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Sample records for optical parametric chirped

  1. Pulse Distortion in Saturated Fiber Optical Parametric Chirped Pulse Amplification

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Da Ros, Francesco; Rottwitt, Karsten

    2012-01-01

    Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation.......Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation....

  2. Scattering-initiated parametric noise in optical parametric chirped-pulse amplification.

    Science.gov (United States)

    Wang, Jing; Ma, Jingui; Yuan, Peng; Tang, Daolong; Zhou, Binjie; Xie, Guoqiang; Qian, Liejia

    2015-07-15

    We experimentally study a new kind of parametric noise that is initiated from signal scattering and enhanced through optical parametric amplification. Such scattering-initiated parametric noise behaves similarly to parametric super-fluorescence in the spatial domain, yet is typically much stronger. In the time domain it inherits the chirp of signal pulses and can be well compressed. We demonstrate that scattering-initiated parametric noise has little influence on the pulse contrast but can degrade the energy conversion efficiency substantially.

  3. Design constraints of optical parametric chirped pulse amplification based on chirped quasi-phase-matching gratings.

    Science.gov (United States)

    Phillips, C R; Mayer, B W; Gallmann, L; Fejer, M M; Keller, U

    2014-04-21

    Chirped quasi-phase-matching (QPM) gratings offer efficient, ultra-broadband optical parametric chirped pulse amplification (OPCPA) in the mid-infrared as well as other spectral regions. Only recently, however, has this potential begun to be realized [1]. In this paper, we study the design of chirped QPM-based OPCPA in detail, revealing several important constraints which must be accounted for in order to obtain broad-band, high-quality amplification. We determine these constraints in terms of the underlying saturated nonlinear processes, and explain how they were met when designing our mid-IR OPCPA system. The issues considered include gain and saturation based on the basic three-wave mixing equations; suppression of unwanted non-collinear gain-guided modes; minimizing and characterizing nonlinear losses associated with random duty cycle errors in the QPM grating; avoiding coincidentally-phase-matched nonlinear processes; and controlling the temporal/spectral characteristics of the saturated nonlinear interaction in order to maintain the chirped-pulse structure required for OPCPA. The issues considered place constraints both on the QPM devices as well as the OPCPA system. The resulting experimental guidelines are detailed. Our results represent the first comprehensive discussion of chirped QPM devices operated in strongly nonlinear regimes, and provide a roadmap for advancing and experimentally implementing OPCPA systems based on these devices.

  4. Ultrashort pulse shaping by optical parametric chirped amplification

    International Nuclear Information System (INIS)

    Nelet, Ambre

    2007-01-01

    The aim of this work is to propose new laser architectures based on optical parametric chirped pulse amplification (OPCPA). Common goals of OPCPA pre-amplifiers are to reach high energy level while maintaining the spectrum width and to adapt geometry of the amplified beam to the high power laser chain optics. We consider OPCPA as a way to control and to sculpt ultrashort pulses. Our first set-up aims at thwarting possible time recovery default between pump and signal pulses, which lower the energy extraction. A regenerative OPCPA, idler resonant, is a way to produce a high-intensity and high-repetition rate train of amplified signal replicas. Our second laser system pre-compensates the spectral gain narrowing by sculpting pulses directly within the OPCPA section, where a temporal shaping of the pump beam permits a spectro-spectral shaping of the amplified signal. Finally, we propose an OPCPA based on spatial coding and uniform amplification of spectral signal components by using a fan-out periodically poled crystal and a zero dispersion line. (author) [fr

  5. Fiber Optical Parametric Chirped Pulse Amplification of Sub-Picosecond Pulses

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Lali-Dastjerdi, Zohreh; Da Ros, Francesco

    2013-01-01

    We demonstrate experimentally, for the first time to our knowledge, fiber optical parametric chirped pulse amplification of 400-fs pulses. The 400-fs signal is stretched, amplified by 26 dB and compressed back to 500 fs.......We demonstrate experimentally, for the first time to our knowledge, fiber optical parametric chirped pulse amplification of 400-fs pulses. The 400-fs signal is stretched, amplified by 26 dB and compressed back to 500 fs....

  6. Optimization and characterization of dual-chirped optical parametric amplification

    International Nuclear Information System (INIS)

    Fu, Yuxi; Takahashi, Eiji J; Midorikawa, Katsumi; Zhang, Qingbin; Lu, Peixiang

    2015-01-01

    We report optimization and characterization of a dual-chirped optical parametric amplification (DC-OPA) scheme (2011 Opt. Express 19 7190). By increasing a pump pulse energy to 100 mJ, a total (signal + idler) output energy exceeding 30 mJ was recorded with higher than 30% conversion efficiency. The feasibility of further increasing the output energy to a higher scale using the DC-OPA scheme was confirmed by a proof-of-principle experiment, in which 30%–40% conversion efficiency was observed. The signal pulse with the center wavelength of 1.4 μm was compressed to 27 fs (FWHM), which was very close to a transform-limited pulse duration of 25 fs. Since the DC-OPA scheme is efficient for generating high-energy infrared (IR) pulses with excellent scaling ability, the design parameters for obtaining hundred-mJ-level and even joule-level IR pulses are discussed and presented in detail. (invited article)

  7. Mismatch characteristics of optical parametric chirped pulse amplification

    Czech Academy of Sciences Publication Activity Database

    Novák, Ondřej; Turčičová, Hana; Divoký, Martin; Huynh, Jaroslav; Straka, Petr

    2014-01-01

    Roč. 11, č. 2 (2014), 1-7 ISSN 1612-2011 R&D Projects: GA ČR GA202/06/0814; GA MŠk(CZ) LC528 Institutional support: RVO:68378271 Keywords : phase matching * phase mismatch * beam mismatch * broadband amplification * parametric amplifiers * OPCPA * iodine laser Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.458, year: 2014

  8. 200 TW 45 fs laser based on optical parametric chirped pulse amplification.

    Science.gov (United States)

    Lozhkarev, V V; Freidman, G I; Ginzburg, V N; Katin, E V; Khazanov, E A; Kirsanov, A V; Luchinin, G A; Mal'shakov, A N; Martyanov, M A; Palashov, O V; Poteomkin, A K; Sergeev, A M; Shaykin, A A; Yakovlev, I V; Garanin, S G; Sukharev, S A; Rukavishnikov, N N; Charukhchev, A V; Gerke, R R; Yashin, V E

    2006-01-09

    200 TW peak power has been achieved experimentally using a Cr:forsterite master oscillator at 1250 nm, a stretcher, three optical parametrical amplifiers based on KD*P (DKDP) crystals providing 14.5 J energy in the chirped pulse at 910 nm central wavelength, and a vacuum compressor. The final parametrical amplifier and the compressor are described in detail. Scaling of such architecture to multipetawatt power is discussed.

  9. Dispersion management for a sub-10-fs, 10 TW optical parametric chirped-pulse amplifier.

    Science.gov (United States)

    Tavella, Franz; Nomura, Yutaka; Veisz, Laszlo; Pervak, Vladimir; Marcinkevicius, Andrius; Krausz, Ferenc

    2007-08-01

    We report the amplification of three-cycle, 8.5 fs optical pulses in a near-infrared noncollinear optical parametric chirped-pulse amplifier (OPCPA) up to energies of 80 mJ. Improved dispersion management in the amplifier by means of a combination of reflection grisms and a chirped-mirror stretcher allowed us to recompress the amplified pulses to within 6% of their Fourier limit. The novel ultrabroad, ultraprecise dispersion control technology presented in this work opens the way to scaling multiterawatt technology to even shorter pulses by optimizing the OPCPA bandwidth.

  10. Highly stable ultrabroadband mid-IR optical parametric chirped-pulse amplifier optimized for superfluorescence suppression.

    Science.gov (United States)

    Moses, J; Huang, S-W; Hong, K-H; Mücke, O D; Falcão-Filho, E L; Benedick, A; Ilday, F O; Dergachev, A; Bolger, J A; Eggleton, B J; Kärtner, F X

    2009-06-01

    We present a 9 GW peak power, three-cycle, 2.2 microm optical parametric chirped-pulse amplification source with 1.5% rms energy and 150 mrad carrier envelope phase fluctuations. These characteristics, in addition to excellent beam, wavefront, and pulse quality, make the source suitable for long-wavelength-driven high-harmonic generation. High stability is achieved by careful optimization of superfluorescence suppression, enabling energy scaling.

  11. Performance scaling via passive pulse shaping in cavity-enhanced optical parametric chirped-pulse amplification.

    Science.gov (United States)

    Siddiqui, Aleem M; Moses, Jeffrey; Hong, Kyung-Han; Lai, Chien-Jen; Kärtner, Franz X

    2010-06-15

    We show that an enhancement cavity seeded at the full repetition rate of the pump laser can automatically reshape small-signal gain across the interacting pulses in an optical parametric chirped-pulse amplifier for close-to-optimal operation, significantly increasing both the gain bandwidth and the conversion efficiency, in addition to boosting gain for high-repetition-rate amplification. Applied to a degenerate amplifier, the technique can provide an octave-spanning gain bandwidth.

  12. Power scaling of supercontinuum seeded megahertz-repetition rate optical parametric chirped pulse amplifiers.

    Science.gov (United States)

    Riedel, R; Stephanides, A; Prandolini, M J; Gronloh, B; Jungbluth, B; Mans, T; Tavella, F

    2014-03-15

    Optical parametric chirped-pulse amplifiers with high average power are possible with novel high-power Yb:YAG amplifiers with kW-level output powers. We demonstrate a compact wavelength-tunable sub-30-fs amplifier with 11.4 W average power with 20.7% pump-to-signal conversion efficiency. For parametric amplification, a beta-barium borate crystal is pumped by a 140 W, 1 ps Yb:YAG InnoSlab amplifier at 3.25 MHz repetition rate. The broadband seed is generated via supercontinuum generation in a YAG crystal.

  13. Combined Yb/Nd driver for optical parametric chirped pulse amplifiers.

    Science.gov (United States)

    Michailovas, Kirilas; Baltuska, Andrius; Pugzlys, Audrius; Smilgevicius, Valerijus; Michailovas, Andrejus; Zaukevicius, Audrius; Danilevicius, Rokas; Frankinas, Saulius; Rusteika, Nerijus

    2016-09-19

    We report on the developed front-end/pump system for optical parametric chirped pulse amplifiers. The system is based on a dual output fiber oscillator/power amplifier which seeds and assures all-optical synchronization of femtosecond Yb and picosecond Nd laser amplifiers operating at a central wavelength of 1030 nm and 1064 nm, respectively. At the central wavelength of 1030 nm, the fiber oscillator generates partially stretched 4 ps pulses with the spectrum supporting a scaling currently is prevented by limited dimensions of the diffraction gratings, which, because of the fast progress in MLD grating manufacturing technologies is only a temporary obstacle.

  14. Broadening and Amplification of an Infrared Femtosecond Pulse for Optical Parametric Chirped-Pulse Amplification

    International Nuclear Information System (INIS)

    Wang He-Lin; Yang Ai-Jun; Leng Yu-Xin

    2011-01-01

    A high-average-power diode-pumped narrowband regenerative chirped pulse amplifier is developed using the thin-rod Nd:YAG laser architecture for optical parametric chirped-pulse amplification (OPCPA). The effect of the etalons on the amplified pulse in the regenerative cavity is studied experimentally and theoretically. By inserting glass etalons of thickness 1 mm and 5 mm into the regenerative cavity, the pre-stretching pulse from an Öffner stretcher is further broadened to above 200ps, which matches the amplification windows of the signal pulses in OPCPA and is suitable for use as a pump source in the OPCPA system. The bandwidth of the amplified pulse is 1.5 nm, and an output energy of 2mJ is achieved at a repetition rate of 10Hz. (fundamental areas of phenomenology (including applications))

  15. Development of optical parametric chirped-pulse amplifiers and their applications

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Nobuhisa

    2006-11-21

    In this work, optical pulse amplification by parametric chirped-pulse amplification (OPCPA) has been applied to the generation of high-energy, few-cycle optical pulses in the near-infrared (NIR) and infrared (IR) spectral regions. Amplification of such pulses is ordinarily difficult to achieve by existing techniques of pulse amplification based on standard laser gain media followed by external compression. Potential applications of few-cycle pulses in the IR have also been demonstrated. The NIR OPCPA system produces 0.5-terawatt (10 fs,5 mJ) pulses by use of noncollinearly phase-matched optical parametric amplification and a down-chirping stretcher and up-chirping compressor pair. An IR OPCPA system was also developed which produces 20-gigawatt (20 fs,350 {mu}J) pulses at 2.1 {mu}m. The IR seed pulse is generated by optical rectification of a broadband pulse and therefore it exhibits a self-stabilized carrier-envelope phase (CEP). In the IR OPCPA a common laser source is used to generate the pump and seed resulting in an inherent sub-picosecond optical synchronization between the two pulses. This was achieved by use of a custom-built Nd:YLF picosecond pump pulse amplifier that is directly seeded with optical pulses from a custom-built ultrabroadband Ti:sapphire oscillator. Synchronization between the pump and seed pulses is critical for efficient and stable amplification. Two spectroscopic applications which utilize these unique sources have been demonstrated. First, the visible supercontinuum was generated in a solid-state media by the infrared optical pulses and through which the carrier-envelope phase (CEP) of the driving pulse was measured with an f-to-3f interferometer. This measurement confirms the self-stabilization mechanism of the CEP in a difference frequency generation process and the preservation of the CEP during optical parametric amplification. Second, high-order harmonics with energies extending beyond 200 eV were generated with the few

  16. High-energy infrared femtosecond pulses generated by dual-chirped optical parametric amplification.

    Science.gov (United States)

    Fu, Yuxi; Takahashi, Eiji J; Midorikawa, Katsumi

    2015-11-01

    We demonstrate high-energy infrared femtosecond pulse generation by a dual-chirped optical parametric amplification (DC-OPA) scheme [Opt. Express19, 7190 (2011)]. By employing a 100 mJ pump laser, a signal pulse energy exceeding 20 mJ at a wavelength of 1.4 μm was achieved before dispersion compensation. A total output energy of 33 mJ was recorded. Under a further energy scaling condition, the signal pulse was compressed to an almost transform-limited duration of 27 fs using a fused silica prism compressor. Since the DC-OPA scheme is efficient and energy scalable, design parameters for obtaining 100 mJ level infrared pulses are presented, which are suitable as driver lasers for the energy scaling of high-order harmonic generation with sub-keV photon energy.

  17. Thermal properties of borate crystals for high power optical parametric chirped-pulse amplification.

    Science.gov (United States)

    Riedel, R; Rothhardt, J; Beil, K; Gronloh, B; Klenke, A; Höppner, H; Schulz, M; Teubner, U; Kränkel, C; Limpert, J; Tünnermann, A; Prandolini, M J; Tavella, F

    2014-07-28

    The potential of borate crystals, BBO, LBO and BiBO, for high average power scaling of optical parametric chirped-pulse amplifiers is investigated. Up-to-date measurements of the absorption coefficients at 515 nm and the thermal conductivities are presented. The measured absorption coefficients are a factor of 10-100 lower than reported by the literature for BBO and LBO. For BBO, a large variation of the absorption coefficients was found between crystals from different manufacturers. The linear and nonlinear absorption coefficients at 515 nm as well as thermal conductivities were determined for the first time for BiBO. Further, different crystal cooling methods are presented. In addition, the limits to power scaling of OPCPAs are discussed.

  18. Design considerations for a high power, ultrabroadband optical parametric chirped-pulse amplifier.

    Science.gov (United States)

    Prandolini, M J; Riedel, R; Schulz, M; Hage, A; Höppner, H; Tavella, F

    2014-01-27

    A conceptual design of a high power, ultrabroadband optical parametric chirped-pulse amplifier (OPCPA) was carried out comparing nonlinear crystals (LBO and BBO) for 810 nm centered, sub-7.0 fs pulses with energies above 1 mJ. These amplifiers are only possible with a parallel development of kilowatt-level OPCPA-pump amplifiers. It is therefore important to know good strategies to use the available OPCPA-pump energy efficiently. Numerical simulations, including self- and cross-phase modulation, were used to investigate the critical parameters to achieve sufficient spectral and spatial quality. At high output powers, thermal absorption in the nonlinear crystals starts to degrade the output beam quality. Strategies to minimize thermal effects and limits to the maximum average power are discussed.

  19. Tunable few-cycle pulses from a dual-chirped optical parametric amplifier pumped by broadband laser

    Science.gov (United States)

    Hong, Zuofei; Zhang, Qingbin; Rezvani, S. Ali; Lan, Pengfei; Lu, Peixiang

    2018-01-01

    We propose a dual-chirped optical parametric amplification (DC-OPA) scheme pumped by a broadband laser pulse. The pump pulse is spectrally broadened in a multi-plate system before amplifying the chirped seed in a BBO crystal. The system performance and phase-matching mechanism with different pump bandwidths are investigated thoroughly. It is found that the broadened pump bandwidth benefits the system most effectively when the pump and seed pulses are oppositely chirped. The idler bandwidth is nearly tripled in the broadband pumped system, supporting a transform-limited (TL) duration of 8.4 fs (∼1.3 cycles), meanwhile the energy bandwidth product of the idler is 72.6% higher. Furthermore, the idler wavelength is tunable between 1700 nm and 2050 nm, with sub-1.5-cycle TL duration and over 14% conversion efficiency. The proposed scheme provides a suitable approach for the generation of few-cycle pulses varying from near-infrared to mid-infrared regions.

  20. Dynamic characterization and amplification of sub-picosecond pulses in fiber optical parametric chirped pulse amplifiers

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Lali-Dastjerdi, Zohreh; Rishøj, Lars Søgaard

    2013-01-01

    We show a first-time demonstration of amplification of 400 fs pulses in a fiber optical parametric amplifier. The 400 fs signal is stretched in time, amplified by 26 dB and compressed back to 500 fs. A significant broadening of the pulses is experimentally shown due to dispersion and limited gain...

  1. Numerical investigations of signal-spectrum shaping based on conformal profile theory in optical parametric chirped pulse amplification

    Science.gov (United States)

    Li, Wenqi; Yu, Lianghong; Peng, Chun; Liang, Xiaoyan

    2017-11-01

    We proposed a theoretical description and numerical model of signal-spectrum shaping based on conformal profile theory and the three-dimensional coupling wave equations for improving the performance of optical parametric chirped pulse amplification (OPCPA). Using our model, we executed quantitative simulations of signal-spectrum shaping and compared the differences of spatiotemporal amplification characteristics between a shaped signal-spectrum and Gaussian signal-spectrum of an OPCPA based on LiB3O5 near 800 nm. By comparison, we found that the conversion efficiency from pump to signal can be dramatically boosted via signal-spectrum shaping. Meanwhile the amplified-spectrum profile, as well as the Fourier-limited pulse, can be improved significantly. We also found that the spatial spot profiles, for injecting a shaped signal or a Gaussian signal in OPCPA, are nearly the same before the saturation regime and at the maximum conversion efficiency or output energy.

  2. Design of a Highly Stable, High-Conversion-Efficiency, Optical Parametric Chirped-Pulse Amplification System with Good Beam Quality

    International Nuclear Information System (INIS)

    Guardalben, M.J.; Keegan, J.; Waxer, L.J.; Bagnoud, V.; Begishev, I.A.; Puth, J.; Zuegel, J.D.

    2003-01-01

    OAK B204 An optical parametric chirped-pulse amplifier (OPCPA) design that provides 40% pump-to-signal conversion efficiency and over-500-mJ signal energy at 1054 nm for front-end injection into a Nd:glass amplifier chain is presented. This OPCPA system is currently being built as the prototype front end for the OMEGA EP (extended performance) laser system at the University of Rochester's Laboratory for Laser Energetics. Using a three-dimensional spatial and temporal numerical model, several design considerations necessary to achieve high conversion efficiency, good output stability, and good beam quality are discussed. The dependence of OPCPA output on the pump beam's spatiotemporal shape and the relative size of seed and pump beams is described. This includes the effects of pump intensity modulation and pump-signal walk-off. The trade-off among efficiency, stability, and low output beam intensity modulation is discussed

  3. Short-pulse optical parametric chirped-pulse amplification for the generation of high-power few-cycle pulses

    International Nuclear Information System (INIS)

    Major, Zs.; Osterhoff, J.; Hoerlein, R.; Karsch, S.; Fuoloep, J.A.; Krausz, F.; Ludwig-Maximilians Universitaet, Muenchen

    2006-01-01

    Complete test of publication follows. In the quest for a way to generate ultrashort, high-power, few-cycle laser pulses the discovery of optical parametric amplification (OPA) has opened up to the path towards a completely new regime, well beyond that of conventional laser amplification technology. The main advantage of this parametric amplification process is that it allows for an extremely broad amplification bandwidth compared to any known laser amplifier medium. When combined with the chirped-pulse amplification (CPA) principle (i.e. OPCPA), on one hand pulses of just 10 fs duration and 8 mJ pulse energy have been demonstrated. On the other hand, pulse energies of up to 30 J were also achieved on a different OPCPA system; the pulse duration in this case, however, was 100 fs. In order to combine ultrashort pulse durations (i.e. pulses in the few-cycle regime) with high pulse energies (i.e. in the Joule range) we propose tu pump on OPCPA chain with TW-scale short pulses (100 fs - 1 ps instead of > 100 ps of previous OPCPA systems) delivered by a conventional CPA system. This approach inherently improves the conditions for generating high-power ultrashort pulses using OPCPA in the following ways. Firstly, the short pump pulse duration reduces the necessary stretching factor for the seed pulse, thereby increasing stretching and compression fidelity. Secondly, also due to the shortened pump pulse duration, a much higher contrast is achieved. Finally, the significantly increased pump power makes the use of thinner OPCPA crystals possible, which implies an even broader amplification bandwidth, thereby allowing for even shorter pulses. We carried out theoretical investigations to show the feasibility of such a set-up. Alongside these studies we will also present preliminary experimental results of an OPCPA system pumped by the output of our Ti:Sapphire ATLAS laser, currently delivering 350 mJ in 43 fs. An insight into the planned scaling of this technique to petawatt

  4. Design of a petawatt optical parametric chirped pulse amplification upgrade of the kilojoule iodine laser PALS

    Czech Academy of Sciences Publication Activity Database

    Novák, Ondřej; Divoký, Martin; Turčičová, Hana; Straka, Petr

    2013-01-01

    Roč. 31, č. 2 (2013), s. 211-218 ISSN 0263-0346 R&D Projects: GA ČR GA202/06/0814; GA MŠk(CZ) LC528; GA MŠk LN00A100 EU Projects: European Commission(XE) 506350 - LASERLAB-EUROPE Institutional support: RVO:68378271 Keywords : VULCAN petawatt * system * prospects * facility * program Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.701, year: 2013 http://journals.cambridge.org/action/displayAbstract?fromPage=online& aid =8950936

  5. High-average-power 2 μm few-cycle optical parametric chirped pulse amplifier at 100 kHz repetition rate.

    Science.gov (United States)

    Shamir, Yariv; Rothhardt, Jan; Hädrich, Steffen; Demmler, Stefan; Tschernajew, Maxim; Limpert, Jens; Tünnermann, Andreas

    2015-12-01

    Sources of long wavelengths few-cycle high repetition rate pulses are becoming increasingly important for a plethora of applications, e.g., in high-field physics. Here, we report on the realization of a tunable optical parametric chirped pulse amplifier at 100 kHz repetition rate. At a central wavelength of 2 μm, the system delivered 33 fs pulses and a 6 W average power corresponding to 60 μJ pulse energy with gigawatt-level peak powers. Idler absorption and its crystal heating is experimentally investigated for a BBO. Strategies for further power scaling to several tens of watts of average power are discussed.

  6. Optimizing the performance of non-collinear optical parametric chirped pulse amplification via multi-pass structure based on two geometry configurations.

    Science.gov (United States)

    Li, Wenqi; Peng, Chun; Xu, Lu; Yu, Lianghong; Liang, Xiaoyan

    2017-11-27

    We propose a method for multi-pass non-collinear optical parametric chirped pulse amplification (MNOPCPA) based on two geometries, tangent phase-matching (TPM) and Poynting vector walk-off compensation (PVWC), which optimize the performance of optical parametric chirped pulse amplification (OPCPA). A feasible design scheme is also presented for use in implementing this approach. Employing this design, we construct and perform a numerical simulation, showing that back-conversion from the signal and idler to the pump can be inhibited, and that the conversion efficiency can be boosted dramatically, approaching the theoretical limit of ~64%, when amplification is nearly saturated at full bandwidth. In the MNOPCPA scheme, the output signal has a wider spectrum and a corresponding shorter Fourier-limited pulse duration with the pump being continuously depleted. A barycenter shift of the signal spot results from a spatial walk-off effect due to the pump, which can be offset and corrected well. To the best of our knowledge, this is the first demonstration of a multi-pass non-collinear OPCPA method employed the scheme of regenerative amplification.

  7. Design of a multi-petawatt optical parametric chirped pulse amplifier for the iodine laser ASTERIX IV

    Czech Academy of Sciences Publication Activity Database

    Matousek, P.; Rus, Bedřich; Ross, I. N.

    2000-01-01

    Roč. 36, č. 2 (2000), s. 158-163 ISSN 0018-9197 R&D Projects: GA MŠk LN00A100; GA AV ČR IAA1010014 Grant - others:HPRI(XE) CT-1999-00053 Institutional research plan: CEZ:AV0Z1010921 Keywords : iodine laser * nonlinear crystals * optical parametric amlification petawatt lasers Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.000, year: 2000

  8. Generation of high-contrast millijoule pulses by optical parametric chirped-pulse amplification in periodically poled KTiOPO4.

    Science.gov (United States)

    Jovanovic, Igor; Brown, Curtis G; Ebbers, Christopher A; Barty, C P J; Forget, Nicolas; Le Blanc, Catherine

    2005-05-01

    A new high-contrast, high-gain optical parametric chirped-pulse amplifier (OPCPA) architecture is demonstrated in periodically poled KTiOPO4 (PPKTP). This architecture overcomes parametric fluorescence contrast limitations of the OPCPA in periodically poled materials. The scheme is based on two passes of a single relay-imaged pump pulse and a free-propagating signal pulse through a 1.5 mm x 5 mm x 7.5 mm PPKTP crystal. The output energy of 1.2 mJ is generated at a center wavelength of 1053 nm by 24 mJ of pump energy. A prepulse contrast level of > 3 x 10(7) was measured with > 10(6) saturated gain in the amplifier. Amplified pulses were compressed to 200 fs. This simple and versatile concept requires only a modest pump energy from a commercial pump laser and represents a possible high-contrast front end for high-energy Nd:glass-based petawatt-class lasers.

  9. Dynamic Characterization of Fiber Optical Chirped Pulse Amplification for Sub-ps Pulses

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Lali-Dastjerdi, Zohreh; Rishøj, Lars Søgaard

    2013-01-01

    We investigate experimentally the propagation of sub-picosecond pulses in fiber optical parametric chirped pulse amplifiers, showing a significant broadening of the pulses from 450 fs up to 720 fs due to dispersion and self-phase modulation.......We investigate experimentally the propagation of sub-picosecond pulses in fiber optical parametric chirped pulse amplifiers, showing a significant broadening of the pulses from 450 fs up to 720 fs due to dispersion and self-phase modulation....

  10. Generation of sub-two-cycle millijoule infrared pulses in an optical parametric chirped-pulse amplifier and their application to soft x-ray absorption spectroscopy with high-flux high harmonics

    Science.gov (United States)

    Ishii, Nobuhisa; Kaneshima, Keisuke; Kanai, Teruto; Watanabe, Shuntaro; Itatani, Jiro

    2018-01-01

    An optical parametric chirped-pulse amplifier (OPCPA) based on bismuth triborate (BiB3O6, BIBO) crystals has been developed to deliver 1.5 mJ, 10.1 fs optical pulses around 1.6 μm with a repetition rate of 1 kHz and a stable carrier-envelope phase. The seed and pump pulses of the BIBO-based OPCPA are provided from two Ti:sapphire chirped-pulse amplification (CPA) systems. In both CPA systems, transmission gratings are used in the stretchers and compressors that result in a high throughput and robust operation without causing any thermal problem and optical damage. The seed pulses of the OPCPA are generated by intrapulse frequency mixing of a spectrally broadened continuum, temporally stretched to approximately 5 ps then, and amplified to more than 1.5 mJ. The amplified pulses are compressed in a fused silica block down to 10.1 fs. This BIBO-based OPCPA has been applied to high-flux high harmonic generation beyond the carbon K edge at 284 eV. The high-flux soft-x-ray continuum allows measuring the x-ray absorption near-edge structure of the carbon K edge within 2 min, which is shorter than a typical measurement time using synchrotron-based light sources. This laser-based table-top soft-x-ray source is a promising candidate for ultrafast soft x-ray spectroscopy with femtosecond to attosecond time resolution.

  11. Optically tunable chirped fiber Bragg grating.

    Science.gov (United States)

    Li, Zhen; Chen, Zhe; Hsiao, V K S; Tang, Jie-Yuan; Zhao, Fuli; Jiang, Shao-Ji

    2012-05-07

    This work presents an optically tunable chirped fiber Bragg grating (CFBG). The CFBG is obtained by a side-polished fiber Bragg grating (SPFBG) whose thickness of the residual cladding layer in the polished area (D(RC)) varies with position along the length of the grating, which is coated with a photoresponsive liquid crystal (LC) overlay. The reflection spectrum of the CFBG is tuned by refractive index (RI) modulation, which comes from the phase transition of the overlaid photoresponsive LC under ultraviolet (UV) light irradiation. The broadening in the reflection spectrum and corresponding shift in the central wavelength are observed with UV light irradiation density of 0.64mW/mm. During the phase transition of the photoresponsive LC, the RI increase of the overlaid LC leads to the change of the CFBG reflection spectrum and the change is reversible and repeatable. The optically tunable CFBGs have potential use in optical DWDM system and an all-fiber telecommunication system.

