow configuration. By coupling the grating cavity oscillation into the power oscillator, a power-enhanced narrow-linewidth laser oscillation is achieved. Compared to the classic grating laser, this simple modification significantly increases the laser output power without considerably broadening the linewidth. With most of the oscillating laser power confined inside the broadband power cavity and lower power incident onto the grating, the new configuration also allows higher pump power, which is typically limited by the thermal deformation of the grating coating at high oscillation power.

  11. Filling a Conical Cavity

    Science.gov (United States)

    Nye, Kyle; Eslam-Panah, Azar

    2016-11-01

    Root canal treatment involves the removal of infected tissue inside the tooth's canal system and filling the space with a dense sealing agent to prevent further infection. A good root canal treatment happens when the canals are filled homogeneously and tightly down to the root apex. Such a tooth is able to provide valuable service for an entire lifetime. However, there are some examples of poorly performed root canals where the anterior and posterior routes are not filled completely. Small packets of air can be trapped in narrow access cavities when restoring with resin composites. Such teeth can cause trouble even after many years and lead the conditions like acute bone infection or abscesses. In this study, the filling of dead-end conical cavities with various liquids is reported. The first case studies included conical cavity models with different angles and lengths to visualize the filling process. In this investigation, the rate and completeness at which a variety of liquids fill the cavity were observed to find ideal conditions for the process. Then, a 3D printed model of the scaled representation of a molar with prepared post spaces was used to simulate the root canal treatment. The results of this study can be used to gain a better understanding of the restoration for endodontically treated teeth.

  12. SPS accelerating cavity

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    See photo 8302397: View from the downstream end of one of the SPS accelerating cavities (200 MHz, travelling wave structure). See 7603195 and 8011289 for more details, 7411032 for the travelling wave structure, and also 8104138. Giacomo Primadei stands on the left.

  13. Cavities/Tooth Decay

    Science.gov (United States)

    ... sharp pain when eating or drinking something sweet, hot or cold Visible holes or pits in your teeth Brown, black or white staining on any surface of a tooth Pain when you bite down When to see a dentist You may not be aware that a cavity is forming. That's why it's important to have regular dental ...

  14. Niobium superconducting cavity

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    This 5-cell superconducting cavity, made from bulk-Nb, stems from the period of general studies, not all directed towards direct use at LEP. This one is dimensioned for 1.5 GHz, the frequency used at CEBAF and also studied at Saclay (LEP RF was 352.2 MHz). See also 7908227, 8007354, 8209255, 8210054, 8312339.

  15. Additive Manufactured Superconducting Cavities

    Science.gov (United States)

    Holland, Eric; Rosen, Yaniv; Woolleet, Nathan; Materise, Nicholas; Voisin, Thomas; Wang, Morris; Mireles, Jorge; Carosi, Gianpaolo; Dubois, Jonathan

    Superconducting radio frequency cavities provide an ultra-low dissipative environment, which has enabled fundamental investigations in quantum mechanics, materials properties, and the search for new particles in and beyond the standard model. However, resonator designs are constrained by limitations in conventional machining techniques. For example, current through a seam is a limiting factor in performance for many waveguide cavities. Development of highly reproducible methods for metallic parts through additive manufacturing, referred to colloquially as 3D printing\\x9D, opens the possibility for novel cavity designs which cannot be implemented through conventional methods. We present preliminary investigations of superconducting cavities made through a selective laser melting process, which compacts a granular powder via a high-power laser according to a digitally defined geometry. Initial work suggests that assuming a loss model and numerically optimizing a geometry to minimize dissipation results in modest improvements in device performance. Furthermore, a subset of titanium alloys, particularly, a titanium, aluminum, vanadium alloy (Ti - 6Al - 4V) exhibits properties indicative of a high kinetic inductance material. This work is supported by LDRD 16-SI-004.

  16. LEP superconducting cavity

    CERN Multimedia

    1995-01-01

    Engineers work in a clean room on one of the superconducting cavities for the upgrade to the LEP accelerator, known as LEP-2. The use of superconductors allow higher electric fields to be produced so that higher beam energies can be reached.

  17. Mirror Metrology Using Nano-Probe Supports

    Science.gov (United States)

    Robinson, David; Hong, Maoling; Byron, Glenn; McClelland, Ryan; Chan, Kai-Wing

    2012-01-01

    Thin, lightweight mirrors are needed for future x-ray space telescopes in order to increase x-ray collecting area while maintaining a reduced mass and volume capable of being launched on existing rockets. However, it is very difficult to determine the undistorted shape of such thin mirrors because the mounting of the mirror during measurement causes distortion. Traditional kinematic mounts have insufficient supports to control the distortion to measurable levels and prevent the mirror from vibrating during measurement. Over-constrained mounts (non-kinematic) result in an unknown force state causing mirror distortion that cannot be determined or analytically removed. In order to measure flexible mirrors, it is necessary to over-constrain the mirror. Over-constraint causes unknown distortions to be applied to the mirror. Even if a kinematic constraint system can be used, necessary imperfections in the kinematic assumption can lead to an unknown force state capable of distorting the mirror. Previously, thicker, stiffer, and heavier mirrors were used to achieve low optical figure distortion. These mirrors could be measured to an acceptable level of precision using traditional kinematic mounts. As lighter weight precision optics have developed, systems such as the whiffle tree or hydraulic supports have been used to provide additional mounting supports while maintaining the kinematic assumption. The purpose of this invention is to over-constrain a mirror for optical measurement without causing unacceptable or unknown distortions. The invention uses force gauges capable of measuring 1/10,000 of a Newton attached to nano-actuators to support a thin x-ray optic with known and controlled forces to allow for figure measurement and knowledge of the undeformed mirror figure. The mirror is hung from strings such that it is minimally distorted and in a known force state. However, the hanging mirror cannot be measured because it is both swinging and vibrating. In order to

  18. Effect of In-plane Mirror Dispersion on Vertical Cavities Based on High-Contrast Grating Mirrors

    DEFF Research Database (Denmark)

    Taghizadeh, Alireza; Mørk, Jesper; Chung, Il-Sug

    2015-01-01

    We report how the in-plane dispersion of a high-index-contrast grating reflector influences the transverse mode properties such as shorter wavelengths for lower-order transverse modes and different transverse-mode wavelength spacings for modes with the same size.......We report how the in-plane dispersion of a high-index-contrast grating reflector influences the transverse mode properties such as shorter wavelengths for lower-order transverse modes and different transverse-mode wavelength spacings for modes with the same size....

  19. Damage characteristics of the optical element in resonant cavity irradiated by high-power continuous-wave laser

    Science.gov (United States)

    Lou, Zhaokai; Han, Kai; Song, Rui; Yan, Baozhu; Liu, Zejin

    2017-05-01

    In order to study the damage characteristic of the contaminated resonating mirror in high power continuous wave (cw) laser system, we established a theoretical model based on the optical transmission theory with a gain medium. The optical propagation in the cavity is calculated utilizing a Fast Fourier Transform (FFT) repeatedly until the convergence of the calculations tend to a steady-state oscillation mode pattern. The influence of the contaminant size, the contaminant number and the cavity structure on the damage characteristic of the resonating mirror is studied in the theoretical model.

  20. Thermal effects in high power cavities for photoneutralization of D{sup −} beams in future neutral beam injectors

    Energy Technology Data Exchange (ETDEWEB)

    Fiorucci, Donatella; Feng, Jiatai; Pichot, Mikhaël; Chaibi, Walid, E-mail: chaibi@oca.eu [ARTEMIS, Université de Nice Sophia Antipolis, Observatoire de la Côte d' Azur and Centre National de la Recherche Scientifique, Boulevard de l' Observatoire - CS 34229 - F 06304 (France)

    2015-04-08

    Photoneutralization may represent a key issue in the neutral beam injectors for future fusion reactors. In fact, photodetachment based neutralization combined with an energy recovery system increase the injector overall efficiency up to 60%. This is the SIPHORE injector concept in which photoneutralization is realized in a refolded cavity [1]. However, about 1 W of the several megaWatts intracavity power is absorbed by the mirrors coatings and gives rise to important thermoelastic distortions. This is expected to change the optical behavior of the mirrors and reduce the enhancement factor of the cavity. In this paper, we estimate these effects and we propose a thermal system to compensate it.

  1. Theory of wakefields in a dielectric-filled cavity

    Directory of Open Access Journals (Sweden)

    J. H. Kim

    2010-07-01

    Full Text Available An analytical solution of a wakefield from a charge moving on the axis of a dielectric-filled cylindrical cavity is derived. A solution to the wakefield in a waveguide with only a boundary at the cavity entrance is already known. To take into account a boundary at the cavity exit, we introduce an imaginary antibeam, with opposite charge, which is created at the same time when the beam passes the exit boundary and continues to move along with the original beam at the same velocity. Although the beam has been annihilated in the net effect, the original beam and the antibeam produce their own wakefields, respectively, because they were created at different times. These superimposed fields are then mirror reflected as usual by the conducting exit boundary and the wakefield can be obtained by properly mirror reflecting them whenever it reaches a boundary. We find a resonance condition to enhance wakefields with multiple bunches of charges, and show that the acceleration gradient increases under that condition.

  2. Changeability of Oral Cavity Environment

    OpenAIRE

    Surdacka, Anna; Strzyka?a, Krystyna; Rydzewska, Anna

    2007-01-01

    Objectives In dentistry, the results of in vivo studies on drugs, dental fillings or prostheses are routinely evaluated based on selected oral cavity environment parameters at specific time points. Such evaluation may be confounded by ongoing changes in the oral cavity environment induced by diet, drug use, stress and other factors. The study aimed to confirm oral cavity environment changeability. Methods 24 healthy individuals aged 20?30 had their oral cavity environment prepared by having p...

  3. Tandem mirror technology demonstration facility

    Energy Technology Data Exchange (ETDEWEB)

    1983-10-01

    This report describes a facility for generating engineering data on the nuclear technologies needed to build an engineering test reactor (ETR). The facility, based on a tandem mirror operating in the Kelley mode, could be used to produce a high neutron flux (1.4 MW/M/sup 2/) on an 8-m/sup 2/ test area for testing fusion blankets. Runs of more than 100 h, with an average availability of 30%, would produce a fluence of 5 mW/yr/m/sup 2/ and give the necessary experience for successful operation of an ETR.

  4. Mirrors, mirrors on the wall…the ubiquitous multiple reflection error.

    Science.gov (United States)

    Lawson, Rebecca

    2012-01-01

    Participants decided when somebody, Janine, could see their face in a horizontal row of adjacent mirrors mounted flat on the same wall. They saw real mirrors and a shop-dummy representing Janine. Such coplanar mirrors reflect different, non-overlapping areas of a scene. However, almost everybody made an unexpected error: they claimed that Janine would see her face reflected in multiple mirrors simultaneously. They therefore responded as if each mirror showed similar information and thus grossly overestimated how much each mirror revealed. Further studies established that this multiple reflection error also occurred for vertical rows of mirrors and for different areas of a single, large mirror. The error was even common if the participant themselves sat in front of a set of covered-up mirrors and indicated where they would be able to see their own reflection. In the latter case, people often made multiple reflection errors despite having seen all the mirrors uncovered immediately before they responded. People's gross overestimation of how much of a scene a mirror reflects and their inability to learn to correct this false belief explains why, despite a lifetime's experience of mirrors, they incorrectly think they will see themselves in all nearby mirrors. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Light weight silicon mirrors for space instrumentation

    Science.gov (United States)

    Bly, Vincent T.; Hill, Peter C.; Hagopian, John G.; Strojny, Carl R.; Miller, Timothy M.

    2012-10-01

    Each mirror produced by this NASA developed process is a monolithic structure from a single crystal of silicon. Due to single crystal silicon's extraordinary homogeneity and lack of internal stress, we light weight after optical polishing. Mirrors produced by our original process were about 1/4th the mass of an equivalent quartz mirror and were typically 1/50th wave or better. We have recently revised our process, replacing the isogrid structures with ones optimized to minimize distortion due to mounting errors. We have also switched from ultrasonic machining to CNC grinding to enable the production of larger mirrors. We report results to date for mirrors produced by the revised process and cryogenic test results for an ultrasonically light weighted mirror.

  6. Standard specification for silvered flat glass mirror

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This specification covers the requirements for silvered flat glass mirrors of rectangular shape supplied as cut sizes, stock sheets or as lehr ends and to which no further processing (such as edgework or other fabrication) has been done. 1.2 This specification covers the quality requirements of silvered annealed monolithic clear and tinted flat glass mirrors up to 6 mm (¼ in.) thick. The mirrors are intended to be used indoors for mirror glazing, for components of decorative accessories or for similar uses. 1.3 This specification does not address safety glazing materials nor requirements for mirror applications. Consult model building codes and other applicable standards for safety glazing applications. 1.4 Mirrors covered in this specification are not intended for use in environments where high humidity or airborne corrosion promoters, or both, are consistently present (such as swimming pool areas, ocean-going vessels, chemical laboratories and other corrosive environments). 1.5 The dimensional val...

  7. Optimization of photonic crystal cavities

    DEFF Research Database (Denmark)

    Wang, Fengwen; Sigmund, Ole

    2017-01-01

    We present optimization of photonic crystal cavities. The optimization problem is formulated to maximize the Purcell factor of a photonic crystal cavity. Both topology optimization and air-hole-based shape optimization are utilized for the design process. Numerical results demonstrate...... that the Purcell factor of the photonic crystal cavity can be significantly improved through optimization....

  8. MIRROR THERAPY: A REVIEW OF EVIDENCES

    OpenAIRE

    Aishath Najiha; Jagatheesan Alagesan; Vandana J. Rathod; Poongundran Paranthaman

    2015-01-01

    The aim of this review was to identify and summarize the existing evidences on mirror box therapy for the management of various musculoskeletal conditions. A systemic literature search was performed to identify studies concerning mirror therapy. The included journal articles were reviewed and assessed for its significance. Fifty one studies were identified and reviewed. Five different patient categories were studied: 24 studies focussed on mirror therapy after stroke, thirteen studies focusse...

  9. Gain-assisted broadband ring cavity enhanced spectroscopy

    Science.gov (United States)

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

    2017-02-01

    Incoherent broadband cavity enhanced spectroscopy can significantly increase the effective path length of light-matter interaction to detect weak absorption lines over broad spectral range, for instance to detect gases in confined environments. Broadband cavity enhancement can be based on the decay time or the intensity drop technique. Decay time measurement is based on using tunable laser source that is expensive and suffers from long scan time. Intensity dependent measurement is usually reported based on broadband source using Fabry-Perot cavity, enabling short measurement time but suffers from the alignment tolerance of the cavity and the cavity insertion loss. In this work we overcome these challenges by using an alignment-free ring cavity made of an optical fiber loop and a directional coupler, while having a gain medium pumped below the lasing threshold to improve the finesse and reduce the insertion loss. Acetylene (C2H2) gas absorption is measured around 1535 nm wavelength using a semiconductor optical amplifier (SOA) gain medium. The system is analyzed for different ring resonator forward coupling coefficient and loses, including the 3-cm long gas cell insertion loss and fiber connector losses used in the experimental verification. The experimental results are obtained for a coupler ratio of 90/10 and a fiber length of 4 m. The broadband source is the amplified spontaneous emission of another SOA and the output is measured using a 70pm-resolution optical spectrum analyzer. The absorption depth and the effective interaction length are improved about an order of magnitude compared to the direct absorption of the gas cell. The presented technique provides an engineering method to improve the finesse and, consequently the effective length, while relaxing the technological constraints on the high reflectivity mirrors and free-space cavity alignment.

  10. Digital Cavity Resonance Monitor, alternative method of measuring cavity microphonics

    Energy Technology Data Exchange (ETDEWEB)

    Tomasz Plawski; G. Davis; Hai Dong; J. Hovater; John Musson; Thomas Powers

    2005-09-20

    As is well known, mechanical vibration or microphonics in a cryomodule causes the cavity resonance frequency to change at the vibration frequency. One way to measure the cavity microphonics is to drive the cavity with a Phase Locked Loop. Measurement of the instantaneous frequency or PLL error signal provides information about the cavity microphonic frequencies. Although the PLL error signal is available directly, precision frequency measurements require additional instrumentation, a Cavity Resonance Monitor (CRM). The analog version of such a device has been successfully used for several cavity tests [1]. In this paper we present a prototype of a Digital Cavity Resonance Monitor designed and built in the last year. The hardware of this instrument consists of an RF downconverter, digital quadrature demodulator and digital processor motherboard (Altera FPGA). The motherboard processes received data and computes frequency changes with a resolution of 0.2 Hz, with a 3 kHz output bandwidth.

  11. Colloquium: cavity optomechanics

    CERN Multimedia

    2011-01-01

    Monday 14 November 2011, 17:00 Ecole de Physique, Auditoire Stueckelberg Université de Genève Cavity optomechanics: controlling micro mechanical oscillators with laser light Prof. Tobias Kippenberg EPFL, Lausanne Laser light can be used to cool and to control trapped ions, atoms and molecules at the quantum level. This has lead to spectacular advances such as the most precise atomic clocks. An outstanding frontier is the control with lasers of nano- and micro-mechancial systems. Recent advances in cavity optomechanics have allowed such elementary control for the first time, enabling mechanical systems to be ground state cooled leading to readout with quantum limited sensitivity and permitting to explore new device concepts resulting from radiation pressure.  

  12. Cavity enhanced atomic magnetometry.

    Science.gov (United States)

    Crepaz, Herbert; Ley, Li Yuan; Dumke, Rainer

    2015-10-20

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage that they can be effectively coated inside with a spin relaxation suppressing layer providing long spin coherence times without addition of a buffer gas. Cavity enhancement shows in an increase in optical polarization rotation and sensitivity compared to single-pass configurations.

  13. Cavity enhanced atomic magnetometry

    CERN Document Server

    Crepaz, Herbert; Dumke, Rainer

    2015-01-01

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage that they can be effectively coated inside with a spin relaxation suppressing layer providing long spin coherence times without addition of a buffer gas. Cavity enhancement shows in an increase in optical polarization rotation and sensitivity compared to single-pass configurations.

  14. Mirror movements in progressive hemifacial atrophy

    Directory of Open Access Journals (Sweden)

    Rajesh Verma

    2015-01-01

    Full Text Available Mirror movements are simultaneous, involuntary, identical movements occurring during contralateral voluntary movements. These movements are considered as soft neurologic signs seen uncommonly in clinical practice. The mirror movements are described in various neurological disorders which include parkinsonism, cranio veretebral junction anamolies, and hemiplegic cerebral palsy. These movements are intriguing and can pose significant disability. However, no such observation regarding mirror movements in progressive hemifacial atrophy have been reported previously. We are reporting a teenage girl suffering from progressive hemifacial atrophy and epilepsy with demonstrable mirror movements in hand.

  15. Single Crystal Silicon Mirrors for Spaceflight Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop a well understood process for manufacturing visible quality SCSi mirrors. Areas of research include stress relief, figure, finish, and light weighting...

  16. Neurodegeneration and Mirror Image Agnosia

    Science.gov (United States)

    Chandra, Sadanandavalli Retnaswami; Issac, Thomas Gregor

    2014-01-01

    Background: Normal Percept with abnormal meaning (Agnosias) has been described from nineteenth century onwards. Later literature became abundant with information on the spectrum of Prosopagnosias. However, selective difficulty in identifying reflected self images with relatively better cognitive functions leads to problems in differentiating it from non-organic psychosis. Aim: In the present study, we investigated patients with dementia who showed difficulty in identifying reflected self images while they were being tested for problems in gnosis with reference to identification of reflected objects, animals, relatives, and themselves and correlate with neuropsychological and radiological parameters. Patients and Methods: Five such patients were identified and tested with a 45 cm × 45 cm mirror kept at 30-cm distance straight ahead of them. Results: Mirror image agnosia is seen in patients with moderate stage posterior dementias who showed neuropsychological and radiological evidence of right parietal dysfunction. Conclusion: Interpretation of reflected self images perception in real time probably involves distinct data-linking circuits in the right parietal lobe, which may get disrupted early in the course of the disease. PMID:25317393

  17. Barstow heliostat mirror glass characterization

    Energy Technology Data Exchange (ETDEWEB)

    Lind, M.A.; Buckwalter, C.Q.

    1980-09-01

    The technical analysis performed on the special run of low iron float glass procured from the Ford Glass Division for the ten megawatt solar thermal/electric pilot power plant to be constructed at Barstow, California is discussed. The topics that are addressed include the optical properties and the relative durability of the glass. Two optical parameters, solar transmittance and optical flatness, were measured as referenced in the specification and found to be better than the stated tolerances. The average solar transmittance exceeded 0.890 transmittance units. The glass also exhibited optical angular flatness deviations less than +-1.0 mrad as required. Both qualitative and quantitative accelerated weathering tests were performed on the glass in order to compare its durability to other soda lime float glass and alternate composition glasses of interest to the solar community. In both the quantitative leaching experiments and the more qualitative room temperature and elevated temperature water vapor exposure experiments the heliostat glass exhibited the same characteristics as the other soda-lime silicate float glasses. As a final test for mirroring compatability, selected samples of the production run of the glass were sent to four different commercial manufacturers for mirror coating. None of the manufacturers reported any difficulty silvering the glass. Based on the tests performed, the glass meets or exceeds all optical specifications for the Barstow heliostat field.

  18. Explaining mirror-touch synesthesia.

    Science.gov (United States)

    Ward, Jamie; Banissy, Michael J

    2015-01-01

    Mirror-touch synesthesia (MTS) is the conscious experience of tactile sensations induced by seeing someone else touched. This paper considers two different, although not mutually exclusive, theoretical explanations and, in the final section, considers the relation between MTS and other forms of synesthesia and also other kinds of vicarious perception (e.g., contagious yawning). The Threshold Theory explains MTS in terms of hyper-activity within a mirror system for touch and/or pain. This offers a good account for some of the evidence (e.g., from fMRI) but fails to explain the whole pattern (e.g., structural brain differences outside of this system; performance on some tests of social cognition). The Self-Other Theory explains MTS in terms of disturbances in the ability to distinguish the self from others. This can be construed in terms of over-extension of the bodily self in to others, or as difficulties in the control of body-based self-other representations. In this account, MTS is a symptom of a broader cognitive profile. We suggest this meets the criteria for synesthesia, despite the proximal causal mechanisms remaining largely unknown, and that the tendency to localize vicarious sensory experiences distinguishes it from other kinds of seemingly related phenomena (e.g., non-localized affective responses to observing pain).

  19. Schroedinger’s Mirrors - exploring mechanical motion in the quantum regime

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    The quantum optical control of solid-state mechanical devices, quantum optomechanics, has emerged as a new frontier of light-matter interactions. Devices currently under investigation cover a mass range of more than 17 orders of magnitude - from nanomechanical waveguides of some picograms to macroscopic, kilogram-weight mirrors of gravitational wave detectors. This development has been enabled by the insight that quantum optics provides a powerful toolbox to generate, manipulate and detect quantum states of mechanical motion, in particular by coupling the mechanics to an optical or microwave cavity field. Originally, such cavity optomechanical systems have been studied from the early 1970s on in the context of gravitational wave antennas. Advancements in micro-fabrication and micro-cavities, however, have resulted in the development of a completely new generation of nano- and micro-optomechanical devices. Today, 10 years after the first demonstrations of laser cooling of micromechanical resonators, the quantu...

  20. Analysis and design of bridge structure for a micro Fabry-Perot cavity

    Science.gov (United States)

    Li, Yuanyuan; Meng, Qinghua; Chen, Sihai; Dong, Yuming

    2016-03-01

    Abstract—This paper describes a MEMS-based tunable Fabry-Perot filter that can be directly integrated on a detector. The Fabry-Perot filter consists of two parallel mirrors and lets the light with particular wavelength pass through. The wavelength depends on the gap between the mirrors. The gap of the micromechanical Fabry-Perot filter can be changed by applying a voltage to the mirrors, an electrostatic force inducing an attraction between the substrate and the top mirror. Based on the comprehensive analysis of the working principle of the micro F-P cavity filter, the optimum tuning scheme of micro F-P cavity filter is established. A simulation of the mechanical behavior was performed based on finite elements, using ANSYS software. We finally establish the L-arm type cantilever to support cavity structure, the micro-bridge can achieve a considerable range of tuning; relatively high fill factor, filter light leakage is avoided; the high abilityto keep parallel can achieve high precision filtering effect; structural stability, it can resist the residual stress of manufacture. This MEMS F-P tunable filter can be a potential application in spectroscopic sensing and optical communication system.

  1. Ultra-short pulse generation in a linear femtosecond fiber laser using a Faraday rotator mirror and semiconductor saturable absorber mirror

    Science.gov (United States)

    Hekmat, M. J.; Gholami, A.; Omoomi, M.; Abdollahi, M.; Bagheri, A.; Normohammadi, H.; Kanani, M.; Ebrahimi, A.

    2018-02-01

    An innovative method for obtaining ultra-short and perfectly stable femtosecond pulses in a linear erbium-doped fiber laser is proposed. A commercial semiconductor saturable absorber mirror and a standard Faraday rotator are used in both sides of the linear fiber optic laser configuration to shorten the pulse duration and suppress undesirable effects on the polarization state. The laser operation is investigated theoretically using a physical model and it is verified using experimental results. The main idea of this research is to apply a Faraday rotator mirror for pulse shortening purposes. For this reason, two types of Er-doped fiber optics with different group velocity dispersion parameters are used to achieve the optimum net group velocity dispersion in the cavity. Output results demonstrate good consistency between theory and experimental results. The output power of the linear oscillator is approximately 45 mW with 135 fs pulses at the 23.5 MHz repetition rate without any pulse compression.

  2. Reflecting on Reflections : Cinema's Complex Mirror Shots

    NARCIS (Netherlands)

    Hanich, Julian; Beugnet, Martine; Cameron, Allan; Fetveit, Arild

    2017-01-01

    This article investigates the effects mirrors in films can have on the composition of a filmic image, the staging of a scene and the viewing activities of the spectators. It discusses four such effects: (1) So-called ‘complex mirror shots’ can modify how spectators look onto the picture as a flat

  3. Technology for large tandem mirror experiments

    Energy Technology Data Exchange (ETDEWEB)

    Thomassen, K.I.

    1980-09-04

    Construction of a large tandem mirror (MFTF-B) will soon begin at Lawrence Livermore National Laboratory (LLNL). Designed to reach break-even plasma conditions, the facility will significantly advance the physics and technology of magnetic-mirror-based fusion reactors. This paper describes the objectives and the design of the facility.

  4. LED structure with enhanced mirror reflectivity

    Science.gov (United States)

    Bergmann, Michael; Donofrio, Matthew; Heikman, Sten; Schneider, Kevin S; Haberern, Kevin W; Edmond, John A

    2014-04-01

    Embodiments of the present invention are generally related to LED chips having improved overall emission by reducing the light-absorbing effects of barrier layers adjacent mirror contacts. In one embodiment, a LED chip comprises one or more LEDs, with each LED having an active region, a first contact under the active region having a highly reflective mirror, and a barrier layer adjacent the mirror. The barrier layer is smaller than the mirror such that it does not extend beyond the periphery of the mirror. In another possible embodiment, an insulator is further provided, with the insulator adjacent the barrier layer and adjacent portions of the mirror not contacted by the active region or by the barrier layer. In yet another embodiment, a second contact is provided on the active region. In a further embodiment, the barrier layer is smaller than the mirror such that the periphery of the mirror is at least 40% free of the barrier layer, and the second contact is below the first contact and accessible from the bottom of the chip.

  5. LHCb ring imaging Cherenkov detector mirrors

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    In a large dark room, men in white move around an immense structure some 7 m high, 10 m wide and nearly 2.5 m deep. Apparently effortlessly, they are installing the two large high-precision spherical mirrors. These mirrors will focus Cherenkov light, created by the charged particles that will traverse this detector, onto the photon detectors.

  6. Mirror QCD and Cosmological Constant

    Directory of Open Access Journals (Sweden)

    Roman Pasechnik

    2017-05-01

    Full Text Available An analog of Quantum Chromo Dynamics (QCD sector known as mirror QCD (mQCD can affect the cosmological evolution due to a non-trivial contribution to the Cosmological Constant analogous to that induced by the ground state in non-perturbative QCD. In this work, we explore a plausible hypothesis for trace anomalies cancellation between the usual QCD and mQCD. Such an anomaly cancellation between the two gauge theories, if it exists in Nature, would lead to a suppression or even elimination of their contributions to the Cosmological Constant. The trace anomaly compensation condition and the form of the non-perturbative mQCD coupling constant in the infrared limit have been proposed by analysing a partial non-perturbative solution of the Einstein–Yang-Mills equations of motion.

  7. New generation of one-dimensional photonic crystal cavities as robust high-efficient frequency converter

    Science.gov (United States)

    Parvini, T. S.; Tehranchi, M. M.; Hamidi, S. M.

    2017-07-01

    An effective method is proposed to design finite one-dimensional photonic crystal cavities (PhCCs) as robust high-efficient frequency converter. For this purpose, we consider two groups of PhCCs which are constructed by stacking m nonlinear (LiNbO3) and n linear (air) layers with variable thicknesses. In the first group, the number of linear layers is less than the nonlinear layers by one and in the second group by two. The conversion efficiency is calculated as a function of the arrangement and thicknesses of the linear and nonlinear layers by benefiting from nonlinear transfer matrix method. Our numerical simulations show that for each group of PhCCs, there is a structural formula by which the configurations with the highest efficiency can be constructed for any values of m and n (i.e. any number of layers). The efficient configurations are equivalent to Fabry-Pérot cavities that depend on the relationship between m and n and the mirrors in two sides of these cavities can be periodic or nonperiodic. The conversion efficiencies of these designed PhCCs are more than 5 orders of magnitude higher than the perfect ones which satisfy photonic bandgap edge and quasi-phase matching. Moreover, the results reveal that conversion efficiencies of Fabry-Pérot cavities with non-periodic mirrors are one order of magnitude higher than those with periodic mirrors. The major physical mechanisms of the enhancement are quasi-phase matching effect, cavity effect induced by dispersive mirrors, and double resonance for the pump and the harmonic fields in defect state. We believe that this method is very beneficial to the design of high-efficient compact optical frequency converters.

  8. Composite structures for optical mirror applications

    Science.gov (United States)

    Brand, Richard A.; Marks, John E.

    1990-10-01

    The employment of composites in RF structures such as antennas, feedhorns, and waveguides is outlined, and focus is placed on the parameters of a composite mirror operating in the 3-5- and 8-12-micron areas. A large beam-steering composite mirror fabricated from ultrahigh-modulus graphite/epoxy is described, including its three subassemblies: the core subassembly and two facesheet subassemblies. Attention is given to an alternative approach in which a gel coat resin is applied to the glass surface and the mirror substrate is pressed to the tool to cover the mirror with the resin. Another method is to seal the composite from the effects of moisture expansion by applying a eutectic coating; voids and crystal-grain growth are the main sources of surface perturbation on such mirror surfaces.

  9. DAMA annual modulation and mirror Dark Matter

    Energy Technology Data Exchange (ETDEWEB)

    Cerulli, R.; Cappella, F. [INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ (Italy); Villar, P. [Universidad de Zaragoza, Laboratorio de Fisica Nuclear y Astroparticulas, Saragossa (Spain); Laboratorio Subterraneo de Canfranc, Canfranc Estacion, Huesca (Spain); Bernabei, R.; Belli, P. [Universita di Roma ' ' Tor Vergata' ' , Dipartimento di Fisica, Rome (Italy); INFN ' ' Tor Vergata' ' , Rome (Italy); Incicchitti, A. [Universita di Roma ' ' La Sapienza' ' , Dipartimento di Fisica, Rome (Italy); INFN, Rome (Italy); Addazi, A.; Berezhiani, Z. [INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ (Italy); Universita di L' Aquila, Dipartimento di Scienze Fisiche e Chimiche, Coppito, AQ (Italy)

    2017-02-15

    The DAMA experiment using ultra low background NaI(Tl) crystal scintillators has measured an annual modulation effect in the keV region which satisfies all the peculiarities of an effect induced by Dark Matter particles. In this paper we analyze this annual modulation effect in terms of mirror Dark Matter, an exact duplicate of ordinary matter from parallel hidden sector, which chemical composition is dominated by mirror helium while it can also contain significant fractions of heavier elements as Carbon and Oxygen. Dark mirror atoms are considered to interact with the target nuclei in the detector via Rutherford-like scattering induced by kinetic mixing between mirror and ordinary photons, both being massless. In the present analysis we consider various possible scenarios for the mirror matter chemical composition. For all the scenarios, the relevant ranges for the kinetic mixing parameter have been obtained taking also into account various existing uncertainties in nuclear and particle physics quantities. (orig.)

  10. The rubber hand illusion in a mirror.

    Science.gov (United States)

    Bertamini, Marco; Berselli, Nausicaa; Bode, Carole; Lawson, Rebecca; Wong, Li Ting

    2011-12-01

    In the rubber hand illusion (RHI) one's hand is hidden, and a fake hand is visible. We explored the situation in which visual information was available indirectly in a mirror. In the mirror condition, compared to the standard condition (fake hand visible directly), we found no reduction of the RHI following synchronised stimulation, as measured by crossmanual pointing and by a questionnaire. We replicated the finding with a smaller mirror that prevented visibility of the face. The RHI was eliminated when a wooden block replaced the fake hand, or when the hand belonged to another person or mannequin. We conclude that awareness of the reflection is the critical variable, despite the distant visual localisation of the hand in a mirror and the third-person perspective. Stimuli seen in a mirror activate the same response as stimuli seen in peripersonal space, through knowledge that they are near one's body. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Replicated Electro-Formed Nickel Alloy Mirror

    Science.gov (United States)

    1999-01-01

    NASA's Space Optics Manufacturing Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies for the NASA program in the 21st century - including the long-term goal of imaging Earth-like planets in distant solar systems. To reduce the cost of mirror fabrication, Marshall Space Flight Center (MSFC) has developed replication techniques, the machinery, and materials to replicate electro-formed nickel mirrors. The process allows fabricating precisely shaped mandrels to be used and reused as masters for replicating high-quality mirrors. Dr. Joe Ritter examines a replicated electro-formed nickel-alloy mirror which exemplifies the improvements in mirror fabrication techniques, with benefits such as dramtic weight reduction that have been achieved at the Marshall Space Flight Center's Space Optics Manufacturing Technology Center (SOMTC).

  12. Vertical-cavity surface-emitting laser vapor sensor using swelling polymer reflection modulation

    DEFF Research Database (Denmark)

    Ansbæk, Thor; Nielsen, Claus Højgård; Dohn, Søren

    2012-01-01

    Vapor detection using a low-refractive index polymer for reflection modulation of the top mirror in a vertical-cavity surface-emitting laser (VCSEL) is demonstrated. The VCSEL sensor concept presents a simple method to detect the response of a sensor polymer in the presence of volatile organic co...... compounds. We model the physics as a change in the top mirror loss caused by swelling of the polymer upon absorbing the target volatile organic compound. Further we show how acetone vapors at 82 000 ppm concentration can change the polymer coated VCSEL output power by 20 mu W....

  13. ISR RF cavities

    CERN Multimedia

    1983-01-01

    In each ISR ring the radiofrequency cavities were installed in one 9 m long straight section. The RF system of the ISR had the main purpose to stack buckets of particles (most of the time protons)coming from the CPS and also to accelerate the stacked beam. The installed RF power per ring was 18 kW giving a peak accelerating voltage of 20 kV. The system had a very fine regulation feature allowing to lower the voltage down to 75 V in a smooth and well controlled fashion.

  14. Archetypal-imaging and mirror-gazing.

    Science.gov (United States)

    Caputo, Giovanni B

    2014-03-01

    Mirrors have been studied by cognitive psychology in order to understand self-recognition, self-identity, and self-consciousness. Moreover, the relevance of mirrors in spirituality, magic and arts may also suggest that mirrors can be symbols of unconscious contents. Carl G. Jung investigated mirrors in relation to the unconscious, particularly in Psychology and Alchemy. However, the relationship between the conscious behavior in front of a mirror and the unconscious meaning of mirrors has not been clarified. Recently, empirical research found that gazing at one's own face in the mirror for a few minutes, at a low illumination level, produces the perception of bodily dysmorphic illusions of strange-faces. Healthy observers usually describe huge distortions of their own faces, monstrous beings, prototypical faces, faces of relatives and deceased, and faces of animals. In the psychiatric population, some schizophrenics show a dramatic increase of strange-face illusions. They can also describe the perception of multiple-others that fill the mirror surface surrounding their strange-face. Schizophrenics are usually convinced that strange-face illusions are truly real and identify themselves with strange-face illusions, diversely from healthy individuals who never identify with them. On the contrary, most patients with major depression do not perceive strange-face illusions, or they perceive very faint changes of their immobile faces in the mirror, like death statues. Strange-face illusions may be the psychodynamic projection of the subject's unconscious archetypal contents into the mirror image. Therefore, strange-face illusions might provide both an ecological setting and an experimental technique for "imaging of the unconscious". Future researches have been proposed.

  15. Archetypal-Imaging and Mirror-Gazing

    Directory of Open Access Journals (Sweden)

    Giovanni B. Caputo

    2013-12-01

    Full Text Available Mirrors have been studied by cognitive psychology in order to understand self-recognition, self-identity, and self-consciousness. Moreover, the relevance of mirrors in spirituality, magic and arts may also suggest that mirrors can be symbols of unconscious contents. Carl G. Jung investigated mirrors in relation to the unconscious, particularly in Psychology and Alchemy. However, the relationship between the conscious behavior in front of a mirror and the unconscious meaning of mirrors has not been clarified. Recently, empirical research found that gazing at one’s own face in the mirror for a few minutes, at a low illumination level, produces the perception of bodily dysmorphic illusions of strange-faces. Healthy observers usually describe huge distortions of their own faces, monstrous beings, prototypical faces, faces of relatives and deceased, and faces of animals. In the psychiatric population, some schizophrenics show a dramatic increase of strange-face illusions. They can also describe the perception of multiple-others that fill the mirror surface surrounding their strange-face. Schizophrenics are usually convinced that strange-face illusions are truly real and identify themselves with strange-face illusions, diversely from healthy individuals who never identify with them. On the contrary, most patients with major depression do not perceive strange-face illusions, or they perceive very faint changes of their immobile faces in the mirror, like death statues. Strange-face illusions may be the psychodynamic projection of the subject’s unconscious archetypal contents into the mirror image. Therefore, strange-face illusions might provide both an ecological setting and an experimental technique for “imaging of the unconscious”. Future researches have been proposed.

  16. Female plastic surgery patients prefer mirror-reversed photographs of themselves: A prospective study.

    Science.gov (United States)

    de Runz, Antoine; Boccara, David; Chaouat, Marc; Locatelli, Katia; Bertheuil, Nicolas; Claudot, Frédérique; Bekara, Farid; Mimoun, Maurice

    2016-01-01

    The use of a patient's image in plastic surgery is common today. Thus, plastic surgeons should master the use of the image and be aware of the implications of the patients' perception of themselves. The mere-exposure effect is a psychological phenomenon in which a person tends to rate things more positively merely because (s)he is familiar with them. Faces are asymmetric, so faces in photos are different from those observed in mirrors. The main objective of this study was to assess whether patients within a plastic surgery population, particularly those undergoing facial aesthetic surgery, preferred standard photographs or mirror-reversed photographs of themselves. A prospective study was conducted in a plastic surgery department, which included women who were admitted to the hospital the day before their procedures. The patients were separated into the following two groups: Group 1 was composed of patients who were undergoing facial aesthetic surgeries, and Group 2 consisted of other patients who presented to the plastic surgery department for surgery. The patients were required to rate their appreciation of their own faces and to choose between standard and mirror-reversed photos of themselves. A total of 214 patients participated. The median age was 47.9 years (interquartile range (IQR): 36.4-60.6), and the median face appreciation was 5 (IQR: 5-7). The preference for the mirror-reversed photograph was significantly different from chance (p Plastic surgery patients have a significant preference for mirror-reversed photographs of themselves over standard photographs. This preference is even more pronounced among patients who are undergoing facial aesthetic surgery. III. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  17. Mode-locked fibre lasers with an adjustable drop-shaped cavity

    Science.gov (United States)

    Nyushkov, B. N.; Kobtsev, S. M.; Koliada, N. A.; Antropov, A. A.; Pivtsov, V. S.; Yakovlev, A. V.

    2017-11-01

    We report the first implementation of a new cavity topology for mode-locked fibre lasers. This new ‘drop-shaped’ cavity topology employs a dual-fibre optical collimator and allows for a relatively simple cavity design with continuously adjustable length. It combines the advantages of the conventional ring cavity topology with the adjustment capabilities of hybrid ring-linear cavities (e.g. σ-cavities). Reliable femtosecond pulsed lasing was demonstrated in the experimental drop-shaped Er-doped fibre lasers, which were mode-locked in two different ways—by exploiting nonlinear polarisation evolution (NPE) and by means of a semiconductor saturable absorber. In the case of NPE-based mode locking, the shortest pulse duration was ~450 fs. The pulse repetition rate could be continuously varied within  ±3 kHz around ~25 MHz in the NPE-mode-locked lasers when the distance between the dual-fibre optical collimator and the cavity mirror was adjusted. This feature could, in principle, allow active stabilisation of the pulse repetition rate. Thus, mode-locked fibre lasers with the proposed drop-shaped cavity topology could be applied in metrology and other fields where a high stability of pulse repetition rate or its synchronization with an external clock is required.

  18. Development of Ultra High Gradient and High Q{sub 0} Superconducting Radio Frequency Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Rongli [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Clemens, William A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Follkie, James E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Harris, Teena M. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Kushnick, Peter W. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Machie, Danny [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Martin, Robert E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Palczewski, Ari D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Perry, Era A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Slack, Gary L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Williams, R. S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Adolphsen, C. [SLAC, Menlo Park, California, (United States); Li, Z. [SLAC, Menlo Park, California, (United States); Hao, J. K. [Peking University, Beijing (China); Li, Y. M. [Peking University, Beijing (China); Liu, K. X. [Peking University, Beijing (China)

    2013-06-01

    We report on the recent progress at Jefferson Lab in developing ultra high gradient and high Q{sub 0} superconducting radio frequency (SRF) cavities for future SRF based machines. A new 1300 MHz 9-cell prototype cavity is being fabricated. This cavity has an optimized shape in terms of the ratio of the peak surface field (both magnetic and electric) to the acceleration gradient, hence the name low surface field (LSF) shape. The goal of the effort is to demonstrate an acceleration gradient of 50 MV/m with Q{sub 0} of 10{sup 10} at 2 K in a 9-cell SRF cavity. Fine-grain niobium material is used. Conventional forming, machining and electron beam welding method are used for cavity fabrication. New techniques are adopted to ensure repeatable, accurate and inexpensive fabrication of components and the full assembly. The completed cavity is to be first mechanically polished to a mirror-finish, a newly acquired in-house capability at JLab, followed by the proven ILC-style processing recipe established already at JLab. In parallel, new single-cell cavities made from large-grain niobium material are made to further advance the cavity treatment and processing procedures, aiming for the demonstration of an acceleration gradient of 50 MV/m with Q{sub 0} of 2-10{sup 10} at 2K.

  19. Double arch mirror study. Part 3: Fabrication and test report

    Science.gov (United States)

    Vukobratovich, D.; Hillman, D.

    1983-01-01

    A method of mounting a cryogenically cooled, lightweight, double arch, glass mirror was developed for infrared, astronomical telescopes such as the Space Infrared Telescope Facility (SIRTF). A 50 cm, fused silica mirror which was previously fabricated was modified for use with a new mount configuration. This mount concept was developed. The modification of the mirror, the fabrication of the mirror mount, and the room temperature testing of the mounted mirror are reported. A design for a SIRTF class primary mirror is suggested.

  20. Oral cavity eumycetoma

    Directory of Open Access Journals (Sweden)

    Gisele Alborghetti Nai

    2011-06-01

    Full Text Available Mycetoma is a pathological process in which eumycotic (fungal or actinomycotic causative agents from exogenous source produce grains. It is a localized chronic and deforming infectious disease of subcutaneous tissue, skin and bones. We report the first case of eumycetoma of the oral cavity in world literature. CASE REPORT: A 43-year-old male patient, complaining of swelling and fistula in the hard palate. On examination, swelling of the anterior and middle hard palate, with fistula draining a dark liquid was observed. The panoramic radiograph showed extensive radiolucent area involving the region of teeth 21-26 and the computerized tomography showed communication with the nasal cavity, suggesting the diagnosis of periapical cyst. Surgery was performed to remove the lesion. Histopathological examination revealed purulent material with characteristic grain. Gram staining for bacteria was negative and Grocott-Gomori staining for the detection of fungi was positive, concluding the diagnosis of eumycetoma. The patient was treated with ketoconazole for nine months, and was considered cured at the end of treatment. CONCLUSION: Histopathological examination, using histochemical staining, and direct microscopic grains examination can provide the distinction between eumycetoma and actinomycetoma accurately.

  1. Chip-integrated plasmonic cavity-enhanced single nitrogen-vacancy center emission.

    Science.gov (United States)

    Siampour, Hamidreza; Kumar, Shailesh; Bozhevolnyi, Sergey I

    2017-11-09

    High temporal stability and spin dynamics of individual nitrogen-vacancy (NV) centers in diamond crystals make them one of the most promising quantum emitters operating at room temperature. We demonstrate a chip-integrated cavity-coupled emission into propagating surface plasmon polariton (SPP) modes narrowing the NV center's broad emission bandwidth with enhanced coupling efficiency. The cavity resonator consists of two distributed Bragg mirrors that are built at opposite sides of the coupled NV emitter and are integrated with a dielectric-loaded SPP waveguide (DLSPPW), using electron-beam lithography of hydrogen silsesquioxane resist deposited on silver-coated silicon substrates. A quality factor of ∼70 for the cavity (full width at half maximum ∼10 nm) with full tunability of the resonance wavelength is demonstrated. An up to 42-fold decay rate enhancement of the spontaneous emission at the cavity resonance is achieved, indicating high DLSPPW mode confinement.

  2. White Lesions in the Oral Cavity: A Clinicopathological Study from a Tertiary Care Dermatology Centre in Kerala, India

    OpenAIRE

    Simi, S. M.; Nandakumar, G; Anish, T. S.

    2013-01-01

    Context: White lesions in the oral cavity may be benign, pre-malignant or malignant. There are no signs and symptoms which can reliably predict whether a leukoplakia will undergo malignant change or not. Many systemic conditions appear initially in the oral cavity and prompt diagnosis and management can help in minimizing disease progression and organ destruction. Aim : The aim of the paper was to study the clinical and histopathological patterns of white lesions in the oral cavity presented ...

  3. A switchable dual-wavelength fiber laser based on asymmetric fiber Bragg grating Fabry-Perot cavity with a SESAM

    Science.gov (United States)

    Huang, Kaiqiang; Li, Qi; Chen, Haiyan

    2016-04-01

    A switchable dual-wavelength fiber laser with an asymmetric fiber Bragg grating (FBG)-Fabry-Perot (FP) cavity based a semiconductor saturable absorber mirror (SESAM) is proposed and experimentally demonstrated. The proof of concept device consists of a FGB laser with an asymmetric FBG-FP cavity, a SESAM as mode loss modulator, and a intracavity FBG as wavelength selector by changing its operation temperature. The results demonstrate the new concept of dual-wavelength fiber laser based SESAM with asymmetric FBG-FP cavity and the technical feasibility.

  4. Water clusters in nonpolar cavities

    OpenAIRE

    Vaitheeswaran, Subramanian; Yin, Hao; Rasaiah, Jayendran C.; Hummer, Gerhard

    2004-01-01

    We explore the structure and thermodynamics of water clusters confined in nonpolar cavities. By calculating the grand-canonical partition function term by term, we show that small nonpolar cavities can be filled at equilibrium with highly structured water clusters. The structural and thermodynamic properties of these encapsulated water clusters are similar to those observed experimentally in the gas phase. Water filling is highly sensitive to the size of the cavity and the strength of the int...

  5. Thickness uniformity improvement for the twin mirrors used in advanced gravitational wave detectors

    Science.gov (United States)

    Sassolas, B.; Benoît, Q.; Flaminio, R.; Forest, D.; Franc, J.; Galimberti, M.; Lacoudre, A.; Michel, C.; Montorio, J.-L.; Morgado, N.; Pinard, L.

    2011-09-01

    Gravitational wave detectors such as Virgo and LIGO use long-baseline Michelson interferometers with high finesse Fabry-Perrot cavity in the arms. The symmetry of these cavities is essential to prevent the interferometer from sensitivity to laser fluctuations. For this purpose the difference between the transmissions of the two input mirrors has to be minimized. Advanced LIGO, the upgrade of LIGO, plans a transmission matching between the two input mirrors as high as 99%. A small deviation in the process fabrication from run to run might induce transmission mismatch larger than 1%. Consequently, the two input mirrors have to be coated during the same coating run. That requires ability to deposit the reflective coating, based on a stack of titanium doped tantala (Ti:Ta2O5) layers and silica layers, uniformly over a 800 mm diameter aperture. This paper presents the study to improve the thickness uniformity of a reflective coating and the preliminary results achieved on two Ø350mm substrates coated in the run.

  6. Cavity coalescence in superplastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Stowell, M.J.; Livesey, D.W.; Ridley, N.

    1984-01-01

    An analysis of the probability distribution function of particles randomly dispersed in a solid has been applied to cavitation during superplastic deformation and a method of predicting cavity coalescence developed. Cavity size distribution data were obtained from two microduplex nickel-silver alloys deformed superplastically to various extents at elevated temperature, and compared to theoretical predictions. Excellent agreement occurred for small void sizes but the model underestimated the number of voids in the largest size groups. It is argued that the discrepancy results from a combination of effects due to non-random cavity distributions and to enhanced growth rates and incomplete spheroidization of the largest cavities.

  7. Design of a Thermal Imaging Diagnostic Using 90-Degree, Off-Axis, Parabolic Mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Malone, Robert M.; Becker, Steven A.; Dolan, Daniel H.; Hacking, Richard G.; Hickman, Randy J.; Kaufman, Morris I.; Stevens, Gerald D.; Turley, William D.

    2006-09-01

    Thermal imaging is an important, though challenging, diagnostic for shockwave experiments. Shock-compressed materials undergo transient temperature changes that cannot be recorded with standard (greater than ms response time) infrared detectors. A further complication arises when optical elements near the experiment are destroyed. We have designed a thermal-imaging system for studying shock temperatures produced inside a gas gun at Sandia National Laboratories. Inexpensive, diamond-turned, parabolic mirrors relay an image of the shocked target to the exterior of the gas gun chamber through a sapphire vacuum port. The 3000–5000-nm portion of this image is directed to an infrared camera which acquires a snapshot of the target with a minimum exposure time of 150 ns. A special mask is inserted at the last intermediate image plane, to provide dynamic thermal background recording during the event. Other wavelength bands of this image are split into high-speed detectors operating at 900–1700 nm, and at 1700–3000 nm for timeresolved pyrometry measurements. This system incorporates 90-degree, off-axis parabolic mirrors, which can collect low f/# light over a broad spectral range, for high-speed imaging. Matched mirror pairs must be used so that aberrations cancel. To eliminate image plane tilt, proper tip-to-tip orientation of the parabolic mirrors is required. If one parabolic mirror is rotated 180 degrees about the optical axis connecting the pair of parabolic mirrors, the resulting image is tilted by 60 degrees. Different focal-length mirrors cannot be used to magnify the image without substantially sacrificing image quality. This paper analyzes performance and aberrations of this imaging diagnostic.

  8. Microsecond-resolved SDR-based cavity ring down ellipsometry.

    Science.gov (United States)

    Sofikitis, D; Spiliotis, A K; Stamataki, K; Katsoprinakis, G E; Bougas, L; Samartzis, P C; Loppinet, B; Rakitzis, T P; Surligas, M; Papadakis, S

    2015-06-20

    We present an experimental apparatus that allows microsecond-resolved ellipsometric and absorption measurements. The apparatus is based on an optical cavity containing a Dove prism, in which light undergoes total internal reflection (TIR), while the data acquisition is based on software defined radio technology and custom-built drivers. We demonstrate the ability to sense rapid variations in the refractive index above the TIR interface for arbitrarily long times with a temporal resolution of at least 2 μs.

  9. Degradation of back surface acrylic mirrors for low concentration and mirror-augmented photovoltaics

    Science.gov (United States)

    Murray, Myles P.; Bruckman, Laura S.; Gordon, Devin; Richardson, Samuel; Reinbolt, Greg; Schuetz, Mark; French, Roger H.

    2012-10-01

    Back-surface acrylic mirrors can be used in low concentration and mirror augmented photovoltaics (LCPV, MAPV) to increase the irradiance on a module. Back-surface mirrors can spectrally filter incoming solar radiation reducing the ultraviolet (UV) and infrared (IR) load on the module, while useful radiation is coupled into a module or photovoltaic cell. Degradation of these mirrors can occur from UV induced photodegradative processes and metallization corrosion. Environmental stresses such as humidity, thermal cycling and exposure to corrosive substances can cause an increase in scattering, reducing mirror performance. In order to increase the lifetime and durability of back-surface acrylic mirrors a better understanding of the degradation modes is necessary. In a study of acrylic back-surface mirrors for LCPV and MAPV applications, optical properties and bidirectional scattering distribution functions (BSDF) were investigated and correlated to simulated exposure protocols. Formulations of Poly(methyl methacrylate) (PMMA) with differing concentration of UV absorbers were used for the aluminum backsurface acrylic mirrors. The formulations of aluminum back-surface acrylic mirrors were exposed in a QUV accelerated weathering tester (QLabs) to ASTM G154 Cycle 4. Total and diffuse reflectance spectra were measured for each mirror under exposure using a diffuse reflectance accessory (DRA) from 180-1800 nm on a Varian Cary 6000i at defined dose intervals. The total reflectance losses in the 250-400 nm region were greater and diffuse-only reflectance increased for formulations of acrylic mirrors that contained the least amount of UV stabilizer after each dose of QUV exposure. Acrylic back-surface mirrors were exposed to salt fog corrosion and QUV and were analyzed using BSDF. There was an increase in scattering from roughening of the mirror surface after exposure to the corrosive environment.

  10. Three-Dimensional Electromagnetic High Frequency Axisymmetric Cavity Scars.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt

    2014-10-01

    This report examines the localization of high frequency electromagnetic fi elds in three-dimensional axisymmetric cavities along periodic paths between opposing sides of the cavity. The cases where these orbits lead to unstable localized modes are known as scars. This report treats both the case where the opposing sides, or mirrors, are convex, where there are no interior foci, and the case where they are concave, leading to interior foci. The scalar problem is treated fi rst but the approximations required to treat the vector fi eld components are also examined. Particular att ention is focused on the normalization through the electromagnetic energy theorem. Both projections of the fi eld along the scarred orbit as well as point statistics are examined. Statistical comparisons are m ade with a numerical calculation of the scars run with an axisymmetric simulation. This axisymmetric cas eformstheoppositeextreme(wherethetwomirror radii at each end of the ray orbit are equal) from the two -dimensional solution examined previously (where one mirror radius is vastly di ff erent from the other). The enhancement of the fi eldontheorbitaxiscanbe larger here than in the two-dimensional case. Intentionally Left Blank

  11. Tandem Mirror Reactor Systems Code (Version I)

    Energy Technology Data Exchange (ETDEWEB)

    Reid, R.L.; Finn, P.A.; Gohar, M.Y.; Barrett, R.J.; Gorker, G.E.; Spampinaton, P.T.; Bulmer, R.H.; Dorn, D.W.; Perkins, L.J.; Ghose, S.

    1985-09-01

    A computer code was developed to model a Tandem Mirror Reactor. Ths is the first Tandem Mirror Reactor model to couple, in detail, the highly linked physics, magnetics, and neutronic analysis into a single code. This report describes the code architecture, provides a summary description of the modules comprising the code, and includes an example execution of the Tandem Mirror Reactor Systems Code. Results from this code for two sensitivity studies are also included. These studies are: (1) to determine the impact of center cell plasma radius, length, and ion temperature on reactor cost and performance at constant fusion power; and (2) to determine the impact of reactor power level on cost.

  12. The First Active Segmented Mirror at ESO

    Science.gov (United States)

    Gonté, Frédéric; Dupuy, Christophe; Frank, Christoph; Araujo, Constanza; Brast, Roland; Frahm, Robert; Karban, Robert; Andolfato, Luigi; Esteves, Regina; Nylund, Matty; Sedghi, Babak; Fischer, Gerhard; Noethe, Lothar; Derie, Frédéric

    2007-06-01

    The Active Phasing Experiment (APE) is part of the Extremely Large Telescope Design Study which is supported by the European Framework Programme 6. This experiment, which is conducted in collaboration with several partners is a demonstrator to test and qualify newly-developed phasing sensors for the alignment of segmented mirrors and test the phasing software within a telescope control system to be developed for a future European Extremely Large Telescope. The segmentation of a primary mirror is simulated by a scaled-down Active Segmented Mirror of 61 segments which has been developed in-house.

  13. Numerical study of optical-cavity misalignment effects for a far-infrared FEL

    CERN Document Server

    Sobajima, M; Yokoyama, M; Oda, F; Kawai, M; Miura, H

    2002-01-01

    A far-infrared FEL will be newly installed in the IR FEL Research Center at the Science University of Tokyo (FEL-SUT) in 2002. In this study, optical cavity misalignment effects for the far-infrared FEL are researched by using the simulation code that has been developed at Kawasaki Heavy Industries, Ltd. Results show not only cavity losses but also the gain reduction by the tilt and the offset of the mirror and the offset of the electron beam. The required alignment accuracy is also obtained in this study.

  14. Enhanced Entanglement in Optomechanical Cavity with a Nonlinear Material χ (3)

    Science.gov (United States)

    Ma, YongHong; Li, DanYang; Wu, E.

    2017-10-01

    We propose a scheme to generate the case of entanglement in the optomechanical cavity, which is made up a Fabry-Perot cavity and a macroscopic vibrating mirror via the nonlinear material χ (3). We analyze the effect of the nonlinear material χ (3) intracavity on the continuous variable entanglements. The results show that the introduction of the nonlinear materials χ (3) can increase the entanglement effectively in the optomechanical system. Such optomechanical system can be used for the realization of continuous variable quantum information interfaces and networks.

  15. Vertical cavity laser

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention provides a vertical cavity laser comprising a grating layer comprising an in-plane grating, the grating layer having a first side and having a second side opposite the first side and comprising a contiguous core grating region having a grating structure, wherein an index......, an index of refraction of the second low-index layer or air being less than 2; and a thickness of the cap layer and a thickness of the grating layer, and a pitch and a duty cycle of the grating structure are selected to obtain a resonance having a free-space resonance wavelength in the interval 300 nm to 3...... microns, the cap layer comprises an active region configured to generate or absorb photons at the free-space resonance wavelength by stimulated emission or absorption when a sufficient forward or reverse bias voltage is applied across the active region, a thickness of the first low-index layer is less...

  16. Shock induced cavity collapse

    Science.gov (United States)

    Skidmore, Jonathan; Doyle, Hugo; Tully, Brett; Betney, Matthew; Foster, Peta; Ringrose, Tim; Ramasamy, Rohan; Parkin, James; Edwards, Tom; Hawker, Nicholas

    2016-10-01

    Results from the experimental investigation of cavity collapse driven by a strong planar shock (>6km/s) are presented. Data from high speed framing cameras, laser backlit diagnostics and time-resolved pyromety are used to validate the results of hydrodynamic front-tracking simulations. As a code validation exercise, a 2-stage light gas gun was used to accelerate a 1g Polycarbonate projectile to velocities exceeding 6km/s; impact with a PMMA target containing a gas filled void results in the formation of a strong shockwave with pressures exceeding 1Mbar. The subsequent phenomena associated with the collapse of the void and excitation of the inert gas fill are recorded and compared to simulated data. Variation of the mass density and atomic number of the gas fill is used to alter the plasma parameters furthering the extent of the code validation.

  17. Variable pathlength cavity spectroscopy development of an automated prototype

    Science.gov (United States)

    Schmeling, Ryan Andrew

    Spectroscopy is the study of the interaction of electromagnetic radiation (EMR) with matter to probe the chemical and physical properties of atoms and molecules. The primary types of analytical spectroscopy are absorption, emission, and scattering methods. Absorption spectroscopy can quantitatively determine the chemical concentration of a given species in a sample by the relationship described by Beer's Law. Upon inspection of Beer's Law, it becomes apparent that for a given analyte concentration, the only experimental variable is the pathlength. Over the past ˜75 years, several approaches to physically increasing the pathlength have been reported in the literature. These have included not only larger cuvettes and novel techniques such as Differential Optical Absorption Spectroscopy, but also numerous designs that are based upon the creation of an optical cavity in which multiple reflections through the sample are made possible. The cavity-based designs range from the White Cell (1942) to Cavity Ring-Down Spectroscopy (O'Keefe and Deacon, 1998). In the White Cell approach, the incident beam is directed off-axis to repeatedly reflect concave mirror surfaces. Numerous variations of the White Cell design have been reported, and it has found wide application in infrared absorption spectroscopy in what have become to be known as "light pipes". In the CRDS design, on the other hand, highly reflective dielectric mirrors situated for on-axis reflections result in the measurement of the exponential decay of trapped light that passes through the exit mirror. CRDS has proven over the past two decades to be a powerful technique for ultra-trace analysis (greenhouse gases to biomedical "breath screening" as a means to identify disease states. In this thesis, a novel approach to ultra-trace analysis by absorption spectroscopy is described. In this approach known as Variable Pathlength Cavity Spectroscopy (VPCS), a high finesse optical cavity is created by two flat, parallel

  18. Morphometry of Glenoid Cavity

    Directory of Open Access Journals (Sweden)

    Mamatha T

    2011-11-01

    Full Text Available Objectives: Knowledge of the shape and dimensions of the glenoid are important in the design and fitting of glenoid components for total shoulder arthroplasty. An understanding of variations in normal anatomy of the glenoid is essential while evaluating pathological conditions like osseous Bankart lesions and osteochondral defects. Methods: This study was done on 202 dry, unpaired adult human scapulae of unknown sex belonging to the south Indian population. Three glenoid diameters were measured, the superior-inferior diameter, anterior-posterior diameter of the lower half and the anterior-posterior diameter of the upper half of the glenoid. Based on a notch present on the anterior glenoid rim, variations in the shape of the glenoid cavity were classified as inverted comma shaped, pear shaped and oval. Results: The average superior-inferior diameter on right and the left sides were 33.67±2.82mm and 33.92±2.87mm respectively. The average anterior-posterior diameter of the lower half of the right glenoid was 23.35±2.04mm and that of the left was 23.02±2.30mm. The mean diameter of the upper half of the right glenoid was 16.27±2.01mm and that of the left was 15.77±1.96mm. Conclusion: The dimensions of the glenoid observed in the present study were lesser than those recorded in the studies done on other populations. This fact may be taken into consideration while designing glenoid prostheses for the south Indian population. The current study recorded a higher percentage of glenoid cavities having the glenoid notch as compared to earlier studies. While evaluating defects/lesions of the glenoid, this fact could be useful.

  19. Output-Mirror-Tuning Terahertz-Wave Parametric Oscillator with an Asymmetrical Porro-Prism Resonator Configuration

    Science.gov (United States)

    Zhang, Ruiliang; Qu, Yanchen; Zhao, Weijiang; Liu, Chuang; Chen, Zhenlei

    2017-06-01

    We demonstrate a terahertz-wave parametric oscillator (TPO) with an asymmetrical porro-prism (PP) resonator configuration, consisting of a close PP corner reflector and a distant output mirror relative to the MgO:LiNbO3 crystal. Based on this cavity, frequency tuning of Stokes and the accompanied terahertz (THz) waves is realized just by rotating the plane mirror. Furthermore, THz output with high efficiency and wide tuning range is obtained. Compared with a conventional TPO employing a plane-parallel resonator of the same cavity length and output loss, the low end of the frequency tuning range is extended to 0.96 THz from 1.2 THz. The highest output obtained at 1.28 THz is enhanced by about 25%, and the oscillation threshold pump energy measured at 1.66 THz is reduced by about 4.5%. This resonator configuration also shows some potential to simplify the structure and application for intracavity TPOs.

  20. Frequency Tuning for a DQW Crab Cavity

    CERN Document Server

    Verdú-Andrés, Silvia; Ben-Zvi, Ilan; Calaga, Rama; Capatina, Ofelia; Leuxe, Raphael; Skaritka, John; Wu, Qiong; Xiao, Binping; Zanoni, Carlo

    2016-01-01

    The nominal operating frequency for the HL-LHC crab cavities is 400.79 MHz within a bandwidth of ±60kHz. Attaining the required cavity tune implies a good understanding of all the processes that influence the cavity frequency from the moment when the cavity parts are being fabricated until the cavity is installed and under operation. Different tuning options will be available for the DQW crab cavity of LHC. This paper details the different steps in the cavity fabrication and preparation that may introduce a shift in the cavity frequency and introduces the different tuning methods foreseen to bring the cavity frequency to meet the specifications.

  1. Intra-cavity frequency-doubled mode-locked semiconductor disk laser at 325 nm.

    Science.gov (United States)

    Bek, Roman; Baumgärtner, Stefan; Sauter, Fabian; Kahle, Hermann; Schwarzbäck, Thomas; Jetter, Michael; Michler, Peter

    2015-07-27

    We present a passively mode-locked semiconductor disk laser (SDL) emitting at 650nm with intra-cavity second harmonic generation to the ultraviolet (UV) spectral range. Both the gain and the absorber structure contain InP quantum dots (QDs) as active material. In a v-shaped cavity using the semiconductor samples as end mirrors, a beta barium borate (BBO) crystal is placed in front of the semiconductor saturable absorber mirror (SESAM) for pulsed UV laser emission in one of the two outcoupled beams. Autocorrelation (AC) measurements at the fundamental wavelength reveal a FWHM pulse duration of 1.22ps. With a repetition frequency of 836MHz, the average output power is 10mW per beam for the red emission and 0.5mW at 325nm.

  2. Modeling and optimization of single-mode vertical cavity surface emitting lasers

    Science.gov (United States)

    Dahiya, Sandeep; Kumar, Suresh; Kaushik, Brajesh Kumar

    2016-10-01

    Vertical cavity surface emitting laser (VCSEL) plays a vital role in optical network. The present investigation reports the performance comparison of the modeling of single-mode VCSELs at room temperature for continuous wave operation. VCSEL for the study consists of InGaAsP-based cavity or active region sandwiched between GaAs/AlGaAs top mirror and GaAs/AlAs bottom mirrors with the aim of increasing the power conversion efficiency (PCE), lasing power, and decreasing the threshold current. It is observed that VCSELs with lower diameter are most suitable to achieve energy-efficient operation. The PCE obtained is ˜50% for the proposed single-mode VCSELs. The proposed VCSELs are suitable for short-reach optical interconnects such as chip-to-chip and board-to-board communication in high-performance computers.

  3. Supersymmetric defect models and mirror symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Hook, Anson; Kachru, Shamit; Torroba, Gonzalo

    2013-11-01

    We study supersymmetric field theories in three space-time dimensions doped by various configurations of electric charges or magnetic fluxes. These are supersymmetric avatars of impurity models. In the presence of additional sources such configurations are shown to preserve half of the supersymmetries. Mirror symmetry relates the two sets of configurations. We discuss the implications for impurity models in 3d NN = 4 QED with a single charged hypermultiplet (and its mirror, the theory of a free hypermultiplet) as well as 3d NN = 2 QED with one flavor and its dual, a supersymmetric Wilson-Fisher fixed point. Mirror symmetry allows us to find backreacted solutions for arbitrary arrays of defects in the IR limit of NN = 4 QED. Our analysis, complemented with appropriate string theory brane constructions, sheds light on various aspects of mirror symmetry, the map between particles and vortices and the emergence of ground state entropy in QED at finite density.

  4. Ultra-Lightweight Hybrid Structured Mirror Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MMCC is proposing herewith a hybrid structured mirror that combines the advantages of SiC membrane and magnesium graphite composite. The significance of magnesium...

  5. Space Optic Manufacturing - X-ray Mirror

    Science.gov (United States)

    1998-01-01

    NASA's Space Optics Manufacturing Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies for the NASA program in the 21st century - including the long-term goal of imaging Earth-like planets in distant solar systems. To reduce the cost of mirror fabrication, Marshall Space Flight Center (MSFC) has developed replication techniques, the machinery and materials to replicate electro-formed nickel mirrors. The process allows fabricating precisely shaped mandrels to be used and reused as masters for replicating high-quality mirrors. This image shows a lightweight replicated x-ray mirror with gold coatings applied.