  12. Normal dispersion femtosecond fiber optical parametric oscillator.

    Science.gov (United States)

    Nguyen, T N; Kieu, K; Maslov, A V; Miyawaki, M; Peyghambarian, N

    2013-09-15

    We propose and demonstrate a synchronously pumped fiber optical parametric oscillator (FOPO) operating in the normal dispersion regime. The FOPO generates chirped pulses at the output, allowing significant pulse energy scaling potential without pulse breaking. The output average power of the FOPO at 1600 nm was ∼60  mW (corresponding to 1.45 nJ pulse energy and ∼55% slope power conversion efficiency). The output pulses directly from the FOPO were highly chirped (∼3  ps duration), and they could be compressed outside of the cavity to 180 fs by using a standard optical fiber compressor. Detailed numerical simulation was also performed to understand the pulse evolution dynamics around the laser cavity. We believe that the proposed design concept is useful for scaling up the pulse energy in the FOPO using different pumping wavelengths.

  13. Output features of optical parametric chirped pulse amplification in LiB3O5 near 800  nm at different phase-matching geometries.

    Science.gov (United States)

    Liu, Xiaodi; Xu, Lu; Liang, Xiaoyan

    2016-12-15

    We theoretically and experimentally investigated the output beam quality and wavefront distortion in four different phase-matching geometries in LBO-OPCPA at 800 nm: broadband noncollinear geometry, collinear geometry, pump-idler the Poynting vector collinear (Sp∥Si) geometry, and pump-signal Poynting vector collinear (Sp∥Ss) geometry. It was found that the output profile is closely related to the noncollinear angle between Poynting vectors of parametric waves. However, the wavefront evolution depends mainly on the angles between the wave vectors. Broadband noncollinear geometry has the largest spatial modulation and wavefront distortion. Good output beam quality can be achieved in collinear geometry with little wavefront distortion, but the bandwidth is only approximately 10 nm. The Sp∥Ss and Sp∥Si configurations result in a bandwidth of more than 20 nm with enhanced beam quality and small wavefront distortion. The two geometries have different output features wherein the former has a relatively lower modulation, and the latter shows smaller wavefront distortion.

  14. Chirp and temperature effects in parametric down conversion from crystals pumped at 800 nm

    Science.gov (United States)

    Sánchez-Lozano, X.; Wiechers, C.; Lucio, J. L.

    2018-04-01

    We consider spontaneous parametric down conversion from aperiodic poled crystals pumped at 800 nm. Our analyses account the effect of internal and external parameters, where, in the former, we include the crystal chirp and length, while in the latter temperature, also the pump chirp and other beam properties. The typical distribution produced is a pop-tab like structure in frequency-momentum space, and our results show that this system is a versatile light source, appropriated to manipulate the frequency and transverse momentum properties of the light produced. We briefly comment on the potential usefulness of the types of telecom wavelength light produced, in particular for quantum information applications.

  15. Short-pulse propagation in fiber optical parametric amplifiers

    DEFF Research Database (Denmark)

    Cristofori, Valentina

    Fiber optical parametric amplifiers (FOPAs) are attractive because they can provide large gain over a broad range of central wavelengths, depending only on the availability of a suitable pump laser. In addition, FOPAs are suitable for the realization of all-optical signal processing functionalities...... is implemented to obtain an all-fiber system. The advantages of all fiber-systems are related to their reliability, long-term stability and compactness. Fiber optical parametric chirped pulse amplification is promising for the amplification of such signals thanks to the inherent compatibility of FOPAs with fiber...... optical systems and high gain over broad bandwidths. In particular, the amplification of 400 fs pulses is investigated in a single-pump fiber optical chirped pulse amplification sc heme. First, a dynamic characterization is carried out both in unsaturated and saturated regimes and, then, amplification...

  16. Generation of frequency-chirped optical pulses with felix

    Energy Technology Data Exchange (ETDEWEB)

    Knippels, G.M.H.; Meer, A.F.G. van der; Mols, R.F.X.A.M. [FOM-Institute for Plasma Physics, Nieuwegein (Netherlands)] [and others

    1995-12-31

    Frequency-chirped optical pulses have been produced in the picosecond regime by varying the energy of the electron beam on a microsecond time scale. These pulses were then compressed close to their bandwidth limit by an external pulse compressor. The amount of chirp can be controlled by varying the sweep rate on the electron beam energy and by cavity desynchronisation. To examine the generated chirp we used the following diagnostics: a pulse compressor, a crossed beam autocorrelator, a multichannel electron spectrometer and multichannel optical spectrometer. The compressor is build entirely using reflective optics to permit broad band operation. The autocorrelator is currently operating from 6 {mu}m to 30 {mu}m with one single crystal. It has been used to measure pulses as short as 500 fs. All diagnostics are evacuated to prevent pulse shape distortion or pulse lengthening caused by absorption in ambient water vapour. Pulse length measurements and optical spectra will be presented for different electron beam sweep rates, showing the presence of a frequency chirp. Results on the compression of the optical pulses to their bandwidth limit are given for different electron sweep rates. More experimental results showing the dependence of the amount of chirp on cavity desynchronisation will be presented.

  17. Fiber-Optical Parametric Amplification of Sub-Picosecond Pulses for High-Speed Optical Communications

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Cristofori, Valentina; Rottwitt, Karsten

    2015-01-01

    This article reviews recent results of amplification of short optical pulses using fiber-optical parametric amplifiers. This includes chirped-pulse amplification of 400 fs pulses, error-free amplification of a 640-Gbit/s optical time-division multiplexed signal with less than a 1-dB power penalty......, and all-optical phase-preserving amplitude regeneration of a 640-Gbit/s return-to-zero differential phase-shift keying optical time-division multiplexed signal.......This article reviews recent results of amplification of short optical pulses using fiber-optical parametric amplifiers. This includes chirped-pulse amplification of 400 fs pulses, error-free amplification of a 640-Gbit/s optical time-division multiplexed signal with less than a 1-dB power penalty...

  18. Optical chirp z-transform processor with a simplified architecture.

    Science.gov (United States)

    Ngo, Nam Quoc

    2014-12-29

    Using a simplified chirp z-transform (CZT) algorithm based on the discrete-time convolution method, this paper presents the synthesis of a simplified architecture of a reconfigurable optical chirp z-transform (OCZT) processor based on the silica-based planar lightwave circuit (PLC) technology. In the simplified architecture of the reconfigurable OCZT, the required number of optical components is small and there are no waveguide crossings which make fabrication easy. The design of a novel type of optical discrete Fourier transform (ODFT) processor as a special case of the synthesized OCZT is then presented to demonstrate its effectiveness. The designed ODFT can be potentially used as an optical demultiplexer at the receiver of an optical fiber orthogonal frequency division multiplexing (OFDM) transmission system.

  19. Frequency domain optical parametric amplification.

    Science.gov (United States)

    Schmidt, Bruno E; Thiré, Nicolas; Boivin, Maxime; Laramée, Antoine; Poitras, François; Lebrun, Guy; Ozaki, Tsuneyuki; Ibrahim, Heide; Légaré, François

    2014-05-07

    Today's ultrafast lasers operate at the physical limits of optical materials to reach extreme performances. Amplification of single-cycle laser pulses with their corresponding octave-spanning spectra still remains a formidable challenge since the universal dilemma of gain narrowing sets limits for both real level pumped amplifiers as well as parametric amplifiers. We demonstrate that employing parametric amplification in the frequency domain rather than in time domain opens up new design opportunities for ultrafast laser science, with the potential to generate single-cycle multi-terawatt pulses. Fundamental restrictions arising from phase mismatch and damage threshold of nonlinear laser crystals are not only circumvented but also exploited to produce a synergy between increased seed spectrum and increased pump energy. This concept was successfully demonstrated by generating carrier envelope phase stable, 1.43 mJ two-cycle pulses at 1.8 μm wavelength.

  20. The optimal input optical pulse shape for the self-phase modulation based chirp generator

    Science.gov (United States)

    Zachinyaev, Yuriy; Rumyantsev, Konstantin

    2018-04-01

    The work is aimed to obtain the optimal shape of the input optical pulse for the proper functioning of the self-phase modulation based chirp generator allowing to achieve high values of chirp frequency deviation. During the research, the structure of the device based on self-phase modulation effect using has been analyzed. The influence of the input optical pulse shape of the transmitting optical module on the chirp frequency deviation has been studied. The relationship between the frequency deviation of the generated chirp and frequency linearity for the three options for implementation of the pulse shape has been also estimated. The results of research are related to the development of the theory of radio processors based on fiber-optic structures and can be used in radars, secure communications, geolocation and tomography.

  1. Self-seeding ring optical parametric oscillator

    Science.gov (United States)

    Smith, Arlee V [Albuquerque, NM; Armstrong, Darrell J [Albuquerque, NM

    2005-12-27

    An optical parametric oscillator apparatus utilizing self-seeding with an external nanosecond-duration pump source to generate a seed pulse resulting in increased conversion efficiency. An optical parametric oscillator with a ring configuration are combined with a pump that injection seeds the optical parametric oscillator with a nanosecond duration, mJ pulse in the reverse direction as the main pulse. A retroreflecting means outside the cavity injects the seed pulse back into the cavity in the direction of the main pulse to seed the main pulse, resulting in higher conversion efficiency.

  2. Chirped pulse digital holography for measuring the sequence of ultrafast optical wavefronts

    Science.gov (United States)

    Karasawa, Naoki

    2018-04-01

    Optical setups for measuring the sequence of ultrafast optical wavefronts using a chirped pulse as a reference wave in digital holography are proposed and analyzed. In this method, multiple ultrafast object pulses are used to probe the temporal evolution of ultrafast phenomena and they are interfered with a chirped reference wave to record a digital hologram. Wavefronts at different times can be reconstructed separately from the recorded hologram when the reference pulse can be treated as a quasi-monochromatic wave during the pulse width of each object pulse. The feasibility of this method is demonstrated by numerical simulation.

  3. The role of input chirp on phase shifters based on slow and fast light effects in semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Xue, Weiqi; Chen, Yaohui; Öhman, Filip

    2009-01-01

    We experimentally investigate the initial chirp dependence of slow and fast light effects in a semiconductor optical amplifier followed by an optical filter. It is shown that the enhancement of the phase shift due to optical filtering strongly depends on the chirp of the input optical signal. We...... demonstrate ~120º phase delay as well as ~170º phase advance at a microwave frequency of 19 GHz for different optimum values of the input chirp. The experimental results are shown to be in good agreement with numerical results based on a four-wave mixing model. Finally, a simple physical explanation based...

  4. Observation of contrast agent response to chirp insonation with a simultaneous optical-acoustical system.

    Science.gov (United States)

    Sun, Yang; Zhao, Shukui; Dayton, Paul A; Ferrara, Katherine W

    2006-06-01

    Rayleigh-Plesset analysis, ultra-high speed photography, and single bubble acoustical recordings previously were applied independently to characterize the radial oscillation and resulting echoes from a microbubble in response to an ultrasonic pulse. In addition, high-speed photography has shown that microbubbles are destroyed over a single pulse or pulse train by diffusion and fragmentation. In order to develop a single model to characterize microbubble echoes based on oscillatory and destructive characteristics, an optical-acoustical system was developed to simultaneously record the optical image and backscattered echo from each microbubble. Combined observation provides the opportunity to compare predictions for oscillation and echoes with experimental results and identify discrepancies due to diffusion or fragmentation. Optimization of agents and insonating pulse parameters may be facilitated with this system. The mean correlation of the predicted and experimental radius-time curves and echoes exceeds 0.7 for the parameters studied here. An important application of this new system is to record and analyze microbubble response to a long pulse in which diffusion is shown to occur over the pulse duration. The microbubble response to an increasing or decreasing chirp is evaluated using this new tool. For chirp insonation beginning with the lower center frequency, low-frequency modulation of the oscillation envelope was obvious. However, low-frequency modulation was not observed in the radial oscillation produced by decreasing chirp insonation. Comparison of the echoes from similar sized microbubbles following increasing and decreasing chirp insonation demonstrated that the echoes were not time-reversed replicas. Using a transmission pressure of 620 kPa, the -6 dB echo length was 0.9 and 1.1 micros for increasing and decreasing chirp insonation, respectively (P = 0.02). The mean power in the low-frequency portion of the echoes was 8 (mV)2 and 13 (mV)2 for increasing

  5. Optical parametric amplification beyond the slowly varying ...

    Indian Academy of Sciences (India)

    The coupled-wave equations describing optical parametric amplification (OPA) are usually solved in the slowly varying amplitude (SVA) approximation regime, in which the second-order derivatives of the signal and idler amplitudes are ignored and in fact the electromagnetic effects due to exit face of the medium is not ...

  6. Narrow linewidth pulsed optical parametric oscillator

    Indian Academy of Sciences (India)

    Abstract. Tunable narrow linewidth radiation by optical parametric oscillation has many applications, particularly in spectroscopic investigation. In this paper, different techniques such as injection seeding, use of spectral selecting element like grating, grat- ing and etalon in combination, grazing angle of incidence, entangled ...

  7. Optical parametrically gated microscopy in scattering media.

    Science.gov (United States)

    Zhao, Youbo; Adie, Steven G; Tu, Haohua; Liu, Yuan; Graf, Benedikt W; Chaney, Eric J; Marjanovic, Marina; Boppart, Stephen A

    2014-09-22

    High-resolution imaging in turbid media has been limited by the intrinsic compromise between the gating efficiency (removal of multiply-scattered light background) and signal strength in the existing optical gating techniques. This leads to shallow depths due to the weak ballistic signal, and/or degraded resolution due to the strong multiply-scattering background--the well-known trade-off between resolution and imaging depth in scattering samples. In this work, we employ a nonlinear optics based optical parametric amplifier (OPA) to address this challenge. We demonstrate that both the imaging depth and the spatial resolution in turbid media can be enhanced simultaneously by the OPA, which provides a high level of signal gain as well as an inherent nonlinear optical gate. This technology shifts the nonlinear interaction to an optical crystal placed in the detection arm (image plane), rather than in the sample, which can be used to exploit the benefits given by the high-order parametric process and the use of an intense laser field. The coherent process makes the OPA potentially useful as a general-purpose optical amplifier applicable to a wide range of optical imaging techniques.

  8. Experimental demonstration of spatially coherent beam combining using optical parametric amplification.

    Science.gov (United States)

    Kurita, Takashi; Sueda, Keiichi; Tsubakimoto, Koji; Miyanaga, Noriaki

    2010-07-05

    We experimentally demonstrated coherent beam combining using optical parametric amplification with a nonlinear crystal pumped by random-phased multiple-beam array of the second harmonic of a Nd:YAG laser at 10-Hz repetition rate. In the proof-of-principle experiment, the phase jump between two pump beams was precisely controlled by a motorized actuator. For the demonstration of multiple-beam combining a random phase plate was used to create random-phased beamlets as a pump pulse. Far-field patterns of the pump, the signal, and the idler indicated that the spatially coherent signal beams were obtained on both cases. This approach allows scaling of the intensity of optical parametric chirped pulse amplification up to the exa-watt level while maintaining diffraction-limited beam quality.

  9. Bidirectional, synchronously pumped, ring optical parametric oscillator.

    Science.gov (United States)

    Meng, X; Diels, J C; Kuehlke, D; Batchko, R; Byer, R

    2001-03-01

    We report the operation of a bidirectional femtosecond pulsed ring optical parametric oscillator based on periodically poled lithium niobate, pumped alternately with nonsimultaneous pulses from a Ti:sapphire mode-locked laser. A beat note between the two counterpropagating beams attests to a gyro response without dead band. The sensitivity of the device to differential phase changes is demonstrated by measurement of the nonlinear index of lithium niobate.

  10. Noiseless attenuation using an optical parametric amplifier

    Science.gov (United States)

    Brewster, R. A.; Nodurft, I. C.; Pittman, T. B.; Franson, J. D.

    2017-10-01

    The process of heralded noiseless amplification, and the inverse process of heralded noiseless attenuation, have potential applications in the context of quantum communications. Although several different physical implementations of heralded noiseless amplifiers have now been demonstrated, the research on heralded noiseless attenuators has been largely confined to a beam-splitter based approach. Here we show that an optical parametric amplifier (OPA), combined with appropriate heralding, can also serve as a heralded noiseless attenuator. The counterintuitive use of an optical amplifier as an attenuator is only possible due to the probabilistic nature of the device.

  11. Airborne Methane Measurements using Optical Parametric Amplifiers

    Science.gov (United States)

    Riris, H.; Numata, K.; Li, S.; Wu, S.; Ramanathan, A.; Dawsey, M.; Abshire, J. B.; Kawa, S. R.; Mao, J.

    2012-12-01

    We report on airborne methane measurements with an active sensing instrument using widely tunable, seeded optical parametric generation (OPG). Methane is a strong greenhouse gas on Earth and it is also a potential biogenic marker on Mars and other planetary bodies. Methane in the Earth's atmosphere survives for a shorter time than CO2 but its impact on climate change can be larger than CO2. Carbon and methane emissions from land are expected to increase as permafrost melts exposing millennial-age carbon stocks to respiration (aerobic-CO2 and anaerobic-CH4) and fires. Methane emissions from clathrates in the Arctic Ocean and on land are also likely to respond to climate warming. However, there is considerable uncertainty in present Arctic flux levels, as well as how fluxes will change with the changing environment and more measurements are needed. In this paper we report on an airborne demonstration of atmospheric methane column optical depth measurements at 1.65 μm using widely tunable, seeded optical parametric amplifier (OPA) and a photon counting detector. Our results show good agreement between the experimentally derived optical depth measurements and theoretical calculations and follow the expected changes for aircraft altitudes from 3 to 11 km. The technique has also been used to measure carbon dioxide and monoxide, water vapor, and other trace gases in the near and mid-infrared spectral regions on the ground.

  12. Parametric uncertainty in optical image modeling

    Science.gov (United States)

    Potzick, James; Marx, Egon; Davidson, Mark

    2006-10-01

    Optical photomask feature metrology and wafer exposure process simulation both rely on optical image modeling for accurate results. While it is fair to question the accuracies of the available models, model results also depend on several input parameters describing the object and imaging system. Errors in these parameter values can lead to significant errors in the modeled image. These parameters include wavelength, illumination and objective NA's, magnification, focus, etc. for the optical system, and topography, complex index of refraction n and k, etc. for the object. In this paper each input parameter is varied over a range about its nominal value and the corresponding images simulated. Second order parameter interactions are not explored. Using the scenario of the optical measurement of photomask features, these parametric sensitivities are quantified by calculating the apparent change of the measured linewidth for a small change in the relevant parameter. Then, using reasonable values for the estimated uncertainties of these parameters, the parametric linewidth uncertainties can be calculated and combined to give a lower limit to the linewidth measurement uncertainty for those parameter uncertainties.

  13. Chirp-pulse-compression three-dimensional lidar imager with fiber optics.

    Science.gov (United States)

    Pearson, Guy N; Ridley, Kevin D; Willetts, David V

    2005-01-10

    A coherent three-dimensional (angle-angle-range) lidar imager using a master-oscillator-power-amplifier concept and operating at a wavelength of 1.5 microm with chirp-pulse compression is described. A fiber-optic delay line in the local oscillator path enables a single continuous-wave semiconductor laser source with a modulated drive waveform to generate both the constant-frequency local oscillator and the frequency chirp. A portion of this chirp is gated out and amplified by a two-stage fiber amplifier. The digitized return signal was compressed by cross correlating it with a sample of the outgoing pulse. In this way a 350-ns, 10-microJ pulse with a 250-MHz frequency sweep is compressed to a width of approximately 8 ns. With a 25-mm output aperture, the lidar has been used to produce three-dimensional images of hard targets out to a range of approximately 2 km with near-diffraction-limited angular resolution and submeter range resolution.

  14. Ultrafast chirped optical waveform recorder using a time microscope

    Science.gov (United States)

    Bennett, Corey Vincent

    2015-04-21

    A new technique for capturing both the amplitude and phase of an optical waveform is presented. This technique can capture signals with many THz of bandwidths in a single shot (e.g., temporal resolution of about 44 fs), or be operated repetitively at a high rate. That is, each temporal window (or frame) is captured single shot, in real time, but the process may be run repeatedly or single-shot. By also including a variety of possible demultiplexing techniques, this process is scalable to recoding continuous signals.

  15. Processing of optical combs with fiber optic parametric amplifiers

    Czech Academy of Sciences Publication Activity Database

    Slavík, Radan; Kakande, J.; Richardson, D.J.; Petropoulos, P.

    2012-01-01

    Roč. 20, č. 9 (2012), s. 10059-10070 ISSN 1094-4087 Institutional support: RVO:67985882 Keywords : Fiber - optic parametric amplifier * Phase sensitive * Spectral coverage Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.546, year: 2012

  16. GHz-rate optical parametric amplifier in hydrogenated amorphous silicon

    International Nuclear Information System (INIS)

    Wang, Ke-Yao; Foster, Amy C

    2015-01-01

    We demonstrate optical parametric amplification operating at GHz-rates at telecommunications wavelengths using a hydrogenated amorphous silicon waveguide through the nonlinear optical process of four-wave mixing. We investigate how the parametric amplification scales with repetition rate. The ability to achieve amplification at GHz-repetition rates shows hydrogenated amorphous silicon’s potential for telecommunication applications and a GHz-rate optical parametric oscillator. (paper)

  17. Manipulating and detecting the chirpiness of spatial chirp signals via fractional Fourier lenses designed by transformation optics.

    Science.gov (United States)

    Chen, Jing; Hu, Jin; Yang, Xiao-Bo; Lu, Xiang-Yang

    2017-11-10

    Estimating the chirpiness of a spatial chirp signal is important in many optical engineering applications. With the help of transformation optics, a new kind of fractional Fourier transform lens is designed by deforming the conventional graded index lens through conformal mapping, which can manipulate the chirpiness of the input chirp signal. The low-input chirpiness is magnified by the transformation material, and the error of the detection is kept approximately the same; thus, the designed lens has enhanced chirpiness detection precision and distinguishability for low chirpiness. The design is validated by numerical simulations.

  18. Improvement of chirped pulse contrast using electro-optic birefringence scanning filter method

    International Nuclear Information System (INIS)

    Zeng Shuguang; Wang Xianglin; Wang Qishan; Zhang Bin; Sun Nianchun; Wang Fei

    2013-01-01

    A method using scanning filter to improve the contrast of chirped pulse is proposed, and the principle of this method is analyzed. The scanning filter is compared with the existing pulse-picking technique and nonlinear filtering technique. The scanning filter is a temporal gate that is independent on the intensity of the pulses, but on the instantaneous wavelengths of light. Taking the electro-optic birefringence scanning filter as an example, the application of scanning filter methods is illustrated. Based on numerical simulation and experimental research, it is found that the electro-optic birefringence scanning filter can eliminate a prepulse which is several hundred picoseconds before the main pulse, and the main pulse can maintain a high transmissivity. (authors)

  19. Interferometric and Chirped Optical Probe Techniques for High-Pressure Equation-of-State Measurements

    International Nuclear Information System (INIS)

    Gold, D. M.; Celliers, P. M.; Collins, G. W.; Budil, K. S.; Cauble, R.; Silva, L. B. da; Foord, M. E.; Stewart, R. E.; Wallace, R. J.; Young, D.

    2000-01-01

    We present experimental work exploring displacement and velocity interferometry as high spatial and temporal resolution diagnostics for measuring target preheat and the speed, planarity, and steadiness of a shock wave. A chirped pulse reflectometry experiment is also proposed as a frequency domain alternative for shock speed measurements. These techniques fill a need for high-precision diagnostics to derive accurate laboratory-based equation-of-state data at shock wave-driven pressures directly relevant to astrophysical systems. The performance of these optical laser probe techniques may exceed conventional passive techniques such as temporally streaked recording of optical emission upon shock breakout or side-on streaked X-ray radiography. Results from Nova laser and high-intensity ultrashort pulse experiments are presented. (c) 2000 The American Astronomical Society

  20. Fiber optical parametric amplifiers in optical communication systems

    DEFF Research Database (Denmark)

    Marhic, Michel E.; Andrekson, Peter A.; Petropoulos, Periklis

    2015-01-01

    The prospects for using fiber optical parametric amplifiers (OPAs) in optical communication systems are reviewed. Phase-insensitive amplifiers (PIAs) and phase-sensitive amplifiers (PSAs) are considered. Low-penalty amplification at/or near 1 Tb/s has been achieved, for both wavelength- and time...... in excess of 14,000 Tb/s x km in realistic wavelength-division multiplexed long-haul networks. Technical challenges remaining to be addressed in order for fiber OPAs to become useful for long-haul communication networks are discussed....

  1. Development of a chirped/differential optical fiber Bragg grating pressure sensor

    International Nuclear Information System (INIS)

    Ho, Yen-Te; Huang, An-Bin; Lee, Jui-ting

    2008-01-01

    With its unique capabilities, the optical fiber Bragg grating has been used as a key component in the development of many sensors. Incorporating the theory of thin plates, the authors have developed an FBG-based pressure sensor by strategically attaching FBGs on the surface of a thin circular plate. The flexural strain in the circular plate induced by pressure applied to the circular plate is sensed by either a single FBG placed radially crossing a neutral point, or two FBGs placed respectively in zones where the strains are of opposite signs. When one FBG is used (i.e., the chirped FBG design), the applied pressure relates to the change in the chirped bandwidth of the FBG reflected waveform. When two FBGs are used (i.e., the differential FBG design), the pressure experienced by the circular plate is correlated to the difference in central wavelength from the two FBGs. In either case the sensing mechanism is immune to temperature fluctuation. The same configuration can potentially be applied for other purposes such as a load cell or displacement transducer. This paper describes the design principles of the FBG pressure sensor and demonstrates its capabilities through laboratory calibrations over a wide range of temperatures

  2. Ultrafast chirped optical waveform recording using referenced heterodyning and a time microscope

    Science.gov (United States)

    Bennett, Corey Vincent

    2010-06-15

    A new technique for capturing both the amplitude and phase of an optical waveform is presented. This technique can capture signals with many THz of bandwidths in a single shot (e.g., temporal resolution of about 44 fs), or be operated repetitively at a high rate. That is, each temporal window (or frame) is captured single shot, in real time, but the process may be run repeatedly or single-shot. This invention expands upon previous work in temporal imaging by adding heterodyning, which can be self-referenced for improved precision and stability, to convert frequency chirp (the second derivative of phase with respect to time) into a time varying intensity modulation. By also including a variety of possible demultiplexing techniques, this process is scalable to recoding continuous signals.

  3. Ultrafast chirped optical waveform recorder using referenced heterodyning and a time microscope

    Science.gov (United States)

    Bennett, Corey Vincent [Livermore, CA

    2011-11-22

    A new technique for capturing both the amplitude and phase of an optical waveform is presented. This technique can capture signals with many THz of bandwidths in a single shot (e.g., temporal resolution of about 44 fs), or be operated repetitively at a high rate. That is, each temporal window (or frame) is captured single shot, in real time, but the process may be run repeatedly or single-shot. This invention expands upon previous work in temporal imaging by adding heterodyning, which can be self-referenced for improved precision and stability, to convert frequency chirp (the second derivative of phase with respect to time) into a time varying intensity modulation. By also including a variety of possible demultiplexing techniques, this process is scalable to recoding continuous signals.

  4. Versatile backconversion-inhibited broadband optical parametric amplification based on an idler-separated QPM configuration.

    Science.gov (United States)

    Li, Ying; Zhong, Haizhe; Yang, Jianlong; Wang, Shiwei; Fan, Dianyuan

    2017-07-15

    Conversion efficiency and phase-matching (PM) bandwidth are both critical issues for broadband parametric processes. In some sense, they determine the highest peak power achieved via the optical parametric amplification. In this Letter, a versatile idler-separated quasi-phase matching scheme capable of both backconversion circumvention and ultra-broadband PM is presented. Full-dimensional spatial-temporal simulations for the typical optical parametric chirped pulse amplification processes at 800 nm and 3.4 μm were presented in detail. By virtue of the broad PM bandwidth on account of the non-collinear PM configuration, the backconversion circumvention on account of the idler-separated design, and the walk-off self-compensation on account of the symmetrical tilting grating patterns, significantly improved gain bandwidth, extremely high conversion efficiency, and a well-preserved beam profile are simultaneously achieved. Compared with the collinear configuration, the peak power can be potentially enhanced by 5-10 times under the same operation circumstances.

  5. Intermodal Parametric Frequency Conversion in Optical Fibers

    Science.gov (United States)

    Demas, Jeffrey D.

    Lasers are an essential technology enabling countless fields of optics, however, their operation wavelengths are limited to isolated regions across the optical spectrum due to the need for suitable gain media. Parametric frequency conversion (PFC) is an attractive means to convert existing lasers to new colors using nonlinear optical interactions rather than the material properties of the host medium, allowing for the development of high power laser sources across the entire optical spectrum. PFC in bulk chi(2) crystals has led to the development of the optical parametric oscillator, which is currently the standard source for high power light at non-traditional wavelengths in the laboratory setting. Ideally, however, one could implement PFC in an optical fiber, thus leveraging the crucial benefits of a guided-wave geometry: alignment-free, compact, and robust operation. Four-wave mixing (FWM) is a nonlinear effect in optical fibers that can be used to convert frequencies, the major challenge being conservation of momentum, or phase matching, between the interacting light waves. Phase matching can be satisfied through the interaction of different spatial modes in a multi-mode fiber, however, previous demonstrations have been limited by mode stability and narrow-band FWM gain. Alternatively, phase matching within the fundamental mode can be realized in high-confinement waveguides (such as photonic crystal fibers), but achieving the anomalous waveguide dispersion necessary for phase matching at pump wavelengths near ˜1 mum (where the highest power fiber lasers emit) comes at the cost of reducing the effective area of the mode, thus limiting power-handling. Here, we specifically consider the class of Bessel-like LP0,m modes in step-index fibers. It has been shown that these modes can be selectively excited and guided stably for long lengths of fiber, and mode stability increases with mode order 'm'. The effective area of modes in these fibers can be very large (>6000

  6. Temporal Simultons in Optical Parametric Oscillators.

    Science.gov (United States)

    Jankowski, Marc; Marandi, Alireza; Phillips, C R; Hamerly, Ryan; Ingold, Kirk A; Byer, Robert L; Fejer, M M

    2018-02-02

    We report the first demonstration of a regime of operation in optical parametric oscillators (OPOs), in which the formation of temporal simultons produces stable femtosecond half-harmonic pulses. Simultons are simultaneous bright-dark solitons of a signal field at frequency ω and the pump field at 2ω, which form in a quadratic nonlinear medium. The formation of simultons in an OPO is due to the interplay of nonlinear pulse acceleration with the timing mismatch between the pump repetition period and the cold-cavity round-trip time and is evidenced by sech^{2} spectra with broad instantaneous bandwidths when the resonator is detuned to a slightly longer round-trip time than the pump repetition period. We provide a theoretical description of an OPO operating in a regime dominated by these dynamics, observe the distinct features of simulton formation in an experiment, and verify our results with numerical simulations. These results represent a new regime of operation in nonlinear resonators, which can lead to efficient and scalable sources of few-cycle frequency combs at arbitrary wavelengths.