  6. Polishing X-ray Mirror Mandrel

    Science.gov (United States)

    1999-01-01

    NASA's Space Optics Manufacturing Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies for the NASA program in the 21st century - including the long-term goal of imaging Earth-like planets in distant solar systems. To reduce the cost of mirror fabrication, Marshall Space Flight Center (MSFC) has developed replication techniques, the machinery, and materials to replicate electro-formed nickel mirrors. The process allows fabricating precisely shaped mandrels to be used and reused as masters for replicating high-quality mirrors. MSFC's Space Optics Manufacturing Technology Center (SOMTC) has grinding and polishing equipment ranging from conventional spindles to custom-designed polishers. These capabilities allow us to grind precisely and polish a variety of optical devices, including x-ray mirror mandrels. This image shows Charlie Griffith polishing the half-meter mandrel at SOMTC.

  7. Silicon Wafer X-ray Mirror Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this one year research project, we propose to do the following four tasks; (1) Design the silicon wafer X-ray mirror demo unit and develop a ray-tracing code to...

  8. Driver ASICs for Advanced Deformable Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The program leverages on our extensive expertise in developing high-performance driver ASICs for deformable mirror systems and seeks to expand the capacities of the...

  9. Development of a FSMP mirror assembly

    Science.gov (United States)

    Kim, Jihun; Kim, Young-Soo; Song, Je Heon; Cho, Myung; Yang, Ho-Soon; Lee, Joohyung; Kim, Ho-Sang; Lee, Kyoung-Don; Park, Won Hyun; Park, Byeong-Gon

    2015-09-01

    A Prototype of Fast-steering Secondary Mirror (FSMP) for the Giant Magellan Telescope (GMT) has been developed by the consortium consisting of institutes in Korea and the US. In 2014 the FSMP development was finalized by combining the two major sub-systems, the mirror fabricated and the mirror cell with the tip-tilt control parts. We have developed an assembly procedure in which potential difficulties, such as handling without contacting mirror surface, and optimizing bonding process, have been resolved. Supporting jigs were produced, and optimized bonding techniques have been developed. The assembled FSMP system was installed in a test tower, and stability of the system were checked. Performance of the FSMP system will be evaluated in static and dynamic environments for the validation of the FSMP system operation as the future works.

  10. High Resolution Silicon Deformable Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposal we describe a plan to build a deformable mirror suitable for space-based operation in systems for high-resolution imaging. The prototype DM will be...

  11. High Resolution Silicon Deformable Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes a plan to build a prototype small stroke, high precision deformable mirror suitable for space-based operation in systems for high-resolution...

  12. Multilayer active shell mirrors for space telescopes

    Science.gov (United States)

    Steeves, John; Jackson, Kathryn; Pellegrino, Sergio; Redding, David; Wallace, J. Kent; Bradford, Samuel Case; Barbee, Troy

    2016-07-01

    A novel active mirror technology based on carbon fiber reinforced polymer (CFRP) substrates and replication techniques has been developed. Multiple additional layers are implemented into the design serving various functions. Nanolaminate metal films are used to provide a high quality reflective front surface. A backing layer of thin active material is implemented to provide the surface-parallel actuation scheme. Printed electronics are used to create a custom electrode pattern and flexible routing layer. Mirrors of this design are thin ( 100 μm PV) down to sub-micron precision. The system has been validated against several traditional techniques including photogrammetry and interferometry. The mirror performance has been characterized using this system, as well as closed-loop figure correction experiments on 150 mm dia. prototypes. The mirrors have demonstrated post-correction figure accuracies of 200 nm RMS (two dead actuators limiting performance).

  13. Silicon Wafer X-ray Mirror Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this one year research project, we propose to do the following four tasks;(1) Design the silicon wafer X-ray mirror demo unit and develop a ray-tracing code to...

  14. Lightweight composite mirrors for telescopes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Lightweight, steady and stiff mirrors are necessary to decrease cost of telescopes such as IXO and GenX used in special NASA missions. Low-density materials are...

  15. Applied physics: Optical trapping for space mirrors.

    Science.gov (United States)

    McGloin, David

    2014-02-27

    Might it be possible to create mirrors for space telescopes, using nothing but microscopic particles held in place by light? A study that exploits a technique called optical binding provides a step towards this goal.

  16. Mirror Advanced Reactor Study interim design report

    Energy Technology Data Exchange (ETDEWEB)

    1983-04-01

    The status of the design of a tenth-of-a-kind commercial tandem-mirror fusion reactor is described at the midpoint of a two-year study. When completed, the design is to serve as a strategic goal for the mirror fusion program. The main objectives of the Mirror Advanced Reactor Study (MARS) are: (1) to design an attractive tandem-mirror fusion reactor producing electricity and synfuels (in alternate versions), (2) to identify key development and technology needs, and (3) to exploit the potential of fusion for safety, low activation, and simple disposal of radioactive waste. In the first year we have emphasized physics and engineering of the central cell and physics of the end cell. Design optimization and trade studies are continuing, and we expect additional modifications in the end cells to further improve the performance of the final design.

  17. Shape characterization of the primary mirror of a mirror based solar concentrator

    Science.gov (United States)

    Trespidi, Franco; Malvisi, Emanuele; Parmesani, Rolando

    2017-09-01

    A diagnostic technique developed to detect possible local deformations in the primary mirrors used in solar concentrators is presented. A grazing illumination technique is used to evaluate the effect of changes in the shape of the mirror surface from the ideal one. The technique provides a qualitative evaluation of the uniformity of the mirror surface and highlights possible imperfections in the surface due to manufacturing process. The optical setup and some experimental results are described together with a simple analysis procedure.

  18. Mechanical Properties of Niobium Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Dhakal, Pashupati [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Matalevich, Joseph R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Myneni, Ganapati Rao [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    The mechanical stability of bulk Nb cavity is an important aspect to be considered in relation to cavity material, geometry and treatments. Mechanical properties of Nb are typically obtained from uniaxial tensile tests of small samples. In this contribution we report the results of measurements of the resonant frequency and local strain along the contour of single-cell cavities made of ingot and fine-grain Nb of different purity subjected to increasing uniform differential pressure, up to 6 atm. Measurements have been done on cavities subjected to different heat treatments. Good agreement between finite element analysis simulations and experimental data in the elastic regime was obtained with a single set of values of Young’s modulus and Poisson’s ratio. The experimental results indicate that the yield strength of medium-purity ingot Nb cavities is higher than that of fine-grain, high-purity Nb.

  19. Technical tasks in superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kenji [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    1997-11-01

    The feature of superconducting rf cavities is an extremely small surface resistance on the wall. It brings a large energy saving in the operation, even those are cooled with liquid helium. That also makes possible to operate themselves in a higher field gradient comparing to normal conducting cavities, and brings to make accelerators compact. These merits are very important for the future accelerator engineering which is planed at JAERI for the neutron material science and nuclear waste transmutation. This machine is a high intensity proton linac and uses sc cavities in the medium and high {beta} sections. In this paper, starting R and D of proton superconducting cavities, several important technical points which come from the small surface resistance of sc cavities, are present to succeed it and also differences between the medium and high - {beta} structures are discussed. (author)

  20. Mirror Writing and a Dissociative Identity Disorder

    OpenAIRE

    Le, Catherine; Smith, Joyce; Cohen, Lewis

    2009-01-01

    Individuals with dissociative identity disorder (DID) have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam—mirror writing. It is not known whether her mirror...

  1. Mirror Therapy for Phantom Limb Pain

    OpenAIRE

    Kim, Sae Young; Kim, Yun Young

    2012-01-01

    Phantom limb pain is a painful sensation that is perceived in a body part that no longer exists. To control this pain, many methods have been used such as medication, physical treatment, nerve block, neuromodulation, surgical treatment and mirror therapy. However, until now, there effects have been uncertain. We report the successful reduction of phantom limb pain using mirror therapy when other treatments initially failed to control the pain.

  2. Action observation: Inferring intentions without mirror neurons

    DEFF Research Database (Denmark)

    Frith, Christopher; Kilner, James M

    2008-01-01

    A recent study has shown, using fMRI, that the mirror neuron system does not mediate action understanding when the observed action is novel or when it is hard to understand.......A recent study has shown, using fMRI, that the mirror neuron system does not mediate action understanding when the observed action is novel or when it is hard to understand....

  3. Anomalous Mirror Symmetry Generated by Optical Illusion

    Directory of Open Access Journals (Sweden)

    Kokichi Sugihara

    2016-04-01

    Full Text Available This paper introduces a new concept of mirror symmetry, called “anomalous mirror symmetry”, which is physically impossible but can be perceived by human vision systems because of optical illusion. This symmetry is characterized geometrically and a method for creating cylindrical surfaces that create this symmetry is constructed. Examples of solid objects constructed by a 3D printer are also shown.

  4. Testing the first neutron mirror flipper

    Energy Technology Data Exchange (ETDEWEB)

    Pleshanov, N.K., E-mail: pnk@pnpi.spb.ru [Neutron Research Department, Petersburg Nuclear Physics Institute, NRC “Kurchatov Institute”, Orlova Roscha, Gatchina, St. Petersburg 188300 (Russian Federation); Syromyatnikov, V.G. [Neutron Research Department, Petersburg Nuclear Physics Institute, NRC “Kurchatov Institute”, Orlova Roscha, Gatchina, St. Petersburg 188300 (Russian Federation); Physical Department, St. Petersburg State University, Ulyanovskaya, 1, Petrodvorets, St. Petersburg 198504 (Russian Federation)

    2016-11-21

    The first neutron mirror flipper built as a magnetic Co{sub 70}Fe{sub 30} (71.1 nm) layer on a non-magnetic periodic multilayer {NiMo(6.96 nm)/Ti(6.17 nm)}×20 was tested. Its efficiency at the Bragg peak was found to exceed 0.966. Thus, the possibility of producing neutron mirror spin turners, including π/2- and π-turners (flippers), was experimentally demonstrated.

  5. On Horizonless Temperature with an Accelerating Mirror

    CERN Document Server

    Good, Michael R R; Ong, Yen Chin

    2016-01-01

    A new solution of a unitary moving mirror is found to produce finite energy and emit thermal radiation despite the absence of an acceleration horizon. In the limit that the mirror approaches the speed of light, the model corresponds to a black hole formed from the collapse of a null shell. For speeds less than light, the black hole correspondence, if it exists, is that of a remnant.

  6. Optimal radii of photonic crystal holes within DBR mirrors in long wavelength VCSEL.

    Science.gov (United States)

    Czyszanowski, Tomasz; Dems, Maciej; Thienpont, Hugo; Panajotov, Krassimir

    2007-02-05

    The modal characteristics of a Photonic-Crystal Vertical-Cavity Surface-Emitting diode Laser (PC-VCSEL) have been investigated. Photonic crystal structure, realized by a regular net of air holes within the layers, has been etched in the upper DBR mirror. An advanced three-dimensional, vectorial electromagnetic model has been applied to a phosphide - based device design featuring InGaAlAs active region, AlGaAs/GaAs mirrors and a tunnel junction to confine the current flow. For the structure under consideration a single mode operation has been found for the hole diameter over photonic crystal lattice constant ratio between 0.1 - 0.3.

  7. Power-efficient III-V/silicon external cavity DBR lasers.

    Science.gov (United States)

    Zilkie, A J; Seddighian, P; Bijlani, B J; Qian, W; Lee, D C; Fathololoumi, S; Fong, J; Shafiiha, R; Feng, D; Luff, B J; Zheng, X; Cunningham, J E; Krishnamoorthy, A V; Asghari, M

    2012-10-08

    We report the design and characterization of external-cavity DBR lasers built with a III-V-semiconductor reflective-SOA with spot-size converter edge-coupled to SOI waveguides containing Bragg grating mirrors. The un-cooled lasers have wall-plug-efficiencies of up to 9.5% at powers of 6 mW. The lasers are suitable for making power efficient, hybrid WDM transmitters in a CMOS-compatible SOI optical platform.

  8. Self-mode-locked vertical-external-cavity surface-emitting laser

    OpenAIRE

    Rahimi-Iman, Arash; Gaafar, Mahmoud; Möller, Christoph; Vaupel, Max; Zhang, Fan; Al-Nakdali, Dalia; Fedorova, Ksenia A.; Stolz, Wolfgang; Rafailov, Edik U.; Koch, Martin

    2016-01-01

    Ultrashort laser pulses from vertical-external-cavity surface-emitting lasers (VECSELs) have been receiving much attention in the semiconductor laser community since the first demonstration of sub-ps-pulsed devices more than a decade ago. Originally relying on semiconductor saturable-absorber mirrors for pulse formation, mode-locked operation has not only become accessible by using a variety of saturable absorbers, but also by using a saturable-absorber-free technique referred to as self-mode...

  9. The uncanny mirror: a re-framing of mirror self-experience.

    Science.gov (United States)

    Rochat, Philippe; Zahavi, Dan

    2011-06-01

    Mirror self-experience is re-casted away from the cognitivist interpretation that has dominated discussions on the issue since the establishment of the mirror mark test. Ideas formulated by Merleau-Ponty on mirror self-experience point to the profoundly unsettling encounter with one's specular double. These ideas, together with developmental evidence are re-visited to provide a new, psychologically and phenomenologically more valid account of mirror self-experience: an experience associated with deep wariness. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Multipartite quantum correlations among atoms in QED cavities

    Science.gov (United States)

    Batle, J.; Farouk, A.; Tarawneh, O.; Abdalla, S.

    2018-02-01

    We study the nonlocality dynamics for two models of atoms in cavity quantum electrodynamics (QED); the first model contains atoms in a single cavity undergoing nearest-neighbor interactions with no initial correlation, and the second contains atoms confined in n different and noninteracting cavities, all of which were initially prepared in a maximally correlated state of n qubits corresponding to the atomic degrees of freedom. The nonlocality evolution of the states in the second model shows that the corresponding maximal violation of a multipartite Bell inequality exhibits revivals at precise times, defining, nonlocality sudden deaths and nonlocality sudden rebirths, in analogy with entanglement. These quantum correlations are provided analytically for the second model to make the study more thorough. Differences in the first model regarding whether the array of atoms inside the cavity is arranged in a periodic or open fashion are crucial to the generation or redistribution of quantum correlations. This contribution paves the way to using the nonlocality multipartite correlation measure for describing the collective complex behavior displayed by slightly interacting cavity QED arrays.

  11. Resonant cavities for efficient LT-GaAs photoconductors operating at λ = 1550 nm

    Directory of Open Access Journals (Sweden)

    M. Billet

    2016-10-01

    Full Text Available We show that photoconductors based on low-temperature-grown GaAs (LT-GaAs can be efficiently operated by 1.55 μm telecom wavelength by using metallic mirror based optical cavities. Two different semi-transparent front mirrors are compared: the first one is a thin gold layer, whereas the second one consists of a gold grating. Light absorption in grating mirror based optical cavities is numerically, analytically, and experimentally investigated allowing for an appropriate optical design. We show a 3 times improvement of the LT-GaAs photoconductor photoresponse by using, as front mirror, the gold grating once compared with the thin gold layer. It reaches around 0.5 mA/W under continuous wave, whereas a transient photoresistivity (Ron as low as 5 Ω is deduced from dc photocurrents measured under femtosecond pulsed laser excitation. This work paves the way to efficient and reliable optoelectronics systems for GHz or THz waves sampling driven by 1.55 μm pulsed lasers widely available.

  12. Resonant cavities for efficient LT-GaAs photoconductors operating at λ = 1550 nm

    Science.gov (United States)

    Billet, M.; Latzel, P.; Pavanello, F.; Ducournau, G.; Lampin, J.-F.; Peytavit, E.

    2016-10-01

    We show that photoconductors based on low-temperature-grown GaAs (LT-GaAs) can be efficiently operated by 1.55 μm telecom wavelength by using metallic mirror based optical cavities. Two different semi-transparent front mirrors are compared: the first one is a thin gold layer, whereas the second one consists of a gold grating. Light absorption in grating mirror based optical cavities is numerically, analytically, and experimentally investigated allowing for an appropriate optical design. We show a 3 times improvement of the LT-GaAs photoconductor photoresponse by using, as front mirror, the gold grating once compared with the thin gold layer. It reaches around 0.5 mA/W under continuous wave, whereas a transient photoresistivity (Ron) as low as 5 Ω is deduced from dc photocurrents measured under femtosecond pulsed laser excitation. This work paves the way to efficient and reliable optoelectronics systems for GHz or THz waves sampling driven by 1.55 μm pulsed lasers widely available.

  13. Nonlocal Intracranial Cavity Extraction

    Science.gov (United States)

    Manjón, José V.; Eskildsen, Simon F.; Coupé, Pierrick; Romero, José E.; Collins, D. Louis; Robles, Montserrat

    2014-01-01

    Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV) is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden. PMID:25328511

  14. Frequency-feedback cavity enhanced spectrometer

    Science.gov (United States)

    Hovde, David Christian; Gomez, Anthony

    2015-08-18

    A spectrometer comprising an optical cavity, a light source capable of producing light at one or more wavelengths transmitted by the cavity and with the light directed at the cavity, a detector and optics positioned to collect light transmitted by the cavity, feedback electronics causing oscillation of amplitude of the optical signal on the detector at a frequency that depends on cavity losses, and a sensor measuring the oscillation frequency to determine the cavity losses.

  15. A USPL functional system with articulated mirror arm for in-vivo applications in dentistry

    Science.gov (United States)

    Schelle, Florian; Meister, Jörg; Dehn, Claudia; Oehme, Bernd; Bourauel, Christoph; Frentzen, Mathias

    Ultra-short pulsed laser (USPL) systems for dental application have overcome many of their initial disadvantages. However, a problem that has not yet been addressed and solved is the beam delivery into the oral cavity. The functional system that is introduced in this study includes an articulated mirror arm, a scanning system as well as a handpiece, allowing for freehand preparations with ultra-short laser pulses. As laser source an Nd:YVO4 laser is employed, emitting pulses with a duration of tp Laser sources with higher average output powers might be needed in order to reach sufficient preparation speeds.

  16. Silicon-photonics light source realized by III-V/Si grating-mirror laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2010-01-01

    A III–V/Si vertical-cavity in-plane-emitting laser structure is suggested and numerically investigated. This hybrid laser consists of a distributed Bragg reflector, a III–V active region, and a high-index-contrast grating HCG connected to an in-plane output waveguide. The HCG and the output...... waveguide are made in the Si layer of a silicon-on-insulator wafer by using Si-electronics-compatible processing. The HCG works as a highly-reflective mirror for vertical resonance and at the same time routes light to the in-plane output waveguide. Numerical simulations show superior performance compared...

  17. Monolithic high-index contrast grating: a material independent high-reflectance VCSEL mirror.

    Science.gov (United States)

    Gębski, M; Dems, M; Szerling, A; Motyka, M; Marona, L; Kruszka, R; Urbańczyk, D; Walczakowski, M; Pałka, N; Wójcik-Jedlińska, A; Wang, Q J; Zhang, D H; Bugajski, M; Wasiak, M; Czyszanowski, T

    2015-05-04

    In this paper we present an extensive theoretical and numerical analysis of monolithic high-index contrast grating, facilitating simple manufacture of compact mirrors for very broad spectrum of vertical-cavity surface-emitting lasers (VCSELs) emitting from ultraviolet to mid-infrared. We provide the theoretical background explaining the phenomenon of high reflectance in monolithic subwavelength gratings. In addition, by using a three-dimensional, fully vectorial optical model, verified by comparison with the experiment, we investigate the optimal parameters of high-index contrast grating enabling more than 99.99% reflectance in the diversity of photonic materials and in the broad range of wavelengths.

  18. Measuring the Dispersion in Laser Cavity Mirrors using White-Light Interferometry

    Science.gov (United States)

    2008-03-01

    how it lends itself to this application. White light is essentially incoherent, like sunlight -- unless one looks on a femtosecond time-scale. Its...dispersion, is group-velocity and the second term σ = 1 , and λ λ ω = 2πν = 2π hc = 2πhcσ . (8.2) hen substitute (8.2) into (8.1) T 2 Δφ ω( )= 1

  19. Transferring a cavity field entangled state in cavity QED

    Energy Technology Data Exchange (ETDEWEB)

    Ye Liu [Anhui Key Laboratory of Information Material and Devices, School of Physics and Material Science, Anhui University, Hefei 230039 (China); Guo Guangcan [Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026 (China)

    2005-08-01

    We propose a scheme for transferring an entanglement of zero- and one-photon states from one cavity to another. The scheme, which has 100% success probability, is mainly based on a two-mode cavity dispersively interacting with a three-level atom in the {lambda} configuration and does not involve Bell-state measurement. This scheme can also be used to teleport an unknown atomic state.

  20. Study of gas detection based on integrated cavity output spectroscopy

    Science.gov (United States)

    Pei, Shixin; Cui, Fenping; Su, Jing; Xu, Linhua; Sun, Tingting

    2013-08-01

    A trace gases detection system based on integrated cavity output spectroscopy (ICOS) was developed, where a NIR tunable diode laser (TDL) was used as light source, an optical cavity composed by two plan-concave mirrors with reflection near 99.7% was used as the absorption cell. Trace water vapour (H2O), carbon dioxide (CO2), methane (CH4), carbon monoxide (CO) and mixture of CO2 and CO were tested by ICOS based on the characteristics absorption. The wavelength calibration, cavity transmission characteristics, quantitative measurement ability and sensitivity of the TDL-ICOS were also studied, and a evaluated minimum detectable sensitivity of 1.15 × 10-7 cm-1 was obtained when the system was used to CH4 detection. The experiment results show that TDL-ICOS is expected to be a reliable and promising system for the detection of trace gases since it has some advantages such as real-time monitoring, simple device, easy operation, high sensitivity, good stability and quantitative ability.

  1. Unravelling the optical responses of nanoplasmonic mirror-on-mirror metamaterials

    NARCIS (Netherlands)

    Sikdar, D.; Hasan, Shakeeb Bin; Urbakh, M.; Edel, J.B.; Kornyshev, A.A.

    2016-01-01

    Mirror-on-mirror platforms based on arrays of metallic nanoparticles, arranged top-down or self-assembled on a thin metallic film, have interesting optical properties. Interaction of localized surface-plasmons in nanoparticles with propagating surface-plasmons in the film underpins the exotic

  2. SRF Cavity Fabrication and Materials

    CERN Document Server

    Singer, W

    2014-07-17

    The technological and metallurgical requirements of material for highgradient superconducting cavities are described. High-purity niobium, as the preferred metal for the fabrication of superconducting accelerating cavities, should meet exact specifications. The content of interstitial impurities such as oxygen, nitrogen, and carbon must be below 10μg/g. The hydrogen content should be kept below 2μg/g to prevent degradation of the Q-value under certain cool-down conditions. The material should be free of flaws (foreign material inclusions or cracks and laminations) that can initiate a thermal breakdown. Defects may be detected by quality control methods such as eddy current scanning and identified by a number of special methods. Conventional and alternative cavity fabrication methods are reviewed. Conventionally, niobium cavities are fabricated from sheet niobium by the formation of half-cells by deep drawing, followed by trim machining and Electron-Beam Welding (EBW). The welding of half-cells is a delicate...

  3. Niobium LEP 2 accelerating cavities

    CERN Multimedia

    An accelerating cavity from LEP. This could be cut open to show the layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities were used in an upgrade of the LEP accelerator to double the energy of the particle beams.

  4. Mirror World at the Large Hadron Collider

    CERN Document Server

    Barbieri, Riccardo; Hall, L J; Barbieri, Riccardo; Gregoire, Thomas; Hall, Lawrence J

    2005-01-01

    A mirror world can modify in a striking way the LHC signals of the Higgs sector. An exact or approximate Z_2 symmetry between the mirror world and our world allows large mixing between the Higgs bosons of these worlds, leading to production rates and branching ratios for these states that are markedly different from the standard model and are characteristic of a mirror world. The constraints on these Higgs boson masses from precision electroweak data differ from the standard model bound, so that the new physics that cancels the quadratic divergence induced by the top quark may appear at a larger scale, possibly beyond the reach of the LHC. However, the scale of new physics needed to cancel the quadratic divergence induced by the Higgs boson is not significantly changed. With small breakings of the Z_2 parity, the lightest mirror quarks (and possibly charged mirror leptons) could be the dark matter in the universe, forming galactic halos that are stable to cooling. A possible signal from the relic radiation de...

  5. Advances in Tandem Mirror fusion power reactors

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, L.J.; Logan, B.G.

    1986-05-20

    The Tandem Mirror exhibits several distinctive features which make the reactor embodiment of the principle very attractive: Simple low-technology linear central cell; steady-state operation; high-..beta.. operation; no driven current or disruptions; divertorless operation; direction conversion of end-loss power; low-surface heat loads; and advanced fusion fuel capability. In this paper, we examine these features in connection with two tandem mirror reactor designs, MARS and MINIMARS, and several advanced reactor concepts including the wall-stabilized reactor and the field-reversed mirror. With a novel compact end plug scheme employing octopole stabilization, MINIMARS is expressly designed for short construction times, factory-built modules, and a small (600 MWe) but economic reactor size. We have also configured the design for low radioactive afterheat and inherent/passive safety under LOCA/LOFA conditions, thereby obviating the need for expensive engineered safety systems. In contrast to the complex and expensive double-quadrupole end-cell of the MARS reactor, the compact octopole end-cell of MINIMARS enables ignition to be achieved with much shorter central cell lengths and considerably improves the economy of scale for small (approx.250 to 600 MWe) tandem mirror reactors. Finally, we examine the prospects for realizing the ultimate potential of the tandem mirror with regard to both innovative configurations and novel neutron energy conversion schemes, and stress that advanced fuel applications could exploit its unique reactor features.

  6. LEP Radio Frequency Copper Cavity

    CERN Document Server

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  7. Single and Coupled Nanobeam Cavities

    DEFF Research Database (Denmark)

    Ivinskaya, Aliaksandra; Lavrinenko, Andrei; Shyroki, Dzmitry M.

    2013-01-01

    of photonic crystal filters. The second part focuses on some aspects of photonic crystals fabrication and relevant applications, such as nitrogen defect technology in diamond, silicon nitride free standing membranes, photonic crystals structures in silicon, photonic crystals for optical sensing....... for analysis and design of photonic crystal devices, such as 2D ring resonators for filters, single and coupled nanobeam cavities, birefringence in photonic crystal cavities, threshold analysis in photonic crystal lasers, gap solitons in photonic crystals, novel photonic atolls, dynamic characteristics...

  8. Mirror, Mirror by the Stairs: The Impact of Mirror Exposure on Stair versus Elevator Use in College Students.

    Science.gov (United States)

    Hodgin, Katie L; Graham, Dan J

    2016-01-01

    Previous research has indicated that self-awareness-inducing mirrors can successfully incite behaviors that align with one's personal values, such as helping others. Other research has found a large discrepancy between the high percentage of young adults who report valuing the healthfulness of physical activity (PA) and the low percentage who actually meet PA participation standards. However, few studies have examined how mirror exposure and both perceived and actual body size influence highly valued PA participation among college students. The present study assessed stair versus elevator use on a western college campus and hypothesized that mirror exposure would increase the more personally healthy transportation method of stair use. In accordance with previous research, it was also hypothesized that males and those with a lower body mass index (BMI) would be more likely to take the stairs, and that body size distorting mirrors would impact the stair-elevator decision. One hundred sixty-seven students (51% male) enrolled in an introductory psychology course were recruited to take a survey about their "transportation choices" at an indoor campus parking garage. Participants were individually exposed to either no mirror, a standard full-length mirror, or a full-length mirror manipulated to make the reflected body size appear either slightly thinner or slightly wider than normal before being asked to go to the fourth floor of the garage for a survey. Participants' choice of floor-climbing method (stairs or elevator) was recorded, and they were administered an Internet-based survey assessing demographic information, BMI, self-awareness, perceived body size, and other variables likely to be associated with stair use. Results from logistic regression analyses revealed that participants who were not exposed to a mirror [odds ratios (OR) = 0.37, 95% CI: 0.14-0.96], males (OR = 0.33, 95% CI: 0.13-0.85), those with lower BMI (OR = 0.84, 95% CI: 0.71-0.99), those

  9. Mirror, Mirror by the Stairs: The Impact of Mirror Exposure on Stair versus Elevator Use in College Students

    Directory of Open Access Journals (Sweden)

    Katie L Hodgin

    2016-04-01

    Full Text Available AbstractPrevious research has indicated that self-awareness-inducing mirrors can successfully incite behaviors that align with one’s personal values, such as helping others. Other research has found a large discrepancy between the high percentage of young adults who report valuing the healthfulness of physical activity (PA and the low percentage who actually meet PA participation standards. Few studies, however, have examined how mirror exposure and both perceived and actual body size influence highly-valued PA participation among college students. The present study assessed stair versus elevator use on a western college campus and hypothesized that mirror exposure would increase the more personally-healthy transportation method of stair use. In accordance with previous research, it was also hypothesized that males and those with a lower body mass index (BMI would be more likely to take the stairs, and that body-size distorting mirrors would impact the stair-elevator decision. One hundred and sixty-seven students (51% male enrolled in an introductory psychology course were recruited to take a survey about their transportation choices at an indoor campus parking garage. Participants were individually exposed to either no mirror, a standard full-length mirror, or a full-length mirror manipulated to make the reflected body size appear either slightly thinner or slightly wider than normal before being asked to go to the fourth floor of the garage for a survey. Participants’ choice of floor climbing method (stairs or elevator was recorded and they were administered an internet-based survey assessing demographic information, BMI, self-awareness, perceived body size, and other variables likely to be associated with stair use. Results from logistic regression analyses revealed that participants who were not exposed to a mirror (OR = 0.37, 95% CI: 0.14 – 0.96, males (OR = 0.33, 95% CI: 0.13 – 0.85, those with lower BMI (OR = 0.84, 95% CI: 0.71

  10. Mirror, Mirror by the Stairs: The Impact of Mirror Exposure on Stair versus Elevator Use in College Students

    Science.gov (United States)

    Hodgin, Katie L.; Graham, Dan J.

    2016-01-01

    Previous research has indicated that self-awareness-inducing mirrors can successfully incite behaviors that align with one’s personal values, such as helping others. Other research has found a large discrepancy between the high percentage of young adults who report valuing the healthfulness of physical activity (PA) and the low percentage who actually meet PA participation standards. However, few studies have examined how mirror exposure and both perceived and actual body size influence highly valued PA participation among college students. The present study assessed stair versus elevator use on a western college campus and hypothesized that mirror exposure would increase the more personally healthy transportation method of stair use. In accordance with previous research, it was also hypothesized that males and those with a lower body mass index (BMI) would be more likely to take the stairs, and that body size distorting mirrors would impact the stair–elevator decision. One hundred sixty-seven students (51% male) enrolled in an introductory psychology course were recruited to take a survey about their “transportation choices” at an indoor campus parking garage. Participants were individually exposed to either no mirror, a standard full-length mirror, or a full-length mirror manipulated to make the reflected body size appear either slightly thinner or slightly wider than normal before being asked to go to the fourth floor of the garage for a survey. Participants’ choice of floor-climbing method (stairs or elevator) was recorded, and they were administered an Internet-based survey assessing demographic information, BMI, self-awareness, perceived body size, and other variables likely to be associated with stair use. Results from logistic regression analyses revealed that participants who were not exposed to a mirror [odds ratios (OR) = 0.37, 95% CI: 0.14–0.96], males (OR = 0.33, 95% CI: 0.13–0.85), those with lower BMI (OR = 0.84, 95% CI: 0

  11. High finesse optical fiber cavities: optimal alignment and robust stabilization (Conference Presentation)

    Science.gov (United States)

    Ratschbacher, Lothar; Gallego, Jose; Ghosh, Sutapa; Alavi, Seyed; Alt, Wolfgang; Martinez-Dorantes, Miguel; Meschede, Dieter

    2016-04-01

    Fiber Fabry-Perot cavities, formed by micro-machined mirrors on the end-facets of optical fibers, are used in an increasing number of technical and scientific applications. Some of the most promising areas of application of these optical micro-resonators with high finesse and small mode volume are in the field of quantum communication and information. The resonator-enhanced light-matter interaction, for instance, provide basis for the realization of efficient optical interfaces between stationary matter-based quantum nodes and flying single-photon qubits. To date fiber Fabry-Perot cavities have been successfully applied in experiments interfacing single photons with a wide range of quantum systems, including cold atoms, ions and solid state emitters as well as quantum optomechanical experiments. Here we address some important practical questions that arise during the experimental implementation of high finesse fiber Fabry-Perot cavities: How can optimal fiber cavity alignment be achieved and how can the efficiency of coupling light from the optical fibers to the cavity mode and vice versa be characterized? How should optical fiber cavities be constructed and stabilized to fulfill their potential for miniaturization and integration into robust scientific and technological devices that can operate outside of dedicated laboratory environments in the future? The first two questions we answer with an analytic mode matching calculation that relates the alignment dependent fiber-to-cavity mode-matching efficiency to the easily measurable dip in the reflected light power at the cavity resonance. Our general analysis provides a simple recipe for the optimal alignment of fiber Fabry-Perot cavities and moreover for the first time explains the asymmetry in their reflective line shapes. The latter question we explore by investigating a novel, intrinsically rigid fiber cavity design that makes use of the high passive stability of a monolithic cavity spacer and employs thermal

  12. Integrated Cavity QED in a linear Ion Trap Chip for Enhanced Light Collection

    Science.gov (United States)

    Benito, Francisco; Jonathan, Sterk; Boyan, Tabakov; Haltli, Raymond; Tigges, Chris; Stick, Daniel; Balin, Matthew; Moehring, David

    2012-06-01

    Realizing a scalable trapped-ion quantum information processor may require integration of tools to manipulate qubits into trapping devices. We present efforts towards integrating a 1 mm optical cavity into a microfabricated surface ion trap to efficiently connect nodes in a quantum network. The cavity is formed by a concave mirror and a flat coated silicon mirror around a linear trap where ytterbium ions can be shuttled in and out of the cavity mode. By utilizing the Purcell effect to increase the rate of spontaneous emission into the cavity mode, we expect to collect up to 13% of the emitted photons. This work was supported by Sandia's Laboratory Directed Research and Development (LDRD) and the Intelligence Advanced Research Projects Activity (IARPA). Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  13. The prediction of difficult intubation in obese patients using mirror indirect laryngoscopy: A prospective pilot study.