  7. Spatiotemporal structures in the internally pumped optical parametric oscillator

    DEFF Research Database (Denmark)

    Lodahl, Peter; Bache, Morten; Saffman, Mark

    2001-01-01

    We analyze pattern formation in doubly resonant second-harmonic generation in the presence of a competing parametric process, also named the internally pumped optical parametric oscillator. Different scenarios are established where either the up- or down-conversion processes dominate...

  8. 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.

  9. Optical stochastic cooling for RHIC using optical parametric amplification

    Directory of Open Access Journals (Sweden)

    M. Babzien

    2004-01-01

    Full Text Available We propose using an optical parametric amplifier, with a ∼12   μm wavelength, for optical-stochastic cooling of ^{79}Au ions in the Relativistic Heavy Ion Collider. While the bandwidth of this amplifier is comparable to that of a Ti:sapphire laser, it has a higher average output power. Its wavelength is longer than that of the laser amplifiers previously considered for such an application. This longer wavelength permits a longer undulator period and higher magnetic field, thereby generating a larger signal from the pickup undulator and ensuring a more efficient interaction in the kicker undulator, both being essential elements in cooling moderately relativistic ions. The transition to a longer wavelength also relaxes the requirements for stability of the path length during ion-beam transport between pickup and kicker undulators.

  10. Optical Parametric Technology for Methane Measurements

    Science.gov (United States)

    Dawsey, Martha; Numata, Kenji; Wu, Stewart; Riris, Haris

    2015-01-01

    Atmospheric methane (CH4) is the second most important anthropogenic greenhouse gas, with approximately 25 times the radiative forcing of carbon dioxide (CO2) per molecule. Yet, lack of understanding of the processes that control CH4 sources and sinks and its potential release from stored carbon reservoirs contributes significant uncertainty to our knowledge of the interaction between carbon cycle and climate change. At Goddard Space Flight Center (GSFC) we have been developing the technology needed to remotely measure CH4 from orbit. Our concept for a CH4 lidar is a nadir viewing instrument that uses the strong laser echoes from the Earth's surface to measure CH4. The instrument uses a tunable, narrow-frequency light source and photon-sensitive detector to make continuous measurements from orbit, in sunlight and darkness, at all latitudes and can be relatively immune to errors introduced by scattering from clouds and aerosols. Our measurement technique uses Integrated Path Differential Absorption (IPDA), which measures the absorption of laser pulses by a trace gas when tuned to a wavelength coincident with an absorption line. We have already demonstrated ground-based and airborne CH4 detection using Optical Parametric Amplifiers (OPA) at 1651 nm using a laser with approximately 10 microJ/pulse at 5kHz with a narrow linewidth. Next, we will upgrade our OPO system to add several more wavelengths in preparation for our September 2015 airborne campaign, and expect that these upgrades will enable CH4 measurements with 1% precision (10-20 ppb).

  11. Fiber optical parametric amplifiers in optical communication systems

    Science.gov (United States)

    Marhic (†), Michel E; Andrekson, Peter A; Petropoulos, Periklis; Radic, Stojan; Peucheret, Christophe; Jazayerifar, Mahmoud

    2015-01-01

    The prospects for using fiber optical parametric amplifiers (OPAs) in optical communication systems are reviewed. Phase-insensitive amplifiers (PIAs) and phase-sensitive amplifiers (PSAs) are considered. Low-penalty amplification at/or near 1 Tb/s has been achieved, for both wavelength- and time-division multiplexed formats. High-quality mid-span spectral inversion has been demonstrated at 0.64 Tb/s, avoiding electronic dispersion compensation. All-optical amplitude regeneration of amplitude-modulated signals has been performed, while PSAs have been used to demonstrate phase regeneration of phase-modulated signals. A PSA with 1.1-dB noise figure has been demonstrated, and preliminary wavelength-division multiplexing experiments have been performed with PSAs. 512 Gb/s have been transmitted over 6,000 km by periodic phase conjugation. Simulations indicate that PIAs could reach data rate x reach products in excess of 14,000 Tb/s × km in realistic wavelength-division multiplexed long-haul networks. Technical challenges remaining to be addressed in order for fiber OPAs to become useful for long-haul communication networks are discussed. PMID:25866588

  12. EFFECT OF OPTICAL FIBER HYDROGEN LOADING ON THE INSCRIPTION EFFICIENCY OF CHIRPED BRAGG GRATINGS BY MEANS OF KrF EXCIMER LASER RADIATION

    Directory of Open Access Journals (Sweden)

    Sergey V. Varzhel

    2016-11-01

    Full Text Available Subject of Research.We present comparative results of the chirped Bragg gratings inscription efficiency in optical fiber of domestic production with and without low-temperature hydrogen loading. Method. Chirped fiber Bragg gratings inscription was made by the Talbot interferometer with chirped phase mask having a chirp rate of 2.3 nm/cm used for the laser beam amplitude separation. The excimer laser system Coherent COMPexPro 150T, working with the gas mixture KrF (248 nm, was used as the radiation source. In order to increase the UV photosensitivity, the optical fiber was placed in a chamber with hydrogen under a pressure of 10 MPa and kept there for 14 days at 40 °C. Main Results. The usage of the chirped phase mask in a Talbot interferometer scheme has made it possible to get a full width at half-maximum of the fiber Bragg grating reflection spectrum of 3.5 nm with induced diffraction structure length of 5 mm. By preliminary hydrogen loading of optical fiber the broad reflection spectrum fiber Bragg gratings with a reflectivity close to 100% has been inscribed. Practical Relevance. The resulting chirped fiber Bragg gratings can be used as dispersion compensators in optical fiber communications, as well as the reflective elements of distributed fiber-optic phase interferometric sensors.

  13. OPTICAL PARAMETRIC OSCILLATORS: Optimal feedback in efficient ring double-cavity optical parametric oscillators

    Science.gov (United States)

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

    2010-09-01

    It is shown that the use of two feedback circuits with matched transfer constants and optimal phase incursions in a nondegenerate optical parametric oscillator (OPO) makes it possible to localise the extremes of intensity distributions of interacting waves on the output face of a nonlinear crystal, which provides maximum possible conversion efficiency of pump energy. The optimisation procedure in this case is rather flexible because it is reduced to ambiguous matching of the period and shift of the extremes of exact analytic solutions of the corresponding problem in the form of cnoidal waves with respect to the nonlinear crystal position. Unlike the single-cavity OPO scheme, both these parameters can substantially exceed the nonlinear crystal length and even tend to infinity, which corresponds to solitary soliton-like solutions.

  14. Spiral intensity patterns in the internally pumped optical parametric oscillator

    DEFF Research Database (Denmark)

    Lodahl, Peter; Bache, Morten; Saffman, Mark

    2001-01-01

    We describe a nonlinear optical system that supports spiral pattern solutions in the field intensity. This new spatial structure is found to bifurcate above a secondary instability in the internally pumped optical parametric oscillator. The analytical predictions of threshold and spatial scale...

  15. Optical design and studies of a tiled single grating pulse compressor for enhanced parametric space and compensation of tiling errors

    Science.gov (United States)

    Daiya, D.; Patidar, R. K.; Sharma, J.; Joshi, A. S.; Naik, P. A.; Gupta, P. D.

    2017-04-01

    A new optical design of tiled single grating pulse compressor has been proposed, set-up and studied. The parametric space, i.e. the laser beam diameters that can be accommodated in the pulse compressor for the given range of compression lengths, has been calculated and shown to have up to two fold enhancement in comparison to our earlier proposed optical designs. The new optical design of the tiled single grating pulse compressor has an additional advantage of self compensation of various tiling errors like longitudinal and lateral piston, tip and groove density mismatch, compared to the earlier designs. Experiments have been carried out for temporal compression of 650 ps positively chirped laser pulses, at central wavelength 1054 nm, down to 235 fs in the tiled grating pulse compressor set up with the proposed design. Further, far field studies have been performed to show the desired compensation of the tiling errors takes place in the new compressor.

  16. Use of conventional and chirped optical fibre Bragg gratings to detect matrix cracking damage in composite materials

    International Nuclear Information System (INIS)

    Palaniappan, J; Wang, H; Ogin, S L; Thorne, A; Reed, G T; Tjin, S C

    2005-01-01

    A comparison is made between conventional (i.e. uniform) and chirped optical fibre Bragg gratings (FBGs) for the detection of matrix cracking damage in composite materials. Matrix cracking damage is generally the first type of visible damage to develop under load in the off-axis plies of laminated composites and is generally the precursor of more serious damage mechanisms, particularly delamination. The detection of this type of damage is thus important, particularly in aerospace applications. Using a uniform FBG, characteristic changes develop in the reflected spectrum which can be used to identify crack development in the composite. The additional advantage of using a chirped grating is that the crack position can also be located

  17. Image-rotating, 4-mirror, ring optical parametric oscillator

    Science.gov (United States)

    Smith, Arlee V.; Armstrong, Darrell J.

    2004-08-10

    A device for optical parametric amplification utilizing four mirrors oriented in a nonplanar configuration where the optical plane formed by two of the mirrors is orthogonal to the optical plane formed by the other two mirrors and with the ratio of lengths of the laser beam paths approximately constant regardless of the scale of the device. With a cavity length of less than approximately 110 mm, a conversion efficiency of greater than 45% can be achieved.

  18. Numerical simulation of extremely chirped pulse formation with an optical fiber

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Tamitake; Nishimura, Akihiko; Tei, Kazuyoku; Matoba, Tohru; Takuma, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yamashita, Mikio; Morita, Ryuji

    1998-03-01

    A nonlinear propagation code which used a symmetric split-step Fourier method as an algorithm was improved to simulate a propagation behavior of extremely chirped pulse in a long fiber. The performances of pulse propagation in noble gases cored hollow fibers and a pulse stretcher using a nonlinear and normal silicate fibers have been simulated by the code. The calculation results in the case of the hollow fiber are consistent with their experimental results. We estimated that this pulse stretcher could give a extremely chirped pulse whose spectral width was 84.2 nm and temporal duration was 1.5 ns. (author)

  19. High-contrast FFT acousto-optical tomography of biological tissues with a frequency-chirped modulation of the ultrasound

    Science.gov (United States)

    Forget, Benoit C.; Atlan, Michael; Selb, Juliette; Pottier, Lionel; Ramaz, Francois; Boccara, Albert C.

    2003-06-01

    Although tumors can show important contrast in their optical properties at an early stage of development, they are difficult to image optically due the diffusive nature of biological tissues. Such tumors can also be detected by "classical" ultrasound (US) imaging, but the acoustic constrast is often weak at early stages. Acousto-optical (AO) imaging combines light and ultrasound : light carries the desired information and ultrasound provides the spatial resolution. Based on a previous work made by the group of L.V. Wang, we present AO images obtained with chirped US. This modulation of the US frequency allows to encode a spatial region of the medium in the frequency spectrum of the AO signal. We can then obtain the optical contrast along the US path with improved resolution. The technique was apply to the imaging of buried objects in phantoms and to the vizualization of the "virtual source".

  20. Numerical Modelling of Spontaneous Emission in Optical Parametric Amplifiers

    DEFF Research Database (Denmark)

    Friis, Søren Michael Mørk; Andersen, Ulrik Lund; Rottwitt, Karsten

    2013-01-01

    Fiber optical parametric processes offer a wide range of applications including phase sensitive as well as phase insensitive amplification, wavelength conversion and signal regeneration. One of the difficult challenges is any of these applications is to predict their associated noise performance...

  1. Light squeezing in optical parametric amplification beyond the ...

    Indian Academy of Sciences (India)

    Optical parametric amplification (OPA) described usually by the coupled-wave equations with the first-order derivatives of the signal and idler waves, is solved under the slowly-varying amplitude approximation (SVA). In this article, by keeping the second-order derivatives in the coupled-wave equations, we obtained an ...

  2. Asymmetric gain-saturated spectrum in fiber optical parametric amplifiers

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Rottwitt, Karsten; Galili, Michael

    2012-01-01

    We demonstrate experimentally and numerically an unexpected spectral asymmetry in the saturated-gain spectrum of single-pump fiber optical parametric amplifiers. The interaction between higher-order four-wave mixing products and dispersive waves radiated as an effect of third-order dispersion...

  3. Gain characteristics of a saturated fiber optic parametric amplifier

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Lorenzen, Michael Rodas; Noordegraaf, Danny

    2008-01-01

    In this work we discuss saturation performance of a fiber optic parametric amplifier. A simple numerical model is described and applied to specific cases. A system experiment using a saturated amplifier illustrates a 4 dB improvement in required signal to noise ratio for a fixed bit error ratio....

  4. Narrow linewidth pulsed optical parametric oscillator

    Indian Academy of Sciences (India)

    Now-a-days with the development of coating technology and with the availability of good optical quality crystals having high damage threshold and deep infrared. (IR) transparency it is possible to extend the tunability of the OPO. Particularly, we have to mention that the development of periodically poled crystal has revolu-.

  5. 500 MW peak power degenerated optical parametric amplifier delivering 52 fs pulses at 97 kHz repetition rate.

    Science.gov (United States)

    Rothhardt, J; Hädrich, S; Röser, F; Limpert, J; Tünnermann, A

    2008-06-09

    We present a high peak power degenerated parametric amplifier operating at 1030 nm and 97 kHz repetition rate. Pulses of a state-of-the art fiber chirped-pulse amplification (FCPA) system with 840 fs pulse duration and 410 microJ pulse energy are used as pump and seed source for a two stage optical parametric amplifier. Additional spectral broadening of the seed signal in a photonic crystal fiber creates enough bandwidth for ultrashort pulse generation. Subsequent amplification of the broadband seed signal in two 1 mm BBO crystals results in 41 microJ output pulse energy. Compression in a SF 11 prism compressor yields 37 microJ pulses as short as 52 fs. Thus, pulse shortening of more than one order of magnitude is achieved. Further scaling in terms of average power and pulse energy seems possible and will be discussed, since both concepts involved, the fiber laser and the parametric amplifier have the reputation to be immune against thermo-optical effects.

  6. Parametric Covariance Model for Horizon-Based Optical Navigation

    Science.gov (United States)

    Hikes, Jacob; Liounis, Andrew J.; Christian, John A.

    2016-01-01

    This Note presents an entirely parametric version of the covariance for horizon-based optical navigation measurements. The covariance can be written as a function of only the spacecraft position, two sensor design parameters, the illumination direction, the size of the observed planet, the size of the lit arc to be used, and the total number of observed horizon points. As a result, one may now more clearly understand the sensitivity of horizon-based optical navigation performance as a function of these key design parameters, which is insight that was obscured in previous (and nonparametric) versions of the covariance. Finally, the new parametric covariance is shown to agree with both the nonparametric analytic covariance and results from a Monte Carlo analysis.

  7. Tunable single-longitudinal-mode fiber optical parametric oscillator.

    Science.gov (United States)

    Yang, Sigang; Cheung, Kim K Y; Zhou, Yue; Wong, Kenneth K Y

    2010-02-15

    A tunable single-longitudinal-mode (SLM) fiber optical parametric oscillator (FOPO) is proposed and demonstrated experimentally. A sub-ring cavity with a short cavity length is used to suppress the longitudinal modes and broaden the longitudinal mode spacing. A fiber loop mirror, consisted of an unpumped erbium-doped fiber, acts as an autotracking filter for providing fine mode restriction and ensuring the single-frequency operation. The measurement based on a homodyne method shows that the FOPO provides the SLM output. Furthermore the SLM FOPO can be tunable over 14 nm for each of the signal and the idler, which is limited only by the gain bandwidth of the fiber optical parametric amplifier.

  8. Effect of idler absorption in pulsed optical parametric oscillators.

    Science.gov (United States)

    Rustad, Gunnar; Arisholm, Gunnar; Farsund, Øystein

    2011-01-31

    Absorption at the idler wavelength in an optical parametric oscillator (OPO) is often considered detrimental. We show through simulations that pulsed OPOs with significant idler absorption can perform better than OPOs with low idler absorption both in terms of conversion efficiency and beam quality. The main reason for this is reduced back conversion. We also show how the beam quality depends on the beam width and pump pulse length, and present scaling relations to use the example simulations for other pulsed nanosecond OPOs.

  9. Ground and airborne methane measurements with an optical parametric amplifier

    Science.gov (United States)

    Numata, Kenji; Riris, Haris; Li, Steve; Wu, Stewart; Kawa, Stephan R.; Dawsey, Martha; Ramanathan, Anand; Mao, Jianping; Krainak, Michael; Abshire, James

    2012-06-01

    We report on ground and airborne atmospheric methane measurements with a differential absorption lidar using an optical parametric amplifier (OPA). Methane is a strong greenhouse gas on Earth and its accurate global mapping is urgently needed to understand climate change. We are developing a nanosecond-pulsed OPA for remote measurements of methane from an Earth-orbiting satellite. We have successfully demonstrated the detection of methane on the ground and from an airplane at ~11-km altitude.

  10. Beam splitter coupled CdSe optical parametric oscillator

    International Nuclear Information System (INIS)

    Levinos, N.J.; Arnold, G.P.

    1980-01-01

    An optical parametric oscillator is disclosed in which the resonant radiation is separated from the pump and output radiation so that it can be manipulated without interfering with them. Thus, for example, very narrow band output may readily be achieved by passing the resonant radiation through a line narrowing device which does not in itself interfere with either the pump radiation or the output radiation

  11. Ground and Airborne Methane Measurements with an Optical Parametric Amplifier

    Science.gov (United States)

    Numata, Kenji

    2012-01-01

    We report on ground and airborne atmospheric methane measurements with a differential absorption lidar using an optical parametric amplifier (OPA). Methane is a strong greenhouse gas on Earth and its accurate global mapping is urgently needed to understand climate change. We are developing a nanosecond-pulsed OPA for remote measurements of methane from an Earth-orbiting satellite. We have successfully demonstrated the detection of methane on the ground and from an airplane at approximately 11-km altitude.

  12. Widely tunable picosecond optical parametric oscillator using highly nonlinear fiber.

    Science.gov (United States)

    Zhou, Yue; Cheung, Kim K Y; Yang, Sigang; Chui, P C; Wong, Kenneth K Y

    2009-04-01

    We demonstrated a fully fiber-integrated widely tunable picosecond optical parametric oscillator based on highly nonlinear fiber. The ring cavity with a 50 m highly nonlinear fiber was synchronously pumped with a picosecond mode-locked fiber laser. The tuning range was from 1413 to 1543 nm and from 1573 to 1695 nm, which was as wide as 250 nm. A high-quality pulse was generated with a pulse width narrower than that of the pump.

  13. Raman-Enhanced Phase-Sensitive Fibre Optical Parametric Amplifier

    Science.gov (United States)

    Fu, Xuelei; Guo, Xiaojie; Shu, Chester

    2016-01-01

    Phase-sensitive amplification is of great research interest owing to its potential in noiseless amplification. One key feature in a phase-sensitive amplifier is the gain extinction ratio defined as the ratio of the maximum to the minimum gains. It quantifies the capability of the amplifier in performing low-noise amplification for high phase-sensitive gain. Considering a phase-sensitive fibre optical parametric amplifier for linear amplification, the gain extinction ratio increases with the phase-insensitive parametric gain achieved from the same pump. In this work, we use backward Raman amplification to increase the phase-insensitive parametric gain, which in turn improves the phase-sensitive operation. Using a 955 mW Raman pump, the gain extinction ratio is increased by 9.2 dB. The improvement in the maximum phase-sensitive gain is 18.7 dB. This scheme can significantly boost the performance of phase-sensitive amplification in a spectral range where the parametric pump is not sufficiently strong but broadband Raman amplification is available. PMID:26830136

  14. Thermal effects in high average power optical parametric amplifiers.

    Science.gov (United States)

    Rothhardt, Jan; Demmler, Stefan; Hädrich, Steffen; Peschel, Thomas; Limpert, Jens; Tünnermann, Andreas

    2013-03-01

    Optical parametric amplifiers (OPAs) have the reputation of being average power scalable due to the instantaneous nature of the parametric process (zero quantum defect). This Letter reveals serious challenges originating from thermal load in the nonlinear crystal caused by absorption. We investigate these thermal effects in high average power OPAs based on beta barium borate. Absorption of both pump and idler waves is identified to contribute significantly to heating of the nonlinear crystal. A temperature increase of up to 148 K with respect to the environment is observed and mechanical tensile stress up to 40 MPa is found, indicating a high risk of crystal fracture under such conditions. By restricting the idler to a wavelength range far from absorption bands and removing the crystal coating we reduce the peak temperature and the resulting temperature gradient significantly. Guidelines for further power scaling of OPAs and other nonlinear devices are given.

  15. Classical and quantum properties of optical parametric oscillators

    CERN Document Server

    Martinelli, M; Nussenzveig, P; Souto-Ribeiro, P H

    2001-01-01

    We present a review of the Optical Parametric Oscillator (OPO), describing its operation and the quantum correlation between the light beams generated by this oscillator. We show the construction of an OPO using a Potassium Titanyl Phosphate crystal, pumped by a frequency doubled Nd:YAG laser, and discuss the stability of the system and related thermal effects. We have measured the quantum correlation of signal and idler beams in a transient regime, obtaining a noise correlation level 39 % below the shot noise level.

  16. Experimental Generation of Multimode Squeezing in an Optical Parametric Amplifier

    International Nuclear Information System (INIS)

    Liu Kui; Cui Shu-Zhen; Yang Rong-Guo; Zhang Jun-Xiang; Gao Jiang-Rui

    2012-01-01

    We experimentally demonstrate that HG 01 (Hermit—Gauss) and HG 10 squeezed states can be generated simultaneously in an optical parametric amplifier. The HG 01 mode is a bright squeezed state and the HG 10 mode is a vacuum squeezed state. The squeezing of the HG 01 mode is −2.8 dB, and the squeezing of the HG 10 mode is −1.6 dB. We also demonstrate that the output field is also continuous-variable entanglement with orbital angular momentum. (general)

  17. Comprehensive Study of Z-Cut Highly Integrated LiNbO3 Optical Modulator with Adjustable Chirp Parameters

    Science.gov (United States)

    Palodiya, Vikram; Raghuwanshi, Sanjeev Kumar

    2017-12-01

    In this paper, the domain inversion is used in a simple fashion to improve the performance of a Z-cut highly integrated LiNbO3 optical modulator (LNOM). The Z-cut modulator having ≤ 3 V switching voltage and bandwidth of 15 GHz for an external modulator in which traveling-wave electrode length L_{m} imposed the modulating voltage, the product of V_π and L_{m} is fixed for a given electro-optic material (EOM). An investigation to achieve a low V_π by both magnitude of the electro-optic coefficient (EOC) for a wide variety of EOMs has been reported. The Sellmeier equation (SE) for the extraordinary index of congruent LiNbO3 is derived. The predictions related to phase matching are accurate between room temperature and 250 °C and wavelength ranging from 0.4 to 5 μm. The SE predicts more accurate refractive indices (RI) at long wavelengths. The different overlaps between the waveguides for the Z-cut structure are shown to yield a chirp parameter that can able to adjust 0-0.7. Theoretical results are perfectly verified by simulated results.

  18. High average power scaling of optical parametric amplification through cascaded difference-frequency generators

    Science.gov (United States)

    Jovanovic, Igor; Comaskey, Brian J.

    2004-09-14

    A first pump pulse and a signal pulse are injected into a first optical parametric amplifier. This produces a first amplified signal pulse. At least one additional pump pulse and the first amplified signal pulse are injected into at least one additional optical parametric amplifier producing an increased power coherent optical pulse.

  19. Compact, high-pulse-energy, picosecond optical parametric oscillator.

    Science.gov (United States)

    Kienle, Florian; Teh, Peh Siong; Alam, Shaif-Ul; Gawith, Corin B E; Hanna, David C; Richardson, David J; Shepherd, David P

    2010-11-01

    We report a high-energy optical parametric oscillator (OPO) synchronously pumped by a 7.19 MHz, Yb:fiber-amplified, picosecond, gain-switched laser diode. The 42-m-long ring cavity maintains a compact design through the use of an intracavity optical fiber. The periodically poled MgO-doped LiNbO(3) OPO provides output pulse energies as high as 0.49 μJ at 1.5 μm (signal) and 0.19 μJ at 3.6 μm (idler). Tunability from 1.5 to 1.7 μm and from 2.9 to 3.6 μm is demonstrated, and typical M(2) values of 1.5 × 1.3 and 2.8 × 1.9 are measured for the signal and idler, respectively, at high power.

  20. Automation of an "Aculight" continuous-wave optical parametric oscillator.

    Science.gov (United States)

    Morrison, Alexander M; Liang, Tao; Douberly, Gary E

    2013-01-01

    We report the automation of a continuous-wave, singly resonant, optical parametric oscillator (Lockheed-Martin Aculight ARGOS 2400-SF-15). This commercially available optical parametric oscillator (OPO) is capable of producing >1 W of continuously tunable idler output between 2.2 and 4.6 μm. An algorithm based on the feedback from a high accuracy wavemeter is implemented to synchronize three separate OPO tuning elements; the translation of a fan-out type periodically poled lithium niobate crystal, the rotation of an intracavity etalon, and the continuous tuning of the pump and idler wavelengths via piezoelectric strain of the tunable fiber pump laser. This allows for several hundred wavenumbers of efficient, automatic, continuous tuning of the idler wave. Continuous feedback from the wavemeter limits the absolute frequency accuracy to ±20 MHz. The broad, automatic tuning of the OPO is demonstrated via its implementation as a probe laser for the infrared action spectroscopy of methanol solvated in helium nanodroplets. LabVIEW virtual instruments for the automation of this OPO laser system are reported, along with detailed schematics of the associated hardware developed at the University of Georgia.

  1. Investigation of coupled optical parametric oscillators for novel applications

    Science.gov (United States)

    Ding, Yujie J.

    2016-03-01

    In this proceedings article, we summarize our previous results on the novel applications using the coupled optical parametric oscillators (OPO's). In a conventional OPO, a single pump wavelength is capable of generating a pair of the signal and idler beams by placing a bulk nonlinear crystal inside an OPO cavity. When a nonlinear crystal composite consisting of periodically-inverted KTiOPO4 (KTP) plates bonded together by the adhesive-free-bonded (AFB) technique is used instead of the bulk nonlinear crystal, the optical parametric oscillation takes place at two sets of the new wavelengths for the signal and idler beams due to the phase shifts occurring at the interfaces of the adjacent domains making up the composite. These two sets of the signal and idler waves are effectively generated by the two OPO's being coupled to each other. These signals and idlers exhibit ultrastability in terms of their frequency separation. We review the progress made by us on the applications being realized by using such coupled OPO's such as THz generation and restoration of the blurred images after propagating through a distortion plate and a phase plate simulating atmospheric turbulence.

  2. Detection of thermal gradients through fiber-optic Chirped Fiber Bragg Grating (CFBG): Medical thermal ablation scenario

    Science.gov (United States)

    Korganbayev, Sanzhar; Orazayev, Yerzhan; Sovetov, Sultan; Bazyl, Ali; Schena, Emiliano; Massaroni, Carlo; Gassino, Riccardo; Vallan, Alberto; Perrone, Guido; Saccomandi, Paola; Arturo Caponero, Michele; Palumbo, Giovanna; Campopiano, Stefania; Iadicicco, Agostino; Tosi, Daniele

    2018-03-01

    In this paper, we describe a novel method for spatially distributed temperature measurement with Chirped Fiber Bragg Grating (CFBG) fiber-optic sensors. The proposed method determines the thermal profile in the CFBG region from demodulation of the CFBG optical spectrum. The method is based on an iterative optimization that aims at minimizing the mismatch between the measured CFBG spectrum and a CFBG model based on coupled-mode theory (CMT), perturbed by a temperature gradient. In the demodulation part, we simulate different temperature distribution patterns with Monte-Carlo approach on simulated CFBG spectra. Afterwards, we obtain cost function that minimizes difference between measured and simulated spectra, and results in final temperature profile. Experiments and simulations have been carried out first with a linear gradient, demonstrating a correct operation (error 2.9 °C); then, a setup has been arranged to measure the temperature pattern on a 5-cm long section exposed to medical laser thermal ablation. Overall, the proposed method can operate as a real-time detection technique for thermal gradients over 1.5-5 cm regions, and turns as a key asset for the estimation of thermal gradients at the micro-scale in biomedical applications.

  3. Wavelength-encoding/temporal-spreading optical code division multiple-access system with in-fiber chirped moiré gratings.

    Science.gov (United States)

    Chen, L R; Smith, P W; de Sterke, C M

    1999-07-20

    We propose an optical code division multiple-access (OCDMA) system that uses in-fiber chirped moiré gratings (CMG's) for encoding and decoding of broadband pulses. In reflection the wavelength-selective and dispersive nature of CMG's can be used to implement wavelength-encoding/temporal-spreading OCDMA. We give examples of codes designed around the constraints imposed by the encoding devices and present numerical simulations that demonstrate the proposed concept.

  4. Continuous-wave terahertz light from optical parametric oscillators

    International Nuclear Information System (INIS)

    Sowade, Rosita

    2010-12-01

    Continuous-wave (cw) optical parametric oscillators (OPOs) are working horses for spectroscopy in the near and mid infrared. However, in the terahertz frequency range (0.1 to 10 THz), the pump threshold is more than 100 W due to the high absorption in nonlinear crystals and thus exceeds the power of standard cw single-frequency pump sources. In this thesis the first cw OPO capable of generating terahertz radiation is demonstrated. To overcome the high threshold, the signal wave of a primary infrared process is resonantly enhanced to serve as the pump wave for a cascaded parametric process with one wave being at the terahertz frequency level. A terahertz output power of more than two microwatts is measured and tuning is achieved from 1.3 to 1.7 THz. This terahertz source emits a narrow-band, diffraction-limited beam which remains mode-hop free over more than one hour. Such a device inhibits high potential for applications in areas like astronomy, telecommunications or high-resolution spectroscopy. (orig.)