    Science.gov (United States)

    Budde, Arne O; Desciak, Matthew; Reddy, Venugopal; Falcucci, Octavio A; Vaida, Sonia J; Pott, Leonard M

    2013-04-01

    The incidence of difficult laryngoscopy and intubation in obese patients is higher than in the general population. Classical predictors of difficult laryngoscopy and intubation have been shown to be unreliable. We prospectively evaluated indirect mirror laryngoscopy as a predictor of difficult laryngoscopy in obese patients. 60 patients with a body mass index (BMI) greater than 30, scheduled to undergo general anesthesia, were enrolled. Indirect mirror laryngoscopy was performed and was graded 1-4 according to Cormack and Lehane. A view of grade 3-4 was classified as predicting difficult laryngoscopy. Additional assessments for comparison were the Samsoon and Young modification of the Mallampati airway classification, Wilson Risk Sum Score, neck circumference, and BMI. The view obtained upon direct laryngoscopy after induction of general anesthesia was classified according to Cormack and Lehane as grade 1-4. Sixty patients met the inclusion criteria; however, 8 (13.3%) patients had an excessive gag reflex, and examination of the larynx was not possible. 15.4% of patients who underwent direct laryngoscopy had a Cormack and Lehane grade 3 or 4 view and were classified as difficult. Mirror laryngoscopy had a tendency toward statistical significance in predicting difficult laryngoscopy in these patients. This study is consistent with previous studies, which have demonstrated that no one individual traditional test has proven to be adequate in predicting difficult airways in the obese population. However, the new application of an old test - indirect mirror laryngoscopy - could be a useful additional test to predict difficult laryngoscopy in obese patients.

  14. Effect of intermediate layers on atomic layer deposition-aluminum oxide protected silver mirrors

    Science.gov (United States)

    Fryauf, David M.; Diaz Leon, Juan J.; Phillips, Andrew C.; Kobayashi, Nobuhiko P.

    2017-07-01

    This work investigates intermediate materials deposited between silver (Ag) thin-film mirrors and an aluminum oxide (AlOx) barrier overlayer and compares the effects on mirror durability to environmental stresses. Physical vapor deposition of various fluorides, oxides, and nitrides in combination with AlOx by atomic layer deposition (ALD) is used to develop several coating recipes. Ag-AlOx samples with different intermediate materials undergo aggressive high-temperature (80°C), high-humidity (80%) (HTHH) testing for 10 days. Reflectivity of mirror samples is measured before and after HTHH testing, and image processing techniques are used to analyze the specular surface of the samples after HTHH testing. Among the seven intermediate materials used in this work, TiN, MgAl2O4, NiO, and Al2O3 intermediate layers offer more robust protection against chemical corrosion and moisture when compared with samples with no intermediate layer. In addition, results show that the performance of the ALD-AlOx barrier overlayer depends significantly on the ALD-growth process temperature. Because higher durability is observed in samples with less transparent TiN and NiO layers, we propose a figure of merit based on post-HTHH testing reflectivity change and specular reflective mirror surface area remaining after HTHH testing to judge overall barrier performance.

  15. Homological mirror symmetry and tropical geometry

    CERN Document Server

    Catanese, Fabrizio; Kontsevich, Maxim; Pantev, Tony; Soibelman, Yan; Zharkov, Ilia

    2014-01-01

    The relationship between Tropical Geometry and Mirror Symmetry goes back to the work of Kontsevich and Y. Soibelman (2000), who applied methods of non-archimedean geometry (in particular, tropical curves) to Homological Mirror Symmetry. In combination with the subsequent work of Mikhalkin on the “tropical” approach to Gromov-Witten theory, and the work of Gross and Siebert, Tropical Geometry has now become a powerful tool. Homological Mirror Symmetry is the area of mathematics concentrated around several categorical equivalences connecting symplectic and holomorphic (or algebraic) geometry. The central ideas first appeared in the work of Maxim Kontsevich (1993). Roughly speaking, the subject can be approached in two ways: either one uses Lagrangian torus fibrations of Calabi-Yau manifolds (the so-called Strominger-Yau-Zaslow picture, further developed by Kontsevich and Soibelman) or one uses Lefschetz fibrations of symplectic manifolds (suggested by Kontsevich and further developed by Seidel). Tropical Ge...

  16. Conference on Complex Geometry and Mirror Symmetry

    CERN Document Server

    Vinet, Luc; Yau, Shing-Tung; Mirror Symmetry III

    1999-01-01

    This book presents surveys from a workshop held during the theme year in geometry and topology at the Centre de recherches mathématiques (CRM, University of Montréal). The volume is in some sense a sequel to Mirror Symmetry I (1998) and Mirror Symmetry II (1996), copublished by the AMS and International Press. Included are recent developments in the theory of mirror manifolds and the related areas of complex and symplectic geometry. The long introductory articles explain the key physical ideas and motivation, namely conformal field theory, supersymmetry, and string theory. Open problems are emphasized. Thus the book provides an efficient way for a very broad audience of mathematicians and physicists to reach the frontier of research in this fast expanding area. - See more at: http://bookstore.ams.org/amsip-10#sthash.DbxEFJDx.dpuf

  17. An advanced KB mirror pair for microfocusing

    CERN Document Server

    Ferme, J J

    2001-01-01

    A new range of micro-focusing mirrors based on KB pairs has been developed by SESO for Beamline Nanospectroscopy at the Elettra Storage Ring in Trieste, Italy. Both the focusing and the aspheric shape are adjustable with stepper motors. The goal of the beamline is to have a high photon density spot with a variable size in the experimental chamber over the whole soft X-ray range. The estimated dimension of the final spot should be smaller than 4 mu m sup 2 FWHM, with a photon density of the order of 10 sup 1 sup 3 photons/s mu m sup 2; this may be achieved only by accepting an angular divergence on these mirrors of between 5 and 10 mrad. This condition can be fulfilled only with elliptical (or plane elliptical) mirrors with very limited residual slope errors (below 1 mu rad RMS) that are able to correct even small focal distance errors.

  18. Mirror symmetry for two parameter models, 2

    CERN Document Server

    Candelas, Philip; Katz, S; Morrison, Douglas Robert Ogston; Philip Candelas; Anamaria Font; Sheldon Katz; David R Morrison

    1994-01-01

    We describe in detail the space of the two K\\"ahler parameters of the Calabi--Yau manifold \\P_4^{(1,1,1,6,9)}[18] by exploiting mirror symmetry. The large complex structure limit of the mirror, which corresponds to the classical large radius limit, is found by studying the monodromy of the periods about the discriminant locus, the boundary of the moduli space corresponding to singular Calabi--Yau manifolds. A symplectic basis of periods is found and the action of the Sp(6,\\Z) generators of the modular group is determined. From the mirror map we compute the instanton expansion of the Yukawa couplings and the generalized N=2 index, arriving at the numbers of instantons of genus zero and genus one of each degree. We also investigate an SL(2,\\Z) symmetry that acts on a boundary of the moduli space.

  19. Massive Particle Reflection from Moving Mirrors

    Science.gov (United States)

    Sfarti, Adrian

    2016-09-01

    We investigate the reflection of massive particles from moving mirrors. The adoption of the formalism based on the energy-momentum allowed us to derive the most general set of formulas, valid for massive and, in the limit, also for massless particles. We show that the momentum change of the reflecting particle always lies along the normal to the mirror, independent of the mirror speed. The subject is interesting not only to physicists designing concentrators for fascicles of massive particles and electron microscopes but also to computer scientists working in raytracing operating in the photon sector. The paper, far from being only theoretical, has profound and novel practical applications in both domains of engineering design and computer science.

  20. An alternative solar pumping approach by a light guide assembly elliptical-cylindrical cavity

    Energy Technology Data Exchange (ETDEWEB)

    Geraldes, Joao P.; Liang, Dawei [CEFITEC, Departamento de Fisica, FCT, Universidade Nova de Lisboa, 2825, Campus de Caparica (Portugal)

    2008-08-15

    To improve solar laser output performance, what we believe to be a novel light guide assembly is proposed to pump a Nd:YAG laser rod within a two-dimensional elliptical-cylindrical (2D-EL-CYL) cavity with intervening optics. Based on refractive and total internal reflection principles, the concentrated solar radiation from a primary parabolic mirror is coupled through the square input face of a fused silica light guide assembly to its rectangular output end, located along the first focal line of the 2D-EL-CYL cavity. Optimized pumping conditions are found through ZEMAX trademark non-sequential ray-tracing software. By comparing with the laser performance of a two-dimensional dielectric compound parabolic concentrator (2D-DCPC) cavity, significant improvements in absorption distribution, TEM{sub 00} laser power and tracking error dependent output power stability are obtained by the proposed pumping approach. (author)

  1. High finesse hollow-core fiber resonating cavity for high sensitivity gas sensing application

    Science.gov (United States)

    Tan, Yanzhen; Jin, Wei; Yang, Fan; Ho, Hoi Lut

    2017-04-01

    We present all-fiber resonating Fabry-Perot gas cells made with a piece of hollow-core photonic bandgap fiber (HCPBF) sandwiched by two single mode fibers with mirrored ends. A HC-PBF cavity made of 6.75-cm-long HC-1550-06 fiber achieved a cavity finesse of 128, corresponding to an effective optical path length of 5.5 m. Such HC-PBF cavities can be used as absorption cells for high sensitivity gas detection with fast response. Preliminary experiment with a 9.4-cm-long resonating gas cell with a finesse of 68 demonstrated a detection limit better than 7.5 p.p.m. acetylene.

  2. Thermal distortions of non-Gaussian beams in Fabry-Perot cavities

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J [IGR, University of Glasgow, University Avenue, Glasgow, G12 8QQ (United Kingdom); Willems, P; Yamamoto, H; Agresti, J; DeSalvo, R [LIGO Laboratory, California Institute of Technology, 1200 E California Blvd, Pasadena, CA 91125 (United States)], E-mail: j.miller@physics.gla.ac.uk

    2008-12-07

    Thermal effects are already important in currently operating interferometric gravitational wave detectors. Planned upgrades of these detectors involve increasing optical power to combat quantum shot noise. We consider the ramifications of this increased power for one particular class of laser beams-wide, flat-topped, mesa beams. In particular we model a single mesa beam Fabry-Perot cavity having thermoelastically deformed mirrors. We calculate the intensity profile of the fundamental cavity eigenmode in the presence of thermal perturbations, and the associated changes in thermal noise. We also outline an idealized method of correcting for such effects. At each stage we contrast our results with those of a comparable Gaussian beam cavity. Although we focus on mesa beams the techniques described are applicable to any azimuthally symmetric system.

  3. Pigmentation of oral cavity: A clinical enigma; A rare case report

    Directory of Open Access Journals (Sweden)

    Shams Ul Nisa

    2016-01-01

    Full Text Available The diagnosis of pigmented lesions of the oral cavity and perioral tissues is challenging for the clinicians. The term orofacial pigmentation refers to a wide range of lesions and conditions, which change the color of the orofacial tissues. Even though some lesions may definitively be diagnosed on clinical grounds alone, the final diagnosis usually requires clinical, biochemical, and histopathologic evaluation. Clinical tests, such as diascopy and radiography, and laboratory investigations, such as blood tests, can be used to confirm a clinical impression and reach a definitive diagnosis. The oral cavity is the mirror of the body and is often the area where systemic diseases first present. Hereby, we are presenting a rare case of macular hyperpigmentation with lace-like pattern of oral cavity and macular hyperpigmentation of the face, skin, and palms, with a diagnosis of pigmentation due to iron-deficiency anemia.

  4. Collimated Magnetron Sputter Deposition for Mirror Coatings

    DEFF Research Database (Denmark)

    Vickery, A.; Cooper-Jensen, Carsten P.; Christensen, Finn Erland

    2008-01-01

    At the Danish National Space Center (DNSC), a planar magnetron sputtering chamber has been established as a research and production coating facility for curved X-ray mirrors for hard X-ray optics for astronomical X-ray telescopes. In the following, we present experimental evidence that a collimat......At the Danish National Space Center (DNSC), a planar magnetron sputtering chamber has been established as a research and production coating facility for curved X-ray mirrors for hard X-ray optics for astronomical X-ray telescopes. In the following, we present experimental evidence...

  5. Mirror Writing and a Dissociative Identity Disorder

    Directory of Open Access Journals (Sweden)

    Catherine Le

    2009-01-01

    Full Text Available Individuals with dissociative identity disorder (DID have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam—mirror writing. It is not known whether her mirror writing had a deeper level of meaning; however, it does emphasize the idiosyncratic nature of dissociative identity disorder.

  6. Mirror writing and a dissociative identity disorder.

    Science.gov (United States)

    Le, Catherine; Smith, Joyce; Cohen, Lewis

    2009-01-01

    Individuals with dissociative identity disorder (DID) have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam-mirror writing. It is not known whether her mirror writing had a deeper level of meaning; however, it does emphasize the idiosyncratic nature of dissociative identity disorder.

  7. Mirroring Mobile Phone in the Clouds

    OpenAIRE

    Frank Z. Wang

    2014-01-01

    This paper presents a framework of Mirroring Mobile Phone in the Clouds (MMPC) to speed up data/computing intensive applications on a mobile phone by taking full advantage of the super computing power of the clouds. An application on the mobile phone is dynamically partitioned in such a way that the heavy-weighted part is always running on a mirrored server in the clouds while the light-weighted part remains on the mobile phone. A performance improvement (an energy consumption reduction of 70...

  8. Lightweight Deployable Mirrors with Tensegrity Supports

    Science.gov (United States)

    Zeiders, Glenn W.; Bradford, Larry J.; Cleve, Richard C.

    2004-01-01

    The upper part of Figure 1 shows a small-scale prototype of a developmental class of lightweight, deployable structures that would support panels in precise alignments. In this case, the panel is hexagonal and supports disks that represent segments of a primary mirror of a large telescope. The lower part of Figure 1 shows a complete conceptual structure containing multiple hexagonal panels that hold mirror segments. The structures of this class are of the tensegrity type, which was invented five decades ago by artist Kenneth Snelson. A tensegrity structure consists of momentfree compression members (struts) and tension members (cables). The structures of this particular developmental class are intended primarily as means to erect large segmented primary mirrors of astronomical telescopes or large radio antennas in outer space. Other classes of tensegrity structures could also be designed for terrestrial use as towers, masts, and supports for general structural panels. An important product of the present development effort is the engineering practice of building a lightweight, deployable structure as an assembly of tensegrity modules like the one shown in Figure 2. This module comprises two octahedral tensegrity subunits that are mirror images of each other joined at their plane of mirror symmetry. In this case, the plane of mirror symmetry is both the upper plane of the lower subunit and the lower plane of the upper subunit, and is delineated by the midheight triangle in Figure 2. In the configuration assumed by the module to balance static forces under mild loading, the upper and lower planes of each sub-unit are rotated about 30 , relative to each other, about the long (vertical) axis of the structure. Larger structures can be assembled by joining multiple modules like this one at their sides or ends. When the module is compressed axially (vertically), the first-order effect is an increase in the rotation angle, but by virtue of the mirror arrangement, the net

  9. Mirror and (absence of) counter-mirror responses to action sounds measured with TMS

    Science.gov (United States)

    Schütz-Bosbach, Simone; Waszak, Florian

    2017-01-01

    Abstract To what extent is the mirror neuron mechanism malleable to experience? The answer to this question can help characterising its ontogeny and its role in social cognition. Some suggest that it develops through sensorimotor associations congruent with our own actions. Others argue for its extreme volatility that will encode any sensorimotor association in the environment. Here, we added to this debate by exploring the effects of short goal-directed ‘mirror’ and ‘counter-mirror’ trainings (a ‘mirror’ training is defined as the first type of training encountered by the participants) on human auditory mirror motor-evoked potentials (MEPs). We recorded MEPs in response to two tones void of previous motor meaning, before and after mirror and counter-mirror trainings in which participants generated two tones of different pitch by performing free-choice button presses. The results showed that mirror MEPs, once established, were protected against an equivalent counter-mirror experience: they became manifest very rapidly and the same number of training trials that lead to the initial association did not suffice to reverse the MEP pattern. This steadiness of the association argues that, by serving direct-matching purposes, the mirror mechanism is a good solution for social cognition. PMID:29036454

  10. Alignment and focus of mirrored facets of a heliosat

    Science.gov (United States)

    Yellowhair, Julius E; Ho, Clifford Kuofei; Diver, Richard B; Moss, Timothy A

    2013-11-12

    Various technologies pertaining to aligning and focusing mirrored facets of a heliostat are described herein. Updating alignment and/or focus of mirrored facets is undertaken through generation of a theoretical image, wherein the theoretical image is indicative of a reflection of the target via the mirrored facets when the mirrored facets are properly aligned. This theoretical image includes reference points that are overlaid on an image of the target as reflected by the mirrored facets of the heliostat. A technician adjusts alignment/focus of a mirrored facet by causing reflected reference markings to become aligned with the reference points in the theoretical image.

  11. Active Beam Shaping System and Method Using Sequential Deformable Mirrors

    Science.gov (United States)

    Norman, Colin A. (Inventor); Pueyo, Laurent A. (Inventor)

    2015-01-01

    An active optical beam shaping system includes a first deformable mirror arranged to at least partially intercept an entrance beam of light and to provide a first reflected beam of light, a second deformable mirror arranged to at least partially intercept the first reflected beam of light from the first deformable mirror and to provide a second reflected beam of light, and a signal processing and control system configured to communicate with the first and second deformable mirrors. The first deformable mirror, the second deformable mirror and the signal processing and control system together provide a large amplitude light modulation range to provide an actively shaped optical beam.

  12. [Mirror, mirror of the wall: mirror therapy in the treatment of phantom limbs and phantom limb pain].

    Science.gov (United States)

    Casale, Roberto; Furnari, Anna; Lamberti, Raul Coelho; Kouloulas, Efthimios; Hagenberg, Annegret; Mallik, Maryam

    2015-01-01

    Phantom limb and phantom limb pain control are pivotal points in the sequence of intervention to bring the amputee to functional autonomy. The alterations of perception and sensation, the pain of the residual limb and the phantom limb are therefore aspects of amputation that should be taken into account in the "prise en charge" of these patients. Within the more advanced physical therapies to control phantom and phantom limb pain there is the use of mirrors (mirror therapy). This article willfocus on its use and on the possible side effects induced by the lack of patient selection and a conflict of body schema restoration through mirror therapy with concurrent prosthetic training and trauma acceptance. Advice on the need to select patients before treatment decisions, with regard to their psychological as well as clinical profile (including time since amputation and clinical setting), and the need to be aware of the possible adverse effects matching different and somehow conflicting therapeutic approaches, are put forward. Thus a coordinated sequence of diagnostic, prognostic and therapeutic procedures carried out by an interdisciplinary rehabilitation team that works globally on all patients' problems is fundamental in the management of amputees and phantom limb pain. Further studies and the development of a multidisciplinary network to study this and other applications of mirror therapy are needed.

  13. Fabrication of elliptical SRF cavities

    Science.gov (United States)

    Singer, W.

    2017-03-01

    The technological and metallurgical requirements of material for high-gradient superconducting cavities are described. High-purity niobium, as the preferred metal for the fabrication of superconducting accelerating cavities, should meet exact specifications. The content of interstitial impurities such as oxygen, nitrogen, and carbon must be below 10 μg g-1. The hydrogen content should be kept below 2 μg g-1 to prevent degradation of the quality factor (Q-value) under certain cool-down conditions. The material should be free of flaws (foreign material inclusions or cracks and laminations) that can initiate a thermal breakdown. Traditional and alternative cavity mechanical fabrication methods are reviewed. Conventionally, niobium cavities are fabricated from sheet niobium by the formation of half-cells by deep drawing, followed by trim machining and electron beam welding. The welding of half-cells is a delicate procedure, requiring intermediate cleaning steps and a careful choice of weld parameters to achieve full penetration of the joints. A challenge for a welded construction is the tight mechanical and electrical tolerances. These can be maintained by a combination of mechanical and radio-frequency measurements on half-cells and by careful tracking of weld shrinkage. The main aspects of quality assurance and quality management are mentioned. The experiences of 800 cavities produced for the European XFEL are presented. Another cavity fabrication approach is slicing discs from the ingot and producing cavities by deep drawing and electron beam welding. Accelerating gradients at the level of 35-45 MV m-1 can be achieved by applying electrochemical polishing treatment. The single-crystal option (grain boundary free) is discussed. It seems that in this case, high performance can be achieved by a simplified treatment procedure. Fabrication of the elliptical resonators from a seamless pipe as an alternative is briefly described. This technology has yielded good

  14. LS1 Report: A stubborn cavity will soon be replaced

    CERN Multimedia

    Katarina Anthony

    2013-01-01

    Testing on the LHC’s replacement RF cryomodule was completed last week in SM18. This module will bring them all to design-level, replacing a faulty cavity that has been acting up since the machine’s start-up.   A LHC cryomodule undergoes testing in SM18. Distributed between four cryomodules, the LHC is home to a total of 16 radiofrequency (RF) cavities. Each is designed to provide a 2 MV accelerating field… and all but one has been succeeding at this job. Ever since the machine’s startup, one stubborn cavity in a Point 4 module has quenched whenever it had to stay at 2 MV. The accelerator team found that no amount of conditioning could get the cavity to behave, and the highest continuous wave voltage it could perform at was 1.3 MV. “This was fine for physics,” says Pierre Maesen, who is leading the repair and replacement of the LHC’s cryomodules. “We were able to compensate for this ‘missing’...

  15. Thermal conditions within tree cavities in ponderosa pine (Pinus ponderosa) forests: potential implications for cavity users

    Science.gov (United States)

    Vierling, Kerri T.; Lorenz, Teresa J.; Cunningham, Patrick; Potterf, Kelsi

    2017-11-01

    Tree cavities provide critical roosting and breeding sites for multiple species, and thermal environments in these cavities are important to understand. Our objectives were to (1) describe thermal characteristics in cavities between June 3 and August 9, 2014, and (2) investigate the environmental factors that influence cavity temperatures. We placed iButtons in 84 different cavities in ponderosa pine (Pinus ponderosa) forests in central Washington, and took hourly measurements for at least 8 days in each cavity. Temperatures above 40 °C are generally lethal to developing avian embryos, and 18% of the cavities had internal temperatures of ≥ 40 °C for at least 1 h of each day. We modeled daily maximum cavity temperature, the amplitude of daily cavity temperatures, and the difference between the mean internal cavity and mean ambient temperatures as a function of several environmental variables. These variables included canopy cover, tree diameter at cavity height, cavity volume, entrance area, the hardness of the cavity body, the hardness of the cavity sill (which is the wood below the cavity entrance which forms the barrier between the cavity and the external environment), and sill width. Ambient temperature had the largest effect size for maximum cavity temperature and amplitude. Larger trees with harder sills may provide more thermally stable cavity environments, and decayed sills were positively associated with maximum cavity temperatures. Summer temperatures are projected to increase in this region, and additional research is needed to determine how the thermal environments of cavities will influence species occupancy, breeding, and survival.

  16. Red-cockaded woodpecker nest-cavity selection: relationships with cavity age and resin production

    Science.gov (United States)

    Richard N. Conner; Daniel Saenz; D. Craig Rudolph; William G. Ross; David L. Kulhavy

    1998-01-01

    The authors evaluated selection of nest sites by male red-cockaded woodpeckers (Picoides borealis) in Texas relative to the age of the cavity when only cavities excavated by the woodpeckers were available and when both naturally excavated cavities and artificial cavities were available. They also evaluated nest-cavity selection relative to the ability of naturally...

  17. Modelocking of a thin-disk laser with the frequency-doubling nonlinear-mirror technique.

    Science.gov (United States)

    Saltarelli, F; Diebold, A; Graumann, I J; Phillips, C R; Keller, U

    2017-09-18

    We demonstrate a frequency-doubling nonlinear-mirror (NLM) modelocked thin-disk laser. This modelocking technique, composed of an intracavity second harmonic crystal in combination with a dichroic output coupler, offers robust operation decoupled from cavity stability (as in semiconductor saturable absorber mirror (SESAM) modelocking) combined with an ultrafast saturable loss and high modulation depth (as in Kerr-lens modelocking (KLM)). With our NLM diode-pumped Yb:YAG thin-disk laser we achieve 21 W of average power at 323-fs pulse duration, which is an order of magnitude shorter than the previously obtained duration with the same technique in bulk lasers. Using these first results, we present a theoretical model for the NLM technique, which accurately predicts its loss modulation properties and the shortest achievable pulse duration without relying on any fitting parameters. Based on this simulation, we expect that the NLM technique will enable thin-disk lasers with average power of more than 100 W, with potentially sub-200 fs pulses. This could potentially solve the pulse duration limitations with SESAM modelocked Yb:YAG thin-disk lasers without imposing strong cavity stability constraints such as in KLM.

  18. I'll Be Your Mirror

    OpenAIRE

    Crowe, Nick; Rawlinson, Ian

    2011-01-01

    I'll be Your Mirror was a group exhibition curated by Daniel McGrath which dealt with the double or doppelgänger in contemporary art. It was presented at the Sheldon Galleries in St Louis in 2011 and subsequently toured to Monte Vista Projects in Los Angeles. We showed the work Two East German Drinking Glasses, 2009.

  19. Electromagnetic deformable mirror development at TNO

    NARCIS (Netherlands)

    Kuiper, S.; Doelman, N.J.; Nieuwkoop, E.; Overtoom, A.J.; Russchenberg, T.; Riel, M.C.J.M. van; Wildschut, J.A.; Baeten, M.J.J.; Human, J.D.; Spruit, W.E.T.; Brinkers, S.; Maniscalco, M.P.

    2016-01-01

    Over the last decade TNO has developed a deformable mirror concept using electromagnetic actuators with the main advantages of having very low non-linearity and hysteresis, low power consumption, and high inherent reliability of the actuators. TNO recently started a program to redesign the

  20. About recognition of mirror-like objects

    Science.gov (United States)

    Kyurkchan, A. G.

    2017-10-01

    We discuss the problem of the visual recognition of mirror-like objects, i.e., bodies with an ideally smooth (analytic) surface. The visual perception of such objects is essentially dependent on their environment, in contrast to bodies with an irregular (rough) surface, whose visual images are independent of the environment.

  1. Classroom Explorations: Pendulums, Mirrors, and Galileo's Drama

    Science.gov (United States)

    Cavicchi, Elizabeth

    2011-01-01

    What do you see in a mirror when not looking at yourself? What goes on as a pendulum swings? Undergraduates in a science class supposed that these behaviors were obvious until their explorations exposed questions with no quick answers. While exploring materials, students researched Galileo, his trial, and its aftermath. Galileo came to life both…

  2. The Mirror DBMS at TREC-8

    NARCIS (Netherlands)

    de Vries, A.P.; Hiemstra, Djoerd; Voorhees, E.M; Harman, D.K.

    1999-01-01

    The database group at University of Twente participates in TREC8 using the Mirror DBMS, a prototype database system especially designed for multimedia and web retrieval. From a database perspective, the purpose has been to check whether we can get sufficient performance, and to prepare for the very

  3. Development of a liquid based deformable mirror

    NARCIS (Netherlands)

    Vuelban, E.M.; Bhattacharya, N.; Braat, J.M.

    2006-01-01

    Recently, a new type of liquid based deformable mirror has been proposed and demonstrated. The device consists of an array of vertically oriented open capillary channels immersed in a pool of two immiscible liquids and a freefloating reflective membrane, which serves as the reflecting surface.

  4. Solid State Replacement of Rotating Mirror Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Frank, A M; Bartolick, J M

    2006-08-25

    Rotating mirror cameras have been the mainstay of mega-frame per second imaging for decades. There is still no electronic camera that can match a film based rotary mirror camera for the combination of frame count, speed, resolution and dynamic range. The rotary mirror cameras are predominantly used in the range of 0.1 to 100 micro-seconds per frame, for 25 to more than a hundred frames. Electron tube gated cameras dominate the sub microsecond regime but are frame count limited. Video cameras are pushing into the microsecond regime but are resolution limited by the high data rates. An all solid state architecture, dubbed ''In-situ Storage Image Sensor'' or ''ISIS'', by Prof. Goji Etoh, has made its first appearance into the market and its evaluation is discussed. Recent work at Lawrence Livermore National Laboratory has concentrated both on evaluation of the presently available technologies and exploring the capabilities of the ISIS architecture. It is clear though there is presently no single chip camera that can simultaneously match the rotary mirror cameras, the ISIS architecture has the potential to approach their performance.

  5. The "Curriculum Vitae": An Imperfect Mirror.

    Science.gov (United States)

    Bennett, John B.

    1992-01-01

    Curriculum vitae for college faculty can be ambiguous and even misleading: they can obscure an individual's primary teaching and instructional achievements, tell less than they appear to, and convey an unintended message. Faculty should evaluate the clarity and force with which their vitae express their accomplishments and mirror their abilities.…

  6. Shape parameters measurement of ultralight mirrors

    Czech Academy of Sciences Publication Activity Database

    Pech, Miroslav; Mandát, Dušan; Hrabovský, Miroslav; Palatka, Miroslav; Schovánek, Petr

    2010-01-01

    Roč. 121, č. 20 (2010), s. 1881-1884 ISSN 0030-4026 R&D Projects: GA MŠk(CZ) 1M06002; GA AV ČR KAN301370701 Institutional research plan: CEZ:AV0Z10100522 Keywords : Hartmann test * roughness * scattering * BRDF * mirror shape Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.454, year: 2010

  7. Analysis of Online Composite Mirror Descent Algorithm.

    Science.gov (United States)

    Lei, Yunwen; Zhou, Ding-Xuan

    2017-03-01

    We study the convergence of the online composite mirror descent algorithm, which involves a mirror map to reflect the geometry of the data and a convex objective function consisting of a loss and a regularizer possibly inducing sparsity. Our error analysis provides convergence rates in terms of properties of the strongly convex differentiable mirror map and the objective function. For a class of objective functions with Hölder continuous gradients, the convergence rates of the excess (regularized) risk under polynomially decaying step sizes have the order [Formula: see text] after [Formula: see text] iterates. Our results improve the existing error analysis for the online composite mirror descent algorithm by avoiding averaging and removing boundedness assumptions, and they sharpen the existing convergence rates of the last iterate for online gradient descent without any boundedness assumptions. Our methodology mainly depends on a novel error decomposition in terms of an excess Bregman distance, refined analysis of self-bounding properties of the objective function, and the resulting one-step progress bounds.

  8. Brane brick models in the mirror

    Energy Technology Data Exchange (ETDEWEB)

    Franco, Sebastián [Physics Department, The City College of the CUNY,160 Convent Avenue, New York, NY 10031 (United States); The Graduate School and University Center, The City University of New York,365 Fifth Avenue, New York NY 10016 (United States); Lee, Sangmin [Center for Theoretical Physics, Seoul National University,Seoul 08826 (Korea, Republic of); Department of Physics and Astronomy, Seoul National University,Seoul 08826 (Korea, Republic of); College of Liberal Studies, Seoul National University,Seoul 08826 (Korea, Republic of); Seong, Rak-Kyeong [School of Physics, Korea Institute for Advanced Study,Seoul 02455 (Korea, Republic of); Vafa, Cumrun [Jefferson Physical Laboratory, Harvard University,Cambridge, MA 02138 (United States)

    2017-02-21

    Brane brick models are Type IIA brane configurations that encode the 2dN=(0,2) gauge theories on the worldvolume of D1-branes probing toric Calabi-Yau 4-folds. We use mirror symmetry to improve our understanding of this correspondence and to provide a systematic approach for constructing brane brick models starting from geometry. The mirror configuration consists of D5-branes wrapping 4-spheres and the gauge theory is determined by how they intersect. We also explain how 2d(0,2) triality is realized in terms of geometric transitions in the mirror geometry. Mirror symmetry leads to a geometric unification of dualities in different dimensions, where the order of duality is n−1 for a Calabi-Yau n-fold. This makes us conjecture the existence of a quadrality symmetry in 0d. Finally, we comment on how the M-theory lift of brane brick models connects to the classification of 2d(0,2) theories in terms of 4-manifolds.

  9. Plasma cleaning of ITER first mirrors

    Science.gov (United States)

    Moser, L.; Marot, L.; Steiner, R.; Reichle, R.; Leipold, F.; Vorpahl, C.; Le Guern, F.; Walach, U.; Alberti, S.; Furno, I.; Yan, R.; Peng, J.; Ben Yaala, M.; Meyer, E.

    2017-12-01

    Nuclear fusion is an extremely attractive option for future generations to compete with the strong increase in energy consumption. Proper control of the fusion plasma is mandatory to reach the ambitious objectives set while preserving the machine’s integrity, which requests a large number of plasma diagnostic systems. Due to the large neutron flux expected in the International Thermonuclear Experimental Reactor (ITER), regular windows or fibre optics are unusable and were replaced by so-called metallic first mirrors (FMs) embedded in the neutron shielding, forming an optical labyrinth. Materials eroded from the first wall reactor through physical or chemical sputtering will migrate and will be deposited onto mirrors. Mirrors subject to net deposition will suffer from reflectivity losses due to the deposition of impurities. Cleaning systems of metallic FMs are required in more than 20 optical diagnostic systems in ITER. Plasma cleaning using radio frequency (RF) generated plasmas is currently being considered the most promising in situ cleaning technique. An update of recent results obtained with this technique will be presented. These include the demonstration of cleaning of several deposit types (beryllium, tungsten and beryllium proxy, i.e. aluminium) at 13.56 or 60 MHz as well as large scale cleaning (mirror size: 200 × 300 mm2). Tests under a strong magnetic field up to 3.5 T in laboratory and first experiments of RF plasma cleaning in EAST tokamak will also be discussed. A specific focus will be given on repetitive cleaning experiments performed on several FM material candidates.

  10. The "Rear-View Mirror" Approach.

    Science.gov (United States)

    Nord, James

    1987-01-01

    The "rear-view mirror" approach referred to by McLuhan refers to new media being used with the methods of older, different media. A Sens-it (SENtence- SENtence- SITuation) cell model is suggested as an effective use of interactive videodisk systems in contrast to the communicative competence approach. (Author/LMO)

  11. Mirrors and Merry-Go-Rounds

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 8. Mirrors and Merry-Go-Rounds. Joseph Samuel. General Article Volume 15 Issue 8 August 2010 pp 711-722. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/015/08/0711-0722. Keywords.

  12. Mirror Neurons and the Evolution of Language

    Science.gov (United States)

    Corballis, Michael C.