  5. Continuous-wave terahertz light from optical parametric oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Sowade, Rosita

    2010-12-15

    Continuous-wave (cw) optical parametric oscillators (OPOs) are working horses for spectroscopy in the near and mid infrared. However, in the terahertz frequency range (0.1 to 10 THz), the pump threshold is more than 100 W due to the high absorption in nonlinear crystals and thus exceeds the power of standard cw single-frequency pump sources. In this thesis the first cw OPO capable of generating terahertz radiation is demonstrated. To overcome the high threshold, the signal wave of a primary infrared process is resonantly enhanced to serve as the pump wave for a cascaded parametric process with one wave being at the terahertz frequency level. A terahertz output power of more than two microwatts is measured and tuning is achieved from 1.3 to 1.7 THz. This terahertz source emits a narrow-band, diffraction-limited beam which remains mode-hop free over more than one hour. Such a device inhibits high potential for applications in areas like astronomy, telecommunications or high-resolution spectroscopy. (orig.)

  6. Phase Sensitive Amplification using Parametric Processes in Optical Fibers

    DEFF Research Database (Denmark)

    Kang, Ning

    Phase sensitive amplification using the parametric processes in fiber has the potential of delivering high gain and broadband operation with ultralow noise. It is able to regenerate both amplitude and phase modulated signals, simultaneously, with the appropriate design. This thesis concerns......, in specific, the design and optimization of such phase sensitive amplifiers (PSAs). For phase sensitive amplification in highly nonlinear fibers, optima points of operation have been identified for both the standard and the novel high stimulated Brillouin scattering (SBS) threshold highly nonlinear fiber...... types. The regeneration capability of PSAs on phase encoded signal in an optical link has been optimized. Flat-top phase sensitive profile has been synthesized. It is able to provide simultaneous amplitude and phase noise squeezing, with enhanced phase noise margin compared to conventional designs...

  7. Testing the energy conservation law in an optical parametric oscillator using phase-controlled femtosecond pulses.

    Science.gov (United States)

    Sun, Jinghua; Gale, Barry J S; Reid, Derryck T

    2007-04-02

    An experimental verification of energy conservation in a parametric oscillator is reported with an optical frequency precision of approximately 200 kHz (< 10(-6) nm). This high precision is made possible by simultaneously measuring the frequency offsets of the pump, signal and idler frequency combs in a singly-resonant femtosecond optical parametric oscillator system.

  8. Ground and Airborne Methane Measurements Using Optical Parametric Amplifiers

    Science.gov (United States)

    Numata, Kenji; Riris, Haris; Li, Steve; Wu, Stewart; Kawa, Stephan R.; Abshire, James Brice; Dawsey, Martha; Ramanathan, Anand

    2011-01-01

    We report on ground and airborne methane measurements with an active sensing instrument using widely tunable, seeded optical parametric generation (OPG). The technique has been used to measure methane, CO2, water vapor, and other trace gases in the near and mid-infrared spectral regions. Methane is a strong greenhouse gas on Earth and it is also a potential biogenic marker on Mars and other planetary bodies. Methane in the Earth's atmosphere survives for a shorter time than CO2 but its impact on climate change can be larger than CO2. Carbon and methane emissions from land are expected to increase as permafrost melts exposing millennial-age carbon stocks to respiration (aerobic-CO2 and anaerobic-CH4) and fires. Methane emissions from c1athrates in the Arctic Ocean and on land are also likely to respond to climate warming. However, there is considerable uncertainty in present Arctic flux levels, as well as how fluxes will change with the changing environment. For Mars, methane measurements are of great interest because of its potential as a strong biogenic marker. A remote sensing instrument that can measure day and night over all seasons and latitudes can localize sources of biogenic gas plumes produced by subsurface chemistry or biology, and aid in the search for extra-terrestrial life. In this paper we report on remote sensing measurements of methane using a high peak power, widely tunable optical parametric generator (OPG) operating at 3.3 micrometers and 1.65 micrometers. We have demonstrated detection of methane at 3.3 micrometers and 1650 nanometers in an open path and compared them to accepted standards. We also report on preliminary airborne demonstration of methane measurements at 1.65 micrometers.

  9. Long-range distributed optical fiber hot-wire anemometer based on chirped-pulse ΦOTDR.

    Science.gov (United States)

    Garcia-Ruiz, Andres; Dominguez-Lopez, Alejandro; Pastor-Graells, Juan; Martins, Hugo F; Martin-Lopez, Sonia; Gonzalez-Herraez, Miguel

    2018-01-08

    We demonstrate a technique allowing to develop a fully distributed optical fiber hot-wire anemometer capable of reaching a wind speed uncertainty of ≈ ±0.15m/s (±0.54km/h) at only 60 mW/m of dissipated power in the sensing fiber, and within only four minutes of measurement time. This corresponds to similar uncertainty values than previous papers on distributed optical fiber anemometry but requires two orders of magnitude smaller dissipated power and covers at least one order of magnitude longer distance. This breakthrough is possible thanks to the extreme temperature sensitivity and single-shot performance of chirped-pulse phase-sensitive optical time domain reflectometry (ΦOTDR), together with the availability of metal-coated fibers. To achieve these results, a modulated current is fed through the metal coating of the fiber, causing a modulated temperature variation of the fiber core due to Joule effect. The amplitude of this temperature modulation is strongly dependent on the wind speed at which the fiber is subject. Continuous monitoring of the temperature modulation along the fiber allows to determine the wind speed with singular low power injection requirements. Moreover, this procedure makes the system immune to temperature drifts of the fiber, potentially allowing for a simple field deployment. Being a much less power-hungry scheme, this method also allows for monitoring over much longer distances, in the orders of 10s of km. We expect that this system can have application in dynamic line rating and lateral wind monitoring in railway catenary wires.

  10. Optical parametric amplification and oscillation assisted by low-frequency stimulated emission.

    Science.gov (United States)

    Longhi, Stefano

    2016-04-15

    Optical parametric amplification and oscillation provide powerful tools for coherent light generation in spectral regions inaccessible to lasers. Parametric gain is based on a frequency down-conversion process and, thus, it cannot be realized for signal waves at a frequency ω3 higher than the frequency of the pump wave ω1. In this Letter, we suggest a route toward the realization of upconversion optical parametric amplification and oscillation, i.e., amplification of the signal wave by a coherent pump wave of lower frequency, assisted by stimulated emission of the auxiliary idler wave. When the signal field is resonated in an optical cavity, parametric oscillation is obtained. Design parameters for the observation of upconversion optical parametric oscillation at λ3=465 nm are given for a periodically poled lithium-niobate (PPLN) crystal doped with Nd(3+) ions.

  11. Two-stage optical parametric amplifier of a low energy nanosecond pulses

    Science.gov (United States)

    Bagdasarov, V. Kh; Bel'kov, S. A.; Garanin, S. G.; Garnov, S. V.; Nikolaev, D. A.; Orlov, S. N.; Polivanov, Y. N.; Sadovskiy, S. P.; Shcherbakov, I. A.; Tsvetkov, V. B.

    2017-05-01

    A two-stage optical parametric amplifier (OPA) design that provides over  -5  ×  107 gain at 1053 nm is presented. Noise level of the parametric amplifier in the signal wave propagation direction was 2  ×  10-6 from the signal level. The parasitic parametric oscillation under intense pump wave and its contribution to the OPA output was measured to be less than 8%.

  12. Ground and Airborne Methane Measurements using Optical Parametric Amplifiers

    Science.gov (United States)

    Riris, Haris; Numata, Kenji; Li, Steve; Wu, Stewart; Kawa, Stephan R.; Abshire, James; Dawsey, Martha; Ramanathan, Anand

    2012-01-01

    We report on an initial airborne demonstration of atmospheric methane column measurements at 1.65 micrometers using a widely tunable, seeded optical parametric amplifier (OPA) lidar and a photon counting detector. Methane is an important greenhouse gas and accurate knowledge of its sources and sinks is needed for climate modeling. Our lidar system uses 20 pulses at increasing wavelengths and integrated path differential absorption (IPDA) to map a methane line at 1650.9 nanometers. The wavelengths are generated by using a Nd:YAG pump laser at 1064.5 nanometers and distributed feedback diode laser at 1650.9 nanometers and a periodically-poled lithium niobate (PPLN) crystal. The pulse width was 3 nanoseconds and the pulse repetition rate was 6.28 KHz. The outgoing energy was approximately 13 microJoules/pulse. A commercial 20 nanometer diameter fiber-coupled telescope with a photon counting detector operated in analog mode with a 0.8 nanometer bandpass filter was used as the lidar receiver. The lidar system was integrated on NASA's DC-8 flying laboratory, based at Dryden Airborne operations Facility (DAOF) in Palmdale CA. Three flights were performed in the central valley of California. Each flight lasted about 2.5 hours and it consisted of several flight segments at constant altitudes at approximately 3, 4.5, 6, 7.6, 9.1, 10.6 km (l0, 15, 20, 25, 30, 35 kft). An in-situ cavity ring down spectrometer made by Picarro Inc. was flown along with the lidar instrument provided us with the "truth" i.e. the local CH4, CO2 and H2O concentrations at the constant flight altitude segments. Using the aircraft's altitude, GPS, and meteorological data we calculated the theoretical differential optical depth of the methane absorption at increasing altitudes. Our results showed good agreement between the experimentally derived optical depth measurements from the lidar instrument and theoretical calculations as the flight altitude was increased from 3 to 10.6 kilometers, assuming a

  13. Active locking and entanglement in type II optical parametric oscillators

    Science.gov (United States)

    Ruiz-Rivas, Joaquín; de Valcárcel, Germán J.; Navarrete-Benlloch, Carlos

    2018-02-01

    Type II optical parametric oscillators are amongst the highest-quality sources of quantum-correlated light. In particular, when pumped above threshold, such devices generate a pair of bright orthogonally-polarized beams with strong continuous-variable entanglement. However, these sources are of limited practical use, because the entangled beams emerge with different frequencies and a diffusing phase difference. It has been proven that the use of an internal wave-plate coupling the modes with orthogonal polarization is capable of locking the frequencies of the emerging beams to half the pump frequency, as well as reducing the phase-difference diffusion, at the expense of reducing the entanglement levels. In this work we characterize theoretically an alternative locking mechanism: the injection of a laser at half the pump frequency. Apart from being less invasive, this method should allow for an easier real-time experimental control. We show that such an injection is capable of generating the desired phase locking between the emerging beams, while still allowing for large levels of entanglement. Moreover, we find an additional region of the parameter space (at relatively large injections) where a mode with well defined polarization is in a highly amplitude-squeezed state.

  14. Mutually incoherent beam combining through optical parametric amplification

    International Nuclear Information System (INIS)

    Tropheme, B.

    2012-01-01

    This work deals with a technique of combination of coherent beams: Optical Parametric Amplification (OPA) with Multiple Pumps. This technique is used to instantly transfer the energy of several pumps on one beam, without energy storage and thus avoiding thermal effects in the amplifying media. It can be useful to combine energy of numerous fiber lasers and to amplify with a high repetition rate very high energy lasers or broadband pulses. With a numerical and experimental study using BBO and LBO as nonlinear crystal, we determine how to dispose the pumps around the signal and the corresponding angular tolerances of such set up. Then we focus our attention on recombining mechanisms between a pump and a non-corresponding idler. We demonstrate experimentally that these cascading effects may decrease the spatial and spectral quality of the amplified signal, and that these phenomena can be avoided with a minimum angle between the different pumps. A novel modelling of multi-pumps OPA links these cascading effects to the gratings generated by the interaction between the pumps. The last part presents a 5 pump OPA experiment. We achieve a pump-to-signal efficiency of 27% and so that a signal more powerful than each pump is obtained. (author) [fr

  15. Wavelength-agile near-IR optical parametric oscillator using a deposited silicon waveguide.

    Science.gov (United States)

    Wang, Ke-Yao; Foster, Mark A; Foster, Amy C

    2015-06-15

    Using a deposited hydrogenated amorphous silicon (a-Si:H) waveguide, we demonstrate ultra-broad bandwidth (60 THz) parametric amplification via four-wave mixing (FWM), and subsequently achieve the first silicon optical parametric oscillator (OPO) at near-IR wavelengths. Utilization of the time-dispersion-tuned technique provides an optical source with active wavelength tuning over 42 THz with a fixed pump wave.

  16. Brillouin suppression in a fiber optical parametric amplifier by combining temperature distribution and phase modulation

    DEFF Research Database (Denmark)

    Lorenzen, Michael Rodas; Noordegraaf, Danny; Nielsen, Carsten Vandel

    2008-01-01

    We demonstrate an increased gain in optical parametric amplier through suppression of stimulated Brillouin scattering by applying a temperature distribution along the fiber resulting in a reduction of the required phase modulation.......We demonstrate an increased gain in optical parametric amplier through suppression of stimulated Brillouin scattering by applying a temperature distribution along the fiber resulting in a reduction of the required phase modulation....

  17. Generation of a chirp-free optical pulse train with tunable pulse width based on a polarization modulator and an intensity modulator.

    Science.gov (United States)

    Pan, Shilong; Yao, Jianping

    2009-07-15

    A simple method for the generation of a chirp-free optical pulse train with tunable pulse width using a polarization modulator (PolM) and a zero-chirp intensity modulator (IM) is proposed and demonstrated. In the proposed system, a light wave with its polarization direction oriented at an angle of 45 degrees with respect to the principal axis of the PolM is polarization modulated by a sinusoidal drive signal. An optical polarizer is connected after the PolM to convert the polarization-modulated signals to a pulse train with the main peaks having a narrow pulse width. Then, the main peaks are selected by the IM, leading to the generation of a short optical pulse train with a repetition rate that is identical to or twice the frequency of the sinusoidal drive signal, depending on the dc bias of the IM. The pulse width of the generated pulse is easily tuned by adjusting the phase modulation index of the PolM. An experiment is carried out, and a pulse train with a duty cycle as small as 8.16% is generated.

  18. Regularized linearization for quantum nonlinear optical cavities: application to degenerate optical parametric oscillators.

    Science.gov (United States)

    Navarrete-Benlloch, Carlos; Roldán, Eugenio; Chang, Yue; Shi, Tao

    2014-10-06

    Nonlinear optical cavities are crucial both in classical and quantum optics; in particular, nowadays optical parametric oscillators are one of the most versatile and tunable sources of coherent light, as well as the sources of the highest quality quantum-correlated light in the continuous variable regime. Being nonlinear systems, they can be driven through critical points in which a solution ceases to exist in favour of a new one, and it is close to these points where quantum correlations are the strongest. The simplest description of such systems consists in writing the quantum fields as the classical part plus some quantum fluctuations, linearizing then the dynamical equations with respect to the latter; however, such an approach breaks down close to critical points, where it provides unphysical predictions such as infinite photon numbers. On the other hand, techniques going beyond the simple linear description become too complicated especially regarding the evaluation of two-time correlators, which are of major importance to compute observables outside the cavity. In this article we provide a regularized linear description of nonlinear cavities, that is, a linearization procedure yielding physical results, taking the degenerate optical parametric oscillator as the guiding example. The method, which we call self-consistent linearization, is shown to be equivalent to a general Gaussian ansatz for the state of the system, and we compare its predictions with those obtained with available exact (or quasi-exact) methods. Apart from its operational value, we believe that our work is valuable also from a fundamental point of view, especially in connection to the question of how far linearized or Gaussian theories can be pushed to describe nonlinear dissipative systems which have access to non-Gaussian states.

  19. Interplay of nonclassicality and entanglement of two-mode Gaussian fields generated in optical parametric processes

    Czech Academy of Sciences Publication Activity Database

    Arkhipov, Ie.I.; Peřina, Jan; Peřina, J.; Miranowicz, A.

    2016-01-01

    Roč. 94, č. 1 (2016), 1-15, č. článku 013807. ISSN 2469-9926 R&D Projects: GA ČR GAP205/12/0382 Institutional support: RVO:68378271 Keywords : two-mode Gaussian fields * optical parametric processes Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.925, year: 2016

  20. Inverse four-wave-mixing and self-parametric amplification effect in optical fibre.

    Science.gov (United States)

    Turitsyn, Sergei K; Bednyakova, Anastasia E; Fedoruk, Mikhail P; Papernyi, Serguei B; Clements, Wallace R L

    2015-09-01

    An important group of nonlinear processes in optical fibre involves the mixing of four waves due to the intensity dependence of the refractive index. It is customary to distinguish between nonlinear effects that require external/pumping waves (cross-phase modulation and parametric processes such as four-wave mixing) and self-action of the propagating optical field (self-phase modulation and modulation instability). Here, we present a new nonlinear self-action effect, self-parametric amplification (SPA), which manifests itself as optical spectrum narrowing in normal dispersion fibre, leading to very stable propagation with a distinctive spectral distribution. The narrowing results from an inverse four-wave mixing, resembling an effective parametric amplification of the central part of the spectrum by energy transfer from the spectral tails. SPA and the observed stable nonlinear spectral propagation with random temporal waveform can find applications in optical communications and high power fibre lasers with nonlinear intra-cavity dynamics.

  1. Gated frequency-resolved optical imaging with an optical parametric amplifier for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, S.M.; Bliss, D.E.

    1997-02-01

    Implementation of optical imagery in a diffuse inhomogeneous medium such as biological tissue requires an understanding of photon migration and multiple scattering processes which act to randomize pathlength and degrade image quality. The nature of transmitted light from soft tissue ranges from the quasi-coherent properties of the minimally scattered component to the random incoherent light of the diffuse component. Recent experimental approaches have emphasized dynamic path-sensitive imaging measurements with either ultrashort laser pulses (ballistic photons) or amplitude modulated laser light launched into tissue (photon density waves) to increase image resolution and transmissive penetration depth. Ballistic imaging seeks to compensate for these {open_quotes}fog-like{close_quotes} effects by temporally isolating the weak early-arriving image-bearing component from the diffusely scattered background using a subpicosecond optical gate superimposed on the transmitted photon time-of-flight distribution. The authors have developed a broadly wavelength tunable (470 nm -2.4 {mu}m), ultrashort amplifying optical gate for transillumination spectral imaging based on optical parametric amplification in a nonlinear crystal. The time-gated image amplification process exhibits low noise and high sensitivity, with gains greater than 104 achievable for low light levels. We report preliminary benchmark experiments in which this system was used to reconstruct, spectrally upcovert, and enhance near-infrared two-dimensional images with feature sizes of 65 {mu}m/mm{sup 2} in background optical attenuations exceeding 10{sup 12}. Phase images of test objects exhibiting both absorptive contrast and diffuse scatter were acquired using a self-referencing Shack-Hartmann wavefront sensor in combination with short-pulse quasi-ballistic gating. The sensor employed a lenslet array based on binary optics technology and was sensitive to optical path distortions approaching {lambda}/100.

  2. Characterization of tunable light source by optical parametric oscillator for high resolution spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J. W. [Ewha Womens Univ., Seoul (Korea); Rhee, B. G. [Sejong Univ., Seoul (Korea); Park, S. W. [Yonsei Univ., Seoul (Korea); Noh, J. W. [Inha Univ., Incheon (Korea)

    1998-04-01

    A tunable light source is developed by the optical parametric oscillator, which is very useful for a high resolution spectroscopy. The electronic structure of molecules and atoms can be examined by a proper coherent light source. Optical parametric oscillator provides light sources stable and widely tunable. In this work, the characteristics of the parametric optical generation are examined in the LiNbO{sub 3}. The theoretical analysis as well as the experimental measurement is performed. The pump laser is a second harmonic of Nd:YAG laser, and the parametric gain is measured. The characteristics of singly resonant oscillator and doubly resonant oscillator is studied as a function of temperature. It is found that 1mole% MgO:LiNbO{sub 3} crystal provides the tunability from 0.6{mu}m to 3.0{mu}m wavelength. Both the critical and noncritical phase matching are studied. The optical damage occurring in a congruent LiNbO{sub 3} crystal was not observed in 1mole% MgO:LiNbO{sub 3} crystal, opening a possibility for a high power optical parametric oscillation generation. The current work can be extended to an experiment employing the fundamental Nd:YAG as pump to provide a coherent light source for the study of molecular vibrations. 28 refs., 14 figs., 3 tabs. (Author)

  3. Broadly, independent-tunable, dual-wavelength mid-infrared ultrafast optical parametric oscillator.

    Science.gov (United States)

    Jin, Yuwei; Cristescu, S M; Harren, Frans J M; Mandon, Julien

    2015-08-10

    We demonstrate a two-crystal mid-infrared dual-wavelength optical parametric oscillator, synchronously pumped by a high power femtosecond Yb:fiber laser. The singly-resonant ring cavity, containing two periodically poled lithium niobate crystals, is capable of generating two synchronized idler wavelengths, independently tunable over 30 THz in the 2.9 - 4.2 μm wavelength region, due to the cascaded quadratic nonlinear effect. The independent tunability of the two idlers makes the optical parametric oscillator a promising source for ultrafast pulse generation towards the THz wavelength region, based on different frequency generation. In addition, the observed frequency doubled idler within the crystal indicates the possibility to realize a broadband optical self-phase locking between pump, signal, idler and higher order generated parametric lights.

  4. Design and optimization of fiber optical parametric oscillators for femtosecond pulse generation.

    Science.gov (United States)

    Zhang, Wen Qi; Sharping, Jay E; White, Richard T; Monro, Tanya M; Afshar V, Shahraam

    2010-08-02

    In this paper, we use a genetic algorithm and pulse-propagation analysis to design and optimize optical parametric oscillators based on soft-glass microstructured optical fibers. The maximum parametric gain, phase-match, walk-off between pump (1560 nm) and signal (880 nm) pulses, signal feedback ratio and signal-pump synchronization of the cavity are optimized. Pulse propagation analysis suggests that one can implement a fiber optical parametric oscillator capable of generating approximately 200-fs pulses at 880 nm with 43% peak-power conversion, high output pulse quality (time-bandwidth product approximately 0.43) and a wavelength tuning range that is limited only by the glass transmission windows.

  5. Signal to Noise Ratio (SNR Enhancement Comparison of Impulse-, Coding- and Novel Linear-Frequency-Chirp-Based Optical Time Domain Reflectometry (OTDR for Passive Optical Network (PON Monitoring Based on Unique Combinations of Wavelength Selective Mirrors

    Directory of Open Access Journals (Sweden)

    Christopher M. Bentz

    2014-03-01

    Full Text Available We compare optical time domain reflectometry (OTDR techniques based on conventional single impulse, coding and linear frequency chirps concerning their signal to noise ratio (SNR enhancements by measurements in a passive optical network (PON with a maximum one-way attenuation of 36.6 dB. A total of six subscribers, each represented by a unique mirror pair with narrow reflection bandwidths, are installed within a distance of 14 m. The spatial resolution of the OTDR set-up is 3.0 m.

  6. Aperture scaling effects with monolithic periodically poled lithium niobate optical parametric oscillators and generators.

    Science.gov (United States)

    Missey, M; Dominic, V; Powers, P; Schepler, K L

    2000-02-15

    We used elliptical beams to demonstrate aperture scaling effects in nanosecond single-grating and multigrating periodically poled lithium niobate (PPLN) monolithic optical parametric oscillators and generators. Increasing the cavity Fresnel number in single-grating crystals broadened both the beam divergence and the spectral bandwidth. Both effects are explained in terms of the phase-matching geometry. These effects are suppressed when a multigrating PPLN crystal is used because the individual gratings provide small effective subapertures. A flood-pumped multigrating optical parametric generator displayed a low output beam divergence and contained 19 pairs of signal and idler frequencies.

  7. Wideband generation of pulses in dual-pump optical parametric amplifier: theory and experiment.

    Science.gov (United States)

    Shoaie, Mohammad Amin; Mohajerin-Ariaei, Amirhossein; Vedadi, Armand; Brès, Camille-Sophie

    2014-02-24

    The generation of pulses in dual-pump fiber optical parametric amplifier is investigated. Theoretically, it is shown that in an analogical manner to pulse generation in single-pump fiber optical parametric amplifiers, the generated pulse shape depends on the linear phase mismatch between the interacting waves. However the dual-pump architecture allows for the bounding of the phase mismatch over a wide bandwidth. This feature permits the generation of uniform pulses over a wide bandwidth, contrary to the single-pump architecture. Using the developed theory, a pulse source with uniform pulses at 5 GHz repetition rate and duty cycle of 0.265 over 40 nm is demonstrated.

  8. Observations of complex frequency comb structure in a harmonically-pumped femtosecond optical parametric oscillator

    International Nuclear Information System (INIS)

    McCracken, Richard A; Balskus, Karolis; Zhang, Zhaowei; Reid, Derryck T

    2015-01-01

    Various schemes allow femtosecond optical parametric oscillators to produce pulses at harmonics of their pump laser repetition frequency, each apparently offering the possibility of generating widely-spaced, tunable frequency combs. Using a 100-MHz Ti:sapphire pump laser, we have compared two alternative optical parametric oscillator architectures, both leading to 300-MHz pulses but one configured in a cavity three times shorter than the pump laser and the other in a cavity one-third longer. Heterodyne measurements between the pump and each of these two systems show that they possess different carrier-envelope offset characteristics, with implications on the coherence and stabilization of the resulting combs

  9. Ultrashort-pulse laser machining system employing a parametric amplifier

    Science.gov (United States)

    Perry, Michael D.

    2004-04-27

    A method and apparatus are provided for increasing the energy of chirped laser pulses to an output in the range 0.001 to over 10 millijoules at a repetition rate 0.010 to 100 kHz by using a two stage optical parametric amplifier utilizing a bulk nonlinear crystal wherein the pump and signal beam size can be independently adjusted in each stage.

  10. Tailoring Chirped Moiré Fiber Bragg Gratings for Wavelength-Division-Multiplexing and Optical Code-Division Multiple-Access Applications

    Science.gov (United States)

    Chen, Lawrence R.; Smith, Peter W. E.

    The design and fabrication of chirped Moiré fiber Bragg gratings (CMGs) are presented, which can be used in either (1) transmission as passband filters for providing wavelength selectivity in wavelength-division-multiplexed (WDM) systems or (2) reflection as encoding/decoding elements to decompose short broadband pulses in both wavelength and time in order to implement an optical code-division multiple-access (OCDMA) system. In transmission, the fabricated CMGs have single or multiple flattened passbands ( 12 dB isolation and near constant in-band group delay. It is shown that these filters do not produce any measurable dispersion-induced power penalties when used to provide wavelength selectivity in 2.5 Gbit/s systems. It is also demonstrated how CMGs can be used in reflection to encode/decode short pulses from a wavelength-tunable mode-locked Er-doped fiber laser.

  11. Highly efficient optical parametric generation in proton exchanged PPLN waveguides

    CERN Document Server

    Chanvillard, L; Baldi, P; De Micheli, M; Ostrowsky, D B; Huang, L; Bamford, G

    1999-01-01

    Summary form only given. Parametric fluorescence, amplification, and oscillation in PPLN waveguides have already been demonstrated. In all previous experiments, the measured efficiencies were smaller than the theoretically predicted values since the waveguide fabrication process utilized, annealed proton exchange (APE) can reduce or even destroy the nonlinear coefficient and/or the periodic domain orientation in a portion of the guiding structure. In the experiment reported here, we used a 2 cm long, Z-cut PPLN with a 18 mu m domain inversion period. The waveguides are created using a direct proton exchange process in a highly diluted melt, which induces no crystallographic phase transition. This allows preserving both the nonlinear coefficient and the domain orientation while fully benefiting from the power confinement associated with the guided wave configuration. (4 refs).

  12. Rapidly tunable continuous-wave optical parametric oscillator pumped by a fiber laser

    NARCIS (Netherlands)

    Klein, M.E.; Gross, P.; Boller, Klaus J.; Auerbach, M.; Wessels, P.; Fallnich, C.

    2003-01-01

    We report on rapid, all-electronically controlled wavelength tuning of a continuous-wave (cw) optical parametric oscillator (OPO) pumped by an ytterbium fiber laser. The OPO is singly resonant for the signal wave and consists of a 40-mm-long periodically poled lithium niobate crystal in a

  13. Traveling wave nanosecond optical parametric oscillator close to the Fourier-transform limit

    NARCIS (Netherlands)

    Mes, J.; Hogervorst, W.; Tugbaev, V.

    2001-01-01

    We report on a novel design for a nanosecond optical parametric oscillator (OPO) based on beta-barium-borate. It involves a travelling-wave ring cavity in a configuration with a grazing incidence grating. This OPO is pumped by the third harmonic of multi-mode as well as a single-mode Nd:YAG lasers.

  14. Travelling-wave nanosecond optical parametric oscillator close to the Fourier-transform limit

    NARCIS (Netherlands)

    Mes, J.; Hogervorst, W.; Tugbaev, V.

    2001-01-01

    We report on a novel design for a nanosecond optical parametric oscillator (OPO) based on beta-barium-borate. It involves a travelling-wave ring cavity in a configuration with a grazing incidence grating. This OPO is pumped by the third harmonic of multi-mode as well as a single-mode Nd:YAG lasers.

  15. Fiber-laser-pumped continuous-wave singly resonant optical parametric oscillator

    NARCIS (Netherlands)

    Gross, P.; Klein, M.E.; Walde, T.; Boller, Klaus J.; Auerbach, M.; Wessels, P.; Fallnich, C.

    2002-01-01

    We report on what is to our knowledge the first continuous-wave (cw) optical parametric oscillator (OPO) that is pumped by a tunable fiber laser. The OPO is singly resonant for the signal wave and consists of a 40-mm-long periodically poled LiNbO3 crystal in a four-mirror ring cavity. At a pump

  16. Fiber Laser Pumped Continuous-wave Singly-resonant Optical Parametric Oscillator

    NARCIS (Netherlands)

    Klein, M.E.; Gross, P.; Walde, T.; Boller, Klaus J.; Auerbach, M.; Wessels, P.; Fallnich, C.; Fejer, Martin M.

    2002-01-01

    We report on the first fiber-pumped CW LiNbO/sub 3/ optical parametric oscillator (OPO). The OPO is singly resonant (SRO) and generates idler wavelengths in the range of 3.0 /spl mu/m to 3.7 /spl mu/m with a maximum output power of 1.9 watt.

  17. Entanglement in optical parametric down-conversion with losses and noise

    Czech Academy of Sciences Publication Activity Database

    Peřina, Jan; Křepelka, Jaromír

    2009-01-01

    Roč. 282, č. 19 (2009), 3918-3923 ISSN 0030-4018 R&D Projects: GA MŠk(CZ) 1M06002; GA AV ČR IAA100100713 Institutional research plan: CEZ:AV0Z10100522 Keywords : quantum measurement * parametric down-conversion * nonclassical light Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.316, year: 2009

  18. Raman and loss induced quantum noise in depleted fiber optical parametric amplifiers

    DEFF Research Database (Denmark)

    Friis, Søren Michael Mørk; Rottwitt, Karsten; McKinstrie, C. J.

    2013-01-01

    We present a semi-classical approach for predicting the quantum noise properties of fiber optical parametric amplifiers. The unavoidable contributors of noise, vacuum fluctuations, loss-induced noise, and spontaneous Raman scattering, are included in the analysis of both phase-insensitive and phase...

  19. Image transmission in mid-IR using a solid state laser pumped optical parametric oscillator

    Science.gov (United States)

    Prasad, Narasimha S.; Kratovil, Pat; Magee, James R.

    2002-04-01

    In this paper, image transmission using a mid-wave IR (MWIR) optical transceiver based free-space data link under low visibility conditions is presented. The all-solid-state MWIR transceiver primarily consisted of a passively Q-switched, short-pulsed Nd:YAG laser pumping a periodically poled lithium niobate (PPLN) based optical parametric oscillator and a Dember effect detector. The MILES transceiver generates pulse position waveforms. The optical data link consisting of transmitter drive electronics, pulse conditioning electronics and a computer generating pulses compatible with the 2400-baud rate RS232 receiver was utilized. Data formatting and RS232 transmission and reception were achieved using a computer. Data formatting transformed an arbitrary image file format compatible with the basic operation of pump laser. Images were transmitted at a date rate of 2400 kbits/sec with 16 bits/pixel. Test images consisting of 50X40 pixels and 100X80 pixels were transmitted through free-space filled with light fog up to 120 ft. Besides optical parametric oscillators, the proposed concept can be extended to optical parametric amplifiers, Raman lasers and other nonlinear optical devices to achieve multi-functionality.

  20. Effect of optical waveguiding mechanism on the lasing action of chirped InAs/AlGaInAs/InP quantum dash lasers

    KAUST Repository

    Khan, Mohammed Zahed Mustafa

    2013-03-04

    We report on the atypical emission dynamics of InAs/AlGaInAs/InP quantum dash (Qdash) lasers employing varying AlGaInAs barrier thickness (multilayer-chirped structure). The analysis is carried out via fabry-perot (FP) ridge (RW) and stripe waveguide (SW) laser characterization corresponding to the index and gain guided waveguiding mechanisms, respectively, and at different current pulse width operations. The laser emissions are found to emerge from the size dispersion of the Qdash ensembles across the four Qdash-barrier stacks, and governed by their overlapping quasi-zero dimensional density of states (DOS). The spectral characteristics demonstrated prominent dependence on the waveguiding mechanism at quasi-continuous wave (QCW) operation (long pulse width). The RW geometry showed unusual spectral split in the emission spectra on increasing current injection while the SW geometry showed typical broadening of lasing spectra. These effects were attributed to the highly inhomogeneous active region, the nonequilibrium carrier distribution and the energy exchange between Qdash groups across the Qdash-barrier stacks. Furthermore, QCW operation showed a progressive red shift of emission spectra with injection current, resulted from active region heating and carrier depopulation, which was observed to be minimal in the short pulse width (SPW) operation. Our investigation sheds light on the device physics of chirped Qdash laser structure and provides guidelines for further optimization in obtaining broad-gain laser diodes. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  1. Optical parametric oscillator-based photoacoustic detection of CO 2 at 4.23 µm allows real-time monitoring of the respiration of small insects

    NARCIS (Netherlands)

    Herpen, van M.M.J.W.; Ngai, A.K.Y.; Bisson, S.E.; Hackstein, J.H.P.; Woltering, E.J.; Harren, F.J.M.

    2006-01-01

    A continuous wave, single frequency and continuously tunable optical parametric oscillator is used in combination with photoacoustic spectroscopy to detect trace emissions of CO2 from insects under atmospheric conditions. The optical parametric oscillator (OPO) contains a periodically poled lithium

  2. Optical parametric oscillator-based photoacoustic detection of CO2 at 4.23 mu m allows real-time monitoring of the respiration of small insects

    NARCIS (Netherlands)

    Herpen, M.M.J.W. van; Ngai, A.K.Y.; Bisson, S.E.; Hackstein, J.H.P.; Woltering, E.J.; Harren, F.J.M.

    2006-01-01

    A continuous wave, single frequency and continuously tunable optical parametric oscillator is used in combination with photoacoustic spectroscopy to detect trace emissions of CO2 from insects under atmospheric conditions. The optical parametric oscillator (OPO) contains a periodically poled lithium

  3. Singly-resonant optical parametric oscillator based on KTA crystal

    Indian Academy of Sciences (India)

    Since the first demonstration of OPO by Giordmaine and Miller in 1965 using. LiNbO3 crystal [1] there has been a lot of improvement in this front making it a real tool for different applications. This becomes possible due to the advent of novel non-linear materials having wide transparency range with very low optical losses,.

  4. Angular spectrum characters of high gain non-critical phase match optical parametric oscillators

    International Nuclear Information System (INIS)

    Liu Jian-Hui; Liu Qiang; Gong Ma-Li

    2011-01-01

    The angular spectrum gain characters and the power magnification characters of high gain non-walk-off colinear optical parametric oscillators have been studied using the non-colinear phase match method for the first time. The experimental results of the KTiOAsO 4 and the KTiOPO 4 crystals are discussed in detail. At the high energy single resonant condition, low reflective ratio of the output mirror for the signal and long non-linear crystal are beneficial for small divergence angles. This method can also be used for other high gain non-walk-off phase match optical parametric processes. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  5. Parametric imaging of viscoelasticity using optical coherence elastography

    Science.gov (United States)

    Wijesinghe, Philip; McLaughlin, Robert A.; Sampson, David D.; Kennedy, Brendan F.

    2015-03-01

    We demonstrate imaging of soft tissue viscoelasticity using optical coherence elastography. Viscoelastic creep deformation is induced in tissue using step-like compressive loading and the resulting time-varying deformation is measured using phase-sensitive optical coherence tomography. From a series of co-located B-scans, we estimate the local strain rate as a function of time, and parameterize it using a four-parameter Kelvin-Voigt model of viscoelastic creep. The estimated viscoelastic strain and time constant are used to visualize viscoelastic creep in 2D, dual-parameter viscoelastograms. We demonstrate our technique on six silicone tissue-simulating phantoms spanning a range of viscoelastic parameters. As an example in soft tissue, we report viscoelastic contrast between muscle and connective tissue in fresh, ex vivo rat gastrocnemius muscle and mouse abdominal transection. Imaging viscoelastic creep deformation has the potential to provide complementary contrast to existing imaging modalities, and may provide greater insight into disease pathology.

  6. Development of Optical Parametric Amplifier for Lidar Measurements of Trace Gases on Earth and Mars

    Science.gov (United States)

    Numata, Kenji; Riris, Haris; Li, Steve; Wu, Stewart; Kawa, Stephen R.; Krainak, Michael; Abshire, James

    2011-01-01

    Trace gases in planetary atmospheres offer important clues as to the origins of the planet's hydrology, geology. atmosphere. and potential for biology. Wc report on the development effort of a nanosecond-pulsed optical parametric amplifier (OPA) for remote trace gas measurements for Mars and Earth. The OP A output light is single frequency with high spectral purity and is widely tunable both at 1600 nm and 3300 nm with an optical-optical conversion efficiency of approximately 40%. We demonstrated open-path atmospheric measurements ofCH4 (3291 nm and 1651 nm). CO2 (1573 nm), H20 (1652 nm) with this laser source.

  7. Novel Optical Parametric Amplifier at 1572 nm Wavelength Using KTP Crystal

    International Nuclear Information System (INIS)

    Li Huan-Huan; Li Shi-Guang; Ma Xiu-Hua; Wang Jun-Tao; Zhu Xiao-Lei

    2012-01-01

    A novel master oscillator/power amplifier architecture for optical parametric conversion of high pulse energy from 1.064 μm to 1.572 μm in KTiOPO 4 crystal is presented. A high gain of more than 80 at 1.572 μm pumped by a high energy Q-switched pulse laser is realized. With a seeding signal energy of 1 mJ, and 400 mJ pump pulse at 100 Hz, an amplified signal pulse energy of over 80 mJ is obtained. The total optical-optical conversion efficiency reaches 21%

  8. Intrinsic chirp of single-cycle pulses

    International Nuclear Information System (INIS)

    Lin Qiang; Zheng Jian; Dai Jianming; Ho, I-Chen; Zhang, X.-C.

    2010-01-01

    The Fourier transform-limited electromagnetic pulse has been regarded to be free of chirps for a long time. This is no longer true if the pulse duration goes down to or less than one optical cycle. We report the experimental observation of intrinsic chirps in such pulses with the sub-single-cycle terahertz (THz) waveforms obtained with a standard THz time-domain spectroscopy system. The results confirm the break down of the carrier-envelope (CE) expression for single-cycle optical pulses, and may influence the experimental measurements and theoretical modeling with single-cycle pulses.

  9. Four-Wave Optical Parametric Amplification in a Raman-Active Gas

    Directory of Open Access Journals (Sweden)

    Yuichiro Kida

    2015-08-01

    Full Text Available Four-wave optical parametric amplification (FWOPA in a Raman-active medium is experimentally investigated by use of an air-filled hollow fiber. A femtosecond pump pulse shorter than the period of molecular motion excites the coherent molecular motion of the Raman-active molecules during the parametric amplification of a signal pulse. The excited coherent motion modulates the frequency of the signal pulse during the parametric amplification, and shifts it to lower frequencies. The magnitude of the frequency redshift depends on the pump intensity, resulting in intensity-dependent spectral characteristics that are different from those in the FWOPA induced in a noble-gas-filled hollow fiber.

  10. 2.5 TW, two-cycle IR laser pulses via frequency domain optical parametric amplification.

    Science.gov (United States)

    Gruson, V; Ernotte, G; Lassonde, P; Laramée, A; Bionta, M R; Chaker, M; Di Mauro, L; Corkum, P B; Ibrahim, H; Schmidt, B E; Legaré, F

    2017-10-30

    Broadband optical parametric amplification in the IR region has reached a new milestone through the use of a non-collinear Frequency domain Optical Parametric Amplification system. We report a laser source delivering 11.6 fs pulses with 30 mJ of energy at a central wavelength of 1.8 μm at 10 Hz repetition rate corresponding to a peak power of 2.5 TW. The peak power scaling is accompanied by a pulse shortening of about 20% upon amplification due to the spectral reshaping with higher gain in the spectral wings. This source paves the way for high flux soft X-ray pulses and IR-driven laser wakefield acceleration.

  11. Parametric imaging of collagen structural changes in human osteoarthritic cartilage using optical polarization tractography

    Science.gov (United States)

    Ravanfar, Mohammadreza; Pfeiffer, Ferris M.; Bozynski, Chantelle C.; Wang, Yuanbo; Yao, Gang

    2017-12-01

    Collagen degeneration is an important pathological feature of osteoarthritis. The purpose of this study is to investigate whether the polarization-sensitive optical coherence tomography (PSOCT)-based optical polarization tractography (OPT) can be useful in imaging collagen structural changes in human osteoarthritic cartilage samples. OPT eliminated the banding artifacts in conventional PSOCT by calculating the depth-resolved local birefringence and fiber orientation. A close comparison between OPT and PSOCT showed that OPT provided improved visualization and characterization of the zonal structure in human cartilage. Experimental results obtained in this study also underlined the importance of knowing the collagen fiber orientation in conventional polarized light microscopy assessment. In addition, parametric OPT imaging was achieved by quantifying the surface roughness, birefringence, and fiber dispersion in the superficial zone of the cartilage. These quantitative parametric images provided complementary information on the structural changes in cartilage, which can be useful for a comprehensive evaluation of collagen damage in osteoarthritic cartilage.

  12. Correlations in photon-numbers and integrated intensities in parametric processes involving three optical fields

    Czech Academy of Sciences Publication Activity Database

    Peřina, Jan; Křepelka, Jaromír; Peřina ml., Jan; Bondani, M.; Allevi, A.; Andreoni, A.

    2009-01-01

    Roč. 53, č. 3 (2009), 373-382 ISSN 1434-6060 R&D Projects: GA AV ČR KAN301370701; GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : parametric process * three-mode state * sub-Poisson statistics * conditional measurement Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.420, year: 2009

  13. Thermal self-frequency locking of doubly-resonant optical parametric oscillator

    DEFF Research Database (Denmark)

    Hansen, P.L.; Buchhave, Preben

    1997-01-01

    The increase in the circulating signal and idler fields that occurs in a high-Q doubly resonant optical parametric oscillator (OPO) as it approaches resonance results in a small increase in the crystal temperature owing to absorption of the generated fields. The temperature change affects....... We show that the experimentally observed effects are consistent with the results of a numerical model of the OPO....

  14. Twin beams, nonlinearity, and walk-off in optical parametric oscillators

    International Nuclear Information System (INIS)

    Zambrini, Roberta; San Miguel, Maxi

    2002-01-01

    We study the quantum properties of the spatially tilted macroscopic signal beams in the transverse pattern formed in a degenerate optical parametric oscillator above threshold. We show that walk-off leads to an imbalance in the intensities and fluctuations of these beams when nonlinear multimode interactions are effective. Still, quantum correlations between the two beams are preserved, so that their intensity difference exhibits sub-Poissonian statistics

  15. Computational Principle and Performance Evaluation of Coherent Ising Machine Based on Degenerate Optical Parametric Oscillator Network

    Directory of Open Access Journals (Sweden)

    Yoshitaka Haribara

    2016-04-01

    Full Text Available We present the operational principle of a coherent Ising machine (CIM based on a degenerate optical parametric oscillator (DOPO network. A quantum theory of CIM is formulated, and the computational ability of CIM is evaluated by numerical simulation based on c-number stochastic differential equations. We also discuss the advanced CIM with quantum measurement-feedback control and various problems which can be solved by CIM.

  16. High energy optical parametric source for multi-wavelength CO2 dial

    Science.gov (United States)

    Barrientos-Barria, Jessica; Dherbecourt, Jean-Baptiste; Raybaut, Myriam; Godard, Antoine; Melkonian, Jean-Michel; Lefebvre, Michel

    2017-11-01

    In the scope of the preparation of spaceborne lidar missions to measure the concentration of greenhouse gases with differential absorption LIDAR techniques, we report on the development of a high energy 2.05 μm optical parametric source based on a versatile architecture enabling multiple wavelengths generation in the vicinity of the R30 absorption line of CO2. The multi-wavelength configuration is under study for a few greenhouse gas active detection missions, such as Ascend.

  17. Microsecond fiber laser pumped, single-frequency optical parametric oscillator for trace gas detection.

    Science.gov (United States)

    Barria, Jessica Barrientos; Roux, Sophie; Dherbecourt, Jean-Baptiste; Raybaut, Myriam; Melkonian, Jean-Michel; Godard, Antoine; Lefebvre, Michel

    2013-07-01

    We report on the first microsecond doubly resonant optical parametric oscillator (OPO). It is based on a nested cavity OPO architecture allowing single longitudinal mode operation and low oscillation threshold (few microjoule). The combination with a master oscillator-power amplifier fiber pump laser provides a versatile optical source widely tunable in the 3.3-3.5 μm range with an adjustable pulse repetition rate (from 40 to 100 kHz), high duty cycle (~10(-2)) and mean power (up to 25 mW in the idler beam). The potential for trace gas sensing applications is demonstrated through photoacoustic detection of atmospheric methane.

  18. Dissipative parametric modulation instability and pattern formation in nonlinear optical systems

    Science.gov (United States)

    Perego, A. M.; Tarasov, N.; Churkin, D. V.; Turitsyn, S. K.; Staliunas, K.

    2016-04-01

    We present the essential features of the dissipative parametric instability, in the universal complex Ginzburg- Landau equation. Dissipative parametric instability is excited through a parametric modulation of frequency dependent losses in a zig-zag fashion in the spectral domain. Such damping is introduced respectively for spectral components in the +ΔF and in the -ΔF region in alternating fashion, where F can represent wavenumber or temporal frequency depending on the applications. Such a spectral modulation can destabilize the homogeneous stationary solution of the system leading to growth of spectral sidebands and to the consequent pattern formation: both stable and unstable patterns in one- and in two-dimensional systems can be excited. The dissipative parametric instability provides an useful and interesting tool for the control of pattern formation in nonlinear optical systems with potentially interesting applications in technological applications, like the design of mode- locked lasers emitting pulse trains with tunable repetition rate; but it could also find realizations in nanophotonics circuits or in dissipative polaritonic Bose-Einstein condensates.

  19. The tunnelling of electromagnetic radiation in chirped dielectric structure

    Directory of Open Access Journals (Sweden)

    Kozar Anatoliy

    2017-01-01

    Full Text Available The tunnelling of optical beams through chirped Bragg grating is considered. Lateral shifts of transmitted and reflected beams were calculated. The saturation of Goos-Hanchen shift of transmitted light beams is shown.

  20. The tunnelling of electromagnetic radiation in chirped dielectric structure

    Science.gov (United States)

    Kozar, Anatoliy; Marchenko, Vladimir; Shestakov, Pavel

    2017-10-01

    The tunnelling of optical beams through chirped Bragg grating is considered. Lateral shifts of transmitted and reflected beams were calculated. The saturation of Goos-Hanchen shift of transmitted light beams is shown.

  1. Photo Parametric Amplifier Using Up & Down Converter Configuration for Optical Receiver

    Science.gov (United States)

    Abdullah, Mohammad Faiz Liew; Elbireki, Majdi Farag Mohammed

    2012-03-01

    A fundamental requirement in the design of an optical receiver is the achievement of high sensitivity and broad bandwidth. These two features are very important in getting reliable system. In this project a receiver circuit based on Photo parametric Amplifier (PPA), which is suggested as one of the alternative for receiver detection and amplification techniques is fully described. The PPA mode of operation involves optical detection and amplification within a single device. It is able to provide selectivity and sensitivity at the same time, as required for wireless optical communications. The most common problem that any communication system might face is the noise which must be eliminated or at least reduce it. In order to reduce the noise, filters have been implemented before the signal is passes through an amplifier. In this project an Up converter has been placed at the transmitter circuit in order to obtain high frequency, while at the receiver circuit, filters has been placed with Down converter to obtain the desired frequency. Photo diode, PIN type has been used to detect any incoming signal at the receiver circuit. Results showed that the output signal has been improved; with addition power strength and noise reduction which showed that photo parametric amplifier is more reliable and suitable to be used in wireless optical communication system.

  2. All-optical switching in a highly efficient parametric fiber mixer: design study.

    Science.gov (United States)

    Pejkic, Ana; Nissim, Ron R; Myslivets, Evgeny; Wiberg, Andreas O J; Alic, Nikola; Radic, Stojan

    2014-09-22

    Ultrafast all-optical switching in a highly nonlinear fiber with a longitudinally varied zero-dispersion wavelength was investigated theoretically and experimentally. We describe fiber-matched methodology for construction of a fast, low energy photon switch. The design relies on static and dynamic models and allows performance target selection, under constraints of physical fiber characteristic. The new design methodology was used to construct one-pump switch in the highly efficient parametric mixer. We demonstrate that such a parametric gate can operate at 100 GHz rate, with 2 aJ control energy, while achieving better than 50% extinction ratio. Theoretical analysis and experimental measurements indicate that accurate mapping of the fiber local dispersion is critical in optimizing the bandwidth and control energy of the switch. Switching performance limits are discussed and means for impairment mitigation are described.

  3. Ground demonstration of trace gas lidar based on optical parametric amplifier

    Science.gov (United States)

    Numata, Kenji; Riris, Haris; Li, Steve; Wu, Stewart; Kawa, Stephan R.; Krainak, Michael; Abshire, James

    2012-01-01

    We report on the development effort of a nanosecond-pulsed optical parametric amplifier (OPA) for remote trace gas measurements for Mars and Earth. The OPA output has ˜500 MHz linewidth and is widely tunable at both near-infrared and mid-infrared wavelengths, with an optical-optical conversion efficiency of up to ˜39%. Using this laser source, we demonstrated open-path measurements of CH4 (3291 and 1652 nm), CO2 (1573 nm), O (1652 nm), and CO (4764 nm) on the ground. The simplicity, tunability, and power scalability of the OPA make it a strong candidate for general planetary lidar instruments, which will offer important information on the origins of the planet's geology, atmosphere, and potential for biology.

  4. A flexible receiver with fiber optical parametric amplifier in OCDMA-FSO communication system

    Science.gov (United States)

    Xia, Min; Yuan, Jin-hui; Sang, Xin-zhu; Yin, Xiao-li; Rao, Lan; Yu, Chong-xiu

    2014-11-01

    A new receiver is proposed, which uses the fiber optical parametric amplifier (FOPA) in optical code division multiple access (OCDMA) over free space optic (FSO) communication system. The noise tolerance as the performance index in this receiver is derived. The receiver can not only improve the noise tolerance but also change the pump data conveniently for adapting to the length variation of the coding sequence under a complex and fast-changing weather condition. The influence of different factors on the noise tolerance is analyzed, and a significant improvement of about 18.77 dB for the noise tolerance can be achieved when the pump power and the length of coding sequence are 5 W and 256, respectively.

  5. General analysis of group velocity effects in collinear optical parametric amplifiers and generators.

    Science.gov (United States)

    Arisholm, Gunnar

    2007-05-14

    Group velocity mismatch (GVM) is a major concern in the design of optical parametric amplifiers (OPAs) and generators (OPGs) for pulses shorter than a few picoseconds. By simplifying the coupled propagation equations and exploiting their scaling properties, the number of free parameters for a collinear OPA is reduced to a level where the parameter space can be studied systematically by simulations. The resulting set of figures show the combinations of material parameters and pulse lengths for which high performance can be achieved, and they can serve as a basis for a design.

  6. Pattern formation without diffraction matching in optical parametric oscillators with a metamaterial.

    Science.gov (United States)

    Tassin, Philippe; Van der Sande, Guy; Veretennicoff, Irina; Kockaert, Pascal; Tlidi, Mustapha

    2009-05-25

    We consider a degenerate optical parametric oscillator containing a left-handed material. We show that the inclusion of a left-handed material layer allows for controlling the strength and sign of the diffraction coefficient at either the pump or the signal frequency. Subsequently, we demonstrate the existence of stable dissipative structures without diffraction matching, i.e., without the usual relationship between the diffraction coefficients of the signal and pump fields. Finally, we investigate the size scaling of these light structures with decreasing diffraction strength.

  7. CW seeded optical parametric amplifier providing wavelength and pulse duration tunable nearly transform limited pulses.

    Science.gov (United States)

    Hädrich, S; Gottschall, T; Rothhardt, J; Limpert, J; Tünnermann, A

    2010-02-01

    An optical parametric amplifier that delivers nearly transform limited pulses is presented. The center wavelength of these pulses can be tuned between 993 nm and 1070 nm and, at the same time, the pulse duration is varied between 206 fs and 650 fs. At the shortest pulse duration the pulse energy was increased up to 7.2 microJ at 50 kHz repetition rate. Variation of the wavelength is achieved by applying a tunable cw seed while the pulse duration can be varied via altering the pump pulse duration. This scheme offers superior flexibility and scaling possibilities.

  8. Narrowband and tunable ring optical parametric oscillator with a volume Bragg grating.

    Science.gov (United States)

    Jacobsson, Björn; Canalias, Carlota; Pasiskevicius, Valdas; Laurell, Fredrik

    2007-11-15

    We demonstrate a tunable nanosecond optical parametric oscillator with a narrowed signal spectrum. This was done by use of a volume Bragg grating based retroreflector, which makes the tuning simple and yields a compact design. Using periodically poled KTiOPO4 as the nonlinear medium, we generated 0.42 mJ of signal energy at 760 nm with a tuning range of 5 nm(2.6 THz) and a bandwidth of 0.25 nm(130 GHz) when the oscillator was pumped at 532 nm with 1.3 mJ of energy.

  9. Fibre Optical Parametric Amplification in Defect Bragg Fibres with Zero Dispersion Slow Light Effect

    International Nuclear Information System (INIS)

    Li, Xiao; Wei, Zhang; Yi-Dong, Huang; Jiang-De, Peng; Hong, Zhao; Ke-Wu, Yang

    2008-01-01

    Nonlinearity enhancement by slow light effect and strong light confinement in defect Bragg fibres is demonstrated and analysed in applications of fibre optical parametric amplifiers. Broadband low group velocity and zero dispersion as well as the strong light confinement by band gap enhances the nonlinear coefficient up to more than one order than the conventional high nonlinear fibres. Moreover, the zero dispersion wavelength of coupled core mode can be designed arbitrarily, under which the phase-matching bandwidth of the nonlinear process can be extended. (fundamental areas of phenomenology (including applications))

  10. Ground Demonstration of Planetary Gas Lidar Based on Optical Parametric Amplifier

    Science.gov (United States)

    Numata, Kenji; Riris, Haris; Li, Steve; Wu, Stewart; Kawa, Stephen R.; Krainak, Michael; Abshire, James

    2012-01-01

    We report on the development effort of a nanosecond-pulsed optical parametric amplifier (OPA) for remote trace gas measurements for Mars and Earth. The OPA output has high spectral purity and is widely tunable both at near-infrared and mid-infrared wavelengths, with an optical-optica1 conversion efficiency of up to approx 39 %. Using this laser source, we demonstrated open-path measurements of CH4 (3291 nm and 1651 nm), CO2 (1573 nm), H2O (1652 nm), and CO (4764 nm) on the ground. The simplicity, tunability. and power scalability of the OPA make it a strong candidate for general planetary lidar instruments, which will offer important information on the origins of the planet's geology, atmosphere, and potential for biology,

  11. All-fiber wavelength-swept optical parametric oscillator at 1 μm band

    Science.gov (United States)

    Yang, Yi; Yang, Si-Gang; Chen, Hong-Wei; Chen, Ming-Hua; Xie, Shi-Zhong

    2017-11-01

    We demonstrate an all-fiber and continuously wavelength-swept fiber optical parametric oscillator (FOPO) based on dispersion tuning technology around 1 μm. The alignment-free FOPO is pumped by a pulse train light, driven by a frequency-swept electric pulse source with a repetition rate ranging from 107.24 MHz to 107.31 MHz. Thus, the FOPO demonstrates a wavelength-swept output with a sweeping range of 100 nm centered at 1065.10 nm. The sweeping rate can be improved up to 100 kHz, while the cumulative speed exceeds 1000 000 nm s‑1. Since the electric scanning is used in an all-fiber setup instead of the traditional mechanical scanning method, it demonstrates better stability under prolonged operation, which is promising to be applied in biomedical imaging, such as optical coherence tomography (OCT) systems and other applications.

  12. Multi-wavelength fiber optical parametric oscillator with ultra-narrow wavelength spacing.

    Science.gov (United States)

    Chen, Daru; Sun, Bing

    2010-08-16

    We propose a novel multi-wavelength fiber optical parametric oscillator (MW-FOPO) based on a ring cavity. A highly nonlinear fiber and a Mach-Zehnder interferometer formed by two 3-dB optical couplers are used as the gain medium and the comb filter, respectively. Multi-wavelength lasing of the MW-FOPO with an ultra-narrow wavelength spacing of about 0.08 nm is achieved. The output spectrum of the MW-FOPO covers a wavelength regime from 1510 nm to 1615 nm (for lasing wavelengths with the power that exceeds -60 dBm). The stability of the MW-FOPO is discussed and experimentally demonstrated. A comparison of the output spectra between the MW-FOPO and the multi-wavelength Erbium-doped fiber laser is also presented.

  13. Creation and measurement of broadband squeezed vacuum from a ring optical parametric oscillator

    Science.gov (United States)

    Serikawa, Takahiro; Yoshikawa, Jun-ichi; Makino, Kenzo; Frusawa, Akira

    2016-12-01

    We report a 65MHz-bandwidth triangular-shaped optical parametric oscillator (OPO) for squeezed vacuum generation at 860nm. The triangle structure of our OPO enables the round-trip length to reach 45mm as a ring cavity, which provides a counter circulating optical path available for introducing a probe beam or generating another squeezed vacuum. Hence our OPO is suitable for the applications in high-speed quantum information processing where two or more squeezed vacua form a complicated interferometer, like continuous-variable quantum teleportation. With a homemade, broadband and low-loss homodyne detector, a direct measurement shows 8.4dB of squeezing at 3MHz and also 2.4dB of squeezing at 100MHz.

  14. Double-pumped multiwavelength fiber optical parametric oscillator based on a Sagnac loop filter.

    Science.gov (United States)

    Sun, Bing; Hu, Kai; Wei, Yizhen; Chen, Daru; Gao, Shiming; Wang, Tianshu; He, Sailing

    2012-01-01

    We propose a double-pumped ring cavity multiwavelength fiber optical parametric oscillator (MW-FOPO) using a highly nonlinear dispersion-shifted fiber (HNL-DSF) as the gain medium and a polarization maintained fiber based Sagnac loop filter as the comblike filter. 22-wavelength lasing of the double-pumped MW-FOPO with a ripple less than ±2.5 dB and a wavelength spacing of about 0.8 nm in a wavelength range from 1541 nm to 1558 nm is experimentally demonstrated. We discussed the power stability of the multiwavelength lasing of the double-pumped MW-FOPO. A comparison of the output spectra between the double-pumped MW-FOPO and single-pumped MW-FOPO is also presented. © 2012 Optical Society of America

  15. Boltzmann sampling for an XY model using a non-degenerate optical parametric oscillator network

    Science.gov (United States)

    Takeda, Y.; Tamate, S.; Yamamoto, Y.; Takesue, H.; Inagaki, T.; Utsunomiya, S.