    2010-01-01

    The mirror system provided a natural platform for the subsequent evolution of language. In nonhuman primates, the system provides for the understanding of biological action, and possibly for imitation, both prerequisites for language. I argue that language evolved from manual gestures, initially as a system of pantomime, but with gestures…

  13. A Virtual Pivot Point MEMS Actuator with Externally Mounted Mirror: Design, Fabrication and Characterization

    Directory of Open Access Journals (Sweden)

    T. M. Fahim AMIN

    2014-12-01

    Full Text Available In this paper, the design, fabrication, and characterization of a virtual pivot point micro electromechanical systems (MEMS electrostatic actuator with externally mounted mirror is presented. The point of rotation of the movable arm of the actuator is distant from the physical actuator. This is a requirement for certain applications, such as an external cavity laser in Littman configuration. A maximum rotational radius of 5 mm from the virtual pivot point was achieved. A detailed analytical analysis for the displacement of the structure is presented. The dynamic characterization of the device with a finite element analysis simulation shows that the resonance frequency of the in-plane rotational mode is well separated from that of the out-of-plane bending mode, confirming high in-plane stability. The devices were fabricated on a silicon-on-insulator wafer with device layer thickness of 100 µm. Thin mirrors were fabricated by dicing a 100 µm thick silicon wafer. A resonance frequency of about 5.9 ´ 102 Hz for the maximum sized mounted mirror (1.7 mm ´ 100 µm ´ 1.0 mm was determined by optical characterization.

  14. Highly selective trapping of enteropathogenic E. coli on Fabry-Pérot sensor mirrors.

    Science.gov (United States)

    Ivanova, Elena P; Truong, Vi Khanh; Gervinskas, Gediminas; Mitik-Dineva, Natasa; Day, Daniel; Jones, Robert T; Crawford, Russell J; Juodkazis, Saulius

    2012-05-15

    Untreated recycled water, such as sewage and graywater, will almost always contain a wide range of agents that are likely to present risks to human health, including chemicals and pathogenic microorganisms. The microbial hazards, such as large numbers of enteric pathogens that can cause gastroenteric illness if ingested, are the main cause of concern for human health. The presence of the enteropathogenic Escherichia coli (EPEC) serotype is of particular concern, as this group of bacteria is responsible for causing severe infant and travelers' diarrhea, gastroenteritis and hemolytic uremic syndrome. A biosensing system based on an optical Fabry-Pérot (FP) cavity, capable of directly detecting the presence of EPEC within 5 min, has been developed using a simple micro-thin double-sided adhesive tape and two semi-transparent FP mirror plates. The system utilizes a poly(methyl methacrylate) (PMMA) or glass substrates sputtered by 40-nm-thick gold thin films serving as FP mirrors. Mirrors have been activated using 0.1M mercaptopropionic acid, influencing an immobilization density of the translocated intimin receptor (TIR) of 100 ng/cm(2). The specificity of recognition was confirmed by exposing TIR functionalized surfaces to four taxonomically related and/or distantly related bacterial strains. It was found that the TIR-functionalized surfaces did not show any bacterial capture for these other bacterial strains within a 15 min incubation period. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. 1.55-μm VCSEL with polarization-independent HCG mirror on SOI.

    Science.gov (United States)

    Tsunemi, Yoshihiro; Yokota, Nobuhide; Majima, Shota; Ikeda, Kazuhiro; Katayama, Takeo; Kawaguchi, Hitoshi

    2013-11-18

    We designed and fabricated a vertical-cavity surface-emitting laser (VCSEL) incorporating a polarization-independent high-index-contrast subwavelength grating (HCG) mirror on silicon-on-insulator (SOI) for a novel polarization-bistable device on a silicon substrate. The VCSEL consists of the HCG mirror, an active layer with InGaAsP quantum wells having optical gain around 1.55 μm, and an Al0.9Ga0.1As/Al0.16Ga0.84As DBR. We used direct wafer bonding for the bonding between the active layer and the AlGaAs DBR, and benzocyclobutene (BCB) bonding for the bonding between the active layer and the polarization-independent HCG mirror. The reflectivity of the HCG embedded with BCB was measured, resulting in a 200-nm-high reflectivity band with reflectivity higher than 99% and a small polarization dependence of ± 1%. We achieved lasing of the fabricated HCG-VCSEL at 1527 nm under an optical short pulse excitation with an average power of 50 mW (~0.2 mJ/cm2) at 240 K.

  16. Some Historical Resources for Teaching about Curved Mirrors.

    Science.gov (United States)

    Mihas, Pavlos

    2002-01-01

    Presents resources from Alhazens' investigations on curved mirrors that investigate diffuse reflection from the moon's surface, composite mirrors, and the problem of possible points of reflection. (Author/YDS)

  17. Size Optimization for Mirror Segments for X-Ray Optics

    Science.gov (United States)

    Biskach, Michael P.; McClelland, Ryan S.; Saha, Timo; Zhang, William W.

    2011-01-01

    The flight mirror assemblies (FMA) for X-ray telescopes similar to that of the International X-ray Observatory (IXO) concept consist of several thousands of individual mirror segments. The size, shape, and location of these mirrors affect many characteristics of the telescope design. Mission requirements among other factors in turn restrict mirror segment parameters such as thickness, axial- length, azimuthal span, and mass density. This paper provides an overview of the critical relationships relating to mirror segment size and configuration throughout the design and analysis of an X-ray mirror assembly. A computational analysis is presented in the form of ray tracing pairs of thin X-ray mirror segments of varying sizes aligned in gravity and supported using kinematic constraints with corresponding self weight distortions calculated using finite element analysis (FEA). The work in this paper may be used as a starting point for determining mirror segment sizes for X-ray missions like that of IXO and beyond.

  18. Constraints on mirror models of dark matter from observable neutron-mirror neutron oscillation

    Science.gov (United States)

    Mohapatra, Rabindra N.; Nussinov, Shmuel

    2018-01-01

    The process of neutron-mirror neutron oscillation, motivated by symmetric mirror dark matter models, is governed by two parameters: n -n‧ mixing parameter δ and n -n‧ mass splitting Δ. For neutron mirror neutron oscillation to be observable, the splitting between their masses Δ must be small and current experiments lead to δ ≤ 2 ×10-27 GeV and Δ ≤10-24 GeV. We show that in mirror universe models where this process is observable, this small mass splitting constrains the way that one must implement asymmetric inflation to satisfy the limits of Big Bang Nucleosynthesis on the number of effective light degrees of freedom. In particular we find that if asymmetric inflation is implemented by inflaton decay to color or electroweak charged particles, the oscillation is unobservable. Also if one uses SM singlet fields for this purpose, they must be weakly coupled to the SM fields.

  19. A Survey of Coronal Cavity Density Profiles

    Science.gov (United States)

    Fuller, J.; Gibson, S. E.

    2009-08-01

    Coronal cavities are common features of the solar corona that appear as darkened regions at the base of coronal helmet streamers in coronagraph images. Their darkened appearance indicates that they are regions of lowered density embedded within the comparatively higher density helmet streamer. Despite interfering projection effects of the surrounding helmet streamer (which we refer to as the cavity rim), Fuller et al. have shown that under certain conditions it is possible to use a Van de Hulst inversion of white-light polarized brightness (pB) data to calculate the electron density of both the cavity and cavity rim plasma. In this article, we apply minor modifications to the methods of Fuller et al. in order to improve the accuracy and versatility of the inversion process, and use the new methods to calculate density profiles for both the cavity and cavity rim in 24 cavity systems. We also examine trends in cavity morphology and how departures from the model geometry affect our density calculations. The density calculations reveal that in all 24 cases the cavity plasma has a flatter density profile than the plasma of the cavity rim, meaning that the cavity has a larger density depletion at low altitudes than it does at high altitudes. We find that the mean cavity density is over four times greater than that of a coronal hole at an altitude of 1.2 R sun and that every cavity in the sample is over twice as dense as a coronal hole at this altitude. Furthermore, we find that different cavity systems near solar maximum span a greater range in density at 1.2 R sun than do cavity systems near solar minimum, with a slight trend toward higher densities for systems nearer to solar maximum. Finally, we found no significant correlation of cavity density properties with cavity height—indeed, cavities show remarkably similar density depletions—except for the two smallest cavities that show significantly greater depletion.

  20. Improved Mirror Source Method in Roomacoustics

    Science.gov (United States)

    Mechel, F. P.

    2002-10-01

    Most authors in room acoustics qualify the mirror source method (MS-method) as the only exact method to evaluate sound fields in auditoria. But evidently nobody applies it. The reason for this discrepancy is the abundantly high numbers of needed mirror sources which are reported in the literature, although such estimations of needed numbers of mirror sources mostly are used for the justification of more or less heuristic modifications of the MS-method. The present, intentionally tutorial article accentuates the analytical foundations of the MS-method whereby the number of needed mirror sources is reduced already. Further, the task of field evaluation in three-dimensional spaces is reduced to a sequence of tasks in two-dimensional room edges. This not only allows the use of easier geometrical computations in two dimensions, but also the sound field in corner areas can be represented by a single (directional) source sitting on the corner line, so that only this "corner source" must be mirror-reflected in the further process. This procedure gives a drastic reduction of the number of needed equivalent sources. Finally, the traditional MS-method is not applicable in rooms with convex corners (the angle between the corner flanks, measured on the room side, exceeds 180°). In such cases, the MS-method is combined below with the second principle of superposition(PSP). It reduces the scattering task at convex corners to two sub-tasks between one flank and the median plane of the room wedge, i.e., always in concave corner areas where the MS-method can be applied.

  1. Next-Generation Lightweight Mirror Modeling Software

    Science.gov (United States)

    Arnold, William R., Sr.; Fitzgerald, Mathew; Rosa, Rubin Jaca; Stahl, Phil

    2013-01-01

    The advances in manufacturing techniques for lightweight mirrors, such as EXELSIS deep core low temperature fusion, Corning's continued improvements in the Frit bonding process and the ability to cast large complex designs, combined with water-jet and conventional diamond machining of glasses and ceramics has created the need for more efficient means of generating finite element models of these structures. Traditional methods of assembling 400,000 + element models can take weeks of effort, severely limiting the range of possible optimization variables. This paper will introduce model generation software developed under NASA sponsorship for the design of both terrestrial and space based mirrors. The software deals with any current mirror manufacturing technique, single substrates, multiple arrays of substrates, as well as the ability to merge submodels into a single large model. The modeler generates both mirror and suspension system elements, suspensions can be created either for each individual petal or the whole mirror. A typical model generation of 250,000 nodes and 450,000 elements only takes 5-10 minutes, much of that time being variable input time. The program can create input decks for ANSYS, ABAQUS and NASTRAN. An archive/retrieval system permits creation of complete trade studies, varying cell size, depth, and petal size, suspension geometry with the ability to recall a particular set of parameters and make small or large changes with ease. The input decks created by the modeler are text files which can be modified by any editor, all the key shell thickness parameters are accessible and comments in deck identify which groups of elements are associated with these parameters. This again makes optimization easier. With ANSYS decks, the nodes representing support attachments are grouped into components; in ABAQUS these are SETS and in NASTRAN as GRIDPOINT SETS, this make integration of these models into large telescope or satellite models possible

  2. Next Generation Lightweight Mirror Modeling Software

    Science.gov (United States)

    Arnold, William R., Sr.; Fitzgerald, Mathew; Rosa, Rubin Jaca; Stahl, H. Philip

    2013-01-01

    The advances in manufacturing techniques for lightweight mirrors, such as EXELSIS deep core low temperature fusion, Corning's continued improvements in the Frit bonding process and the ability to cast large complex designs, combined with water-jet and conventional diamond machining of glasses and ceramics has created the need for more efficient means of generating finite element models of these structures. Traditional methods of assembling 400,000 + element models can take weeks of effort, severely limiting the range of possible optimization variables. This paper will introduce model generation software developed under NASA sponsorship for the design of both terrestrial and space based mirrors. The software deals with any current mirror manufacturing technique, single substrates, multiple arrays of substrates, as well as the ability to merge submodels into a single large model. The modeler generates both mirror and suspension system elements, suspensions can be created either for each individual petal or the whole mirror. A typical model generation of 250,000 nodes and 450,000 elements only takes 5-10 minutes, much of that time being variable input time. The program can create input decks for ANSYS, ABAQUS and NASTRAN. An archive/retrieval system permits creation of complete trade studies, varying cell size, depth, and petal size, suspension geometry with the ability to recall a particular set of parameters and make small or large changes with ease. The input decks created by the modeler are text files which can be modified by any editor, all the key shell thickness parameters are accessible and comments in deck identify which groups of elements are associated with these parameters. This again makes optimization easier. With ANSYS decks, the nodes representing support attachments are grouped into components; in ABAQUS these are SETS and in NASTRAN as GRIDPOINT SETS, this make integration of these models into large telescope or satellite models easier.

  3. Application of Novel Focusing Mirrors in Gyrotron Transmission Lines

    OpenAIRE

    Ogawa, I.; Miyake, Y.; IDEHARA, T; SABCHEVSKI, S

    2002-01-01

    A novel focusing mirror based on the shifting of the beam phase according to the Gaussian beam optics enabled us to realize a focusing elements with different focal lengths in different directions and to convert the gyrotron output into a Gaussian-like beam. In this paper, we compare the quality of beams produced by the new system (which includes novel mirrors) and a conventional system consisting of a quasi-optical antenna, an ellipsoidal mirror and two parabolic cylinder mirrors.

  4. Cavity Solitons in VCSEL Devices

    Directory of Open Access Journals (Sweden)

    S. Barbay

    2011-01-01

    Full Text Available We review advances on the experimental study of cavity solitons in VCSELs in the past decade. We emphasize on the design and fabrication of electrically or optically pumped broad-area VCSELs used for CSs formation and review different experimental configurations. Potential applications of CSs in the field of photonics are discussed, in particular the use of CSs for all-optical processing of information and for VCSELs characterization. Prospects on self-localization studies based on vertical cavity devices involving new physical mechanisms are also given.

  5. Sterility of the uterine cavity

    DEFF Research Database (Denmark)

    Møller, Birger R.; Kristiansen, Frank V.; Thorsen, Poul

    1995-01-01

    In a prospective open study the sterility of the uterine cavity was evaluated in 99 women admitted for hysterectomy. The indications for hysterectomy were in most cases persistent irregular vaginal bleeding and fibromyomas of the uterus. Samples for both aerobic and anaerobic bacteria, Chlamydia...... trachomatis, yeasts and viruses were taken preoperatively from the apex of the vagina and cervical os. Immediately after hysterectomy the uterus was opened under sterile conditions and samples obtained from the isthmus and fundus of the uterine cavity for microbiological examination. Wet smears were taken...

  6. Monitoring of absolute mirror alignment at COMPASS RICH-1 detector

    NARCIS (Netherlands)

    Alexeev, M.; Birsa, R.; Bradamante, F.; Bressan, A.; Chiosso, M.; Ciliberti, P.; Dalla Torre, S.; Denisov, O.; Duic, V.; Ferrero, A.; Finger, M.; Finger, M.; Gayde, J. Ch; Giorgi, M.; Gobbo, B.; Levorato, S.; Maggiora, A.; Martin, A.; Menon, G.; Panzieri, D.; Pesaro, G.; Polak, J.; Rocco, E.; Sbrizzai, G.; Schiavon, P.; Slunecka, M.; Sozzi, F.; Steiger, L.; Sulc, M.; Takekawa, S.; Tessarotto, F.

    2014-01-01

    The gaseous COMPASS RICH-1 detector uses two spherical mirror surfaces, segmented into 116 individual mirrors, to focus the Cherenkov photons onto the detector plane. Any mirror misalignment directly affects the detector resolution. The on-line Continuous Line Alignment and Monitoring (CLAM)

  7. Titanium Alloy Strong Back for IXO Mirror Segments

    Science.gov (United States)

    Byron, Glenn P.; Kai-Wang, Chan

    2011-01-01

    A titanium-alloy mirror-holding fixture called a strong back allows the temporary and permanent bonding of a 50 degree D263 glass x-ray mirror (IXO here stands for International X-ray Observatory). The strong back is used to hold and position a mirror segment so that mounting tabs may be bonded to the mirror with ultra-low distortion of the optical surface. Ti-15%Mo alloy was the material of choice for the strong back and tabs because the coefficient of thermal expansion closely matches that of the D263 glass and the material is relatively easy to machine. This invention has the ability to transfer bonded mounting points from a temporary location on the strong back to a permanent location on the strong back with minimal distortion. Secondly, it converts a single mirror segment into a rigid body with an acceptable amount of distortion of the mirror, and then maneuvers that rigid body into optical alignment such that the mirror segment can be bonded into a housing simulator or mirror module. Key problems are that the mirrors are 0.4-mm thick and have a very low coefficient of thermal expansion (CTE). Because the mirrors are so thin, they are very flexible and are easily distorted. When permanently bonding the mirror, the goal is to achieve a less than 1-micron distortion. Temperature deviations in the lab, which have been measured to be around 1 C, have caused significant distortions in the mirror segment.

  8. ASTRONAUT ALDRIN UNDERGOES SPACESUIT CHECKS

    Science.gov (United States)

    1969-01-01

    ASTRONAUT ALDRIN UNDERGOES SPACESUIT CHECKS KSC-69PC-0374 69-HC-742,S-266,ARCHIVE-00337 White undergoing spacesuit checks, Apollo 11 lunar module pilot Edwin E. Aldrin, Jr., watches Astronauts Neil A. Armstrong and Michael Collins suit up for launch.

  9. Hydrogen Degassing Study During the Heat Treatment of 1.3-GHZ SRF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Mijoung [Fermilab; Kim, H. J. [IBS, Daejeon; Rowe, A. [Fermilab; Wong, M. [Fermilab

    2013-10-02

    Superconducting radio frequency (SRF) cavities undergo a number of processes as part of its manufacturing procedure in order to optimize their performance. Among these processes is a high temperature hydrogen degas heat treatment used to prevent 'Q' decrease. The heat treatment occurs in the processing sequence after either chemically or mechanically polishing the cavity. This paper summarizes the hydrogen measurements during the heat treatment of a sample of chemically and mechanically polished single-cell and nine-cell 1.3-GHz cavities. The hydrogen measurements are analyzed according the polishing method, the polishing history, the amount of time that the cavity was baked at 800°C, and the temperature ramp rate.

  10. Synaesthesia in phantom limbs induced with mirrors.

    Science.gov (United States)

    Ramachandran, V S; Rogers-Ramachandran, D

    1996-04-22

    Although there is a vast clinical literature on phantom limbs, there have been no experimental studies on the effects of visual input on phantom sensations. We introduce an inexpensive new device--a 'virtual reality box'--to resurrect the phantom visually to study inter-sensory effects. A mirror is placed vertically on the table so that the mirror reflection of the patient's intact had is 'superimposed' on the felt position of the phantom. We used this procedure on ten patients and found the following results. 1. In six patients, when the normal hand was moved, so that the phantom was perceived to move in the mirror, it was also felt to move; i.e. kinesthetic sensations emerged in the phantom. In D.S. this effect occurred even though he had never experienced any movements in the phantom for ten years before we tested him. He found the return of sensations very enjoyable. 2. Repeated practice led to a permanent 'disappearance' of the phantom arm in patient D.S. and the hand became telescoped into the stump near the shoulder. 3. Using an optical trick, impossible postures--e.g. extreme hyperextension of the fingers--could be induced visually in the phantom. In one case this was felt as a transient 'painful tug' in the phantom. 4. Five patients experienced involuntary painful 'clenching spasms' in the phantom hand and in four of them the spasms were relieved when the mirror was used to facilitate 'opening' of the phantom hand; opening was not possible without the mirror. 5. In three patients, touching the normal hand evoked precisely localized touch sensations in the phantom. Interestingly, the referral was especially pronounced when the patients actually 'saw' their phantom being touched in the mirror. Indeed, in a fourth patient (R.L.) the referral occurred only if he saw his phantom being touched: a curious form of synaesthesia. These experiments lend themselves readily to imaging studies using PET and fMRI. Taken collectively, they suggest that there is a

  11. Axisymmetric Magnetic Mirror Fusion-Fission Hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martovetsky, N. N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Molvik, A. W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ryutov, D. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Simonen, T. C. [Univ. of California, Berkeley, CA (United States)

    2011-05-13

    The achieved performance of the gas dynamic trap version of magnetic mirrors and today’s technology we believe are sufficient with modest further efforts for a neutron source for material testing (Q=Pfusion/Pinput~0.1). The performance needed for commercial power production requires considerable further advances to achieve the necessary high Q>>10. An early application of the mirror, requiring intermediate performance and intermediate values of Q~1 are the hybrid applications. The Axisymmetric Mirror has a number of attractive features as a driver for a fusion-fission hybrid system: geometrical simplicity, inherently steady-state operation, and the presence of the natural divertors in the form of end tanks. This level of physics performance has the virtue of low risk and only modest R&D needed and its simplicity promises economy advantages. Operation at Q~1 allows for relatively low electron temperatures, in the range of 4 keV, for the DT injection energy ~ 80 keV. A simple mirror with the plasma diameter of 1 m and mirror-to-mirror length of 35 m is discussed. Simple circular superconducting coils are based on today’s technology. The positive ion neutral beams are similar to existing units but designed for steady state. A brief qualitative discussion of three groups of physics issues is presented: axial heat loss, MHD stability in the axisymmetric geometry, microstability of sloshing ions. Burning fission reactor wastes by fissioning actinides (transuranics: Pu, Np, Am, Cm, .. or just minor actinides: Np, Am, Cm, …) in the hybrid will multiply fusion’s energy by a factor of ~10 or more and diminish the Q needed to less than 1 to overcome the cost of recirculating power for good economics. The economic value of destroying actinides by fissioning is rather low based on either the cost of long-term storage or even deep geologic disposal so most of the revenues of hybrids will come from electrical power. Hybrids that obtain revenues from

  12. Mirror symmetry in the presence of branes

    Energy Technology Data Exchange (ETDEWEB)

    Mertens, Adrian

    2011-10-11

    This work deals with mirror symmetry for N=1 compactifications on compact Calabi-Yau threefolds with branes. The mayor tool is a combined deformation space for the Calabi-Yau and a hypersurface within it. Periods of this deformation space contain information about B-type branes within the hypersurface in addition to the usual closed string data. To study these periods we generalize techniques used in closed string mirror symmetry. We derive the Picard-Fuchs system and encode the information in extended toric polytopes. Solutions of the Picard-Fuchs equations give superpotentials for certain brane configurations. This is an efficient way to calculate superpotentials. The deformations we consider are massive for all branes with non trivial superpotential. Depending on a choice of a family of hypersurfaces, the superpotential of the effective low energy theory depends on different massive fields. A priori there is no reason for these fields to be lighter then other fields that are not included. We find however examples where the superpotential is nearly at. In these examples we use the Gauss-Manin connection on the combined deformation space to define an open string mirror map. We find instanton generated superpotentials of A-type branes. This gives predictions for Ooguri-Vafa invariants counting holomorphic disks that end on a Lagrangian brane on the Quintic. A second class of examples does not have preferred nearly massless deformations and different families of hypersurfaces can be used to calculate the same on-shell superpotential. We calculate examples of superpotentials for branes in Calabi-Yau manifolds with several moduli. The on-shell superpotentials are mapped to the mirror A-model to study the instanton expansion and to obtain predictions for disk invariants. The combined deformation spaces are equivalent to the quantum corrected Kaehler deformation spaces of certain non compact Calabi-Yau fourfolds. These fourfolds are fibrations of Calabi-Yau threefolds

  13. Of cavities – and kings

    NARCIS (Netherlands)

    Schram, Frederick R.

    1997-01-01

    Review of and commentary on: Body Cavities: Function and Phylogeny, edited by G. Lanzavecchia, R. Valvassori, and M.D. Candia Carnevali. Mucchi Editore/Modena, 1995, 280 pp., ISBN 88-7000-259-4. “The time has come”, the Walrus said, “To talk of many things: Of shoes – and ships – and sealing wax –

  14. Seismic resonances of acoustic cavities

    Science.gov (United States)

    Schneider, F. M.; Esterhazy, S.; Perugia, I.; Bokelmann, G.

    2016-12-01

    The goal of an On-Site Inspection (OSI) is to clarify at a possible testsite whether a member state of the Comprehensive nuclear Test Ban Treaty (CTBT)has violated its rules by conducting a underground nuclear test. Compared toatmospheric and underwater tests underground nuclear explosions are the mostdifficult to detect.One primary structural target for the field team during an OSI is the detectionof an underground cavity, created by underground nuclear explosions. Theapplication of seismic-resonances of the cavity for its detection has beenproposed in the CTBT by mentioning "resonance seismometry" as possibletechnique during OSIs. We modeled the interaction of a seismic wave-field withan underground cavity by a sphere filled with an acoustic medium surrounded byan elastic full space. For this setting the solution of the seismic wave-fieldcan be computed analytically. Using this approach the appearance of acousticresonances can be predicted in the theoretical calculations. Resonance peaksappear in the spectrum derived for the elastic domain surrounding the acousticcavity, which scale in width with the density of the acoustic medium. For lowdensities in the acoustic medium as for an gas-filled cavity, the spectralpeaks become very narrow and therefore hard to resolve. The resonancefrequencies, however can be correlated to the discrete set of eigenmodes of theacoustic cavity and can thus be predicted if the dimension of the cavity isknown. Origin of the resonance peaks are internal reverberations of wavescoupling in the acoustic domain and causing an echoing signal that couples outto the elastic domain again. In the gas-filled case the amplitudes in timedomain are very low.Beside theoretical considerations we seek to find real data examples fromsimilar settings. As example we analyze a 3D active seismic data set fromFelsőpetény, Hungary that has been conducted between 2012 and 2014 on behalf ofthe CTBTO. In the subsurface of this area a former clay mine is

  15. Quality evaluation of spaceborne SiC mirrors (I): analytical examination of the effects on mirror accuracy by variation in the thermal expansion property of the mirror surface.

    Science.gov (United States)

    Kotani, Masaki; Imai, Tadashi; Katayama, Haruyoshi; Yui, Yukari; Tange, Yoshio; Kaneda, Hidehiro; Nakagawa, Takao; Enya, Keigo

    2013-07-10

    The Japan Aerospace Exploration Agency has studied a large-scale lightweight mirror constructed of reaction-bonded silicon carbide-based material as a key technology in future astronomical and earth observation missions. The authors selected silicon carbide as the promising candidate due to excellent characteristics of specific stiffness and thermal stability. One of the most important technical issues for large-scale ceramic components is the uniformity of the material's property, depending on part and processing. It might influence mirror accuracy due to uneven thermal deformation. The authors conducted systematic case studies for the conditions of CTE by finite element analysis to know the typical influence of material property nonuniformity on mirror accuracy and consequently derived a comprehensive empirical equation for the series of CTE's main factors. In addition, the authors computationally reproduced the mirror accuracy profile of a small prototype mirror shown in cryogenic testing and hereby verified wide-range practical computational evaluation technology of mirror accuracy.

  16. Three Cavity Tunable MEMS Fabry Perot Interferometer

    Directory of Open Access Journals (Sweden)

    Narayanswamy Sivakumar

    2007-12-01

    Full Text Available In this paper a four-mirror tunable micro electro-mechanical systems (MEMSFabry Perot Interferometer (FPI concept is proposed with the mathematical model. Thespectral range of the proposed FPI lies in the infrared spectrum ranging from 2400 to 4018(nm. FPI can be finely tuned by deflecting the two middle mirrors (or by changing the threecavity lengths. Two different cases were separately considered for the tuning. In case one,tuning was achieved by deflecting mirror 2 only and in case two, both mirrors 2 and 3 weredeflected for the tuning of the FPI.

  17. [Moving Mirror Scanning System Based on the Flexible Hinge Support].

    Science.gov (United States)

    Xie, Fei; Feng, Fei; Wang, Fu-bei; Wu, Qiong-shui; Zeng, Li-bo

    2015-08-01

    In order to improve moving mirror drive of Fourier transform infrared spectrometer, we design a dynamic scanning system based on flexible hinge support. Using the flexible hinge support way and the voice coil motor drive mode. Specifically, Using right Angle with high accuracy high stability type flexible hinge support mechanism support moving mirror, dynamic mirror can be moved forward and backward driven by voice coil motor reciprocating motion, DSP control system to control the moving mirror at a constant speed. The experimental results show that the designed of moving mirror scanning system has advantages of stability direction, speed stability, superior seismic performance.

  18. Octave spanning wedge dispersive mirrors with low dispersion oscillations.

    Science.gov (United States)

    Habel, Florian; Shirvanyan, Vage; Trubetskov, Michael; Burger, Christian; Sommer, Annkatrin; Kling, Matthias F; Schultze, Martin; Pervak, Vladimir

    2016-05-02

    A novel concept for octave spanning dispersive mirrors with low spectral dispersion oscillations is presented. The key element of the so-called wedge dispersive mirror is a slightly wedged layer which is coated on a specially optimized dispersive multilayer stack by a common sputter coating process. The group delay dispersion (GDD) of a pulse reflected on a wedge dispersive mirror is nearly free of oscillations. Fabricated mirrors with negative GDD demonstrate the compression of a pulse down to 3.8 fs as good as double angled mirrors optimized for the same bandwidth.

  19. Light-weight spherical mirrors for Cherenkov detectors

    CERN Document Server

    Cisbani, E; Colilli, S; Crateri, R; Cusanno, F; De Leo, R; Fratoni, R; Frullani, S; Garibaldi, F; Giuliani, F; Gricia, M; Iodice, M; Iommi, R; Lagamba, L; Lucentini, M; Mostarda, A; Nappi, E; Pierangeli, L; Santavenere, F; Urciuoli, G M; Vernin, P

    2003-01-01

    Light-weight spherical mirrors have been appositely designed and built for the gas threshold Cherenkov detectors of the two Hall A spectrometers. The mirrors are made of a 1 mm thick aluminized plexiglass sheet, reinforced by a rigid backing consisting of a phenolic honeycomb sandwiched between two carbon fiber mats epoxy glued. The produced mirrors have a thickness equivalent to 0.55% of radiation length, and an optical slope error of about 5.5 mrad. These characteristics make these mirrors suitable for the implementation in Cherenkov threshold detectors. Ways to improve the mirror features are also discussed in view of their possible employment in RICH detectors.

  20. Temperature tunability of quantum emitter - cavity coupling in a photonic wire microcavity with shielded sidewall loss

    CERN Document Server

    Bernard, M

    2016-01-01

    Recent technological advancements have allowed to implement in solid-state cavity-based devices phenomena of quantum nature such as vacuum Rabi splitting, controllable single photon emission and quantum entanglement. For a sufficiently strong coupling between a quantum emitter and a cavity, large quality factors ($Q$) along with small modal volume ($V_{eff}$) are essential. Here we show that by applying a 5nm Al coating to the sidewalls of a submicrometer-sized Fabry-P\\'{e}rot microcavity, the cavity $Q$ can be temperature-tuned from few hundreds at room temperatures to 2$\\times$10$^5$ below 30~K. This is achieved by, first, a complete shielding of the sidewall loss with ideally reflecting lateral metallic mirrors and, secondly, a dramatic decrease of the cavity's axial loss for small-sized devices due to the largely off-axis wavevector within the multilayered structure. Our findings offer a novel temperature-tunable platform to study quantum electrodynamical phenomena of emitter-cavity coupling. We demonstra...

  1. High finesse optical cavity coupled with a quartz-enhanced photoacoustic spectroscopic sensor.

    Science.gov (United States)

    Patimisco, Pietro; Borri, Simone; Galli, Iacopo; Mazzotti, Davide; Giusfredi, Giovanni; Akikusa, Naota; Yamanishi, Masamichi; Scamarcio, Gaetano; De Natale, Paolo; Spagnolo, Vincenzo

    2015-02-07

    An ultra-sensitive and selective quartz-enhanced photoacoustic spectroscopy (QEPAS) combined with a high-finesse cavity sensor platform is proposed as a novel method for trace gas sensing. We call this technique Intra-cavity QEPAS (I-QEPAS). In the proposed scheme, a single-mode continuous wave quantum cascade laser (QCL) is coupled into a bow-tie optical cavity. The cavity is locked to the QCL emission frequency by means of a feedback-locking loop that acts directly on a piezoelectric actuator mounted behind one of the cavity mirrors. A power enhancement factor of ∼240 was achieved, corresponding to an intracavity power of ∼0.72 W. CO2 was selected as the target gas to validate our sensor. For the P(42) CO2 absorption line, located at 2311.105 cm(-1), a minimum detection limit of 300 parts per trillion by volume at a total gas pressure of 50 mbar was achieved with a 20 s integration time. This corresponds to a normalized noise equivalent absorption of 3.2 × 10(-10) W cm(-1) Hz(-1/2), comparable with the best results reported for the QEPAS technique on much faster relaxing gases. A comparison with standard QEPAS performed under the same experimental conditions confirms that the I-QEPAS sensitivity scales with the intracavity laser power enhancement factor.

  2. JWST NIRCam pick-off mirror grounding

    Science.gov (United States)

    Demroff, Howard; Mammini, Paul V.; Jacoby, Mike S.; Jones, Brian; Hu, Sidney; Dammann, Ron; Mathieson, James

    2013-09-01

    The optics train of the Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST) includes a pick-off mirror (POM) mounted in the focus and alignment mechanism (FAM). Over the course of the mission, the POM will have a narrow view of the L2 space environment. Charged particles will impinge and collect on the mirror surface increasing the possibility of arcing to the adjacent baffle. A technique to ground the POM and remove accumulated charge has been qualified and implemented on the flight instrument. This paper will provide an overview of the qualification process including cryogenic resistance measurements, vibration testing and optical surface error measurements. To measure the efficiency of this grounding technique, a POM engineering model was exposed to representative mission electron fluence and results with the POM grounded and ungrounded will be presented.

  3. Increased sensitivity to mirror symmetry in autism.

    Directory of Open Access Journals (Sweden)

    Audrey Perreault

    2011-04-01

    Full Text Available Can autistic people see the forest for the trees? Ongoing uncertainty about the integrity and role of global processing in autism gives special importance to the question of how autistic individuals group local stimulus attributes into meaningful spatial patterns. We investigated visual grouping in autism by measuring sensitivity to mirror symmetry, a highly-salient perceptual image attribute preceding object recognition. Autistic and non-autistic individuals were asked to detect mirror symmetry oriented along vertical, oblique, and horizontal axes. Both groups performed best when the axis was vertical, but across all randomly-presented axis orientations, autistics were significantly more sensitive to symmetry than non-autistics. We suggest that under some circumstances, autistic individuals can take advantage of parallel access to local and global information. In other words, autistics may sometimes see the forest and the trees, and may therefore extract from noisy environments genuine regularities which elude non-autistic observers.

  4. Electrochromic mirror using viologen-anchored nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han Na [Electronics and Telecommunications Research Institute, Nature-mimic I/O interface Research Section, 218 Gajeong-roYuseong-gu, Daejeon 305-700 (Korea, Republic of); University of Science and Technology, Advanced Device Technology, 217 Gajeong-roYuseong-gu, Daejeon 305-350 (Korea, Republic of); Cho, Seong M.; Ah, Chil Seong; Song, Juhee; Ryu, Hojun; Kim, Yong Hae [Electronics and Telecommunications Research Institute, Nature-mimic I/O interface Research Section, 218 Gajeong-roYuseong-gu, Daejeon 305-700 (Korea, Republic of); Kim, Tae-Youb, E-mail: youby@etri.re.kr [Electronics and Telecommunications Research Institute, Nature-mimic I/O interface Research Section, 218 Gajeong-roYuseong-gu, Daejeon 305-700 (Korea, Republic of); University of Science and Technology, Advanced Device Technology, 217 Gajeong-roYuseong-gu, Daejeon 305-350 (Korea, Republic of)

    2016-10-15

    Highlights: • Three types of ECM device were fabricated using viologen-anchored ECDs. • The devices were investigated according to their optical structures. • The anti-reflection material affects the reflectance and the coloration efficiency. • The device design of ECMs is a crucial factor for clear reflected images. - Abstract: Electrochromic mirrors (ECMs) that are used in automobile mirrors need to have high reflectance, a high contrast ratio, and a clear image. In particular, it is critical that distortions of clear images are minimized for safety. Therefore, an ECM is fabricated using viologen-anchored nanoparticles and a magnesium fluoride (MgF{sub 2}) layer with an anti-reflection function. The ECM has approximately 30.42% in the reflectance dynamic range and 125 cm{sup 2}/C high coloration efficiency.

  5. Superradiance by mini black holes with mirror

    OpenAIRE

    Lee, Jong-Phil

    2011-01-01

    The superradiant scattering of massive scalar particles by a rotating mini black hole is investigated. Imposing the mirror boundary condition, the system becomes the so called black-hole bomb where the rotation energy of the black hole is transferred to the scattered particle exponentially with time. Bulk emissions as well as brane emissions are considered altogether. It is found that the largest effects are expected for the brane emission of lower angular modes with lighter mass and larger a...

  6. Local coal consumption mirrors depressed economy

    Energy Technology Data Exchange (ETDEWEB)

    1993-02-01

    The article gives the views of Allen Sealey, chairman of Randcoal, speaking in his annual statement. He maintains that until real political progress is made, opening the way for new investment, the depressed state of the economy will continue and will be mirrored by low coal consumption by the South African industrial market and Eskom. He discussed the detrimental effects of inflation and unemployment on the coal industry.

  7. A note on ODEs from mirror symmetry

    CERN Document Server

    Klemm, A D; Roan, S S; Yau, S T

    1994-01-01

    We give close formulas for the counting functions of rational curves on complete intersection Calabi-Yau manifolds in terms of special solutions of generalized hypergeometric differential systems. For the one modulus cases we derive a differential equation for the Mirror map, which can be viewed as a generalization of the Schwarzian equation. We also derive a nonlinear seventh order differential equation which directly governs the instanton corrected Yukawa coupling.

  8. Compensation for gravitational sag of bent mirror

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Chengwen; Jiang, Hui; He, Yan; Liang, Dongxu; Lan, Xuying; Yan, Shuai [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, CAS, Shanghai 201800 (China); Shu, De-ming [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Li, Aiguo, E-mail: aiguo.li@sinap.ac.cn [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, CAS, Shanghai 201800 (China)

    2017-05-01

    The gravitational sag of aspheric bent mirrors with face-up or face-down geometry produces a nonnegligible optical error. As an effective compensation, width optimization is used to match the combined effects of the gravitational and bending moments. This method is described by analytical expressions and two calculation algorithms. The results of theoretical simulations and finite element analysis have proved that this method can reduce the slope error resulting from gravitational sag to the level of nano radians.

  9. Multilayer Active Shell Mirrors for Space Telescopes

    OpenAIRE

    Steeves, John; Jackson, Kathryn; Pellegrino, Sergio; Redding, David; Wallace, J. Kent; Bradford, Samuel Case; Barbee, Troy

    2016-01-01

    A novel active mirror technology based on carbon fiber reinforced polymer (CFRP) substrates and replication techniques has been developed. Multiple additional layers are implemented into the design serving various functions. Nanolaminate metal films are used to provide a high quality reflective front surface. A backing layer of thin active material is implemented to provide the surface-parallel actuation scheme. Printed electronics are used to create a custom electrode pattern and flexible ro...

  10. Graded Mirror Self-Recognition by Clark’s Nutcrackers

    Science.gov (United States)

    Clary, Dawson; Kelly, Debbie M.

    2016-01-01

    The traditional ‘mark test’ has shown some large-brained species are capable of mirror self-recognition. During this test a mark is inconspicuously placed on an animal’s body where it can only be seen with the aid of a mirror. If the animal increases the number of actions directed to the mark region when presented with a mirror, the animal is presumed to have recognized the mirror image as its reflection. However, the pass/fail nature of the mark test presupposes self-recognition exists in entirety or not at all. We developed a novel mirror-recognition task, to supplement the mark test, which revealed gradation in the self-recognition of Clark’s nutcrackers, a large-brained corvid. To do so, nutcrackers cached food alone, observed by another nutcracker, or with a regular or blurry mirror. The nutcrackers suppressed caching with a regular mirror, a behavioural response to prevent cache theft by conspecifics, but did not suppress caching with a blurry mirror. Likewise, during the mark test, most nutcrackers made more self-directed actions to the mark with a blurry mirror than a regular mirror. Both results suggest self-recognition was more readily achieved with the blurry mirror and that self-recognition may be more broadly present among animals than currently thought. PMID:27811974

  11. "Mirror agnosia" in a patient with right occipitotemporal infarct

    Directory of Open Access Journals (Sweden)

    Menon Bijoy

    2006-01-01

    Full Text Available We report the clinical profile and investigation of K, a patient suffering from agnosia for the concept of "mirrors". Normal people rarely confuse a mirror image for the real image. Our patient ′K′ has intact attention, memory and language with a left visual neglect with left hemianopia. When shown an object on his left with a mirror kept sagitally on his right, K grabs for the reflection and even gropes behind the mirror for it. Yet, when shown the mirror alone, he is able to tell that it is a mirror. Thus the concept of a ′mirror′ is lost in the experimental paradigm. An explanation for mirror ′agnosia′ is provided and recent controversies in the analysis of visuospatial functions in humans is highlighted.

  12. The Chilled-Mirror Humidity Sensor: Improved Radiosonde Measurements

    Science.gov (United States)

    Schmidlin, F. J.

    1999-01-01

    Chilled-mirror humidity sensor technology recently was adapted for use with the VIZ radiosonde. The principle of the chilled-mirror operation is to lower its temperature until dew forms on the mirror, at that point the dew point temperature is noted and the mirror is then heated to evaporate the moisture. The cycle is repeated. Research conducted from NASA's Wallops Flight Facility has provided comparisons between the chilled-mirror sensor and the carbon hygristor of VIZ, and the capacitive sensors of AIR Inc. and Vaisala Co. We believe the chilled-mirror sensor is accurate and would serve as a reference standard for evaluating operational radiosonde relative humidity sensors. Thus, differences seen in the comparisons are beginning to furnish insight into developing better humidity sensors. We discuss these comparison results as well as reproducibility results from a dual chilled-mirror measurement.

  13. Monitoring of absolute mirror alignment at COMPASS RICH-1 detector

    Energy Technology Data Exchange (ETDEWEB)

    Alexeev, M. [INFN, Sezione di Torino and University of East Piemonte, Alessandria (Italy); INFN, Sezione di Trieste and University of Bari, Bari (Italy); Birsa, R. [INFN, Sezione di Trieste, Trieste (Italy); Bradamante, F.; Bressan, A. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Chiosso, M. [INFN, Sezione di Torino and University of Torino, Torino (Italy); Ciliberti, P. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Dalla Torre, S. [INFN, Sezione di Trieste, Trieste (Italy); Denisov, O. [INFN, Sezione di Torino, Torino (Italy); Duic, V. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Ferrero, A. [INFN, Sezione di Torino and University of Torino, Torino (Italy); Finger, M.; Finger, M. [Charles University, Prague (Czech Republic); JINR, Dubna (Russian Federation); Gayde, J.Ch. [CERN, European Organization for Nuclear Research, Geneva (Switzerland); Giorgi, M. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Gobbo, B.; Levorato, S. [INFN, Sezione di Trieste, Trieste (Italy); Maggiora, A. [INFN, Sezione di Torino, Torino (Italy); Martin, A. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Menon, G. [INFN, Sezione di Trieste, Trieste (Italy); Panzieri, D. [INFN, Sezione di Torino and University of East Piemonte, Alessandria (Italy); and others

    2014-12-01

    The gaseous COMPASS RICH-1 detector uses two spherical mirror surfaces, segmented into 116 individual mirrors, to focus the Cherenkov photons onto the detector plane. Any mirror misalignment directly affects the detector resolution. The on-line Continuous Line Alignment and Monitoring (CLAM) photogrammetry-based method has been implemented to measure the alignment of individual mirrors which can be characterized by the center of curvature. The mirror wall reflects a regular grid of retroreflective strips placed inside the detector vessel. Then, the position of each mirror is determined from the image of the grid reflection. The images are collected by four cameras. Any small mirror misalignment results in changes of the grid lines’ positions in the image. The accuracy limits of the CLAM method were checked by laser interferometry and are below 0.1 mrad.

  14. Optimisation and characterisation of parabolic membrane mirrors

    Science.gov (United States)

    Hellmuth, T.; Khrennikov, K.; Kronast, W.; Huster, R.; Mescheder, U.

    2008-04-01

    MOEMS-based thin silicon membrane mirrors with a useable diameter of 5mm and fast (up to 1kHz) tunable focal length (80 mm to 1m) have been realized. A ring shaped counter electrode is used to achieve a parabolic membrane deformation by electrostatic forces. A circular kerf at the outer perimeter of the membrane provides a soft suspension to the rim and thus reduces the needed driving voltage. FEM has been used for optimisation of the design, especially of the soft suspension, which is realized by a controlled thinning of the outer rim of the Si-membrane. A critical issue for demanding applications is the membrane distortion induced by material stress and the fabrication process. Membrane residual stress reduction has been obtained by using SOI-technology (c-silicon) and by optimisation of the Al deposition process (Al-coated Si-membrane). For dynamic tests of the optical mirror properties a stroboscopic interferometer has been realized. A pulsed laser diode with a pulse duration of 10μs is used as a light source which is synchronized with the modulated electrical field driving the membrane mirror. The interference pattern is recorded with a CCD and evaluated with conventional phaseshift techniques. The geometry is similar to a Mach-Zehnder interferometer. The reference path length can be varied with a piezoceramic to induce the phase shift.

  15. Stages of Lip and Oral Cavity Cancer

    Science.gov (United States)

    ... Head and Neck Cancer Patient Hypopharyngeal Cancer Treatment Laryngeal Cancer Treatment Lip & Oral Cavity Treatment Metastatic Squamous Neck ... Oropharyngeal Cancer Screening Health Professional Hypopharyngeal Cancer Treatment Laryngeal Cancer Treatment Lip & Oral Cavity Treatment Metastatic Squamous Neck ...

  16. Correlations of electromagnetic fields in chaotic cavities

    CERN Document Server

    Eckhardt, B; Kühl, T; Stöckmann, H J

    1999-01-01

    We consider the fluctuations of electromagnetic fields in chaotic microwave cavities. We calculate the transversal and longitudinal correlation function based on a random wave assumption and compare the predictions with measurements on two- and three-dimensional microwave cavities.

  17. An economical wireless cavity-nest viewer

    Science.gov (United States)

    Daniel P. Huebner; Sarah R. Hurteau

    2007-01-01

    Inspection of cavity nests and nest boxes is often required during studies of cavity-nesting birds, and fiberscopes and pole-mounted video cameras are sometimes used for such inspection. However, the cost of these systems may be prohibitive for some potential users. We describe a user-built, wireless cavity viewer that can be used to access cavities as high as 15 m and...

  18. Prototype storage cavity for LEP accelerating RF

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    The principle of an RF storage cavity was demonstrated with this prototype, working at 500 MHz. Ian Wilso seems to hold it in his hands. The storage cavities had 4 portholes, 1 each for: RF feed; tuning; connection to the accelerating cavity; vacuum pump. The final storage cavities were larger, to suit the lower LEP accelerating frequency of 352.2 MHz. See also 8002294, 8006510X, 8109346, 8407619X, and Annual Report 1980, p.115.

  19. Cavity QED experiments with ion Coulomb crystals

    DEFF Research Database (Denmark)

    Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan

    2009-01-01

    Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained.......Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained....

  20. Theory and technology for superconducting cavities

    CERN Document Server

    Lengeler, Herbert

    1993-01-01

    The course will address Physicist and Engineers who are newcomers in the field of accelerators and accelerating cavities. The elements of RF-Superconductivity will be presented with special relevance to accelerating cavities. The present ststus of achievable accelerating fields and RF losses will be given and their link to the special technologies for cavity fabrication and surface treatments will be stressed. Cavity auxiliaries like main couplers, higher order mode couplers and frequency tuners will be described.

  1. Doppler Broadening Thermometry Based on Cavity Ring-Down Spectroscopy

    Science.gov (United States)

    Hu, Shui-Ming; Cheng, Cunfeng; Wang, Jin; Tan, Yan; Sun, Yu Robert; Liu, An-Wen; Zhang, Jin-Tao

    2014-06-01

    A Doppler broadening thermometry is implemented using a laser-locked cavity ring-down spectrometer [1,2] combined with a temperature-stabilized sample cell. The temperature fluctuation of the gas sample cell is kept below 1 mK for hours. The probing laser is frequency locked at a longitudinal mode of a Fabry-Pérot interferometer made of ultra-low-expansion glass, and the spectral scan is implemented by scanning the sideband produced by an electro-optic modulator. As a result, a kHz precision has been maintained during the measurement of the spectrum of 10 GHz wide. A ro-vibrational line of C_2H_2 is measured at sample pressures of a few Pa. Using a pair of mirrors with a reflectivity of 0.99997 at 787 nm, we are able to detect absorption line profiles with a signal-to-noise ratio of 10^5. Fitting of the recorded spectra allows us to determine the Doppler width with a statistical uncertainty of 10 ppm. Further improvements on the experimental reproducibility and investigations on the collision effects will probably lead to an optical determination of the Boltzmann constant with an uncertainty of a few ppm. H. Pan, C.-F. Cheng, Y. R. Sun, B. Gao, A.-W. Liu, S.-M. Hu, ``Laser-locked, continuously tunable high resolution cavity ring-down spectrometer," Rev. Sci. Instrum. 82, 103110 (2011) Y. R. Sun, H. Pan, C.-F. Cheng, A.-W. Liu, J.-T. Zhang, S.-M. Hu, ``Application of cavity ring-down spectroscopy to the Boltzmann constant determination," Opt. Express, 19, 19993 (2011)

  2. Cavity Enhanced Velocity Modulation Spectroscopy

    Science.gov (United States)

    Siller, Brian; Mills, Andrew; Porambo, Michael; McCall, Benjamin

    2010-11-01

    Over the past several decades, velocity modulation spectroscopy has been used to study dozens of molecular ions of astronomical importance. This technique has been so productive because it provides the advantage of ion-neutral discrimination, which is critically important when interfering neutral molecules are many orders of magnitude more abundant, and when combined with heterodyne techniques, its sensitivity can approach the shot noise limit. Traditionally, velocity modulation experiments have utilized unidirectional multipass White cells to achieve up to about 8 passes through a positive column discharge cell. But by positioning the cell within an optical cavity, it is possible to obtain an effective path length orders of magnitude longer than was previously possible. We have demonstrated this novel technique using a Ti:Sapp laser in the near-IR to observe rovibronic transitions of N2+. By demodulating at twice the modulation frequency, 2nd derivative-like lineshapes are observed for ions that are velocity-modulated, while Gaussian lineshapes are observed for excited neutral that are concentration-modulated. The signals for N2+ and N2+* have been observed to be 78° out of phase with one another, so ion-neutral discrimination is retained. And due to the laser power enhancement and geometry of the optical cavity, Doppler-free saturation spectroscopy is now possible. Observed Lamb dips have widths of 50 MHz, and when combined with calibration by an optical frequency comb, this allows for determination of line centers to within 1 MHz. In our original demonstration of this technique, our sensitivity was limited by noise in the laser-cavity lock. Since then, we have integrated Noise Immune Cavity Enhanced Optical Heterodyne Molecular Spectroscopy (NICE-OHMS) by adding sidebands to the laser at an exact multiple of the cavity free spectral range, and demodulating at the sideband frequency before sending the signal to a lock-in amplifier for demodulating at twice the

  3. Mirror, Mirror

    Science.gov (United States)

    Fuentes, Sarah Quebec

    2015-01-01

    NCTM's "Principles to Actions: Ensuring Mathematical Success for All" (2014), outlines eight teaching practices for effective teaching and learning mathematics. One of them, facilitate meaningful mathematical discourse, states, "Effective teaching of mathematics facilitates discourse among students to build shared understanding of…

  4. Mirror, mirror

    OpenAIRE

    Sayyid, S.

    2005-01-01

    Abstract The article examines the relationship between political forms and cultural identity. It sets out to explore the way in which notions of `democracy? and despotism are associated with distinct cultural formations. The identity of a political regime is less a matter of its political practices and procedures and more a function of the extent to which it can be considered `western? or...

  5. Diagram of a LEP superconducting cavity

    CERN Multimedia

    1991-01-01

    This diagram gives a schematic representation of the superconducting radio-frequency cavities at LEP. Liquid helium is used to cool the cavity to 4.5 degrees above absolute zero so that very high electric fields can be produced, increasing the operating energy of the accelerator. Superconducting cavities were used only in the LEP-2 phase of the accelerator, from 1996 to 2000.

  6. A Many-Atom Cavity QED System with Homogeneous Atom-Cavity Coupling

    CERN Document Server

    Lee, Jongmin; Teper, Igor; Hosten, Onur; Kasevich, Mark A

    2013-01-01

    We demonstrate a many-atom-cavity system with a high-finesse dual-wavelength standing wave cavity in which all participating rubidium atoms are nearly identically coupled to a 780-nm cavity mode. This homogeneous coupling is enforced by a one-dimensional optical lattice formed by the field of a 1560-nm cavity mode.

  7. Does the availability of artificial cavities affect cavity excavation rates in red-cockaded woodpeckers?

    Science.gov (United States)

    Richard N. Conner; Daniel Saenz; D. Craig Rudolph; Richard R. Schaefer

    2002-01-01

    Rates of cavity excavation by Red-cockaded Woodpeckers (Picoides borealis) were examined from 1983 to 1999 on the Angelina National Forest in east Texas. We compared the rare of natural cavity excavation between 1983 and 1990 (before artificial cavities were available) with the rate of cavity excavation between 1992 and 1993, a period when...

  8. Spontaneous Photon Emission in Cavities

    Directory of Open Access Journals (Sweden)

    Alber G.

    2014-01-01

    Full Text Available We investigate spontaneous photon emission processes of two-level atoms in parabolic and ellipsoidal cavities thereby taking into account the full multimode scenario. In particular, we calculate the excitation probabilities of the atoms and the energy density of the resulting few-photon electromagnetic radiation field by using semiclassical methods for the description of the multimode scenario. Based on this approach photon path representations are developed for relevant transition probability amplitudes which are valid in the optical frequency regime where the dipole and the rotating-wave approximations apply. Comparisons with numerical results demonstrate the quality of these semiclassical results even in cases in which the wave length of a spontaneously emitted photon becomes comparable or even larger than characteristic length scales of the cavity. This is the dynamical regime in which diffraction effects become important so that geometric optical considerations are typically not applicable.

  9. Gastrophysics of the Oral Cavity.

    Science.gov (United States)

    Mouritsen, Ole G

    2016-01-01

    Gastrophysics is the science that pertains to the physical and physico-chemical description of the empirical world of gastronomy, with focus on sensory perception in the oral cavity and how it is related to the materials properties of food and cooking processes. Flavor (taste and smell), mouthfeel, chemesthesis, and astringency are all related to the chemical properties and the texture of the food and how the food is transformed in the oral cavity. The present topical review will primarily focus attention on the somatosensory perception of food (mouthfeel or texture) and how it interacts with basic tastes (sour, bitter, sweet, salty, and umami) and chemesthetic action. Issues regarding diet, nutrition, and health will be put into an evolutionary perspective, and some mention will be made of umami and its importance for (oral) health.

  10. Droplet based cavities and lasers

    DEFF Research Database (Denmark)

    Mølhave, Kristian; Kristensen, Anders; Mortensen, Asger

    2009-01-01

    The self-organized and molecularly smooth surface on liquid microdroplets makes them attractive as optical cavities with very high quality factors. This chapter describes the basic theory of optical modes in spherical droplets. The mechanical properties including vibrational excitation are also...... described, and their implications for microdroplet resonator technology are discussed. Optofluidic implementations of microdroplet resonators are reviewed with emphasis on the basic optomechanical properties....

  11. LHC crab cavity final report

    CERN Document Server

    Burt, G et al

    2013-01-01

    A compact 400 MHz SRF crab cavity is designed for LHC. The design has low surface fields, has no hard multipactor barriers and fits within the transverse space available on the HL-LHC. The structure has been designed to have a constant deflecting voltage across the beam-pipe aperture and this has been verified on an aluminium model. The structure includes designs for the input and lower order mode couplers.

  12. Electron transport through a quantum dot assisted by cavity photons

    Science.gov (United States)

    Abdullah, Nzar Rauf; Tang, Chi-Shung; Manolescu, Andrei; Gudmundsson, Vidar

    2013-11-01

    We investigate transient transport of electrons through a single quantum dot controlled by a plunger gate. The dot is embedded in a finite wire with length Lx assumed to lie along the x-direction with a parabolic confinement in the y-direction. The quantum wire, originally with hard-wall confinement at its ends, ±Lx/2, is weakly coupled at t = 0 to left and right leads acting as external electron reservoirs. The central system, the dot and the finite wire, is strongly coupled to a single cavity photon mode. A non-Markovian density-matrix formalism is employed to take into account the full electron-photon interaction in the transient regime. In the absence of a photon cavity, a resonant current peak can be found by tuning the plunger-gate voltage to lift a many-body state of the system into the source-drain bias window. In the presence of an x-polarized photon field, additional side peaks can be found due to photon-assisted transport. By appropriately tuning the plunger-gate voltage, the electrons in the left lead are allowed to undergo coherent inelastic scattering to a two-photon state above the bias window if initially one photon was present in the cavity. However, this photon-assisted feature is suppressed in the case of a y-polarized photon field due to the anisotropy of our system caused by its geometry.

  13. Status of the ILC Crab Cavity Development

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Dexter, A.; /Cockcroft Inst. Accel. Sci. Tech.; Beard, C.; Goudket, P.; McIntosh, P.; /Daresbury; Bellantoni, L.; /Fermilab; Grimm, T.; Li, Z.; Xiao, L.; /SLAC

    2011-10-20

    The International Linear Collider (ILC) will require two dipole cavities to 'crab' the electron and positron bunches prior to their collision. It is proposed to use two 9 cell SCRF dipole cavities operating at a frequency of 3.9 GHz, with a transverse gradient of 3.8MV/m in order to provide the required transverse kick. Extensive numerical modelling of this cavity and its couplers has been performed. Aluminium prototypes have been manufactured and tested to measure the RF properties of the cavity and couplers. In addition single cell niobium prototypes have been manufactured and tested in a vertical cryostat. The International Collider (ILC) [1] collides bunches of electrons and positrons at a crossing angle of 14 mrad. The angle between these bunches causes a loss in luminosity due to geometric effects [2]. The luminosity lost from this geometric effect can be recovered by rotating the bunches into alignment prior to collision. One possible method of rotating the bunches is to use a crab cavity [3]. A crab cavity is a transverse defecting cavity, where the phase of the cavity is such that the head and tail of the bunch receive equal and opposite kicks. As the bunches are only 500 nm wide in the horizontal plane, the cavity phase must be strictly controlled to avoid the bunch centre being deflected too much. In order to keep the phase stability within the required limits it is required that the cavity be superconducting to avoid thermal effects in both the cavity and its RF source. At the location of the crab cavity in the ILC there is only 23 cm separation between the centre of the cavity and the extraction line, hence the cavity must be small enough to fit in this space. This, along with the difficulty of making high frequency SRF components, set the frequency of the cavity to 3.9 GHz.

  14. Optomechanic interactions in phoxonic cavities

    Directory of Open Access Journals (Sweden)

    Bahram Djafari-Rouhani

    2014-12-01

    Full Text Available Phoxonic crystals are periodic structures exhibiting simultaneous phononic and photonic band gaps, thus allowing the confinement of both excitations in the same cavity. The phonon-photon interaction can be enhanced due to the overlap of both waves in the cavity. In this paper, we discuss some of our recent theoretical works on the strength of the optomechanic coupling, based on both photoelastic and moving interfaces mechanisms, in different (2D, slabs, strips phoxonic crystals cavities. The cases of two-dimensional infinite and slab structures will enable us to mention the important role of the symmetry and degeneracy of the modes, as well as the role of the materials whose photoelastic constants can be wavelength dependent. Depending on the phonon-photon pair, the photoelastic and moving interface mechanisms can contribute in phase or out-of-phase. Then, the main part of the paper will be devoted to the optomechanic interaction in a corrugated nanobeam waveguide exhibiting dual phononic/photonic band gaps. Such structures can provide photonic modes with very high quality factor, high frequency phononic modes of a few GHz inside a gap and optomechanical coupling rate reaching a few MHz.

  15. Optomechanic interactions in phoxonic cavities

    Energy Technology Data Exchange (ETDEWEB)

    Djafari-Rouhani, Bahram; Oudich, Mourad; Pennec, Yan [Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, UFR de physique, Université Lille1, Cité Scientifique, 59652, Villeneuve d’Ascq (France); El-Jallal, Said [Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, UFR de physique, Université Lille1, Cité Scientifique, 59652, Villeneuve d’Ascq (France); Physique du Rayonnement et de l’Interaction Laser Matière, Faculté des sciences, Université de Moulay Ismail, Meknès (Morocco)

    2014-12-15

    Phoxonic crystals are periodic structures exhibiting simultaneous phononic and photonic band gaps, thus allowing the confinement of both excitations in the same cavity. The phonon-photon interaction can be enhanced due to the overlap of both waves in the cavity. In this paper, we discuss some of our recent theoretical works on the strength of the optomechanic coupling, based on both photoelastic and moving interfaces mechanisms, in different (2D, slabs, strips) phoxonic crystals cavities. The cases of two-dimensional infinite and slab structures will enable us to mention the important role of the symmetry and degeneracy of the modes, as well as the role of the materials whose photoelastic constants can be wavelength dependent. Depending on the phonon-photon pair, the photoelastic and moving interface mechanisms can contribute in phase or out-of-phase. Then, the main part of the paper will be devoted to the optomechanic interaction in a corrugated nanobeam waveguide exhibiting dual phononic/photonic band gaps. Such structures can provide photonic modes with very high quality factor, high frequency phononic modes of a few GHz inside a gap and optomechanical coupling rate reaching a few MHz.

  16. Optical fabrication of lightweighted 3D printed mirrors

    Science.gov (United States)

    Herzog, Harrison; Segal, Jacob; Smith, Jeremy; Bates, Richard; Calis, Jacob; De La Torre, Alyssa; Kim, Dae Wook; Mici, Joni; Mireles, Jorge; Stubbs, David M.; Wicker, Ryan

    2015-09-01

    Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM) 3D printing technologies were utilized to create lightweight, optical grade mirrors out of AlSi10Mg aluminum and Ti6Al4V titanium alloys at the University of Arizona in Tucson. The mirror prototypes were polished to meet the λ/20 RMS and λ/4 P-V surface figure requirements. The intent of this project was to design topologically optimized mirrors that had a high specific stiffness and low surface displacement. Two models were designed using Altair Inspire software, and the mirrors had to endure the polishing process with the necessary stiffness to eliminate print-through. Mitigating porosity of the 3D printed mirror blanks was a challenge in the face of reconciling new printing technologies with traditional optical polishing methods. The prototypes underwent Hot Isostatic Press (HIP) and heat treatment to improve density, eliminate porosity, and relieve internal stresses. Metal 3D printing allows for nearly unlimited topological constraints on design and virtually eliminates the need for a machine shop when creating an optical quality mirror. This research can lead to an increase in mirror mounting support complexity in the manufacturing of lightweight mirrors and improve overall process efficiency. The project aspired to have many future applications of light weighted 3D printed mirrors, such as spaceflight. This paper covers the design/fab/polish/test of 3D printed mirrors, thermal/structural finite element analysis, and results.

  17. Distributed microscopic actuation analysis of deformable plate membrane mirrors

    Science.gov (United States)

    Lu, Yifan; Yue, Honghao; Deng, Zongquan; Tzou, Hornsen

    2018-02-01

    To further reduce the areal density of optical mirrors used in space telescopes and other space-borne optical structures, the concept of flexible membrane deformable mirror has been proposed. Because of their high flexibility, poor stiffness and low damping properties, environmental excitations such as orbital maneuver, path changing, and non-uniform heating may induce unexpected vibrations and thus reduce working performance. Therefore, active vibration control is essential for these membrane mirrors. In this paper, two different mirror models, i.e., the plate membrane model and pure membrane model, are studied respectively. In order to investigate the modal vibration characteristics of the mirror, a piezoelectric layer is fully laminated on its non-reflective side to serve as actuators. Dynamic equations of the mirror laminated with piezoelectric actuators are presented first. Then, the actuator induced modal control force is defined. When the actuator area shrinks to infinitesimal, the expressions of microscopic local modal control force and its two components are obtained to predict the spatial microscopic actuation behavior of the mirror. Different membrane pretension forces are also applied to reveal the tension effects on the actuation of the mirror. Analyses indicate that the spatial distribution of modal micro-control forces is exactly the same with the sensing signals distribution of the mirror, which provides crucial guidelines for optimal actuator placement of membrane deformable mirrors.

  18. Mesoscale cavities in hollow-core waveguides for quantum optics with atomic ensembles

    Directory of Open Access Journals (Sweden)

    Haapamaki C.M.

    2016-08-01

    Full Text Available Single-mode hollow-core waveguides loaded with atomic ensembles offer an excellent platform for light–matter interactions and nonlinear optics at low photon levels. We review and discuss possible approaches for incorporating mirrors, cavities, and Bragg gratings into these waveguides without obstructing their hollow cores. With these additional features controlling the light propagation in the hollow-core waveguides, one could potentially achieve optical nonlinearities controllable by single photons in systems with small footprints that can be integrated on a chip. We propose possible applications such as single-photon transistors and superradiant lasers that could be implemented in these enhanced hollow-core waveguides.

  19. Integration of fiber-tip cavities in single-ion traps for quantum sensing

    Science.gov (United States)

    Horak, Peter; Podoliak, Nina; Takahashi, Hiroki; Keller, Matthias

    2017-04-01

    We investigate geometries for efficient coupling of single ions to fiber-coupled light fields for applications in quantum sensing, quantum metrology, and quantum information processing. Specifically, we discuss the integration of fiber-tip microcavities into radio-frequency ion traps. The distortions of the trapping fields induced by the presence of the optical fibers are simulated for a range of ion trap geometries and the most promising arrangements are identified. Finally, we investigate the use of fiber-tip microcavities with non-spherical mirrors for enhanced ion-light coupling at the center of the trap by appropriate shaping of the cavity modes.

  20. SPS RF System an Accelerating Cavity

    CERN Multimedia

    CERN PhotoLab

    1975-01-01

    The picture shows one of the two initially installed cavities. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also gradually increased: by end 1980 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412017X, 7411048X.

  1. Novel Geometries for the LHC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    B. Hall, G. Burt, C. Lingwood, R. Rimmer, H. Wang

    2010-05-23

    The planned luminosity upgrade to LHC is likely to necessitate a large crossing angle and a local crab crossing scheme. For this scheme crab cavities align bunches prior to collision. The scheme requires at least four such cavities, a pair on each beam line either side of the interaction point (IP). Upstream cavities initiate rotation and downstream cavities cancel rotation. Cancellation is usually done at a location where the optics has re-aligned the bunch. The beam line separation near the IP necessitates a more compact design than is possible with elliptical cavities such as those used at KEK. The reduction in size must be achieved without an increase in the operational frequency to maintain compatibility with the long bunch length of the LHC. This paper proposes a suitable superconducting variant of a four rod coaxial deflecting cavity (to be phased as a crab cavity), and presents analytical models and simulations of suitable designs.

  2. Novel Geometries for the LHC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    B. Hall,G. Burt,C. Lingwood,Robert Rimmer,Haipeng Wang; Hall, B. [CI Lancaster University (Great Britain); Burt, G. [CI Lancaster University (Great Britain); Lingwood, C. [CI Lancaster University (Great Britain); Rimmer, Robert [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Wang, Haipeng [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2010-05-01

    The planned luminosity upgrade to LHC is likely to necessitate a large crossing angle and a local crab crossing scheme. For this scheme crab cavities align bunches prior to collision. The scheme requires at least four such cavities, a pair on each beam line either side of the interaction point (IP). Upstream cavities initiate rotation and downstream cavities cancel rotation. Cancellation is usually done at a location where the optics has re-aligned the bunch. The beam line separation near the IP necessitates a more compact design than is possible with elliptical cavities such as those used at KEK. The reduction in size must be achieved without an increase in the operational frequency to maintain compatibility with the long bunch length of the LHC. This paper proposes a suitable superconducting variant of a four rod coaxial deflecting cavity (to be phased as a crab cavity), and presents analytical models and simulations of suitable designs.

  3. Shape Determination for Deformed Electromagnetic Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Akcelik, Volkan; Ko, Kwok; Lee, Lie-Quan; Li, Zhenghai; Ng, Cho-Kuen; Xiao, Liling; /SLAC

    2007-12-10

    The measured physical parameters of a superconducting cavity differ from those of the designed ideal cavity. This is due to shape deviations caused by both loose machine tolerances during fabrication and by the tuning process for the accelerating mode. We present a shape determination algorithm to solve for the unknown deviations from the ideal cavity using experimentally measured cavity data. The objective is to match the results of the deformed cavity model to experimental data through least-squares minimization. The inversion variables are unknown shape deformation parameters that describe perturbations of the ideal cavity. The constraint is the Maxwell eigenvalue problem. We solve the nonlinear optimization problem using a line-search based reduced space Gauss-Newton method where we compute shape sensitivities with a discrete adjoint approach. We present two shape determination examples, one from synthetic and the other from experimental data. The results demonstrate that the proposed algorithm is very effective in determining the deformed cavity shape.