    2018-01-01

    We present an experimental scheme of implementing multiple spins in a classical XY model using a non-degenerate optical parametric oscillator (NOPO) network. We built an NOPO network to simulate a one-dimensional XY Hamiltonian with 5000 spins and externally controllable effective temperatures. The XY spin variables in our scheme are mapped onto the phases of multiple NOPO pulses in a single ring cavity and interactions between XY spins are implemented by mutual injections between NOPOs. We show the steady-state distribution of optical phases of such NOPO pulses is equivalent to the Boltzmann distribution of the corresponding XY model. Estimated effective temperatures converged to the setting values, and the estimated temperatures and the mean energy exhibited good agreement with the numerical simulations of the Langevin dynamics of NOPO phases.

  16. Dynamics of a periodically modulated optical parametric oscillator near lasing threshold

    International Nuclear Information System (INIS)

    Brazhnyi, V. A.; Konotop, V. V.; Taki, M.

    2009-01-01

    We present analytical investigation of the nonlinear dynamics of a degenerate optical parametric oscillator with periodic modulation of transverse refraction index. By a proper choice of the injected external field that must compensate for losses and match with the modulation period, nonlinear optical cavities can exhibit dissipative Bloch waves which are attracting solutions of nonequilibrium system. This allows us to propose method of experimental visualization of the band structure of the cavity medium. Using multiple-scale expansion near the leasing threshold, we obtain the equation of evolution of the small-amplitude envelop of the signal field which appears strongly affected by the periodic modulation of the refractive index. We discuss the physical meaning of the obtained equation.

  17. Idler-resonant optical parametric oscillator based on KTiOAsO4

    Science.gov (United States)

    Bai, Fen; Wang, Qingpu; Liu, Zhaojun; Zhang, Xingyu; Lan, Weixia; Tao, Xutang; Sun, Youxuan

    2013-08-01

    An idler-resonant KTiOAsO4 (KTA) optical parametric oscillator is demonstrated within a diode-end-pumped acousto-optically Q-switched Nd:YAG laser. With an X-cut KTA crystal, idler wave at 3467 nm and signal wave at 1535 nm are generated. Under an incident diode pump power of 15.4 W, the idler output power of 105 mW and signal power of 720 mW are obtained at a pulse repetition rate of 40 kHz. The pulse widths of the idler and signal waves are 7.2 and 3.1 ns, respectively. The beam quality factors (M2) of the idler wave are within 1.2 in both horizontal and vertical directions.

  18. Fast Harmonic Chirp Summation

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Jensen, Tobias Lindstrøm; Jensen, Jesper Rindom

    2017-01-01

    -robust to noise, or very computationally inten- sive. In this paper, we propose a fast algorithm for the harmonic chirp summation method which has been demonstrated in the liter- ature to be accurate and robust to noise. The proposed algorithm is orders of magnitudes faster than previous algorithms which is also...

  19. How to tune quantum correlations with an intracavity photonic crystal in an optical parametric oscillator

    Science.gov (United States)

    Garcia-March, Miguel; de Castro, Maria; Gomila, Damia; Zambrini, Roberta

    2011-05-01

    We study the effect of periodic modulations on the quantum correlations of light in a nonlinear optical system, considering an intracavity photonic crystal in a type I optical parametric oscillator (OPO). We use a few modes linear approximation below threshold to obtain analytical expressions for the correlations comparing them with numerical results obtained from Langevin equations below (and also above) threshold. First, we find that the parametric threshold can be either raised or lowered through the amplitude of the photonic crystal, due to the interplay of two competing mechanism, i.e, inhibition of the signal spatial instability and the imprint of a spatial modulation on the pump favouring the instability process. Second, we find that, above threshold, the break of translational invariance provides a mechanism to reduce the quadrature quantum fluctuations leading to squeezing over a larger range of quadrature angles. Finally, inseparable and EPR entangled spatial beams are found in the presence of the PC. Funded by FISICOS (FIS2007-60327), CoQuSys (200450E566), MEC, Fulbright Commision, and FECYT.

  20. Subharmonic synchronously intracavity pumped picosecond optical parametric oscillator for intracavity phase interferometry

    Science.gov (United States)

    Zavadilová, Alena; Vyhlídal, David; Kubeček, Václav; Šulc, Jan

    2014-12-01

    The laser system suitable for precise intracavity phase interferometry is presented. The system is based on an intracavity pumped PPLN linear optical parametrical oscillator (OPO). For synchronous pumping of OPO a SESAM-mode-locked, picosecond, diode-pumped Nd:YVO4 linear oscillator, operating at 1.06 µm was used. The OPO cavity was set to be twice as long as the pumping Nd:YVO4 laser cavity. The pumping laser was set in such a manner that the parametric gain inside the PPLN overcame the OPO threshold only for one direction of pumping pulse propagation. This leads to the generation of two independent trains of pulses at the 1.5 µm spectral range. To verify the system performance, a LiNbO3 electro-optic phase modulator was placed inside the OPO. The RF-signal derived from the pumping pulse train, detected by a fast photodiode and divided by two, was applied on the modulator. A stable beat-note signal between the two OPO trains was successfully measured for the first time from such a compact, all-diode-pumped laser system. For RF-signal amplitude from 100 up to 700 mV beat-note frequency varied from 232 up to 1847 Hz which corresponded to detected phase-shift 36-250 µrad. The bandwidth of beat-note was less than 1 Hz (FWHM) resulting in phase-shift measurement error 1.5 × 10-7 rad.

  1. Dual-wavelength, two-crystal, continuous-wave optical parametric oscillator.

    Science.gov (United States)

    Samanta, G K; Ebrahim-Zadeh, M

    2011-08-15

    We report a cw optical parametric oscillator (OPO) in a novel architecture comprising two nonlinear crystals in a single cavity, providing two independently tunable pairs of signal and idler wavelengths. Based on a singly resonant oscillator design, the device permits access to arbitrary signal and idler wavelength combinations within the parametric gain bandwidth and reflectivity of the OPO cavity mirrors. Using two identical 30 mm long MgO:sPPLT crystals in a compact four-mirror ring resonator pumped at 532 nm, we generate two pairs of signal and idler wavelengths with arbitrary tuning across 850-1430 nm, and demonstrate a frequency separation in the resonant signal waves down to 0.55 THz. Moreover, near wavelength-matched condition, coherent energy coupling between the resonant signal waves, results in reduced operation threshold and increased output power. A total output power >2.8 W with peak-to-peak power stability of 16% over 2 h is obtained. © 2011 Optical Society of America

  2. Parametric imaging of the local attenuation coefficient in human axillary lymph nodes assessed using optical coherence tomography

    Science.gov (United States)

    Scolaro, Loretta; McLaughlin, Robert A.; Klyen, Blake R.; Wood, Benjamin A.; Robbins, Peter D.; Saunders, Christobel M.; Jacques, Steven L.; Sampson, David D.

    2012-01-01

    We report the use of optical coherence tomography (OCT) to determine spatially localized optical attenuation coefficients of human axillary lymph nodes and their use to generate parametric images of lymphoid tissue. 3D-OCT images were obtained from excised lymph nodes and optical attenuation coefficients were extracted assuming a single scattering model of OCT. We present the measured attenuation coefficients for several tissue regions in benign and reactive lymph nodes, as identified by histopathology. We show parametric images of the measured attenuation coefficients as well as segmented images of tissue type based on thresholding of the attenuation coefficient values. Comparison to histology demonstrates the enhancement of contrast in parametric images relative to OCT images. This enhancement is a step towards the use of OCT for in situ assessment of lymph nodes. PMID:22312589

  3. Generation of green frequency comb from chirped χ{sup (2)} nonlinear photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lai, C.-M. [Department of Electronic Engineering, Ming Chuan University, Taoyuan, Taiwan (China); Chang, K.-H.; Yang, Z.-Y.; Fu, S.-H.; Tsai, S.-T.; Hsu, C.-W.; Peng, L.-H. [Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan (China); Yu, N. E. [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Boudrioua, A. [LPL, CNRS - UMR 7538, Université Paris 13, Sorbone Paris Cité (France); Kung, A. H. [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan (China); Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan (China)

    2014-12-01

    Spectrally broad frequency comb generation over 510–555 nm range was reported on chirped quasi-phase-matching (QPM) χ{sup (2)} nonlinear photonic crystals of 12 mm length with periodicity stepwise increased from 5.9 μm to 7.1 μm. When pumped with nanosecond infrared (IR) frequency comb derived from a QPM optical parametric oscillator (OPO) and spanned over 1040 nm to 1090 nm wavelength range, the 520 nm to 545 nm up-converted green spectra were shown to consist of contributions from (a) second-harmonic generation among the signal or the idler modes, and (b) sum-frequency generation (SFG) from the neighboring pairs of the signal or the idler modes. These mechanisms led the up-converted green frequency comb to have the same mode spacing of 450 GHz as that in the IR-OPO pump comb. As the pump was further detuned from the aforementioned near-degeneracy point and moved toward the signal (1020–1040 nm) and the idler (1090–1110 nm) spectral range, the above QPM parametric processes were preserved in the chirped QPM devices to support up-converted green generation in the 510–520 nm and the 545–555 nm spectral regime. Additional 530–535 nm green spectral generation was also observed due to concurrence of multi-wavelength SFG processes between the (signal, idler) mode pairs. These mechanisms facilitate the chirped QPM device to support a single-pass up-conversion efficiency ∼10% when subject to an IR-OPO pump comb with 200 mW average power operated near- or off- the degeneracy point.

  4. High-efficiency mid-infrared optical parametric amplifier with approximate uniform rectangular pump distribution

    Science.gov (United States)

    Wei, Xingbin; Peng, Yuefeng; Luo, Xingwang; Zhou, Tangjian; Peng, Jue; Nie, Zan; Gao, Jianrong

    2017-10-01

    We present a high-efficiency mid-infrared optical parametric amplifier (OPA) pumped by a Nd:YAG slab laser with rectangular beam distribution. To improve the conversion efficiency of OPA, we used an approximate uniform pump beam, which helped most of the pump area maintain the optimal intensity to reduce the back conversion effect. The uniform pump distribution without any peak intensity also reduced the damage chances of the nonlinear crystal of PPMgOLN and increased its pump power capability in power-scaling operations. To make sufficient usage of the narrow and small interface of PPMgOLN, we chose a rectangular pump shape whose size was adjusted to match the maximum effective interface of PPMgOLN. The idler laser of 3.82 μm from an optical parametric oscillator (OPO) was powerscaled in the following OPA system. We used two 1.064 μm lasers to pump the OPO and OPA separately. The pulsewidth adjustment and pulse synchronization of the 1 μm pump laser and 3.82 μm seed laser were realized by changing the parameters of the two acoustic-optical Q-switches in the two pump lasers. With the input pump power of 293.4 W, the amplified 3.82 μm laser power was 40.3 W deducting the injected seed laser power of 2.9 W from OPO. The corresponding conversion efficiency from the pump to the idler was 13.7% for the PPMgOLN OPA.

  5. Ultra-Low Threshold Power On-Chip Optical Parametric Oscillation in AlGaAs-On-Insulator Microresonator

    DEFF Research Database (Denmark)

    Pu, Minhao; Ottaviano, Luisa; Semenova, Elizaveta

    2015-01-01

    We present a record-low threshold power of 7 mW at ~1.55 µm for on-chip optical parametric oscillation using a high quality factor micro-ring-resonator in a new nonlinear photonics platform: AlGaAs-on-insulator......We present a record-low threshold power of 7 mW at ~1.55 µm for on-chip optical parametric oscillation using a high quality factor micro-ring-resonator in a new nonlinear photonics platform: AlGaAs-on-insulator...

  6. Concurrent optical parametric down-conversion in χ(2) nonlinear photonic crystals.

    Science.gov (United States)

    Chen, L; Xu, P; Bai, Y F; Luo, X W; Zhong, M L; Dai, M; Lu, M H; Zhu, S N

    2014-06-02

    We experimentally investigated concurrent parametric downconversion processes in a two-dimensional hexagonally poled lithium tantalate crystal. The substantial enhancement of parametric gain was observed when concurrent processes shared a common parametric beam. Both degenerate and nondegenerate concurrent parametric downconversion processes were studied. Analyses of the spatial forms and output angles showed a strong dependence on the working temperature, during which a well-defined beamlike parametric output was observed. Our results will stimulate the design for coherent high-gain generation of multiple parametric beams and also shed light on the compact engineering of path-entanglement with specific spatial forms based on concurrent spontaneous parametric downconversion processes.

  7. Rapidly tunable optical parametric oscillator based on aperiodic quasi-phase matching.

    Science.gov (United States)

    Descloux, Delphine; Dherbecourt, Jean-Baptiste; Melkonian, Jean-Michel; Raybaut, Myriam; Lai, Jui-Yu; Drag, Cyril; Godard, Antoine

    2016-05-16

    A new optical parametric oscillator (OPO) architecture with high tuning speed capability is demonstrated. This device exploits the versatility offered by aperiodic quasi-phase matching (QPM) to provide a broad parametric gain spectrum without changing the temperature, angle, or position of the nonlinear crystal. Rapid tuning is then straightforwardly achieved using a fast intracavity spectral filter. This concept is demonstrated here for a picosecond synchronously pumped OPO containing an aperiodically poled MgO-doped LiNbO3 crystal and a rapidly tunable spectral filter based on a diffraction grating. Tuning over 160 nm around 3.86 μm is achieved at fixed temperature and a fast tuning over 30 nm in 40 μs is demonstrated. Different configurations are tested and compared. The cavity length detuning is analyzed and discussed. This device is successfully used to detect N2O by absorption. This approach could be generalized to other spectral ranges (e.g., visible) and temporal regimes (e.g., continuous-wave or nanosecond).

  8. A high-flux entanglement source based on a doubly resonant optical parametric amplifier

    International Nuclear Information System (INIS)

    Kuklewicz, Christopher E; Keskiner, Eser; Wong, Franco N C; Shapiro, Jeffrey H

    2002-01-01

    A 532 nm pumped type-II phase-matched, doubly resonant KTP optical parametric amplifier (OPA) was operated near frequency degeneracy to yield an inferred downconverted photon pair production rate of 1.7x10 6 s -1 at a pump power of 100 μW. The OPA output consisted of three components: narrowband doubly resonant mode pairs; narrowband singly resonant mode pairs for which either the signal or idler was resonant with the cavity and broadband nonresonant mode pairs. Under frequency-degenerate operation, the broadband nonresonant mode pairs were polarization triplet states. We observed quantum interference between the orthogonally polarized photons of the triplet states when they were analysed with a polarizer set at 45 deg. relative to the OPA's output polarizations, leading to reduced coincidence counts

  9. Polarization quantum properties in a type-II optical parametric oscillator below threshold

    International Nuclear Information System (INIS)

    Zambrini, Roberta; Miguel, Maxi San; Gatti, Alessandra; Lugiato, Luigi

    2003-01-01

    We study the far-field spatial distribution of the quantum fluctuations in the transverse profile of the output light beam generated by a type-II optical parametric oscillator below threshold, including the effects of transverse walk-off. We study how quadrature field correlations depend on the polarization. We find spatial Einstein-Podolsky-Rosen entanglement in quadrature-polarization components. For the far-field points not affected by walk-off there is almost complete noise suppression in the proper quadratures difference of any orthogonal polarization components. We show the entanglement of the state of symmetric, intense, or macroscopic, spatial light modes. We also investigate nonclassical polarization properties in terms of the Stokes operators. We find perfect correlations in all Stokes parameters measured in opposite far-field points in the direction orthogonal to the walk-off, while locally the field is unpolarized and we find no polarization squeezing

  10. Continuous-wave singly resonant optical parametric oscillator placed inside a ring laser.

    Science.gov (United States)

    Abitan, Haim; Buchhave, Preben

    2003-11-20

    A cw singly resonant optical parametric oscillator (SRO) was built and placed inside the cavity of a ring laser. The system consists of a diode-end-pumped Nd:YVO4 ring laser with intracavity periodically poled lithium niobate as the nonlinear gain medium of the SRO. When the laser was operated in a unidirectional mode, we obtained more than 520 mW of signal power in one beam. When the laser was operated in a bidirectional mode, we obtained 600 mW of signal power (300 mW in two separate beams). The power and the spectral features of the laser in the unidirectional and bidirectional modes were measured while the laser was coupled with the SRO. The results show that it is preferable to couple a SRO with a unidirectional ring laser.

  11. Efficient conversion from 1 to 2 microm by a KTP-based ring optical parametric oscillator.

    Science.gov (United States)

    Arisholm, G; Lippert, E; Rustad, G; Stenersen, K

    2002-08-01

    Conversion of Q -switched 1.064-microm Nd:YAG laser pulses to the 2-2.2-mu; m region with 46% efficiency is demonstrated with a KTP-based type 2 phase-matched optical parametric oscillator (OPO) with two pairs of walk-off compensating crystals in a ring resonator. With 10 mJ of pump energy, we obtain 2.5 mJ at the 2.06-microm signal and 2.1 mJ at the 2.2-microm idler, with a beam quality of M(2) approximately 1.4 . With a ZnGeP(2) -based OPO pumped by the signal from the KTP OPO we achieved 14% conversion efficiency from 1.064microm to the 3-5-microm range.

  12. Continuous-wave singly resonant optical parametric oscillator placed inside a ring laser

    DEFF Research Database (Denmark)

    Abitan, Haim; Buchhave, Preben

    2003-01-01

    in a unidirectional mode, we obtained more than 520 mW of signal power in one beam. When the laser was operated in a bidirectional mode, we obtained 600 mW of signal power (300 mW in two separate beams). The power and the spectral features of the laser in the unidirectional and bidirectional modes were measured while......A cw singly resonant optical parametric oscillator (SRO) was built and placed inside the cavity of a ring laser. The system consists of a diode-end-pumped Nd:YVO4 ring laser with intracavity periodically poled lithium niobate as the nonlinear gain medium of the SRO. When the laser was operated...... the laser was coupled with the SRO. The results show that it is preferable to couple a SRO with a unidirectional ring laser....

  13. Network of time-multiplexed optical parametric oscillators as a coherent Ising machine

    Science.gov (United States)

    Marandi, Alireza; Wang, Zhe; Takata, Kenta; Byer, Robert L.; Yamamoto, Yoshihisa

    2014-12-01

    Finding the ground states of the Ising Hamiltonian maps to various combinatorial optimization problems in biology, medicine, wireless communications, artificial intelligence and social network. So far, no efficient classical and quantum algorithm is known for these problems and intensive research is focused on creating physical systems—Ising machines—capable of finding the absolute or approximate ground states of the Ising Hamiltonian. Here, we report an Ising machine using a network of degenerate optical parametric oscillators (OPOs). Spins are represented with above-threshold binary phases of the OPOs and the Ising couplings are realized by mutual injections. The network is implemented in a single OPO ring cavity with multiple trains of femtosecond pulses and configurable mutual couplings, and operates at room temperature. We programmed a small non-deterministic polynomial time-hard problem on a 4-OPO Ising machine and in 1,000 runs no computational error was detected.

  14. Theoretical and simulation analysis of the fiber optical parametric amplifier (FOPA) with cascaded structure

    Science.gov (United States)

    Gao, Jie; Cao, Yongsheng; Chen, Fushen; Sun, Bao; Hu, Zhefeng

    2012-02-01

    A novel scheme is proposed to obviously improve the amplified gain, gain flatness and bandwidth characteristics of FOPA by applying a cascaded fiber structure. The basic structure of the cascaded fiber optical parametric amplifier (CFOPA) is introduced. Then, the expression of signals pass gain characteristic is obtained by utilizing a set of coupled equations. The gain, bandwidth and gain flatness characteristics of the CFOPA with the different parameters of DCF, such as fiber length l/, dispersion slope dD//dλ, and so on, are theoretical analyzed and optimized. Furthermore, simulation analysis is applied to verify the theoretical results by using Optisystem 7.0 software. Although, there are a few deviations between the simulation and the theoretical results, the simulation results effectively demonstrate the validity and feasibility of the theoretical analysis.

  15. Design and analysis of all-optical switches based on fiber parametric devices

    Science.gov (United States)

    Ma, Jing; Jiang, Chun

    2008-05-01

    We propose a novel 2 × 2 wavelength-convertible optical switch based on dual-pump fiber parametric devices: one is driven by linearly parallel pumps, and the other one by perpendicular pumps. Theoretical analysis is made on the polarization effects on the switching performance of the two devices. The result predicts that two incident signals which are positioned symmetrically with respect to one pump can be switched independently, with judicious combinations of the relative pump-signal polarization states. Simulations performed in OptiSystem show that the scheme can achieve crosstalk-free packet switching with acceptable extinction ratios for both signals. Besides, future applications of this novel scheme in high-speed switching nodes are discussed.

  16. Optimized design of six-wave fiber optical parametric amplifiers by using a genetic algorithm.

    Science.gov (United States)

    Li, Peipei; Zhu, Hongna; Taccheo, Stefano; Gao, Xiaorong; Wang, Zeyong

    2017-05-20

    A governing equation of the six-wave fiber optical parametric amplifier (FOPA) for the power and phase difference evolution of the six interacting waves is deduced. To optimize the gain of the six-wave FOPA, a multivariate stochastic optimization algorithm, i.e., the genetic algorithm (GA), is applied. The effect of pump depletion on the gain characteristic of the six-wave FOPA is emphasized and the effect of the fiber length, the wavelength, and the power of two pumps on bandwidth, flatness, and magnitude of the gain spectrum has also been studied. A broader and flatter six-wave FOPA gain is obtained by adopting optimum design parameters, which theoretically provide a uniform gain of 65 dB with 0.3 dB uniformity over a 110 nm bandwidth for the six-wave FOPA.

  17. Laser Gyroscope Based on Synchronously Pumped Bidirectional Fiber Optical Parametric Oscillator

    Science.gov (United States)

    Noble, Jeffrey

    This master thesis presents an experimental design of a laser gyroscope based on a stabilized fiber optical parametric oscillator frequency comb and the results of testing of the proposed design. Before going into the experimental details, a background for different types of gyroscopes is discussed. This new laser gyroscope design is made up of only polarization maintaining (PM) fiber and PM fiber components. By using only fiber and fiber components, we were able to minimize size, weight, and alignment issues that are typical in bulk optical designs for OPO's and gyroscopes. The fiber-based OPO produces counter propagating ultrafast pulses that overlap only twice in the cavity, resulting in a beatnote signal when combined outside of the laser cavity. A mode-locked laser is used as a pump source so the lock-in effect (or deadband region) is avoided for the experiment. The drift of this beatnote signal represents the rotation sensitivity of the experimental setup. Issues seen in past iterations, such as stability of mode-locked pump source and beatnote drift overtime due to environmental variables, have been reduced in this experiment. This has been done by comprising the entire pump source of PM components, and by placing the entire setup in an insulating box to minimize acoustic and temperature fluctuations. By creating a frequency comb and locking the laser gyroscope to an optical clock, this experiment can be used for very precise rotation sensing in comparison to other gyro designs currently available.

  18. Continuous-wave, singly resonant parametric oscillator-based mid-infrared optical vortex source.

    Science.gov (United States)

    Aadhi, A; Sharma, Varun; Singh, R P; Samanta, G K

    2017-09-15

    We report on a high-power, continuous-wave source of optical vortices tunable in the mid-infrared (mid-IR) wavelength range. Using the orbital angular momentum (OAM) conservation of the parametric processes and the threshold conditions of the cavity modes of the singly resonant optical parametric oscillator (SRO), we have transferred the OAM of the pump beam at the near-infrared wavelength to the idler beam tunable in the mid-IR. Pumped with a vortex beam of order l p =1 at 1064 nm, the SRO, configured in a four curved mirror-based ring cavity with a 50 mm long MgO-doped periodically poled LiNbO 3 crystal, produces an idler beam with an output power in excess of 2 W in a vortex spatial profile with the order l i =1, tunable across 2217-3574 nm and corresponding signal beam in Gaussian intensity distribution across 1515-2046 nm. For pump vortices of the order l p =1 and 2, and a power of 22 W, the SRO produces idler vortices of the same order as that of the pump beam with a maximum power of 5.23 and 2.3 W, corresponding to near-IR to mid-IR vortex conversion efficiency of 23.8% and 10.4%, respectively. The idler vortex beam has a spectral width, and a passive rms power stability of 101 MHz and 4.9% over 2 h, respectively.

  19. Intracavity KTiOAsO4 optical parametric oscillator pumped by an actively Q-switched Nd:YAG laser

    Science.gov (United States)

    Lan, W. X.; Wang, Q. P.; Liu, Z. J.; Zhang, X. Y.; Wan, X. B.; Bai, F.; Shen, H. B.; Lv, G. P.; Jin, G. F.; Tao, X. T.; Sun, Y. X.

    2012-04-01

    A KTiOAsO4 (KTA) intracavity optical parametric oscillator (IOPO) is achieved within a diode end-pumped acousto-optically Q-switched Nd:YAG laser. With a 25-mm-long X-cut KTA crystal, efficient parametric conversions to signal (1535 nm) and idler (3467 nm) waves are realized. At an incident diode power of 14.9 W, the highest output power of 1.83 W including 1.37 W of signal and 0.46 W of idler radiations are obtained at a repetition rate of 40 kHz, corresponding to a total optical-to-optical conversion efficiency of 12.3%. Rate equations model are used to simulate this system, and the theoretical results agree with the experimental ones.

  20. Midinfrared optical parametric oscillator based on the wide-bandgap BaGa4S7 nonlinear crystal.

    Science.gov (United States)

    Tyazhev, Aleksey; Kolker, Dmitri; Marchev, Georgi; Badikov, Valeriy; Badikov, Dmitrii; Shevyrdyaeva, Galina; Panyutin, Vladimir; Petrov, Valentin

    2012-10-01

    The orthorhombic biaxial crystal BaGa(4)S(7) has been employed in a 1064 nm pumped optical parametric oscillator generating 217 μm and average power of ~50 mW at 100 Hz. Notwithstanding the relatively low nonlinearity, ~3 times above threshold operation has been achieved at pump intensities more than 5 times below the crystal surface damage limit.

  1. Selective trace gas detection of complex molecules with a continuous wave optical parametric oscillator using a planar jet expansion

    NARCIS (Netherlands)

    Ngai, A.K.Y.; Persijn, S.T.; Harren, F.J.M.; Verbraak, H.; Linnartz, H.

    2007-01-01

    The authors present a trace gas detection method for complex molecules using continuous cavity ring-down spectroscopy in combination with a continuous wave optical parametric oscillator (tunability wavelength: 2.8-4.8 mu m; power: 1 W) sampling a supersonic planar jet expansion (nozzle dimension: 3

  2. Automatically tunable continuous-wave optical parametric oscillator for high-resolution spectroscopy and sensitive trace-gas detection

    NARCIS (Netherlands)

    Ngai, A.K.Y.; Persijn, S.T.; Basum, G. von; Harren, F.J.M.

    2006-01-01

    We present a high-power (2.75 W), broadly tunable (2.75-3.83 mu m) continuous-wave optical parametric oscillator based on MgO-doped periodically poled lithium niobate. Automated tuning of the pump laser, etalon and crystal temperature results in a continuous wavelength coverage up to 450 cm(-1) per

  3. Combined wide pump tuning and high power of a continuous-wave, singly resonant optical parametric oscillator

    NARCIS (Netherlands)

    Herpen, M.M.J.W. van; Bisson, S.E.; Ngai, A.K.Y.; Harren, F.J.M.

    2004-01-01

    A new singly resonant, single-frequency optical parametric oscillator (OPO) has been developed for the 2.6-4.7 mum infrared wavelength region, using a high power (>20 W), widely tunable (1024-1034 nm) Yb:YAG pump source. With the OPO frequency stabilized with an intracavity etalon, the OPO achieved

  4. Mid-infrared continuous wave cavity ring down spectroscopy of molecular ions using an optical parametric oscillator

    NARCIS (Netherlands)

    Verbraak, H.; Ngai, A.K.Y.; Persijn, S.T.; Harren, F.J.M.; Linnartz, H.

    2007-01-01

    A sensitive infrared detection scheme is presented in which continuous wave cavity ring down spectroscopy is used to record rovibrational spectra of molecular ions in direct absorption through supersonically expanding planar plasma. A cw optical parametric oscillator is used as a light source and

  5. Suppression of Brillouin scattering in fibre-optical parametric amplifier by applying temperature control and phase modulation

    DEFF Research Database (Denmark)

    Lorenzen, Michael Rodas; Noordegraaf, Danny; Nielsen, Carsten Vandel

    2009-01-01

    An increased gain in a fibre-optical parametric amplifier through suppression of stimulated Brillouin scattering is demonstrated by applying a temperature distribution along the fibre for a fixed phase modulation of the pump. The temperature distribution slightly impacts the gain spectrum....

  6. Demonstration of Cascaded In-Line Single-Pump Fiber Optical Parametric Amplifiers in Recirculating Loop Transmission

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Ozolins, Oskars; An, Yi

    2012-01-01

    The performance of cascaded single-pump fiber optical parametric amplifiers (FOPAs) is experimentally studied for the first time using recirculating loop transmission with 80-km dispersion managed spans. Error-free performance has been achieved over 320 km for 40-Gbit/s CSRZ-OOK and CSRZ...

  7. Directly phase-modulation-mode-locked doubly-resonant optical parametric oscillator.

    Science.gov (United States)

    Devi, Kavita; Kumar, S Chaitanya; Ebrahim-Zadeh, M

    2013-10-07

    We present results on direct mode-locking of a doubly-resonant optical parametric oscillator (DRO) using an electro-optic phase modulator with low resonant frequency of 80 MHz as the single mode-locking element. Pumped by a cw laser at 532 nm and based on MgO:sPPLT as the nonlinear material, the DRO generates 533 ps pulses at 80 MHz and 471 ps pulses at 160 MHz. Stable train of mode-locked pulses is obtained at a modulation depth of 1.83 radians when the modulation frequency is precisely tuned and the cavity length is carefully adjusted. The effects of frequency detuning, modulation depth, input laser pump power, crystal temperature and position of modulator inside the cavity, on pulse duration and repetition rate have been studied. Operating at degeneracy, under mode-locked condition, the signal-idler spectrum exhibits a bandwidth of ~31 nm, and the spectrum has been investigated for different phase-matching temperatures. Mode-locked operation has been confirmed by second-harmonic-generation of the DRO output in a β-BaB₂O₄ crystal, where a 4 times enhancement in green power is observed compared to cw operation.