  4. Cavities

    Science.gov (United States)

    ... a snack removes some of the sugar, but brushing the teeth is more effective. Drinking artificially sweetened soft drinks ... also used to restore areas damaged by overzealous brushing. Root canal treatment and tooth extraction When tooth decay advances far enough to ...

  5. Exploring ultrafast negative Kerr Effect for self-mode-locking vertical external-cavity surface-emitting lasers

    Science.gov (United States)

    Albrecht, Alexander R.; Seletskiy, Denis V.; Wang, Yi; Cederberg, Jeffrey G.; Sheik-Bahae, Mansoor

    2014-03-01

    Quasi-stable self-mode-locking of an InGaAs vertical external-cavity surface-emitting laser (VECSEL) emitting around 1020 nm has been observed, resulting in 500 fs pulses at a repetition rate of 1 GHz. The mechanism is attributed to negative ultrafast Kerr lensing in the semiconductor gain structure. Our calculations show that a mode narrowing on the order of 0.5% can be obtained at the concave cavity end-mirror or at the gain medium. This is consistent with experimental observations, as mode-locking can be achieved by placing a (hard) aperture before the concave cavity end mirror inside the VECSEL cavity, or by the soft aperture created by changing the pump spot size in relation to the lasing mode on the gain chip. The pulse train generated by the VECSEL has been analyzed by a fast InGaAs photo diode and oscilloscope, RF spectrum analyzer, and second harmonic intensity autocorrelation. The effect of dispersion on pulse width has been studied, hinting at soliton-like pulse formation.

  6. The prediction of difficult intubation in obese patients using mirror indirect laryngoscopy: A prospective pilot study

    Directory of Open Access Journals (Sweden)

    Arne O Budde

    2013-01-01

    Full Text Available Background: The incidence of difficult laryngoscopy and intubation in obese patients is higher than in the general population. Classical predictors of difficult laryngoscopy and intubation have been shown to be unreliable. We prospectively evaluated indirect mirror laryngoscopy as a predictor of difficult laryngoscopy in obese patients. Materials and Methods: 60 patients with a body mass index (BMI greater than 30, scheduled to undergo general anesthesia, were enrolled. Indirect mirror laryngoscopy was performed and was graded 1-4 according to Cormack and Lehane. A view of grade 3-4 was classified as predicting difficult laryngoscopy. Additional assessments for comparison were the Samsoon and Young modification of the Mallampati airway classification, Wilson Risk Sum Score, neck circumference, and BMI. The view obtained upon direct laryngoscopy after induction of general anesthesia was classified according to Cormack and Lehane as grade 1-4. Results: Sixty patients met the inclusion criteria; however, 8 (13.3% patients had an excessive gag reflex, and examination of the larynx was not possible. 15.4% of patients who underwent direct laryngoscopy had a Cormack and Lehane grade 3 or 4 view and were classified as difficult. Mirror laryngoscopy had a tendency toward statistical significance in predicting difficult laryngoscopy in these patients. Conclusions: This study is consistent with previous studies, which have demonstrated that no one individual traditional test has proven to be adequate in predicting difficult airways in the obese population. However, the new application of an old test - indirect mirror laryngoscopy - could be a useful additional test to predict difficult laryngoscopy in obese patients.

  7. Mirror neurons, language, and embodied cognition.

    Science.gov (United States)

    Perlovsky, Leonid I; Ilin, Roman

    2013-05-01

    Basic mechanisms of the mind, cognition, language, its semantic and emotional mechanisms are modeled using dynamic logic (DL). This cognitively and mathematically motivated model leads to a dual-model hypothesis of language and cognition. The paper emphasizes that abstract cognition cannot evolve without language. The developed model is consistent with a joint emergence of language and cognition from a mirror neuron system. The dual language-cognition model leads to the dual mental hierarchy. The nature of cognition embodiment in the hierarchy is analyzed. Future theoretical and experimental research is discussed. Published by Elsevier Ltd.

  8. Characterizing solar mirror materials using portable reflectometers

    Energy Technology Data Exchange (ETDEWEB)

    Pettit, R.B.

    1982-09-01

    Currently available portable instrumentation for hemispherical and specular reflectance measurements of solar mirror materials is discussed. Particular attention is given to the wavelength dependence of the measurement spectrum, which in most cases does not approximate a solar spectral distribution, and to other limitations of each instrument. Because a portable instrument is not available that can determine the solar averaged specular reflectance from a single measurement, two procedures are recommended for obtaining a reasonable estimate for this quantity using the existing portable equipment. Finally, future developments in this area are briefly discussed.

  9. COMPASS mirror wall of RICH 1

    CERN Multimedia

    Patrice Loïez

    2001-01-01

    The COMPASS experiment uses ring imaging Cherenkov (RICH) counters to identify particles produced in high-energy muon collisions, to better understand the spin structure of the nucleon. Charged particles moving faster than the speed of light in the medium through which they are travelling emit a cone of Cherenkov radiation in the direction of their motion. The light in this cone is reflected from these mirrors onto a photo detector so that the size of the cone can be measured, which gives the energy of the particle.

  10. 100 years of mirror blanks from SCHOTT

    Science.gov (United States)

    Hartmann, Peter; Morian, Hans F.

    2004-07-01

    A hundred years ago SCHOTT delivered the first mirror blank for astronomy, a 720 mm crown glass disk for the Waltz telescope of the Landessternwarte Heidelberg, Germany. Since then significant progress has been made. Larger blanks out of optical glass have been followed by borosilicate disks. In the beginning of the 1970s SCHOTT introduced the zero-expansion glass ceramic ZERODUR. It has been applied for outstanding astronomy projects both ground based and space-borne. The paper gives an overview over the highlights of the last hundred years with some prospects to present and future developments.

  11. Operators and higher genus mirror curves

    Energy Technology Data Exchange (ETDEWEB)

    Codesido, Santiago [Département de Physique Théorique et section de Mathématiques,Université de Genève,Genève, CH-1211 (Switzerland); Gu, Jie [Laboratoire de Physique Théorique de l’École Normale Supérieure,CNRS, PSL Research University,Sorbonne Universités, UPMC, 75005 Paris (France); Mariño, Marcos [Département de Physique Théorique et section de Mathématiques,Université de Genève,Genève, CH-1211 (Switzerland)

    2017-02-17

    We perform further tests of the correspondence between spectral theory and topological strings, focusing on mirror curves of genus greater than one with nontrivial mass parameters. In particular, we analyze the geometry relevant to the SU(3) relativistic Toda lattice, and the resolved ℂ{sup 3}/ℤ{sub 6} orbifold. Furthermore, we give evidence that the correspondence holds for arbitrary values of the mass parameters, where the quantization problem leads to resonant states. We also explore the relation between this correspondence and cluster integrable systems.

  12. Electrocurtain coating process for coating solar mirrors

    Science.gov (United States)

    Kabagambe, Benjamin; Boyd, Donald W.; Buchanan, Michael J.; Kelly, Patrick; Kutilek, Luke A.; McCamy, James W.; McPheron, Douglas A.; Orosz, Gary R.; Limbacher, Raymond D.

    2013-10-15

    An electrically conductive protective coating or film is provided over the surface of a reflective coating of a solar mirror by flowing or directing a cation containing liquid and an anion containing liquid onto the conductive surface. The cation and the anion containing liquids are spaced from, and preferably out of contact with one another on the surface of the reflective coating as an electric current is moved through the anion containing liquid, the conductive surface between the liquids and the cation containing liquid to coat the conductive surface with the electrically conductive coating.

  13. Error reduction techniques for measuring long synchrotron mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Irick, S.

    1998-07-01

    Many instruments and techniques are used for measuring long mirror surfaces. A Fizeau interferometer may be used to measure mirrors much longer than the interferometer aperture size by using grazing incidence at the mirror surface and analyzing the light reflected from a flat end mirror. Advantages of this technique are data acquisition speed and use of a common instrument. Disadvantages are reduced sampling interval, uncertainty of tangential position, and sagittal/tangential aspect ratio other than unity. Also, deep aspheric surfaces cannot be measured on a Fizeau interferometer without a specially made fringe nulling holographic plate. Other scanning instruments have been developed for measuring height, slope, or curvature profiles of the surface, but lack accuracy for very long scans required for X-ray synchrotron mirrors. The Long Trace Profiler (LTP) was developed specifically for long x-ray mirror measurement, and still outperforms other instruments, especially for aspheres. Thus, this paper focuses on error reduction techniques for the LTP.

  14. Directional radiative cooling thermal compensation for gravitational wave interferometer mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Justin Kamp, Carl [Department of Chemical Reaction Engineering, Chalmers University of Technology, SE-412 96 Goteborg (Sweden)], E-mail: carl.kamp@chalmers.se; Kawamura, Hinata [Yokoyama Junior High School, Sanda, Hachioji, Tokyo 193-0832 (Japan); Passaquieti, Roberto [Dipartimento di Fisica ' Enrico Fermi' and INFN Sezione di Pisa, Universita' di Pisa, Largo Bruno Pontecorvo, I-56127 Pisa (Italy); DeSalvo, Riccardo [LIGO Observatories, California Institute of Technology, Pasadena, CA 91125 (United States)

    2009-08-21

    The concept of utilizing directional radiative cooling to correct the problem of thermal lensing in the mirrors of the LIGO/VIRGO gravitational wave detectors has been shown and has prospects for future use. Two different designs utilizing this concept, referred to as the baffled and parabolic mirror solutions, have been proposed with different means of controlling the cooling power. The technique takes advantage of the power naturally radiated by the mirror surfaces at room temperature to prevent their heating by the powerful stored laser beams. The baffled solution has been simulated via COMSOL Multiphysics as a design tool. Finally, the parabolic mirror concept was experimentally validated with the results falling in close agreement with theoretical cooling calculations. The technique of directional radiative thermal correction can be reversed to image heat rings on the mirrors periphery to remotely and dynamically correct their radius of curvature without subjecting the mirror to relevant perturbations.

  15. James Webb Space Telescope Optical Telescope Element Mirror Coatings

    Science.gov (United States)

    Keski-Kuha, Ritva A.; Bowers, Charles W.; Quijada, Manuel A.; Heaney, James B.; Gallagher, Benjamin; McKay, Andrew; Stevenson, Ian

    2012-01-01

    James Webb Space Telescope (JWST) Optical Telescope Element (OTE) mirror coating program has been completed. The science goals of the JWST mission require a uniform, low stress, durable optical coating with high reflectivity over the JWST spectral region. The coating has to be environmentally stable, radiation resistant and compatible with the cryogenic operating environment. The large size, 1.52 m point to point, light weight, beryllium primary mirror (PM) segments and flawless coating process during the flight mirror coating program that consisted coating of 21 flight mirrors were among many technical challenges. This paper provides an overview of the JWST telescope mirror coating program. The paper summarizes the coating development program and performance of the flight mirrors.

  16. The Rubber-Hand Illusion in a Mirror

    Science.gov (United States)

    Bertamini, Marco

    2011-01-01

    In the rubber-hand illusion (RHI) one's hand is hidden, and a fake hand is visible. We explored the situation in which visual information was available indirectly in a mirror. Unlike most species, humans are capable of mirror self-recognition. In the mirror condition, compared to the standard condition (fake hand visible directly), we found no reduction of the RHI following synchronised stimulation, as measured by crossmanual pointing and a questionnaire. We replicated the finding with a smaller mirror that prevented visibility of the face. The RHI was eliminated when a wooden block replaced the fake hand, or when the hand belonged to another person. We conclude that awareness of the reflection is the critical variable, despite the distant visual localisation of the hand in a mirror and the third-person perspective. Stimuli seen in a mirror activate the same response as stimuli seen in peripersonal space, through knowledge that they are near one's body.

  17. Disassembling and reintegration of large telescope primary mirror

    Science.gov (United States)

    Xu, Qi-rui; Fan, Bin; Zhang, Ming

    2014-09-01

    The success of the large telescope is largely linked to the excellent performance and reliability of the primary mirror. In order to maintain the quality of its reflective surface at the high expectations of astronomers, the primary mirror after almost two or three years of astronomical observations, needs to be removed and reinstalled for its cleaning and re-coating operation. There are a series of procedures such as the primary mirror cell dissembling from telescope, mirror handling, transportation, reintegration, alignment and so on. This paper will describe the experiences of disassembling and reintegration of large telescope primary mirror, taking a two meter grade primary mirror for example. As with all advanced and complex opto-mechanical systems, there has been the usual problems and trouble shooting.

  18. A Smart Home Center Platform Solution Based on Smart Mirror

    Directory of Open Access Journals (Sweden)

    Deng Xibo

    2017-01-01

    Full Text Available With the popularization of the concept of smart home, people have raised requirements on the experience of smart living. A smart home platform center solution is put forward in order to solve the intelligent interoperability and information integration of smart home, which enable people to have a more intelligent and convenient life experience. This platform center is achieved through the Smart Mirror. The Smart Mirror refers to a smart furniture, on the basis of the traditional concept of mirror, combining Raspberry Pi, the application of one-way mirror imaging principle, the touch-enabled design, voice and video interaction. Smart Mirror can provide a series of intelligent experience for the residents, such as controlling all the intelligent furniture through Smart Mirror; accessing and displaying the weather, time, news and other life information; monitoring the home environment; remote interconnection operation.

  19. Mirror position determination for the alignment of Cherenkov Telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Adam, J. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Ahnen, M.L. [ETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Baack, D. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Balbo, M. [University of Geneva, ISDC Data Center for Astrophysics Chemin Ecogia 16, 1290 Versoix (Switzerland); Bergmann, M. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Würzburg (Germany); Biland, A. [ETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Blank, M. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Würzburg (Germany); Bretz, T. [ETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich (Switzerland); RWTH Aachen (Germany); Bruegge, K.A.; Buss, J. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Dmytriiev, A. [University of Geneva, ISDC Data Center for Astrophysics Chemin Ecogia 16, 1290 Versoix (Switzerland); Domke, M. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Dorner, D. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Würzburg (Germany); FAU Erlangen (Germany); Einecke, S. [TU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund (Germany); Hempfling, C. [Universität Würzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Würzburg (Germany); and others

    2017-07-11

    Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures to map the faint Cherenkov light emitted in extensive air showers onto their image sensors. Segmented reflectors fulfill these needs using mass produced and light weight mirror facets. However, as the overall image is the sum of the individual mirror facet images, alignment is important. Here we present a method to determine the mirror facet positions on a segmented reflector in a very direct way. Our method reconstructs the mirror facet positions from photographs and a laser distance meter measurement which goes from the center of the image sensor plane to the center of each mirror facet. We use our method to both align the mirror facet positions and to feed the measured positions into our IACT simulation. We demonstrate our implementation on the 4 m First Geiger-mode Avalanche Cherenkov Telescope (FACT).

  20. Optimized bimorph flexible mirrors for laser beam correction and shaping

    Science.gov (United States)

    Sobolev, A. S.; Cherezova, T. Y.; Kudryashov, A. V.

    2005-08-01

    In this paper a new algorithm of bimorph deformable mirror the best-suited electrodes shape and position determination is suggested. This algorithm is based on solving an inverse problem of defining the best electrodes position from the required phase distribution formation. The first part of the algorithm is an approximate determination of mirror electrodes position, which is based on linear dependence of electrical field in piezoceramics from laplasian of corresponding mirror deformation. Exact locating of the electrodes is the second part of the algorithm and is performed during iterative procedure. During the procedure relative root mean square deviation of computed mirror profile from the demanded one is minimized. To calculate mirror deformation on every iteration step we use a specially developed finite element model of the bimorph mirror. By using the developed algorithm, we demonstrate possibility to increase quality of reproducing various phase profiles, for example those, corresponding to human eye aberrations and even to form vortex beam.

  1. Measurement and analysis of active synchrotron mirrors under operating conditions

    Science.gov (United States)

    Sutter, John P.; Alcock, Simon G.; Sawhney, Kawal

    2013-05-01

    At the Diamond Light Source, in situ slope error measurements using the pencil-beam method have enabled X-ray mirror surfaces to be examined in their beamline environment. A surface corrugation common to several bimorph mirrors and the removal of that corrugation by repolishing were both confirmed using this method. In the same way, mirrors curved in a controlled way with bending actuators and sag compensators could also be optimized. Fits to the elastic bending of ideal beams using the Euler-Bernoulli model have been performed on the slope errors of a mechanically bent mirror in order to distinguish bender curvatures from gravitational distortion and to calculate the compensating force that most reduces the latter effect. A successful improvement of the sag compensation mechanism of a vertically focusing mirror was also achieved, aided by a previously tested method for optimizing the settings of a mirror's actuators using pencil-beam scans.

  2. The PVLAS experiment: measuring vacuum magnetic birefringence and dichroism with a birefringent Fabry-Perot cavity

    Energy Technology Data Exchange (ETDEWEB)

    Della Valle, Federico; Milotti, Edoardo [INFN, Trieste (Italy); Universita di Trieste, Dipt. di Fisica, Trieste (Italy); Ejlli, Aldo; Messineo, Giuseppe; Zavattini, Guido [INFN, Ferrara (Italy); Universita di Ferrara, Dipt. di Fisica e Scienze della Terra, Ferrara (Italy); Gastaldi, Ugo [INFN, Ferrara (Italy); Pengo, Ruggero; Ruoso, Giuseppe [INFN, Lab. Nazionale di Legnaro, Legnaro (Italy)

    2016-01-15

    Vacuum magnetic birefringence was predicted long time ago and is still lacking a direct experimental confirmation. Several experimental efforts are striving to reach this goal, and the sequence of results promises a success in the next few years. This measurement generally is accompanied by the search for hypothetical light particles that couple to two photons. The PVLAS experiment employs a sensitive polarimeter based on a high finesse Fabry-Perot cavity. In this paper we report on the latest experimental results of this experiment. The data are analysed taking into account the intrinsic birefringence of the dielectric mirrors of the cavity. Besides a new limit on the vacuum magnetic birefringence, the measurements also allow the model-independent exclusion of new regions in the parameter space of axion-like and milli-charged particles. In particular, these last limits hold also for all types of neutrinos, resulting in a laboratory limit on their charge. (orig.)

  3. The PVLAS experiment: measuring vacuum magnetic birefringence and dichroism with a birefringent Fabry-Perot cavity

    CERN Document Server

    Della Valle, F; Ejlli, A; Gastaldi, U; Messineo, G; Zavattini, G; Pengo, R; Ruoso, G

    2015-01-01

    Vacuum magnetic birefringence was predicted long time ago and is still lacking a direct experimental confirmation. Several experimental efforts are striving to reach this goal, and the sequence of results promises a success in the next few years. This measurement generally is accompanied by the search for hypothetical light particles that couple to two photons. The PVLAS experiment employs a sensitive polarimeter based on a high finesse Fabry-Perot cavity. In this paper we report on the latest experimental results of this experiment. The data are analysed taking into account the intrinsic birefringence of the dielectric mirrors of the cavity. Besides the limit on the vacuum magnetic birefringence, the measurements also allow the model-independent exclusion of new regions in the parameter space of axion-like and milli-charged particles. In particular, these last limits hold also for all types of neutrinos, resulting in a laboratory limit on their charge.

  4. Widely tunable all-fiber SESAM mode-locked Ytterbium laser with a linear cavity

    Science.gov (United States)

    Zou, Feng; Wang, Zhaokun; Wang, Ziwei; Bai, Yang; Li, Qiurui; Zhou, Jun

    2017-07-01

    We present a widely tunable all-fiber mode-locked laser based on semiconductor saturable absorber mirror (SESAM) with a linear cavity design. An easy-to-use tunable bandpass filter based on thin film cavity technology is employed to tune the wavelength. By tuning the filter and adjusting the polarization controller, mode-locked operation can be achieved over the range of 1023 nm-1060 nm. With the polarization controller settled, mode-locked operation can be preserved and the wavelength can be continuously tuned from 1030 nm to 1053 nm. At 1030 nm, the laser delivers 9.6 mw average output power with 15.4 ps 10.96 MHz pulses at fundamental mode-locked operation.

  5. Very high finesse optical-feedback cavity-enhanced absorption spectrometer for low concentration water vapor isotope analyses.

    Science.gov (United States)

    Landsberg, J; Romanini, D; Kerstel, E

    2014-04-01

    So far, cavity-enhanced absorption spectroscopy (CEAS) has been based on optical cavities with a high finesse F that, however, has been limited by mirror reflectivity and by cavity transmission considerations to a few times 10,000. Here, we demonstrate a compact near-infrared optical-feedback CEAS instrument for water vapor isotope ratio measurements, with F>140,000. We show that this very high finesse can be effectively exploited to improve the detection sensitivity to the full extent predicted by the increased effective path length to reach a noise equivalent absorption sensitivity of 5.7×10(-11)  cm(-1) Hz(-1/2) for a full spectrum registration (including possible effects of interference fringes and fit model inadequacies).

  6. Room temperature continuous wave InGaAsN quantum well vertical cavity lasers emitting at 1.3 um

    Energy Technology Data Exchange (ETDEWEB)

    CHOQUETTE,KENT D.; KLEM,JOHN F.; FISCHER,ARTHUR J.; SPAHN,OLGA B.; ALLERMAN,ANDREW A.; FRITZ,IAN J.; KURTZ,STEVEN R.; BREILAND,WILLIAM G.; SIEG,ROBERT M.; GEIB,KENT M.; SCOTT,J.W.; NAONE,R.L.

    2000-06-05

    Selectively oxidized vertical cavity lasers emitting at 1294 nm using InGaAsN quantum wells are reported for the first time which operate continuous wave at and above room temperature. The lasers employ two n-type Al{sub 0.94}Ga{sub 0.06}As/GaAs distributed Bragg reflectors each with a selectively oxidized current aperture adjacent to the optical cavity, and the top output mirror contains a tunnel junction to inject holes into the active region. Continuous wave single mode lasing is observed up to 55 C. These lasers exhibit the longest wavelength reported to date for vertical cavity surface emitting lasers grown on GaAs substrates.

  7. Mirror Movements Identified in Patients with Moebius Syndrome

    OpenAIRE

    Webb, Bryn D.; Frempong, Tamiesha; Naidich, Thomas P.; Gaspar, Harald; Jabs, Ethylin Wang; Rucker, Janet C

    2014-01-01

    Background Moebius syndrome is a rare disorder with minimum clinical criteria of congenital facial weakness in association with impairment in abduction of one or both eyes. Mirror movements are not known to be associated with Moebius syndrome. Case Report We present three patients who meet minimum criteria for a diagnosis of Moebius syndrome and who also display mirror movements. Discussion This case series suggests that Moebius syndrome may be associated with mirror movements. Further invest...

  8. Giant pandas failed to show mirror self-recognition.

    Science.gov (United States)

    Ma, Xiaozan; Jin, Yuan; Luo, Bo; Zhang, Guiquan; Wei, Rongping; Liu, Dingzhen

    2015-05-01

    Mirror self-recognition (MSR), i.e., the ability to recognize oneself in a mirror, is considered a potential index of self-recognition and the foundation of individual development. A wealth of literature on MSR is available for social animals, such as chimpanzees, Asian elephants and dolphins, yet little is known about MSR in solitary mammalian species. We aimed to evaluate whether the giant panda can recognize itself in the mirror, and whether this capacity varies with age. Thirty-four captive giant pandas (F:M = 18:16; juveniles, sub-adults and adults) were subjected to four mirror tests: covered mirror tests, open mirror tests, water mark control tests, and mark tests. The results showed that, though adult, sub-adult and juvenile pandas exposed to mirrors spent similar amounts of time in social mirror-directed behaviors (χ(2) = 0.719, P = 0.698), none of them used the mirror to touch the mark on their head, a self-directed behavior suggesting MSR. Individuals of all age groups initially displayed attacking, threatening, foot scraping and backwards walking behaviors when exposed to their self-images in the mirror. Our data indicate that, regardless of age, the giant pandas did not recognize their self-image in the mirror, but instead considered the image to be a conspecific. Our results add to the available information on mirror self-recognition in large mammals, provide new information on a solitary species, and will be useful for enclosure design and captive animal management.

  9. Winter School on Mirror Symmetry, Vector Bundles and Lagrangian Submanifolds

    CERN Document Server

    Yau, S-T

    2002-01-01

    The collection of articles in this volume are based on lectures presented during the Winter School on Mirror Symmetry held at Harvard University. There are many new directions suggested by mirror symmetry which could potentially have very rich connections in physics and mathematics. This book brings together the latest research in a major area of mathematical physics, including the recent progress in mirror manifolds and Lagrangian submanifolds. In particular, several articles describing homological approach and related topics are included.

  10. Constraints on mirror models of dark matter from observable neutron-mirror neutron oscillation

    Directory of Open Access Journals (Sweden)

    Rabindra N. Mohapatra

    2018-01-01

    Full Text Available The process of neutron-mirror neutron oscillation, motivated by symmetric mirror dark matter models, is governed by two parameters: n−n′ mixing parameter δ and n−n′ mass splitting Δ. For neutron mirror neutron oscillation to be observable, the splitting between their masses Δ must be small and current experiments lead to δ≤2×10−27 GeV and Δ≤10−24 GeV. We show that in mirror universe models where this process is observable, this small mass splitting constrains the way that one must implement asymmetric inflation to satisfy the limits of Big Bang Nucleosynthesis on the number of effective light degrees of freedom. In particular we find that if asymmetric inflation is implemented by inflaton decay to color or electroweak charged particles, the oscillation is unobservable. Also if one uses SM singlet fields for this purpose, they must be weakly coupled to the SM fields.

  11. A Research on the Primary Mirror Manipulator of Large Segmented-mirror Telescope

    Science.gov (United States)

    Zuo, H.

    2012-09-01

    Since Galileo firstly used the telescope to observe the sky 400 years ago, the aperture of the telescope has become larger and larger to observe the deeper universe, and the segmented-mirror telescope is becoming more and more popular with increasing aperture. In the early 21st century, a series of segmented-mirror telescopes have been constructed including the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) of China. LAMOST is a meridian reflecting Schmidt telescope, and the dimension of the primary mirror is about 6.7 m× 6 m, which is composed of 37 hexagonal sub-mirrors. However, a problem about the mirror installation appears with the increasing aperture. If there are hundreds of sub-mirrors in the telescope, it is a challenging job to mount and dismount them to the truss. This problem is discussed in this paper and a manipulator for the primary mirror of LAMOST is designed to perform the mount and dismount work. In chapter 1, all the segmented-mirror telescopes in the world are introduced and how the sub-mirrors of these telescopes are installed has been investigated. After comparing with the serial and the parallel robot, a serial robot manipulator proposal, which has several redundant degrees of freedom (DOFs), has been chosen from a series of design proposals. In chapter 2, the theoretical analysis has been carried out on the basis of the design proposal, which includes the forward kinematics and the inverse kinematics. Firstly the D-H coordinate is built according to the structure of the manipulator, so it is possible to obtain the end-effector position and orientation from the individual joint motion thanks to the forward kinematics. Because of the redundant DOFs of the manipulator, the inverse kinematics solution can be a very trick task, and the result may not be only, therefore a kind of simulation is carried out to get the numerical solution using ADAMS (Automatic Dynamic Analysis of Mechanical System). In the dynamics analysis the

  12. Analysis of structurally sensitive loss in GaN-based VCSEL cavities and its effect on modal discrimination.

    Science.gov (United States)

    Hashemi, Ehsan; Bengtsson, Jörgen; Gustavsson, Johan; Stattin, Martin; Cosendey, Gatien; Grandjean, Nicolas; Haglund, Asa

    2014-01-13

    Lateral loss causes optical energy to leave the laser cavity in the transverse, lateral, direction, and is sometimes neglected to simplify the numerical simulations. However, in contrast to outcoupling and absorption losses, we show that the lateral loss can change drastically with only nanometer-sized changes of the cavity structure, from being virtually zero to becoming the major source of cavity loss, since the cavity becomes antiguiding. This can be explained as the opening of a channel of efficient resonant lateral leakage of optical power at a certain oblique propagation angle. A number of different realizations of current apertures and top mirror designs in GaN-based VCSEL cavities, which have been suggested for realization of microcavity lasers emitting in the blue wavelength range, are simulated. Many of these are shown to lead to unintentional antiguiding, which can more than double the threshold gain for lasing. Notably, for strong enough antiguiding the resonant lateral leakage decreases so that the threshold gain values might again be tolerable. This regime has been suggested for robust single-mode operation since earlier predictions, building on analogies with slab waveguides, hinted at a very strong suppression of higher order modes. However, our simulations indicate that for the VCSEL cavities the derived formulas grossly overestimate the modal discrimination.

  13. Timing stability enhancement of an Erbium Doped mode locked Fiber Laser using SESAM mirror

    Science.gov (United States)

    Afifi, G.; Khedr, M. Atta; Badr, Y.; Danailov, M.; Sigalotti, P.; Cinquegrana, P.; Alsous, M. B.; Galaly, A. R.

    2016-05-01

    We report on an examination of pulse timing stability of a home built Erbium Doped Fiber Laser (EDFL) passively mode locked via nonlinear polarization rotation by inserting semiconductor saturable absorber mirror (SESAM) in laser cavity. A very low root mean square (RMS) timing jitter (less than 27 fsec) and faster self-starting mode locking have been established. In order to get clear, low noise signal for time resolving measurements, synchronization of EDFL laser with an external high precision electronic oscillator have been established. Subsequently, it is synchronized and optically cross-correlated with a Ti:Sapphire laser source (Micra). The measured relative timing jitter was found to be less than 65 fsec. In this way, the two, well synchronized Ti:Sapphire and EDFL laser pulses prove to be a powerful tool for time resolving measurements.

  14. Subwavelength grating as both emission mirror and electrical contact for VCSELs in any material system

    Science.gov (United States)

    Czyszanowski, Tomasz; Gebski, Marcin; Dems, Maciej; Wasiak, Michał; Sarzała, Robert; Panajotov, Krassimir

    2017-01-01

    Semiconductor-metal subwavelength grating (SMSG) can serve a dual purpose in vertical-cavity surface-emitting lasers (VCSELs), as both optical coupler and current injector. SMSGs provide optical as well as lateral current confinement, eliminating the need for ring contacts and lateral build-in optical and current confinement, allowing their implementation on arbitrarily large surfaces. Using an SMSG as the top mirror enables fabrication of monolithic VCSELs from any type of semiconductor crystal. The construction of VCSELs with SMSGs requires significantly less p-type material, in comparison to conventional VCSELs. In this paper, using a three-dimensional, fully vectorial optical model, we analyse the properties of the stand-alone SMSG in a number of semiconductor materials for a broad range of wavelengths. Integrating the optical model with thermal and electrical numerical models, we then simulate the threshold operation of an exemplary SMSG VCSEL.

  15. Mirror movements identified in patients with moebius syndrome.

    Science.gov (United States)

    Webb, Bryn D; Frempong, Tamiesha; Naidich, Thomas P; Gaspar, Harald; Jabs, Ethylin Wang; Rucker, Janet C

    2014-01-01

    Moebius syndrome is a rare disorder with minimum clinical criteria of congenital facial weakness in association with impairment in abduction of one or both eyes. Mirror movements are not known to be associated with Moebius syndrome. We present three patients who meet minimum criteria for a diagnosis of Moebius syndrome and who also display mirror movements. This case series suggests that Moebius syndrome may be associated with mirror movements. Further investigation to delineate the genetic etiologies of Moebius syndrome is ongoing. Patients with Moebius syndrome and mirror movements may represent a specific subclass of this disorder.

  16. Mirror Advanced Reactor Study (MARS) final report summary

    Energy Technology Data Exchange (ETDEWEB)

    Henning, C.D.; Logan, B.G.; Carlson, G.A.; Perkins, L.J.; Werner, R.W.; Gordon, J.D.; Parmer, J.F.; Bilton, J.R.; Glancy, J.E.; Kulcinski, G.L.

    1983-12-08

    The Mirror Advanced Reactor Study (MARS) has resulted in an overview of a first-generation tandem mirror reactor. The central cell fusion plasma is self-sustained by alpha heating (ignition), while electron-cyclotron resonance heating and negative ion beams maintain the electrostatic confining potentials in the end plugs. Plug injection power is reduced by the use of high-field choke coils and thermal barriers, concepts to be tested in the Tandem Mirror Experiment-Upgrade (TMX-U) and Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermore National Laboratory.

  17. Advanced Actuator Concepts for High Precision Deformable Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — TRS Technologies proposes to develop a variety of single crystal actuators for adaptive optics deformable mirrors. Single crystal piezoelectric actuators are...

  18. Magnetic-mirror principle as applied to fusion research

    Energy Technology Data Exchange (ETDEWEB)

    Post, R.F.

    1983-08-11

    A tutorial account is given of the key physics issues in the confinement of high temperature plasma in magnetic mirror systems. The role of adiabatic invariants and particle drifts and their relationship to equilibrium and stability are discussed, in the context of the various forms of mirror field geometry. Collisional effects and the development and the control of ambipolar potentials are reviewed. The topic of microinstabilities is discussed together with the means for their control. The properties and advantages for fusion power purposes of various special embodiments of the mirror idea, including tandem mirrors, are discussed.

  19. Silicon Carbide Corrugated Mirrors for Space Telescopes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Trex Enterprises Corporation (Trex) proposes technology development to manufacture monolithic, lightweight silicon carbide corrugated mirrors (SCCM) suitable for...

  20. Dynamic range of low-voltage cascode current mirrors

    DEFF Research Database (Denmark)

    Bruun, Erik; Shah, Peter Jivan

    1995-01-01

    Low-voltage cascode current mirrors are reviewed with respect to the design limitations imposed if all transistors in the mirror are required to operate in the saturation region. It is found that both a lower limit and an upper limit exist for the cascode transistor bias voltage. Further, the use....... The proposed configuration has the advantage of simplicity combined with a complete elimination of the need for fixed bias voltages or bias currents in the current mirror. A disadvantage is that it requires a higher input voltage to the current mirror...

  1. Assessment of MODIS Scan Mirror Reflectance Changes On-Orbit

    Science.gov (United States)

    Xiong, Xiaoxiong; Wu, A.; Angal, A.