  8. Remote Optical Imagery of Obscured Objects in Low-Visibility Environments Using Parametric Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Asher, R.B.; Bliss, D.E.; Cameron, S.M.; Hamil, R.A.

    1998-10-14

    The development of unconventional active optical sensors to remotely detect and spatially resolve suspected threats obscured by low-visibility observation conditions (adverse weather, clouds, dust, smoke, precipitation, etc.) is fundamental to maintaining tactical supremacy in the battlespace. In this report, the authors describe an innovative frequency-agile image intensifier technology based on time-gated optical parametic amplification (OPA) for enhanced light-based remote sensing through pervasive scattering and/or turbulent environments. Improved dynamic range characteristics derived from the amplified passband of the OPA receiver combined with temporal discrimination in the image capture process will offset radiant power extinction losses, while defeating the deugradative effects & multipath dispersion and ,diffuse backscatter noise along the line-of-sight on resultant image contrast and range resolution. Our approach extends the operational utility of the detection channel in existing laser radar systems by increasing sensitivity to low-level target reffectivities, adding ballistic rejection of scatter and clutter in the range coordinate, and introducing multispectral and polarization discrimination capability in a wavelen~h-tunable, high gain nonlinear optical component with strong potential for source miniaturization. A key advantage of integrating amplification and tlequency up-conversion functions within a phasematched three-wave mixing parametric device is the ability to petiorm background-free imaging with eye-safe or longer inilared illumination wavelengths (idler) less susceptible to scatter without sacrificing quantum efficiency in the detection process at the corresponding signal wavelength. We report benchmark laboratory experiments in which the OPA gating process has been successfidly demonstrated in both transillumination and reflection test geometries with extended pathlengths representative of realistic coastal sea water and cumulus cloud

  9. Chirped-pulse coherent-OTDR with predistortion

    Science.gov (United States)

    Xiong, Ji; Jiang, Jialin; Wu, Yue; Chen, Yongxiang; Xie, Lianlian; Fu, Yun; Wang, Zinan

    2018-03-01

    In this paper, a novel method for generating high-quality chirped pulses with IQ modulator is studied theoretically and experimentally, which is a crucial building block for high-performance coherent optical time-domain reflectometry (COTDR). In order to compensate the nonlinearity of the modulator transfer function, we present a predistortion technique for chirped-pulse coherent optical time-domain reflectometry (CP-COTDR), the arcsin predistortion method and the single sideband with a suppressed carrier analog modulation used to generate the high quality chirped optical pulse. The high order sidebands, due to the large amplitude of the modulation signal and the nonlinear transfer function of the IQ modulator, can be relieved by the predistortion process, which means the power and the quality of the generated chirped pulse has been improved. In the experiment, this method increases the peak power of the chirped pulse by 4.2 dB compared to the case without predistortion process, as for the CP-COTDR system, this method increases the signal-to-noise ratio of the demodulated phase variation by 6.3 dB.

  10. Effects of moderate pump and Stokes chirp on chirped-probe pulse femtosecond coherent anti-Stokes Raman scattering thermometry

    KAUST Repository

    Gu, Mingming

    2018-01-08

    The effects of moderate levels of chirp in the pump and Stokes pulses on chirped-probe-pulse femtosecond coherent anti-Stokes Raman scattering (CPP fs CARS) were investigated. The frequency chirp in the pump and Stokes pulses was introduced by placing SF11 glass disks with thicknesses of 10 mm or 20 mm in the optical path for these beams. The magnitude of the chirp in the probe beam was much greater and was induced by placing a 30-cm rod of SF10 glass in the beam path. The temperature measurements were performed in hydrogen/air non-premixed flames stabilized on a Hencken burner at equivalence ratios of 0.3, 0.5, 0.7, and 1.0. We performed measurements with no disks in pump and Stokes beam paths, and then with disks of 10 mm and 20 mm placed in both beam paths. The spectrum of the nonresonant background four-wave mixing signal narrowed considerably with increasing pump and Stokes chirp, while the resonant CARS signal was relatively unaffected. Consequently, the interference of the nonresonant background with the resonant CARS signal in the frequency-spread dephasing region of the spectrum was minimized. The increased rate of decay of the resonant CARS signal with increasing temperature was thus readily apparent. We have started to analyze the CPP fs CARS thermometry data and initial results indicate improved accuracy and precision are obtained due to moderate chirp in the pump and Stokes laser pulses.

  11. Tunable High Harmonic Generation driven by a Visible Optical Parametric Amplifier

    Directory of Open Access Journals (Sweden)

    Keathley P.

    2013-03-01

    Full Text Available We studied high-harmonic generation (HHG in Ar, Ne and He gas jets using a broadly tunable, high-energy optical parametric amplifier (OPA in the visible wavelength range. We optimized the noncollinear OPA to deliver tunable, femtosecond pulses with 200-500 μJ energy at 1-kHz repetition rate with excellent spatiotemporal properties, suitable for HHG experiments. By tuning the central wavelength of the OPA while keeping energy, duration and beam size constant, we experimentally studied the scaling law of conversion efficiency and cut-off energy with the driver wavelength in argon and helium respectively. Our measurements show a λ−5.9±0.9 wavelength dependence of the conversion efficiency and a λ1.7±0.2 dependence of the HHG cut-off photon energy over the full visible range in agreement with previous experiments of near- and mid-IR wavelengths. By tuning the central wavelength of the driver source and changing the gas, the high order harmonic spectra in the extreme ultraviolet cover the full range of photon energy between ~25 eV and ~100 eV. Due to the high coherence intrinsic in HHG, as well as the broad and continuous tunability in the extreme UV range, a high energy, high repetition rate version of this source might be an ideal seed for free electron lasers.

  12. High energy eye-safe and mid-infrared optical parametric oscillator

    International Nuclear Information System (INIS)

    Liu, J; Liu, Q; Huang, L; Gong, M

    2010-01-01

    A high energy eye-safe and mid-infrared optical parametric oscillator (OPO) is demonstrated. The nonlinear media is a Y-cut KTA crystal with the length of 20 mm, which is pumped by a Nd:YAG laser. Both eye-safe and mid-infrared laser are output with high energy. When the pump energy is 1 J and the pulse duration is 10 ns, we get 53 mJ idler at 3.632 μm and 151 mJ signal at 1.505 μm. As we know, the idler energy is the highest at the wavelength beyond 3.5 μm and the signal energy is the highest with Y-cut KTA. The results prove that the Y-cut KTA crystal can produce the signal and idler with the energies as high as these in the paper. We have tested the temperature-tuning characters and the coefficient of the idler is 0.26 nm/°C

  13. Antiresonant ring output-coupled continuous-wave optical parametric oscillator.

    Science.gov (United States)

    Devi, Kavita; Kumar, S Chaitanya; Esteban-Martin, A; Ebrahim-Zadeh, M

    2012-08-13

    We demonstrate the successful deployment of an antiresonant ring (ARR) interferometer for the attainment of optimum output coupling in a continuous-wave (cw) optical parametric oscillator (OPO). The cw OPO, configured as a singly-resonant oscillator (SRO), is based on a 50-mm-long MgO:PPLN crystal and pumped by cw Ytterbium-fiber laser at 1064 nm, with the ARR interferometer integrated into one arm of the standing-wave cavity. By fine adjustment of the ARR transmission, a continuously variable signal output coupling from 0.8% to 7.3% has been achieved, providing optimum output coupling for signal and optimum power extraction for the idler, at different input pumping levels. The experimental results are compared with theoretical calculations for conventional output-coupled cw SRO, and the study shows that by reducing the insertion loss of the ARR elements, the performance of the ARR-coupled cw SRO can be further enhanced. We also show that the use of the ARR does not lead to any degradation in the cw SRO output beam quality. The proof-of-principle demonstration confirms the effectiveness of the technique for continuous, in situ, and fine control of output coupling in cw OPOs to achieve maximum output power at any arbitrary pumping level above threshold.

  14. Continuous-wave optical parametric oscillator pumped by a fiber laser green source at 532 nm.

    Science.gov (United States)

    Samanta, G K; Kumar, S Chaitanya; Das, Ritwick; Ebrahim-Zadeh, M

    2009-08-01

    We report a high-power, cw, singly resonant optical parametric oscillator (SRO) using a simple, compact fiber pump laser architecture in the green. The SRO, based on MgO:sPPLT, is pumped by 9.6 W of single-frequency cw radiation at 532 nm obtained by single-pass second-harmonic generation (SHG) of a 30 W Yb fiber laser, also in MgO:sPPLT. Using two identical crystals of 30 mm length for SHG and SRO, we generate cw idler powers of up to 2 W over 855-1408 nm, with a peak-to-peak power stability <11.7% over 40 min, in a TEM(00) spatial mode with M(2)<1.26. Using finite output coupling of the resonant wave, we extract 800 mW of signal power with peak-to-peak power stability <10.7% over 40 min, and a frequency stability <75 MHz over 15 min. The signal and idler output have TEM(00) beam profile with M(2)<1.52 across the tuning range.

  15. Frequency-locked, injection-seeded, pulsed narrowband optical parametric generator.

    Science.gov (United States)

    Reichardt, Thomas A; Bambha, Ray P; Kulp, Thomas J; Schmitt, Randal L

    2003-06-20

    A frequency-locked, injection-seeded, pulsed optical parametric generator (OPG) has been developed for short-range infrared differential absorption lidar (DIAL) applications. The periodically poled lithium niobate OPG is pumped by a passively Q-switched Nd:YAG microlaser and is seeded by a distributed feedback (DFB) diode laser. The OPG is designed for DIAL measurement of a narrow R-branch transition of methane at 3.2704 microm. The output of the OPG is a two-pulse sequence with a 100-micros temporal separation between the pulses, where the first pulse is absorbed by methane and the second pulse is not absorbed. The first pulse is actively locked to the methane absorption feature by use of the derivative of the transmission spectrum through a reference cell. Although the device was not optimized for output power, the 3.27-microm OPG output energies of the first and second pulses are 5.5 and 5.9 microJ, respectively, producing 21 mW when operated at 1818 Hz.

  16. Parametric study of dielectric loaded surface plasmon polariton add-drop filters for hybrid silicon/plasmonic optical circuitry

    Science.gov (United States)

    Dereux, A.; Hassan, K.; Weeber, J.-C.; Djellali, N.; Bozhevolnyi, S. I.; Tsilipakos, O.; Pitilakis, A.; Kriezis, E.; Papaioannou, S.; Vyrsokinos, K.; Pleros, N.; Tekin, T.; Baus, M.; Kalavrouziotis, D.; Giannoulis, G.; Avramopoulos, H.

    2011-01-01

    Surface plasmons polaritons are electromagnetic waves propagating along the surface of a conductor. Surface plasmons photonics is a promising candidate to satisfy the constraints of miniaturization of optical interconnects. This contribution reviews an experimental parametric study of dielectric loaded surface plasmon waveguides ring resonators and add-drop filters within the perspective of the recently suggested hybrid technology merging plasmonic and silicon photonics on a single board (European FP7 project PLATON "Merging Plasmonic and Silicon Photonics Technology towards Tb/s routing in optical interconnects"). Conclusions relevant for dielectric loaded surface plasmon switches to be integrated in silicon photonic circuitry will be drawn. They rely on the opportunity offered by plasmonic circuitry to carry optical signals and electric currents through the same thin metal circuitry. The heating of the dielectric loading by the electric current enables to design low foot-print thermo-optical switches driving the optical signal flow.

  17. Amplification of DWDM channels at 1.28 Tb/s in a bidirectional fiber optical parametric amplifier.

    Science.gov (United States)

    Lei, Gordon K P; Marhic, Michel E

    2014-04-07

    We experimentally demonstrate amplification of 1.28 Tb/s DWDM channels using a bidirectional fiber optical parametric amplifier. The amplifier can provide more than 13 dB on-off gain on all 32 DWDM channels. Error-free operation has been achieved for all data streams, with an average power penalty of 2.5 dB compared with conventional unidirectional configuration.

  18. A 22-watt mid-infrared optical parametric oscillator with V-shaped 3-mirror ring resonator.

    Science.gov (United States)

    Lippert, Espen; Fonnum, Helge; Arisholm, Gunnar; Stenersen, Knut

    2010-12-06

    We report on a ZnGeP(2)-based optical parametric oscillator (OPO) with 22 W of output power in the 3-5 µm range and a beam quality factor M(2) ≈1.4. The OPO uses a novel V-shaped 3-mirror ring resonator that allows two passes of the beams through the same nonlinear crystal. The pump is a 39 W hybrid Tm:fiber laser/Ho:YAG laser.

  19. All optical wavelength conversion and parametric amplification in Ti:PPLN channel waveguides for telecommunication applications

    Energy Technology Data Exchange (ETDEWEB)

    Nouroozi, Rahman

    2010-10-19

    Efficient ultra-fast integrated all-optical wavelength converters and parametric amplifiers transparent to the polarization, phase, and modulation-level and -format are investigated. The devices take advantage of the optical nonlinearity of Ti:PPLN waveguides exploiting difference frequency generation (DFG). In a DFG, the signal ({lambda}{sub s}) is mixed with a pump ({lambda}{sub p}) to generate a wavelength shifted idler (1/{lambda}{sub i}=1/{lambda}{sub p}-1/{lambda}{sub s}). Efficient generation of the pump in Ti:PPLN channel guides is investigated using different approaches. In the waveguide resonators, first a resonance of the fundamental wave alone is considered. It is shown that the maximum power enhancement of the fundamental wave, and therefore the maximum second-harmonic generation (SHG) efficiency, can be achieved with low loss matched resonators. By this way, SHG efficiency of {proportional_to}10300%/W (10.3 %/mW) has been achieved in a 65 mm long waveguide resonator. Its operation for cSHG/DFG requires narrowband reflector for fundamental wave only. Thus, the SH (pump) wave resonator is investigated. The SH-wave resonator enhances the intracavity SH power only. Based on this scheme, an improvement of {proportional_to}10 dB for cSHG/DFG based wavelength conversion efficiency has been achieved with 50 mW of coupled fundamental power in a 30 mm long Ti:PPLN. However, operation was limited to relatively small fundamental power levels (<50 mW) due to the onset of photorefractive instabilities destroying the cavity stabilization. The cSHG/DFG efficiency can be considerably improved by using a double-pass configuration in which all the interacting waves were reflected by a broadband dielectric mirror deposited on the one endface of the waveguide. Three different approaches are investigated and up to 9 dB improvement of the wavelength conversion efficiency in comparison with the single-pass configuration is achieved. Polarization-insensitive wavelength

  20. 730-nm optical parametric conversion from near- to short-wave infrared band

    DEFF Research Database (Denmark)

    Boggio, J.M.C.; Windmiller, J.R.; Knutzen, M.

    2008-01-01

    A record 730 nm parametric conversion in silica fiber from the near-infrared to the short-wave infrared band is reported and analyzed. A parametric gain in excess of 30 dB was measured for a signal at 1300 nm (with corresponding idler at 2030 nm). This conversion was performed in a travelling sin...... single-pass one-pump parametric architecture and high efficiency is achieved by a combination of high peak power and a nonlinear fiber with a reduced fourth-order dispersion coefficient.......A record 730 nm parametric conversion in silica fiber from the near-infrared to the short-wave infrared band is reported and analyzed. A parametric gain in excess of 30 dB was measured for a signal at 1300 nm (with corresponding idler at 2030 nm). This conversion was performed in a travelling...

  1. An optimized device for UF6 laser isotopic photochemistry using an optical parametric oscillator and a down converter

    International Nuclear Information System (INIS)

    Kupecek, P.; Weulersse, J.M.; Isnard, P.; Alexandre, M.; Clerc, M.

    1983-01-01

    We developped a tunable coherent source near 16 μm for selective photochemistry studies on UF 6 . The device uses a YAG:Nd 3+ pumped lithium niobate optical parametric oscillator coupled with a cadmium selenide frequency down converter. The components and physical parameters have been optimized leading to an overall optical conversion efficiency of about 6.10 -3 , that is a quantum yield of 0.1. The main characteristics such as beam quality and spectral width have been measured, the last one beeing 60 mK at 16 μm, for 1.5mJ pulses [fr

  2. Next generation Chirped Pulse Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Nees, J.; Biswal, S.; Mourou, G. [Univ. Michigan, Center for Ultrafast Optical Science, Ann Arbor, MI (United States); Nishimura, Akihiko; Takuma, Hiroshi

    1998-03-01

    The limiting factors of Chirped Pulse Amplification (CPA) are discussed and experimental results of CPA in Yb:glass regenerative amplifier are given. Scaling of Yb:glass to the petawatt level is briefly discussed. (author)

  3. Trace Gas Measurements on Mars and Earth Using Optical Parametric Generation

    Science.gov (United States)

    Numata, Kenji; Haris, Riris; Li, Steve; Sun, Xiaoli; Abshire, James Brice

    2010-01-01

    Trace gases and their isotopic ratios in planetary atmospheres offer important but subtle clues as to the origins of a planet's atmosphere, hydrology, geology, and potential for biology. An orbiting laser remote sensing instrument is capable of measuring trace gases on a global scale with unprecedented accuracy, and higher spatial resolution that can be obtained by passive instruments. We have developed an active sensing instrument for the remote measurement of trace gases in planetary atmospheres (including Earth). The technique uses widely tunable, seeded optical parametric generation (OPG) to measure methane, CO2, water vapor, and other trace gases in the near and mid-infrared spectral regions. Methane is a strong greenhouse gas on Earth and it is also a potential biogenic marker on Mars and other planets. Methane in the Earth's atmosphere survives for a shorter time than CO2 but its impact on climate change can be larger than CO2. Methane levels have remained relatively constant over the last decade around 1.78 parts per million (ppm) but recent observations indicate that methane levels may be on the rise. Increasing methane concentrations may trigger a positive feedback loop and a subsequent runaway greenhouse effect, where increasing temperatures result in increasing methane levels. The NRC Decadal Survey recognized the importance of global observations of greenhouse gases and called for simultaneous CH4, CO, and CO2 measurements but also underlined the technological limitations for these observations. For Mars, methane measurements are of great interest because of its potential as a strong biogenic marker. A remote sensing instrument that can measure day and night over all seasons and latitudes can identify and localize sources of biogenic gas plumes produced by subsurface chemistry or biology, and aid in the search for extra-terrestrial life. It can identify the dynamics of methane generation over time and latitude and identify future lander mission sites

  4. Parametric Phase-sensitive and Phase-insensitive All-optical Signal Processing on Multiple Nonlinear Platforms - Invited talk

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Da Ros, Francesco; Vukovic, Dragana

    -optical signal processing. In this presentation, we will review our recent results on the demonstration of all-optical para- metric signal processing using dierent nonlinear platforms, including highly nonlinear optical bers (HNLFs), silicon nanowires, and periodically-poled lithium niobate (PPLN) waveguides......Parametric processes in materials presenting a second- or third-order nonlinearity have been widely used to demonstrate a wide range of all-optical signal processing functionalities, including amplication, wavelength conversion, regeneration, sampling, switching, modulation format conver- sion....... In particu- lar, we will show how phase-sensitive processes can be engineered to demonstrate phase-quadrature separation, which we have recently demonstrated in HNLFs [1] and PPLN waveguides [2]. Silicon nanowires are particularly attractive for signal processing thanks to their compact size, CMOS...

  5. 730-nm optical parametric conversion from near- to short-wave infrared band.

    Science.gov (United States)

    Chavez Boggio, J M; Windmiller, J R; Knutzen, M; Jiang, R; Bres, C; Alic, N; Stossel, B; Rottwitt, K; Radic, S

    2008-04-14

    A record 730 nm parametric conversion in silica fiber from the near-infrared to the short-wave infrared band is reported and analyzed. A parametric gain in excess of 30 dB was measured for a signal at 1300 nm (with corresponding idler at 2030 nm). This conversion was performed in a travelling single-pass one-pump parametric architecture and high efficiency is achieved by a combination of high peak power and a nonlinear fiber with a reduced fourth-order dispersion coefficient.

  6. Quantum and Raman Noise in a Depleted Fiber Optical Parametric Amplifier

    DEFF Research Database (Denmark)

    Friis, Søren Michael Mørk; Rottwitt, Karsten; McKinstrie, Colin J.

    2013-01-01

    The noise properties of both phase-sensitive and phase-insensitive saturated parametric amplifiers are studied using a semi-classical approach. Vacuum fluctuations as well as spontaneous Raman scattering are included in the analysis....

  7. A comparison of nonlinear media for parametric all-optical signal processing

    DEFF Research Database (Denmark)

    Martinez Diaz, Jordi; Bohigas Nadal, Jaume; Vukovic, Dragana

    2013-01-01

    We systematically compare nonlinear media for parametric signal processing by determining the minimum pump power that is required for a given conversion efficiency in a degenerate four-wave mixing process, including the effect of nonlinear loss.......We systematically compare nonlinear media for parametric signal processing by determining the minimum pump power that is required for a given conversion efficiency in a degenerate four-wave mixing process, including the effect of nonlinear loss....

  8. Dynamic range enhancement and amplitude regeneration in single pump fibre optic parametric amplifiers using DPSK modulation

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Lorenzen, Michael Rodas; Seoane, Jorge

    2008-01-01

    Input power dynamic range enhancement and amplitude regeneration of highly distorted signals are demonstrated experimentally for 40 Gbit/s RZ-DPSK in a single-pump fibre parametric amplifier with 22 dB smallsignal gain.......Input power dynamic range enhancement and amplitude regeneration of highly distorted signals are demonstrated experimentally for 40 Gbit/s RZ-DPSK in a single-pump fibre parametric amplifier with 22 dB smallsignal gain....

  9. Ultra-broadband optical parametric amplification by tailoring the group-velocity dispersion of Bragg reflection waveguides

    International Nuclear Information System (INIS)

    Das, Ritwick

    2009-01-01

    The possibility of extending the signal-acceptance bandwidth for a non-degenerate optical parametric amplification process using a non-linear Bragg reflection waveguide (BRW) is explored. The strongly dispersive features of BRWs made up of semiconductors, such as GaN/Al x Ga 1-x N, are employed to maintain the phase-matching condition over a broad range of signal wavelengths. It is found that the signal-acceptance bandwidth could extend over 20 THz in the optical communication band (∼193 THz) which could facilitate simultaneous parametric amplification and wavelength conversion across the entire S-C-L band. Moreover, this idea could also find important applications in optical communication schemes involving ultra-short pulses. The broad bandwidth is essentially a direct consequence of appropriate phase- and group-velocity dispersion compensation by the idler mode in order to preserve the phase-matching condition over a broad spectral range. Since the idea exploits the dispersive features of Bragg reflection based geometries, the scheme could be implemented to realize broadband frequency conversion in any desired spectral region within the constraints imposed by the transparency of non-linear materials and the possibility of periodic poling.

  10. Optomechanical design and construction of a vacuum-compatible optical parametric oscillator for generation of squeezed light.

    Science.gov (United States)

    Wade, A R; Mansell, G L; McRae, T G; Chua, S S Y; Yap, M J; Ward, R L; Slagmolen, B J J; Shaddock, D A; McClelland, D E

    2016-06-01

    With the recent detection of gravitational waves, non-classical light sources are likely to become an essential element of future detectors engaged in gravitational wave astronomy and cosmology. Operating a squeezed light source under high vacuum has the advantages of reducing optical losses and phase noise compared to techniques where the squeezed light is introduced from outside the vacuum. This will ultimately provide enhanced sensitivity for modern interferometric gravitational wave detectors that will soon become limited by quantum noise across much of the detection bandwidth. Here we describe the optomechanical design choices and construction techniques of a near monolithic glass optical parametric oscillator that has been operated under a vacuum of 10(-6) mbar. The optical parametric oscillator described here has been shown to produce 8.6 dB of quadrature squeezed light in the audio frequency band down to 10 Hz. This performance has been maintained for periods of around an hour and the system has been under vacuum continuously for several months without a degradation of this performance.

  11. An all-fiber continuously time-dispersion-tuned picosecond optical parametric oscillator at 1 μm region.

    Science.gov (United States)

    Zhang, Lei; Yang, Sigang; Li, Pengxiao; Wang, Xiaojian; Gou, Doudou; Chen, Wei; Luo, Wenyong; Chen, Hongwei; Chen, Minghua; Xie, Shizhong

    2013-10-21

    We report the experimental demonstration of a fully fiber-integrated picosecond optical parametric oscillator. The gain is provided by a 50-meters homemade photonic crystal fiber in the ring cavity. A time-dispersion-tuned technique is used to allow the oscillator to select the oscillating wavelength adaptively and synchronize with the pump pulse train. The output wavelength of the oscillator can be continuously tuned from 988 to 1046 nm and from 1085 to 1151 nm by adjusting the pump wavelength and the time-dispersion-tuned technique simultaneously.

  12. Pump-tunable continuous-wave singly resonant optical parametric oscillator from 2.5 to 4.4 microm.

    Science.gov (United States)

    Siltanen, Mikael; Vainio, Markku; Halonen, Lauri

    2010-06-21

    We report a continuous-wave singly resonant optical parametric oscillator pumped by a widely tunable titanium-doped sapphire ring laser. It produces up to 0.8 W of mid-infrared power. The wavelength can be tuned in a few seconds from 2.5 to 3.5 microm or from 3.4 to 4.4 microm and scanned up to 40 GHz without mode-hops by only changing the pump beam wavelength. Spectroscopic capability is demonstrated by measuring parts of the photoacoustic absorption spectrum of NH(3) near 3196 cm(-1).

  13. High-power, single-frequency, continuous-wave optical parametric oscillator employing a variable reflectivity volume Bragg grating.

    Science.gov (United States)

    Zeil, Peter; Thilmann, Nicky; Pasiskevicius, Valdas; Laurell, Fredrik

    2014-12-01

    A continuous-wave singly-resonant optical parametric oscillator (SRO) with an optimum extraction efficiency, that can be adjusted independent of the pump power, is demonstrated. The scheme employs a variable-reflectivity volume Bragg grating (VBG) as the output coupler of a ring cavity, omitting any additional intra-cavity elements. In this configuration, we obtained a 75%-efficient SRO with a combined signal (19 W @ 1.55 µm) and idler (11 W @ 3.4 µm) output power of 30 W.

  14. 650-nJ pulses from a cavity-dumped Yb:fiber-pumped ultrafast optical parametric oscillator.

    Science.gov (United States)

    Lamour, Tobias P; Reid, Derryck T

    2011-08-29

    Sub-250-fs pulses with energies of up to 650 nJ and peak powers up to 2.07 MW were generated from a cavity-dumped optical parametric oscillator, synchronously-pumped at 15.3 MHz with sub-400-fs pulses from an Yb:fiber laser. The average beam quality factor of the dumped output was M2 ~1.2 and the total relative-intensity noise was 8 mdBc, making the system a promising candidate for ultrafast laser inscription of infrared materials.

  15. Low Noise Frequency Comb Sources Based on Synchronously Pumped Doubly Resonant Optical Parametric Oscillators

    Science.gov (United States)

    Wan, Chenchen

    Optical frequency combs are coherent light sources consist of thousands of equally spaced frequency lines. Frequency combs have achieved success in applications of metrology, spectroscopy and precise pulse manipulation and control. The most common way to generate frequency combs is based on mode-locked lasers which has the output spectrum of comb structures. To generate stable frequency combs, the output from mode-locked lasers need to be phase stabilized. The whole comb lines will be stabilized if the pulse train repetition rate corresponding to comb spacing and the pulse carrier envelope offset (CEO) frequency are both stabilized. The output from a laser always has fluctuations in parameters known as noise. In laser applications, noise is an important factor to limit the performance and often need to be well controlled. For example in precision measurement such as frequency metrology and precise spectroscopy, low laser intensity and phase noise is required. In mode-locked lasers there are different types of noise like intensity noise, pulse temporal position noise also known as timing jitter, optical phase noise. In term for frequency combs, these noise dynamics is more complex and often related. Understanding the noise behavior is not only of great interest in practical applications but also help understand fundamental laser physics. In this dissertation, the noise of frequency combs and mode-locked lasers will be studied in two projects. First, the CEO frequency phase noise of a synchronously pumped doubly resonant optical parametric oscillators (OPO) will be explored. This is very important for applications of the OPO as a coherent frequency comb source. Another project will focus on the intensity noise coupling in a soliton fiber oscillator, the finding of different noise coupling in soliton pulses and the dispersive waves generated from soliton perturbation can provide very practical guidance for low noise soliton laser design. OPOs are used to generate

  16. Fiber optical parametric oscillator based on photonic crystal fiber pumped with all-normal-dispersion mode-locked Yb:fiber laser

    International Nuclear Information System (INIS)

    Gou Dou-Dou; Yang Si-Gang; Zhang Lei; Wang Xiao-Jian; Chen Hong-Wei; Chen Ming-Hua; Xie Shi-Zhong; Chen Wei; Luo Wen-Yong

    2014-01-01

    We demonstrate a cost effective, linearly tunable fiber optical parametric oscillator based on a home-made photonic crystal fiber pumped with a mode-locked ytterbium-doped fiber laser, providing linely tuning ranges from 1018 nm to 1038 nm for the idler wavelength and from 1097 nm to 1117 nm for the signal wavelength by tuning the pump wavelength and the cavity length. In order to obtain the desired fiber with a zero dispersion wavelength around 1060 nm, eight samples of photonic crystal fibers with gradually changed structural parameters are fabricated for the reason that it is difficult to accurately customize the structural dimensions during fabrication. We verify the usability of the fabricated fiber experimentally via optical parametric generation and conclude a successful procedure of design, fabirication, and verification. A seed source of home-made all-normal-dispersion mode-locked ytterbium-doped fiber laser with 38.57 ps pulsewidth around the 1064 nm wavelength is used to pump the fiber optical parametric oscillator. The wide picosecond pulse pump laser enables a larger walk-off tolerance between the pump light and the oscillating light as well as a longer photonic crystal fiber of 20 m superior to the femtosecond pulse lasers, resulting in a larger parametric amplification and a lower threshold pump power of 15.8 dBm of the fiber optical parametric oscillator. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  17. High-speed CH planar laser-induced fluorescence imaging using a multimode-pumped optical parametric oscillator.