    2008-01-01

    Since launch, the NASA EOS Terra and Aqua MODIS have operated successfully for more than 8 and 6 years, respectively. MODIS collects data using a two-sided scan mirror over a large scan angular range. The scan mirror is made of a polished, nickel-plated beryllium base coated with high purity silver, which is then over-coated with the Denton proprietary silicon monoxide and silicon dioxide mixture. The scan mirror's reflectance was characterized pre-launch using its witness samples, and the response versus scan angle was measured at the sensor system level. In this study, we present an assessment of MODIS scan mirror on-orbit degradation by examining changes of spectral band response over each sensor's mission lifetime. Results show that the scan mirror's optical properties for both Terra and Aqua MODIS have experienced significant degradation since launch in the VIS spectral region, which is mirror side dependent as well as scan angle dependent. In general, the mirror degradation is more severe for Terra MODIS than Aqua MODIS, especially during recent years. For Terra MODIS, the degradation rate is noticeably different between the mirror sides. On the other hand, there has been little mirror side dependent difference for Aqua MODIS.

  2. Development of light-weight spherical mirrors for RICH detectors

    CERN Document Server

    Metlica, Fabio

    2007-01-01

    Glass-coated beryllium and carbon-fiber light-weight spherical mirrors, with radii of curvature of $\\sim$ 2700mm, have been successfully developed and tested as part of the LHCb RICH experimental programme. The low mass mirror is necessary to minimize the amount of material within the LHCb spectrometer acceptance, with a requirement of less than 2% of a radiation length. Both technologies are suitable for light-weight mirror applications. The R&D and characterization of the mirrors are reported.

  3. Low Cost, Light Weight Materials for Mirrors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed STTR is the combination of a small business with unique materials experience, and Northwestern Unviersity, with expertise in Mirror applications,...

  4. Large Scale Cleaning Telescope Mirrors with Electron Beams Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Cleaning Lenses and Mirrored Surfaces with Electrons tasks include: Development of Fractal Wand Geometries; Vacuum Chamber testing for Fractal Wand Prototypes;...

  5. Observing the Unobservable? Modeling Coronal Cavity Densities

    Science.gov (United States)

    Fuller, J.; Gibson, S. E.; de Toma, G.; Fan, Y.

    2008-05-01

    Prominence cavities in coronal helmet streamers are readily detectable in white-light coronagraph images, yet their interpretation may be complicated by projection effects. In order to determine a cavity's density structure, it is essential to quantify the contribution of noncavity features along the line of sight. We model the coronal cavity as an axisymmetric torus that encircles the Sun at constant latitude and fit it to observations of a white-light cavity observed by the Mauna Loa Solar Observatory (MLSO) MK4 coronagraph from 2006 January 25 to 30. We demonstrate that spurious noncavity contributions (including departures from axisymmetry) are minimal enough to be incorporated in a density analysis as conservatively estimated uncertainties in the data. We calculate a radial density profile for cavity material and for the surrounding helmet streamer (which we refer to as the "cavity rim") and find that the cavity density is depleted by a maximum of 40% compared to the surrounding helmet streamer at low altitudes (1.18 R⊙) but is consistently higher (double or more) than in coronal holes. We also find that the relative density depletion between cavity and surrounding helmet decreases as a function of height. We show that both increased temperature in the cavity relative to the surrounding helmet streamer and a magnetic flux rope configuration might lead to such a flattened density profile. Finally, our model provides general observational guidelines that can be used to determine when a cavity is sufficiently unobstructed to be a good candidate for plasma diagnostics.

  6. Soiling and degradation analysis of solar mirrors

    Science.gov (United States)

    Delord, Christine; Blaise, Anthony; Fernandez-García, Aránzazu; Martínez-Arcos, Lucía; Sutter, Florian; Reche-Navarro, Tomás Jesús

    2016-05-01

    The degradation and the soiling of the mirrors are dependent of the solar field and the mirrors technologies, the local climate, the meteorological events, the O&M tasks and the human activities around the site. In the frame of the European project SFERA II, the SODAM project has been the opportunity to compare the soiling and the degradation mechanisms on a Fresnel solar field installed in the South of France and on a parabolic-through solar field installed in the South of Spain. The analysis of the soiling has shown equivalent maximum weekly reflectance loss due to soiling in both sites but a double mean weekly reflectance loss in Spain respect to France, as well as typical meteorological events to be taken into account to adapt the cleaning strategies. Among the meteorological parameters mainly influencing the soiling, the study has revealed the effect of the rain and of the DNI. In parallel, the analysis of the degradation mechanisms has highlighted a common chalking of the protective back paint layers due to the irradiation. This chalking being associated to a leaching of the paint layers in the site of Cadarache due to the high presence of liquid water. A difference in the speed of corrosion of the silver layer has been also noticed, leading to a difference in the mechanisms of delamination of the paints layers.

  7. Development of a miniaturized deformable mirror controller

    Science.gov (United States)

    Bendek, Eduardo; Lynch, Dana; Pluzhnik, Eugene; Belikov, Ruslan; Klamm, Benjamin; Hyde, Elizabeth; Mumm, Katherine

    2016-07-01

    High-Performance Adaptive Optics systems are rapidly spreading as useful applications in the fields of astronomy, ophthalmology, and telecommunications. This technology is critical to enable coronagraphic direct imaging of exoplanets utilized in ground-based telescopes and future space missions such as WFIRST, EXO-C, HabEx, and LUVOIR. We have developed a miniaturized Deformable Mirror controller to enable active optics on small space imaging mission. The system is based on the Boston Micromachines Corporation Kilo-DM, which is one of the most widespread DMs on the market. The system has three main components: The Deformable Mirror, the Driving Electronics, and the Mechanical and Heat management. The system is designed to be extremely compact and have lowpower consumption to enable its use not only on exoplanet missions, but also in a wide-range of applications that require precision optical systems, such as direct line-of-sight laser communications, and guidance systems. The controller is capable of handling 1,024 actuators with 220V maximum dynamic range, 16bit resolution, and 14bit accuracy, and operating at up to 1kHz frequency. The system fits in a 10x10x5cm volume, weighs less than 0.5kg, and consumes less than 8W. We have developed a turnkey solution reducing the risk for currently planned as well as future missions, lowering their cost by significantly reducing volume, weight and power consumption of the wavefront control hardware.

  8. Cancer of the oral cavity.

    Science.gov (United States)

    Montero, Pablo H; Patel, Snehal G

    2015-07-01

    Cancer of the oral cavity is one of the most common malignancies worldwide. Although early diagnosis is relatively easy, presentation with advanced disease is not uncommon. The standard of care is primary surgical resection with or without postoperative adjuvant therapy. Improvements in surgical techniques combined with the routine use of postoperative radiation or chemoradiation therapy have resulted in improved survival. Successful treatment is predicated on multidisciplinary treatment strategies to maximize oncologic control and minimize impact of therapy on form and function. Prevention of oral cancer requires better education about lifestyle-related risk factors, and improved awareness and tools for early diagnosis. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Basketballs as spherical acoustic cavities

    Science.gov (United States)

    Russell, Daniel A.

    2010-06-01

    The sound field resulting from striking a basketball is found to be rich in frequency content, with over 50 partials in the frequency range of 0-12 kHz. The frequencies are found to closely match theoretical expectations for standing wave patterns inside a spherical cavity. Because of the degenerate nature of the mode shapes, explicit identification of the modes is not possible without internal investigation with a microphone probe. A basketball proves to be an interesting application of a boundary value problem involving spherical coordinates.

  10. Management of oral cavity carcinoma.

    Science.gov (United States)

    Varvares, Mark A

    2008-01-01

    Oral cavity cancer continues to be a major health issue in the state of Missouri, largely due to the high rate of tobacco use. Pretreatment evaluation and planning should be done by a multidisciplinary team. Surgical resection is the primary method of treatment. Adjuvant therapy is frequently needed to control intermediate and advanced disease. There are significant functional effects of surgery; reconstructive efforts are focused on restoring the patient to as normal a condition as possible. Acoordinated approach by an experienced team can achieve good local control and minimize morbidity.

  11. Wavelength shifting of intra-cavity photons: Adiabatic wavelength tuning in rapidly wavelength-swept lasers.

    Science.gov (United States)

    Jirauschek, Christian; Huber, Robert

    2015-07-01

    We analyze the physics behind the newest generation of rapidly wavelength tunable sources for optical coherence tomography (OCT), retaining a single longitudinal cavity mode during operation without repeated build up of lasing. In this context, we theoretically investigate the currently existing concepts of rapidly wavelength-swept lasers based on tuning of the cavity length or refractive index, leading to an altered optical path length inside the resonator. Specifically, we consider vertical-cavity surface-emitting lasers (VCSELs) with microelectromechanical system (MEMS) mirrors as well as Fourier domain mode-locked (FDML) and Vernier-tuned distributed Bragg reflector (VT-DBR) lasers. Based on heuristic arguments and exact analytical solutions of Maxwell's equations for a fundamental laser resonator model, we show that adiabatic wavelength tuning is achieved, i.e., hopping between cavity modes associated with a repeated build up of lasing is avoided, and the photon number is conserved. As a consequence, no fundamental limit exists for the wavelength tuning speed, in principle enabling wide-range wavelength sweeps at arbitrary tuning speeds with narrow instantaneous linewidth.

  12. Owning the body in the mirror: The effect of visual perspective and mirror view on the full-body illusion.

    Science.gov (United States)

    Preston, Catherine; Kuper-Smith, Benjamin J; Ehrsson, Henrik H

    2015-12-17

    Mirrors allow us to view our own body from a third-person (observer) perspective. However, how viewing ourselves through a mirror affects central body representations compared with true third-person perspective is not fully understood. Across a series of experiments, multisensory full-body illusions were used to modulate feelings of ownership over a mannequin body that was viewed from a third-person perspective through a mirror, from a third-person perspective without a mirror, and from a first-person perspective. In contrast to non-mirror third-person perspective, synchronously touching the participant's actual body and the mannequin body viewed in the mirror elicited strong feelings of ownership over the mannequin and increased physiological responses to the mannequin being threatened compared to the equivalent asynchronous (non-ownership) control condition. Subjective reports of ownership viewing the mannequin through a mirror were also statistically equivalent to those following the first-person perspective illusion. These findings suggest that mirrors have a special role for viewing the self. The results also support the importance of egocentric reference frames for body ownership and suggest that mirror reflections of one's own body are related to peripersonal space, which enables updating of central body representations.

  13. Owning the body in the mirror: The effect of visual perspective and mirror view on the full-body illusion

    Science.gov (United States)

    Preston, Catherine; Kuper-Smith, Benjamin J.; Henrik Ehrsson, H.

    2015-01-01

    Mirrors allow us to view our own body from a third-person (observer) perspective. However, how viewing ourselves through a mirror affects central body representations compared with true third-person perspective is not fully understood. Across a series of experiments, multisensory full-body illusions were used to modulate feelings of ownership over a mannequin body that was viewed from a third-person perspective through a mirror, from a third-person perspective without a mirror, and from a first-person perspective. In contrast to non-mirror third-person perspective, synchronously touching the participant’s actual body and the mannequin body viewed in the mirror elicited strong feelings of ownership over the mannequin and increased physiological responses to the mannequin being threatened compared to the equivalent asynchronous (non-ownership) control condition. Subjective reports of ownership viewing the mannequin through a mirror were also statistically equivalent to those following the first-person perspective illusion. These findings suggest that mirrors have a special role for viewing the self. The results also support the importance of egocentric reference frames for body ownership and suggest that mirror reflections of one’s own body are related to peripersonal space, which enables updating of central body representations. PMID:26678091

  14. Rationale for designing cavity preparations.

    Science.gov (United States)

    Laswell, H R; Welk, D A

    1985-04-01

    Increased resistance to caries, increased dental awareness, superior diagnostic capabilities, better illumination, optical aids that significantly enhance vision, improved and standardized materials for restoration, and a deeper understanding of the caries process enable a far more conservative approach to tooth preparation. The dentist can concentrate on preserving as much sound tooth structure as possible with less attention being devoted to resistance and retention form that previously demanded in bulk restorations and massive channels and locks that are no longer appropriate. Although caries inhibitory effects have been shown with materials such as silicate cement, glass ionomers, and resins that leach fluoride, in general, dentists should not rely on restorative materials to inhibit the development of future decay. Characteristics of the carious lesion are unique for each tooth according to many factors centering around the plaque pattern for that tooth and not according to zones of natural susceptibility or immunity strictly dictated by morphology. Therefore, no single cavity preparation duplicated from a textbook is likely to be satisfactory for an individual tooth. Furthermore, novices learning the subject of cavity preparation often leave decalcified enamel when they attempt to replicate under clinical conditions that which they have learned in technique courses. This is the major invitation to future caries reappearing adjacent to restorations. Also, failure to duplicate the exact morphology of the tooth surface that has been replaced is likely to alter the pattern of plaque accumulation and create other caries prone areas.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Esthesioneuroblastoma of the nasal cavity.

    Science.gov (United States)

    Hollen, Tyler R; Morris, Christopher G; Kirwan, Jessica M; Amdur, Robert J; Werning, John W; Vaysberg, Mikhail; Mendenhall, William M

    2015-06-01

    Esthesioneuroblastoma is an uncommon cancer of the nasal cavity. We describe the outcomes for 26 patients treated with curative intent with photon radiotherapy (RT) at the University of Florida. Between May 1972 and June 2007, 26 patients received RT for previously untreated esthesioneuroblastoma of the nasal cavity. Sixteen patients were males and 10 were females with a median age of 55 years (range, 3 to 82 y). The modified Kadish stage distribution was: B, 7 patients; C, 17 patients; and D, 2 patients. Treatment modalities included the following: definitive RT, 5 patients; preoperative RT, 2 patients; and postoperative RT after resection, 19 patients. Elective neck irradiation (ENI) was performed in 17 (71%) of 24 N0 patients. Rates of local control, cause-specific survival, and absolute overall survival at 5 years were 79%, 72%, and 69%, respectively. Overall survival among patients treated with definitive RT was 20% at 5 years, compared with 81% among those who underwent surgery and adjuvant RT (P=0.01). One (6%) of 17 patients who received ENI developed a recurrence in the neck and was successfully salvaged. Ultimate neck control was 100% at 5 years for patients who received ENI versus 69% among those not receiving ENI (P=0.0173). Resection combined with adjuvant RT is more effective than surgery or RT alone in the treatment of esthesioneuroblastoma. ENI reduces the risk of regional relapse in patients with Kadish stage B and C cancers.

  16. Rebuild of Capture Cavity 1 at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Harms, E. [Fermilab; Arkan, T. [Fermilab; Borissov, E. [Fermilab; Dhanaraj, N. [Fermilab; Hocker, A. [Fermilab; Orlov, Y. [Fermilab; Peterson, T. [Fermilab; Premo, K. [Fermilab

    2014-01-01

    The front end of the proposed Advanced Superconducting Test Accelerator at Fermilab employs two single cavity cryomodules, known as 'Capture Cavity 1' and 'Capture Cavity 2', for the first stage of acceleration. Capture Cavity 1 was previously used as the accelerating structure for the A0 Photoinjector to a peak energy of ~14 MeV. In its new location a gradient of ~25 MV/m is required. This has necessitated a major rebuild of the cryomodule including replacement of the cavity with a higher gradient one. Retrofitting the cavity and making upgrades to the module required significant redesign. The design choices and their rationale, summary of the rebuild, and early test results are presented.

  17. Density and Morphology of Coronal Prominence Cavities

    Science.gov (United States)

    Gibson, Sarah; Fuller, J.

    2009-05-01

    Coronal prominence cavities are fundamental parts of prominences. They hold clues to the magnetic structure of pre-CME equilibria, and better represent the coronal source of the expanding volume in CMEs and magnetic clouds than a prominence does alone. However, prominence cavities have not been nearly as comprehensively observed and studied as prominences. This is in part due to projection effects which can complicate interpretation of observations, and in part because spectroscopic diagnostic studies require targeted observations, which have only recently been attempted. I will present recent work using white-light observations of cavities to model the morphological and density properties of polar crown filament cavities, with projection effects taken into account. I will also comment on recent attempts to obtain spectral diagnostics of coronal prominence cavities, and will discuss the implications of all of these observations for cavity stability and thermal and magnetic properties.

  18. Mirror therapy in children with hemiplegia: a pilot study.

    Science.gov (United States)

    Gygax, Marine Jequier; Schneider, Patrick; Newman, Christopher John

    2011-05-01

    Mirror therapy, which provides the visual illusion of a functional paretic limb by using the mirror reflection of the non-paretic arm, is used in the rehabilitation of hemiparesis after stroke in adults. We tested the effectiveness and feasibility of mirror therapy in children with hemiplegia by performing a pilot crossover study in ten participants (aged 6-14 y; five males, five females; Manual Ability Classification System levels: one at level I, two at level II, four at level III, three at level IV) randomly assigned to 15 minutes of daily bimanual training with and without a mirror for 3 weeks. Assessments of maximal grasp and pinch strengths, and upper limb function measured by the Shriner's Hospital Upper Extremity Evaluation were performed at weeks 0 (baseline), 3, 6 (intervention), and 9 (wash-out). Testing of grasp strength behind the mirror improved performance by 15% (p=0.004). Training with the mirror significantly improved grasp strength (with mirror +20.4%, p=0.033; without +5.9%, p>0.1) and upper limb dynamic position (with mirror +4.6%, p=0.044; without +1.2%, p>0.1), while training without a mirror significantly improved pinch strength (with mirror +6.9%, p>0.1; without +21.9%, p=0.026). This preliminary study demonstrates the feasibility of mirror therapy in children with hemiplegia and that it may improve strength and dynamic function of the paretic arm. © The Authors. Developmental Medicine & Child Neurology © 2011 Mac Keith Press.

  19. Induced Cavities for Photonic Quantum Gates

    Science.gov (United States)

    Lahad, Ohr; Firstenberg, Ofer

    2017-09-01

    Effective cavities can be optically induced in atomic media and employed to strengthen optical nonlinearities. Here we study the integration of induced cavities with a photonic quantum gate based on Rydberg blockade. Accounting for loss in the atomic medium, we calculate the corresponding finesse and gate infidelity. Our analysis shows that the conventional limits imposed by the blockade optical depth are mitigated by the induced cavity in long media, thus establishing the total optical depth of the medium as a complementary resource.

  20. Novel Geometries for the LHC CRAB Cavity

    CERN Document Server

    Hall, Ben

    2010-01-01

    In 2017 the LHC is envisioned to increase its luminosity via an upgrade. This upgrade is likely to require a large crossing angle hence a crab cavity is required to align the bunches prior to collision. There are two possible schemes for crab cavity implementation, global and local. In a global crab cavity the crab cavity is far from the IP and the bunch rotates back and forward as it traverses around the accelerator in a closed orbit. For this scheme a two-cell elliptical squashed cavity at 800 MHz is preferred. To avoid any potential beam instabilities all the parasitic modes of the cavities must be damped strongly, however crab cavities have lower order and same order modes in addition to the usual higher order modes and hence a novel damping scheme must be used to provide sufficient damping of these modes. In the local scheme two crab cavities are placed at each side of the IP two start and stop rotation of the bunches. This would require crab cavities much smaller transversely than in the global scheme b...

  1. Temperature stabilization of optofluidic photonic crystal cavities

    DEFF Research Database (Denmark)

    Kamutsch, Christian; Smith, Cameron L.C.; Graham, Alexandra

    2009-01-01

    demonstrate a PhC cavity with a quality factor of Q15 000 that exhibits a temperature-independent resonance. Temperature-stable cavities constitute a major building block in the development of a large suite of applications from high-sensitivity sensor systems for chemical and biomedical applications......We present a principle for the temperature stabilization of photonic crystal (PhC) cavities based on optofluidics. We introduce an analytic method enabling a specific mode of a cavity to be made wavelength insensitive to changes in ambient temperature. Using this analysis, we experimentally...

  2. Mechanical Properties of Ingot Nb Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi; Dhakal, Pashupati; Kneisel, Peter; Mammosser, John; Matalevich, Joseph; Rao Myneni, Ganapati

    2014-07-01

    This contribution presents the results of measurements of the resonant frequency and of strain along the contour of a single-cell cavity made of ingot Nb subjected to increasing uniform differential pressure, up to 6 atm. The data were used to infer mechanical properties of this material after cavity fabrication, by comparison with the results from simulation calculations done with ANSYS. The objective is to provide useful information about the mechanical properties of ingot Nb cavities which can be used in the design phase of SRF cavities intended to be built with this material.

  3. Development of a Cryogenic Radiation Detector for Mapping Radio Frequency Superconducting Cavity Field Emissions

    CERN Document Server

    Dotson, Danny W

    2005-01-01

    There is a relationship between field emissions in a Super Conducting RF cavity and the production of radiation (mostly X-rays). External (room temperature) detectors are shielded from the onset of low energy X-rays by the vacuum and cryogenic stainless steel module walls. An internal measuring system for mapping field emissions would assist scientists and engineers in perfecting surface deposition and acid washing module surfaces. Two measurement systems are undergoing cryogenic testing at JLab. One is an active CsI photodiode array and the second is an X-ray film camera. The CsI array has operated sucessfully in a cavity in liquid Helium but saturated at higher power due to scattering in the cavity. A shield with an aperature similar to the X-ray film detector is being designed for the next series of tests which will be completed before PAC-05.

  4. An achromatic four-mirror compensator for spectral ellipsometers

    Science.gov (United States)

    Kovalev, V. I.; Rukovishnikov, A. I.; Kovalev, S. V.; Kovalev, V. V.; Rossukanyi, N. M.

    2017-07-01

    Measurement and calculation results are presented that confirm that design four-mirror compensators can be designed for the spectral range of 200-2000 nm that is widely used in modern spectral ellipsometers. Measurements and calculations according to standard ellipsometric programs have been carried out on a broadband LED spectral ellipsometer with switching of orthogonal polarization states. Mirrors with the structure of glass substrate/Al2O3 layer (20-30 nm thick)/Al layer (150 nm thick)/upper Al2O3 layer (with specified thickness d) have been prepared by vacuum-evaporation method. It is shown that the phase-shift spectra of a four-mirror compensator, two mirrors of which have a native oxide 5.5 nm thick and the two others of which have an oxide layer 36 nm thick, measured on the ellipsometer, are flattened in comparison with similar spectra of a compensator, all four mirrors of which have a native oxide, especially in the short-wavelength spectral region. The results of calculating the phase-shift spectra of the four-mirror compensator with six variable parameters (angles of incidence of radiation on the mirrors and thicknesses of oxide layers on four mirrors) are presented. High-quality achromatization in a wide spectral range can be achieved for certain sets of parameters.

  5. Street mirrors, surveillance, and urban communities in early modern Finland

    NARCIS (Netherlands)

    Ylimaunu, T.; Symonds, J.; Mullins, P.R.; Salmi, A.-K.; Nurmi, R.; Kallio-Seppä, T.; Kuokkanen, T.; Tranberg, A.

    2014-01-01

    This article discusses street mirrors or ‘gossip mirrors’, in terms of urban social relations and surveillance. Street mirrors were introduced to coastal towns in Sweden and Finland in the 18th and early 19th centuries and may still be found in well-preserved towns with historic wooden centres. The

  6. Recent results on solving the first mirror problem

    Energy Technology Data Exchange (ETDEWEB)

    Voitsenya, V.S.; Bondarenko, V.N.; Konovalov, V.G.; Naidenkova, D.I.; Ryzhkov, V.I.; Shapoval, A.N.; Shtan, A.F.; Solodovchenko, S.I. [NSC KIPT, Kharkov (Ukraine); Vukolov, K.Y.; Bardamid, A.F. [T.Shevchenko National Univ., Kiev (Ukraine); Belyaeva, A.I.; Galuza, A.A. [National Technical Univ., Kharkov (Ukraine); Donne, A.J.H. [FOM-Institute for Plasma Physicsn Rijnhuizen (Netherlands); Gil, Ch.; Lipa, M.; Schunke, B. [Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Gorshkov, A. [RNC Kurchatov Institute, Moscow (Russian Federation); Litnovski, A. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstr. Garching (Germany); Malaquais, A. [International Atomic Energy Agency (IAEA), Vienna (Austria); Rubel, M. [Alfven Laboratory, Royal Institute of Technology, Stockholm (Sweden); Sagara, A.; Wienhold, W. [National Institute for Fusion Science, Oroshi-cho, Toki-shi, Gifu-ken (Japan)

    2004-07-01

    This paper reviews the results of exposition of Mo, Cu and film mirrors in various places inside 5 fusion devices: LHD (large helical device), T-10, Tore-Supra, Textor and Jet. We can draw the following conclusions. First only plasma facing mirrors close to the hot plasma can remain free from deposition of contaminating film due to the possibility that the CXA sputtering rate predominates over the rate of film deposition (LHD, Tore-Supra). For such mirrors the guarantee of their long-term performance is to fabricate them from single crystalline material. However, more data are necessary from these and other fusion devices since in T-10 all plasma facing mirror samples became coated with C films. Secondly, mirrors that do not face plasma are likely to be protected from the growing of the deposit (T-10, Textor) but this statement must be checked in experiments on other large scale fusion devices. Thirdly, some progress has been achieved in understanding how to make the Mo and Rh film mirrors with good adhesion. Fourthly, the mirrors from amorphous metals can maintain their initial optical properties while being subjected to long-term sputtering. And fifthly, laser-induced damage threshold has been measured for Cu poly-crystal and single crystal Mo and W mirrors up to 150 thousand laser shots. (A.C.)

  7. Development of a Piezoelectric Adaptive Mirror for Laser Beam Control

    CSIR Research Space (South Africa)

    Long, CS

    2008-06-01

    Full Text Available piezoelectric disc, providing a small, low-cost deformable mirror for this application. The mirror is required to be able to deform in the shape of each of the lower order Zernike polynomials, which describe aberrations in optical systems. Numerical modelling...

  8. Effect of hydrogen-switchable mirrors on the Casimir force

    NARCIS (Netherlands)

    Iannuzzi, D.; Lisanti, M.; Capasso, F.

    2004-01-01

    We present systematic measurements of the Casimir force between a gold-coated plate and a sphere coated with a hydrogen-switchable mirror. Hydrogen-switchable mirrors are shiny metals that can become transparent upon hydrogenation. Despite such a dramatic change of the optical properties of the

  9. Polarization-Independent Wideband High-Index-Contrast Grating Mirror

    DEFF Research Database (Denmark)

    Bekele, Dagmawi Alemayehu; Park, Gyeong Cheol; Malureanu, Radu

    2015-01-01

    Island-type two-dimensional high-index-contrast grating mirror based on a standard silicon-on-insulator wafer have been experimentally demonstrated. The measured spectra shows a bandwidth of ∼192 nm with a reflectivity over 99% as well as polarization independence. Numerical simulations show...... that the designed mirror has large tolerance to fabrication errors....

  10. Contraction of Perceived Size and Perceived Depth in Mirrors

    Science.gov (United States)

    Higashiyama, Atsuki; Shimono, Koichi; Zaitsu, Wataru

    2005-01-01

    We investigated how size and depth are perceived in a plane or convex mirror. In Experiment 1, using a plane or convex mirror, 20 observers viewed a separation between two objects that were presented at a constant distance and reproduced it by a separation between other two objects in a natural viewing situation. The mean matches generally…

  11. Generalisation of action sequences in RNNPB networks with mirror properties

    NARCIS (Netherlands)

    Cuijpers, R.H.; Stuijt, F.H.A.; Sprinkhuizen-Kuyper, I.G.

    2009-01-01

    The human mirror neuron system (MNS) is supposed to be involved in recognition of observed action sequences. However, it remains unclear how such a system could learn to recognise a large variety of action sequences. Here we investigated a neural network with mirror properties, the Recurrent Neural

  12. Validation of a new adaptive deformable mirror concept

    NARCIS (Netherlands)

    Hamelinck, R.F.M.M.; Ellenbroek, R.; Rosielle, N.; Steinbuch, M.; Verhaegen, M.; Doelman, N.J.

    2008-01-01

    A new prototype adaptive deformable mirror for future AO-systems is presented that consists of a thin continuous membrane on which push-pull actuators impose out-of-plane displacements. Each actuator has ±10μm stroke, nanometer resolution and only mW's heat dissipation. The mirror's modular design

  13. Dichroic mirror for diode pumped YAG:Nd-laser

    DEFF Research Database (Denmark)

    Dinca, Andreea; Skettrup, Torben; Lupei, V.

    1996-01-01

    The paper describes the design and realization of a dichroic mirror for a diode pumped YAG:Nd laser. The mirror is deposed on an optical glass substrate and works in optical contact with the laser crystal. The design was performed by admittance matching of the basic stack with the adjacent media...

  14. Modelling mirror aberrations in FEL oscillators using OPC

    NARCIS (Netherlands)

    van der Slot, Petrus J.M.; Karssenberg, J.G.; Boller, Klaus J.

    2007-01-01

    Several high power free-electron lasers (FELs) are currently under design, operational or being upgraded. One central issue is the beam outcoupling and mirror deformation due to absorbed power. Here we present an extension to the OPC code that allows it to model mirror distorions. We use this code

  15. Action observation: mirroring across our spontaneous movement tempo

    Science.gov (United States)

    Avanzino, Laura; Lagravinese, Giovanna; Bisio, Ambra; Perasso, Luisa; Ruggeri, Piero; Bove, Marco

    2015-01-01

    During action observation (AO), the activity of the “mirror system” is influenced by the viewer’s expertise in the observed action. A question that remains open is whether the temporal aspects of the subjective motor repertoire can influence the “mirror system” activation. PMID:25989029

  16. Why our brains cherish humanity: Mirror neurons and colamus humanitatem

    Directory of Open Access Journals (Sweden)

    John R. Skoyles

    2008-06-01

    Full Text Available Commonsense says we are isolated. After all, our bodies are physically separate. But Seneca’s colamus humanitatem, and John Donne’s observation that “no man is an island” suggests we are neither entirely isolated nor separate. A recent discovery in neuroscience—that of mirror neurons—argues that the brain and the mind is neither built nor functions remote from what happens in other individuals. What are mirror neurons? They are brain cells that process both what happens to or is done by an individual, and, as it were, its perceived “refl ection,” when that same thing happens or is done by another individual. Thus, mirror neurons are both activated when an individual does a particular action, and when that individual perceives that same action done by another. The discovery of mirror neurons suggests we need to radically revise our notions of human nature since they offer a means by which we may not be so separated as we think. Humans unlike other apes are adapted to mirror interact nonverbally when together. Notably, our faces have been evolved to display agile and nimble movements. While this is usually explained as enabling nonverbal communication, a better description would be nonverbal commune based upon mirror neurons. I argue we cherish humanity, colamus humanitatem, because mirror neurons and our adapted mirror interpersonal interface blur the physical boundaries that separate us.

  17. Language comprehension warps the mirror neuron system.

    Science.gov (United States)

    Zarr, Noah; Ferguson, Ryan; Glenberg, Arthur M

    2013-01-01

    Is the mirror neuron system (MNS) used in language understanding? According to embodied accounts of language comprehension, understanding sentences describing actions makes use of neural mechanisms of action control, including the MNS. Consequently, repeatedly comprehending sentences describing similar actions should induce adaptation of the MNS thereby warping its use in other cognitive processes such as action recognition and prediction. To test this prediction, participants read blocks of multiple sentences where each sentence in the block described transfer of objects in a direction away or toward the reader. Following each block, adaptation was measured by having participants predict the end-point of videotaped actions. The adapting sentences disrupted prediction of actions in the same direction, but (a) only for videos of biological motion, and (b) only when the effector implied by the language (e.g., the hand) matched the videos. These findings are signatures of the MNS.

  18. Mirror suspension system for the TAMA SAS

    CERN Document Server

    Takamori, A; Bertolini, A; Cella, G; DeSalvo, R; Fukushima, M; Iida, Y; Jacquier, F; Kawamura, S; Marka, S; Nishi, Y; Numata, K; Sannibale, V; Somiya, K; Takahashi, R; Tariq, H; Tsubono, K; Ugas, J; Viboud, N; Yamamoto, H; Yoda, T; Wang Chen Yang

    2002-01-01

    Several R and D programmes are ongoing to develop the next generation of interferometric gravitational wave detectors providing the superior sensitivity desired for refined astronomical observations. In order to obtain a wide observation band at low frequencies, the optics need to be isolated from the seismic noise. The TAMA SAS (seismic attenuation system) has been developed within an international collaboration between TAMA, LIGO, and some European institutes, with the main objective of achieving sufficient low-frequency seismic attenuation (-180 dB at 10 HZ). The system suppresses seismic noise well below the other noise levels starting at very low frequencies above 10 Hz. It also includes an active inertial damping system to decrease the residual motion of the optics enough to allow a stable operation of the interferometer. The TAMA SAS also comprises a sophisticated mirror suspension subsystem (SUS). The SUS provides support for the optics and vibration isolation complementing the SAS performance. The SU...

  19. Video quality assessment for web content mirroring

    Science.gov (United States)

    He, Ye; Fei, Kevin; Fernandez, Gustavo A.; Delp, Edward J.

    2014-03-01

    Due to the increasing user expectation on watching experience, moving web high quality video streaming content from the small screen in mobile devices to the larger TV screen has become popular. It is crucial to develop video quality metrics to measure the quality change for various devices or network conditions. In this paper, we propose an automated scoring system to quantify user satisfaction. We compare the quality of local videos with the videos transmitted to a TV. Four video quality metrics, namely Image Quality, Rendering Quality, Freeze Time Ratio and Rate of Freeze Events are used to measure video quality change during web content mirroring. To measure image quality and rendering quality, we compare the matched frames between the source video and the destination video using barcode tools. Freeze time ratio and rate of freeze events are measured after extracting video timestamps. Several user studies are conducted to evaluate the impact of each objective video quality metric on the subjective user watching experience.

  20. Electrostatic instabilities in a mirror trap revisited

    Science.gov (United States)

    Kotelnikov, Igor A.; Chernoshtanov, Ivan S.; Prikhodko, Vadim V.

    2017-12-01

    The conditions for the stabilization of the Drift-Cyclotron Loss-Cone (DCLC) and Double-Humped (DH) microinstabilities in a mirror trap are critically revisited assuming the plasma is confined in the kinetic regime, which is characterized by an empty loss cone. The temperature of warm ions, necessary for stabilization of the DH instability, is calculated. The fraction of warm ions necessary to stabilize the DCLC instability at a given radial density gradient is calculated. Assuming the wavelength is much shorter than the Larmor radius, a simple criterion for the stability of drift-cyclotron loss-cone oscillations is derived whose accuracy is verified by comparison with the solution of the exact dispersion equation and with known experimental data obtained in the past decades in PR-6, 2XII, 2XIIB, TMX, and TMX-U devices for plasma confinement.