    Science.gov (United States)

    Miller, Joseph D; Engel, Sascha R; Meyer, Terrence R; Seeger, Thomas; Leipertz, Alfred

    2011-10-01

    We report on high-speed CH planar laser-induced fluorescence (PLIF) imaging in turbulent diffusion flames using a multimode-pumped optical parametric oscillator (OPO). The OPO is pumped by the third-harmonic output of a multimode Nd:YAG cluster for direct signal excitation in the A-X (0,0) band of the CH radical. The lasing threshold, conversion efficiency, and linewidth are shown to depend on the number of pump passes in the ring cavity of the OPO. Single-shot CH PLIF images are acquired at 10 kHz with excitation energy up to 6 mJ/pulse at 431.1 nm. Signal-to-noise ratios of ~25-35 are the highest yet reported for high-speed CH PLIF. © 2011 Optical Society of America

  18. Flat and ultra-broadband two-pump fiber optical parametric amplifiers based on photonic crystal fibers

    Science.gov (United States)

    Cao, Nan; Zhu, Hongna; Li, Peipei; Taccheo, Stefano; Zhu, Yuanna; Gao, Xiaorong; Wang, Zeyong

    2018-03-01

    A two-pump fiber optical parametric amplifier (FOPA) based on the photonic crystal fiber (PCF) in the telecommunication region is investigated numerically. The fiber loss and pump depletion are considered. The influences of the fiber length, input signal power, input pump power, and the center pump wavelength on the gain bandwidth, flatness, and peak gain are discussed. The 6-wave model-based analysis of two-pump FOPA is also achieved and compared with that based on the 4-wave model; furthermore, the gain properties of the FOPA based on the 6-wave model are optimized and investigated. The comparison results show that the PCF-based two-pump FOPA achieves flatter and wider gain spectra with less fiber length and input pump power compared to the two-pump FOPA based on the normal highly nonlinear fiber, where the obtained results show the great potential of the FOPA for the optical communication system.

  19. Broadly tunable, beta-barium-borate-based, pulsed optical parametric oscillators and their potential applications in medicine

    Science.gov (United States)

    Sobey, Mark S.; Clark, Jim; Johnson, Bertram C.

    1995-05-01

    With the recent availability of Beta Barium Borate (BBO) crystals in useful sizes at acceptable market prices, the promise of Optical Parametric Oscillators (OPOs) becoming practical tunable systems is finally being realized. Wavelength coverage from such systems extends from 420 nm to over 2400 nm when pumped in the UV. For medical applications their usage will be limited in the near term to low repetition rates (suitable for selective absorption applications in medicine such as colored tattoo removal or treating vascular lesions. For such high energy devices peak powers necessitate the use of articulating arms for beam delivery. For high repetition rate systems, energy outputs will be in the range of 100 to 500 (mu) J at kHz frequencies (up to 1 W average power). Peak powers are low enough that fiber optic delivery is possible. These systems may find selective absorption applications in ophthalmology.

  20. Optical parametric oscillator lidar for the gas constituents sensing in the spectral range of 3-4 μm

    Science.gov (United States)

    Kharchenko, O. V.; Romanovskii, O. A.; Sadovnikov, S. A.; Yakovlev, S. V.

    2017-10-01

    The applicability of a KTA crystal-based laser system with optical parametric oscillators (OPO) generation to lidar sounding of the atmosphere in the spectral range 3-4 μm is studied in this work. A technique developed for lidar sounding of trace atmospheric gases (TAG) is based on differential absorption lidar (DIAL) method and differential optical absorption spectroscopy (DOAS). The DIAL-DOAS technique is tested to estimate its efficiency for lidar sounding of atmospheric trace gases. The numerical simulation performed shows that a KTA-based OPO laser is a promising source of radiation for remote DIAL-DOAS sounding of the TAGs under study along surface tropospheric paths. A possibility of using Ophir PE25-C and PE10-C piezoelectric sensors for the DIAL gas analysis of the atmosphere is shown. Echoes of the broadband lidar in the above ranges are experimentally detected.

  1. Performance Analysis of a Hybrid Raman Optical Parametric Amplifier in the O- and E-Bands for CWDM PONs

    Directory of Open Access Journals (Sweden)

    Sasanthi Peiris

    2014-12-01

    Full Text Available We describe a hybrid Raman-optical parametric amplifier (HROPA operating at the O- and E-bands and designed for coarse wavelength division multiplexed (CWDM passive optical networks (PONs. We present the mathematical model and simulation results for the optimization of this HROPA design. Our analysis shows that separating the two amplification processes allows for optimization of each one separately, e.g., proper selection of pump optical powers and wavelengths to achieve maximum gain bandwidth and low gain ripple. Furthermore, we show that the proper design of optical filters incorporated in the HROPA architecture can suppress idlers generated during the OPA process, as well as other crosstalk that leaks through the passive optical components. The design approach enables error free performance for all nine wavelengths within the low half of the CWDM band, assigned to upstream traffic in a CWDM PON architecture, for all possible transmitter wavelength misalignments (±6 nm from the center wavelength of the channel band. We show that the HROPA can achieve error-free performance with a 170-nm gain bandwidth (e.g., 1264 nm–1436 nm, a gain of >20 dB and a gain ripple of <4 dB.

  2. Characteristics of infrared pulses generated by optical parametric oscillator from LiNbO sub 3 crystal

    CERN Document Server

    Park, S Y; Kim, D S; Rhee, B K; Park, S H

    2000-01-01

    The optical parametric oscillation (OPO) characteristics of LiNbO sub 3 , which is normally pumped by using the 1.064-mu m laser output from a nanosecond Nd:YAG laser, were investigated. A 5-cm-long LiNbO sub 3 crystal was cut at theta=47 .deg. , and the OPO cavity was formed by using two plain mirrors. The output coupler reflectivity in the 1.40 - 1.60 mu m range was 80.0%, and the back mirror had a reflectivity of 99.5% in the 1.45 - 1.55 mu m range. At a cavity length of 7 cm and a pump pulse energy of 156 mJ (1.7 times above threshold), the optical parametric oscillator generated nanosecond pulses (signal 1.6 mu m and idler 3.18 mu m) up to 16mJ. The change in the output energy was studied as the cavity length was varied from 7 cm to 16 cm at a fixed pump pulse energy of 145 mJ. We also measured the OPO output energy as a function of the reflectivity of the output coupler.

  3. Intracavity KTP optical parametric oscillator driven by a KLM Nd:GGG laser with a single AO modulator

    Science.gov (United States)

    Chu, Hongwei; Zhao, Shengzhi; Yang, Kejian; Zhao, Jia; Li, Yufei; Li, Tao; Li, Guiqiu; Li, Dechun; Qiao, Wenchao

    2015-05-01

    An intracavity KTiOPO4 (KTP) optical parametric oscillator (OPO) pumped by a Kerr lens mode-locking (KLM) Nd:GGG laser near 1062 nm with a single AO modulator was realized for the first time. The mode-locking pulses of the signal wave were obtained with a short duration of subnanosecond and a repetition rate of several kilohertz (kHz). Under a diode pump power of 8.25 W, a maximum output power of 104 mW at signal wavelength near 1569 nm was obtained at a repetition rate of 2 kHz. The highest pulse energy and peak power were estimated to be 80 μJ and 102 kW at a repetition rate of 1 kHz, respectively. The shortest pulse duration was measured to be 749 ps. By considering the Gaussian spatial distribution of the photon density and the Kerr-lens effect in the gain medium, a set of the coupled rate equations for QML intracavity optical parametric oscillator are given and the numerical simulations are basically fitted with the experimental results.

  4. Compact, single-frequency, doubly resonant optical parametric oscillator pumped in an achromatic phase-adapted double-pass geometry.

    Science.gov (United States)

    Hardy, B; Berrou, A; Guilbaud, S; Raybaut, M; Godard, A; Lefebvre, M

    2011-03-01

    We report on a nested-cavity, doubly resonant optical parametric oscillator (NesCOPO) architecture for widely tunable, mid-IR, single-frequency generation. By use of an achromatic phase-adapted double-pass pumping scheme, this new, low-threshold, semimonolithic architecture only requires two free-standing cavity mirrors and a nonlinear crystal with a mirror coating deposited on its input facet while the other facet is antireflection coated. It is thus as simple and compact as any basic linear optical parametric oscillator cavity, is easily tunable, and displays low sensitivity to mechanical vibrations. Using a high-repetition-rate (4.8 kHz) microlaser as the pump source of the NesCOPO, we demonstrate a compact source that provides pulsed, stable single-frequency output over a wide spectral range (3.8-4.3 μm) with a high peak power (up to 50 W), which are properties well suited for practical gas sensing applications.

  5. Chirped fiber Bragg grating detonation velocity sensing.

    Science.gov (United States)

    Rodriguez, G; Sandberg, R L; McCulloch, Q; Jackson, S I; Vincent, S W; Udd, E

    2013-01-01

    An all optical-fiber-based approach to measuring high explosive detonation front position and velocity is described. By measuring total light return using an incoherent light source reflected from a linearly chirped fiber Bragg grating sensor in contact with the explosive, dynamic mapping of the detonation front position and velocity versus time is obtained. We demonstrate two calibration procedures and provide several examples of detonation front measurements: PBX 9502 cylindrical rate stick, radial detonation front in PBX 9501, and PBX 9501 detonation along curved meridian line. In the cylindrical rate stick measurement, excellent agreement with complementary diagnostics (electrical pins and streak camera imaging) is achieved, demonstrating accuracy in the detonation front velocity to below the 0.3% level when compared to the results from the pin data. Finally, an estimate on the linear spatial and temporal resolution of the system shows that sub-mm and sub-μs levels are attainable with proper consideration of the recording speed, detection sensitivity, spectrum, and chirp properties of the grating.

  6. Peculiarities of laser phase behavior associated with the accelerated electron in a chirped laser pulse

    International Nuclear Information System (INIS)

    Song, Q.; Wu, X. Y.; Wang, J. X.; Kawata, S.; Wang, P. X.

    2014-01-01

    In this paper, we qualitatively analyzed peculiarities of laser phase behavior associated with the accelerated electron in a chirped laser pulse. We unveiled the relationship between the changes in the orientation of the electron trajectory and the cusps in magnitude of the phase velocity of the optical field along the electron trajectory in a chirped laser pulse. We also explained how the chirp effect induced the singular point of the phase velocity. Finally, we discussed the phase velocity and phase witnessed by the electron in the particle's moving instantaneous frame

  7. Optical Parametric Amplification Techniques for the Generation of High-Energy Few-Optical-Cycles IR Pulses for Strong Field Applications

    Directory of Open Access Journals (Sweden)

    Anna G. Ciriolo

    2017-03-01

    Full Text Available Over the last few decades, the investigation of ultrafast phenomena occurring in atoms, molecules and solid-state systems under a strong-field regime of light-matter interaction has attracted great attention. The increasing request for a suitable optical technology is significantly boosting the development of powerful ultrafast laser sources. In this framework, Optical Parametric Amplification (OPA is currently becoming a leading solution for applications in high-power ultra-broadband light burst generation. The main advantage provided by the OPA scheme consists of the possibility of exploring spectral ranges that are inaccessible by other laser technologies, as the InfraRed (IR window. In this paper, we will give an overview on recent progress in the development of high-power few-optical-cycle parametric amplifiers in the near-IR and in the mid-IR spectral domain. In particular, the design of the most advanced OPA implementations is provided, containing a discussion on the key technical aspects. In addition, a review on their application to the study of strong-field ultrafast physical processes is reported.

  8. Parametric study of optical forces acting upon nanoparticles in a single, or a standing, evanescent wave

    Czech Academy of Sciences Publication Activity Database

    Šiler, Martin; Zemánek, Pavel

    2011-01-01

    Roč. 13, č. 4 (2011), 044016:1-9 ISSN 2040-8978 R&D Projects: GA MŠk(CZ) LC06007; GA MŠk OC08034; GA MŠk ED0017/01/01 Institutional research plan: CEZ:AV0Z20650511 Keywords : optical tweezers * optical lattice * optical force * evanescent wave Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.573, year: 2011

  9. Quantitative evaluation of standard deviations of group velocity dispersion in optical fibre using parametric amplification

    DEFF Research Database (Denmark)

    Rishøj, Lars Søgaard; Svane, Ask Sebastian; Lund-Hansen, Toke

    2014-01-01

    A numerical model for parametric amplifiers, which include stochastic variations of the group velocity dispersion (GVD), is presented. The impact on the gain is investigated, both with respect to the magnitude of the variations and by the effect caused by changing the wavelength of the pump. It i....... It is demonstrated that the described model is able to predict the experimental results and thereby provide a quantitative evaluation of the standard deviation of the GVD. For the investigated fibre, a standard deviation of 0.01 ps/(nm km) was found....

  10. Simultaneous measurement of patterns in the signal and idler near and far fields from a confocal optical parametrical oscillator with applications in quantum optics

    DEFF Research Database (Denmark)

    Lassen, Mikael Østergaard; Tidemand-Lichtenberg, Peter; Buchhave, Preben

    2005-01-01

    We present the results of an experimental investigation of multimode intensity patterns from an optical parametric oscillator operating above threshold and show that it oscillates in 10-15 transverse modes strongly coupled through the nonlinear crystal, which makes this setup useful for future in...... also show that the oscillator can be stabilized by optical feedback, indicating a possible route for controlling the generated intensity patterns....... investigation of quantum correlations in the transverse plane. We describe the experimental setup for simultaneous measurements of signal and idler near- and far-field patterns and analyze the effects of various experimental complications such as walk-off and thermal index changes on the generated patterns. We...

  11. A novel method for length of chirped fiber Bragg grating sensor

    Science.gov (United States)

    Li, Zhenwei; Wei, Peng; Liu, Taolin

    2018-03-01

    Length of chirped fiber Bragg grating sensor is very important for detonation velocity. Different from other ways, we proposed a novel method based on the optical frequency domain reflection theory to measure the length of chirped fiber grating sensor in non-contact condition. This method adopts a tunable laser source to provide wavelength scanning laser, which covers the Full Width at Half Maximum of spectrum of the chirped fiber Bragg grating sensor. A Michelson interferometer is used to produce optical interference signal. Finally, the grating's length is attainable by distance domain signal. In theory, length resolution of chirped fiber Bragg grating sensor could be 0.02 mm. We perform a series of length measurement experiments for chirped fiber grating sensor, including comparison experiments with hot-tip method. And the experiment results show that the novel method could accurately measure the length of chirped fiber Bragg grating sensors, and the length differences between the optical frequency domain reflection method and the hot-tip probe method are very small.

  12. Hyper dispersion pulse compressor for chirped pulse amplification systems

    Science.gov (United States)

    Barty, Christopher P. J.

    2011-11-29

    A grating pulse compressor configuration is introduced for increasing the optical dispersion for a given footprint and to make practical the application for chirped pulse amplification (CPA) to quasi-narrow bandwidth materials, such as Nd:YAG. The grating configurations often use cascaded pairs of gratings to increase angular dispersion an order of magnitude or more. Increased angular dispersion allows for decreased grating separation and a smaller compressor footprint.

  13. First observation of E{sub 2} coherent phonon modes in CdS using a noncollinear optical parametric amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Daisuke; Kunugita, Hideyuki; Ema, Kazuhiro, E-mail: daisuk-s@sophia.ac.j [Department of Engineering and Applied Sciences, Sophia University, 7-1, Kioi-cho, Chiyoda-ku, Tokyo, 102-8554 (Japan)

    2009-11-15

    We report the first observation of E{sub 2} coherent phonon modes in CdS using a noncollinear optical parametric amplifier. We studied the intensity, temperature and excitation energy dependences of the high- and low-frequency E{sub 2} modes. We obtain that generation mechanism under non- and near resonant regions is impulsive stimulated Raman scattering (ISRS) and E{sub 2} modes are barely affected by Froehlich interaction. As temperature increases, E{sub 2} modes are affected by anharmonic effect. The observed phonon lifetime of the low- and high-E{sub 2} modes in CdS is 243 {+-} 37 and 11.4 {+-} 0.4 ps, respectively, at 83 K. From fitting, we can estimate the lifetime of the high-E{sub 2} mode at the low-temperature limit to be 49.3 ps.

  14. First observation of E2 coherent phonon modes in CdS using a noncollinear optical parametric amplifier

    Science.gov (United States)

    Suzuki, Daisuke; Kunugita, Hideyuki; Ema, Kazuhiro

    2009-11-01

    We report the first observation of E2 coherent phonon modes in CdS using a noncollinear optical parametric amplifier. We studied the intensity, temperature and excitation energy dependences of the high- and low-frequency E2 modes. We obtain that generation mechanism under non- and near resonant regions is impulsive stimulated Raman scattering (ISRS) and E2 modes are barely affected by Fröhlich interaction. As temperature increases, E2 modes are affected by anharmonic effect. The observed phonon lifetime of the low- and high-E2 modes in CdS is 243 ± 37 and 11.4 ± 0.4 ps, respectively, at 83 K. From fitting, we can estimate the lifetime of the high-E2 mode at the low-temperature limit to be 49.3 ps.

  15. Broadband and tunable optical parametric generator for remote detection of gas molecules in the short and mid-infrared.

    Science.gov (United States)

    Lambert-Girard, Simon; Allard, Martin; Piché, Michel; Babin, François

    2015-04-01

    The development of a novel broadband and tunable optical parametric generator (OPG) is presented. The OPG properties are studied numerically and experimentally in order to optimize the generator's use in a broadband spectroscopic LIDAR operating in the short and mid-infrared. This paper discusses trade-offs to be made on the properties of the pump, crystal, and seeding signal in order to optimize the pulse spectral density and divergence while enabling energy scaling. A seed with a large spectral bandwidth is shown to enhance the pulse-to-pulse stability and optimize the pulse spectral density. A numerical model shows excellent agreement with output power measurements; the model predicts that a pump having a large number of longitudinal modes improves conversion efficiency and pulse stability.

  16. Investigation on the quantum-to-classical transition by optical parametric amplification: Generation and detection of multiphoton quantum superposition

    Science.gov (United States)

    De Martini, Francesco; Sciarrino, Fabio

    2015-02-01

    We review an extended research carried out on the theoretical and experimental realization of a macroscopic quantum superposition (MQS) made up with photons. The described scheme is based on a nonlinear process, the quantum injected optical parametric amplification, that transforms the quantum coherence of a single particle state, i.e. a Micro-qubit, into a Macro-qubit, consisting in a large number M of photons in quantum superposition. Since the adopted scheme was found resilient to decoherence, the MQS demonstration was carried out experimentally at room temperature with M ≥104. This result elicited an extended study on quantum cloning, quantum amplification and quantum decoherence. The MQS interference patterns for large M were revealed in the experiment and the bipartite Micro-Macro entanglement was also demonstrated for a limited number of generated particles. At last, the perspectives opened by this new method are considered in the view of further studies on quantum foundations and quantum measurement.

  17. Two-crystal mid-infrared optical parametric oscillator for absorption and dispersion dual-comb spectroscopy.

    Science.gov (United States)

    Jin, Yuwei; Cristescu, Simona M; Harren, Frans J M; Mandon, Julien

    2014-06-01

    We present a femtosecond optical parametric oscillator (OPO) containing two magnesium-doped periodically poled lithium niobate crystals in a singly resonant ring cavity, pumped by two mode-locked Yb-fiber lasers. As such, the OPO generates two idler combs (up to 220 mW), covering a wavelength range from 2.7 to 4.2 μm, from which a mid-infrared dual-comb Fourier transform spectrometer is constructed. By detecting the heterodyning signal between the two idler beams a full broadband spectrum of a molecular gas can be observed over 250  cm(-1) within 70 μs with a spectral resolution of 15 GHz. The absorption and dispersion spectra of acetylene and methane have been measured around 3000  cm(-1), indicating that this OPO represents an ideal broadband mid-infrared source for fast chemical sensing.

  18. Third-order spontaneous parametric down-conversion in thin optical fibers as a photon-triplet source

    Energy Technology Data Exchange (ETDEWEB)

    Corona, Maria [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, apdo. postal 70-543, DF 04510 Mexico City (Mexico); Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Apartado Postal 2732, BC 22860 Ensenada (Mexico); Garay-Palmett, Karina; U' Ren, Alfred B. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, apdo. postal 70-543, DF 04510 Mexico City (Mexico)

    2011-09-15

    We study the third-order spontaneous parametric down-conversion (TOSPDC) process, as a means to generate entangled photon triplets. Specifically, we consider thin optical fibers as the nonlinear medium to be used as the basis for TOSPDC in configurations where phase matching is attained through the use of more than one fiber transverse modes. Our analysis in this paper, which follows from our earlier paper [Opt. Lett. 36, 190-192 (2011)], aims to supply experimentalists with the details required in order to design a TOSPDC photon-triplet source. Specifically, our analysis focuses on the photon triplet state, on the rate of emission, and on the TOSPDC phase-matching characteristics for the cases of frequency-degenerate and frequency nondegenerate TOSPDC.

  19. Off-axis quartz-enhanced photoacoustic spectroscopy using a pulsed nanosecond mid-infrared optical parametric oscillator.

    Science.gov (United States)

    Lassen, Mikael; Lamard, Laurent; Feng, Yuyang; Peremans, Andre; Petersen, Jan C

    2016-09-01

    A trace-gas sensor, based on quartz-enhanced photoacoustic spectroscopy (QEPAS), consisting of two acoustically coupled micro-resonators (mR) with an off-axis 20 kHz quartz tuning fork (QTF) is demonstrated. The complete acoustically coupled mR system is optimized based on finite-element simulations and is experimentally verified. The QEPAS sensor is pumped resonantly by a nanosecond pulsed single-mode mid-infrared optical parametric oscillator. The sensor is used for spectroscopic measurements on methane in the 3.1-3.5 μm wavelength region with a resolution bandwidth of 1  cm-1 and a detection limit of 0.8 ppm. An Allan deviation analysis shows that the detection limit at the optimum integration time for the QEPAS sensor is 32 ppbv at 190 s, and that the background noise is due solely to the thermal noise of the QTF.

  20. Third-order spontaneous parametric down-conversion in thin optical fibers as a photon-triplet source

    International Nuclear Information System (INIS)

    Corona, Maria; Garay-Palmett, Karina; U'Ren, Alfred B.

    2011-01-01

    We study the third-order spontaneous parametric down-conversion (TOSPDC) process, as a means to generate entangled photon triplets. Specifically, we consider thin optical fibers as the nonlinear medium to be used as the basis for TOSPDC in configurations where phase matching is attained through the use of more than one fiber transverse modes. Our analysis in this paper, which follows from our earlier paper [Opt. Lett. 36, 190-192 (2011)], aims to supply experimentalists with the details required in order to design a TOSPDC photon-triplet source. Specifically, our analysis focuses on the photon triplet state, on the rate of emission, and on the TOSPDC phase-matching characteristics for the cases of frequency-degenerate and frequency nondegenerate TOSPDC.

  1. Parametric generation and characterization of femtosecond mid-infrared pulses in ZnGeP2.

    Science.gov (United States)

    Wandel, Scott; Lin, Ming-Wei; Yin, Yanchun; Xu, Guibao; Jovanovic, Igor

    2016-03-07

    Ultrafast mid-infrared (IR) coherent radiation plays an important role in strong-field physics, wherein the use of longer wavelengths has reduced the optical intensities needed to drive light-matter interactions by orders of magnitude in comparison to near-IR radiation. Optimizing parametric interactions for generation and characterization of mid-IR pulses is an enabling step for those applications. We report on the production of >50 µJ femtosecond pulses centered at 5 µm in a two-stage optical parametric amplifier (OPA) based on ZnGeP 2 , a high-performance optical material in this spectral region. The OPA is pumped by an ultrafast 2-µm source. Amplified pulses have been characterized by parametric upconversion, enabling the use of standard silicon detectors. A numerical model of the system has been developed and tested to control dispersion, group-velocity mismatch, and off-axis parametric fluorescence. The source architecture is suitable for production of mJ-level mid-IR ultrafast pulses without the use of chirped-pulse amplification, where convenient pumping could be realized directly by mid-IR laser sources based on materials such as Cr:ZnSe or Cr:ZnS.

  2. Light radiation pressure upon a wrinkled membrane – parametrization of an optically orthotropic model

    Science.gov (United States)

    Nerovny, N. A.; Zimin, V. N.

    2018-04-01

    In this paper, the problem of representing the light pressure force upon the surface of a thin wrinkled film is discussed. The common source of wrinkles is the shear deformation of the membrane sample. The optical model of such a membrane is assumed to be optically orthotropic and an analytic equation for infinitesimal light pressure force is written. A linear regression model in the case of wrinkle geometry, where a surface element can have different optical parameters, is constructed and the Bayesian approach is used to calculate the parameters of this model.

  3. Fully programmable spectrum sliced chirped microwave photonic filter.

    Science.gov (United States)

    Leitner, Peter; Yi, Xiaoke; Li, Liwei; Huang, Thomas X H

    2015-02-23

    A novel chirped microwave photonic filter (MPF) capable of achieving a large radio frequency (RF) group delay slope and a single passband response free from high frequency fading is presented. The design is based upon a Fourier domain optical processor (FD-OP) and a single sideband modulator. The FD-OP is utilized to generate both constant time delay to tune the filter and first order dispersion to induce the RF chirp, enabling full software control of the MPF without the need for manual adjustment. An optimized optical parameter region based on a large optical bandwidth >750 GHz and low slicing dispersion passband noise. Experimental results confirm that the structure simultaneously achieves a large in-band RF chirp of -4.2 ns/GHz, centre frequency invariant tuning and independent reconfiguration of the RF amplitude and phase response. Finally, a stochastic study of the device passband noise performance under tuning and reconfiguration is presented, indicating a low passband noise <-120 dB/Hz.

  4. Optical parametric generation by a simultaneously Q-switched mode-locked single-oscillator thulium-doped fiber laser in orientation-patterned gallium arsenide.

    Science.gov (United States)

    Donelan, Brenda; Kneis, Christian; Scurria, Giuseppe; Cadier, Benoît; Robin, Thierry; Lallier, Eric; Grisard, Arnaud; Gérard, Bruno; Eichhorn, Marc; Kieleck, Christelle

    2016-11-01

    Optical parametric generation is demonstrated in orientation-patterned gallium arsenide, pumped by a novel single-oscillator simultaneously Q-switched and mode-locked thulium-doped fiber laser, downconverting the pump radiation into the mid-infrared wavelength regime. The maximum output energy reached is greater than 2.0 μJ per pump pulse.

  5. Experimental investigation of saturation effect on pump-to-signal intensity modulation transfer in single-pump phase-insensitive fiber optic parametric amplifiers

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Lali-Dastjerdi, Zohreh; Lund-Hansen, Toke

    2013-01-01

    We present an experimental characterization of how signal gain saturation affects the transfer of intensity modulation from the pump to the signal in single-pump, phase-insensitive fiber optic parametric amplifiers (FOPAs). In this work, we demonstrate experimentally for the first time, to our...

  6. Chirped fields for Rb+Cs photoassociation

    Science.gov (United States)

    Homer, A.; Roberts, G.

    2008-11-01

    This paper presents model numerical simulations of photoassociation and ionization of cold Rb+Cs atoms steered by broadband optical pulses operating within the weak-field limit over a picosecond time scale. The primary focus of the work is on generation of RbCs molecules in bound levels of the (1)0+ (XΣ+1) electronic ground state through a sequence of pump-dump transitions between (1)0+ and (4)0+ states driven by a field centered at 811nm with different phase modulations. It is found that chirped fields generate substantially bound oscillator levels of the XΣ+1 state by avoiding promotion of amplitude to vibrational levels in the upper state whose Franck-Condon factors for stimulated emission to levels in the XΣ+1 state are detrimentally low, but which otherwise come into play when the driving field is transform limited. Optimal generation of molecules in the electronic ground state irrespective of vibrational level selectivity is calculated to occur when the temporal phase of the driving field is modulated by the classical energy difference for promotion of (4)0+←(1)0+ photon absorption. Conversely, generation of deeply bound vibrational eigenlevels of the XΣ+1 state is optimally promoted by a field whose temporal phase enhances (4)0+→(1)0+ stimulated emission. Driving fields phase modulated by the classical difference potential or linearly down-chirped enhance molecule formation vis-à-vis the thermal collision; fields whose temporal phase is modulated according to the shape of the (1)0+ potential energy curve or which are linearly up-chirped suppress molecule formation relative to the thermal probability, but generate deeply bound XΣ+1 vibrational levels. Application of a bichromatic field comprising temporally overlapped components centered 811 and 622nm also improves the probability of generating deeply bound vibrational levels, but at the expense of increased ionization. Model calculations of transition probabilities between neutral and ionic states

  7. Low-Threshold Optical Parametric Oscillations in a Whispering Gallery Mode Resonator

    DEFF Research Database (Denmark)

    Fürst, J. U.; Strekalov, D. V.; Elser, D.

    2010-01-01

    In whispering gallery mode (WGM) resonator light is guided by continuous total internal reflection along a curved surface. Fabricating such resonators from an optically nonlinear material one takes advantage of their exceptionally high quality factors and small mode volumes to achieve extremely...

  8. Amplitude regeneration of RZ-DPSK signals in single-pump fiber-optic parametric amplifiers

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Lorenzen, Michael Rodas; Seoane, Jorge

    2009-01-01

    to demonstrate amplitude regeneration of a distorted RZ-DPSK signal in a gain-saturated FOPA. An optical signal-to-noise ratio penalty of 3.5 dB after amplitude distortion is shown to be reduced to 0.2 dB after the FOPA, thus clearly demonstrating the regenerative nature of saturated FOPAs for RZ-DPSK modulation....

  9. 20 dB net-gain polarization-insensitive fiber optical parametric amplifier with >2 THz bandwidth.

    Science.gov (United States)

    Stephens, M F C; Gordienko, V; Doran, N J

    2017-05-01

    A black-box polarization insensitive fiber optical parametric amplifier (PI-FOPA) is characterized for the first time using a commercial 127 Gb/s polarization-division multiplexed PDM-QPSK transponder within a multiplex of twenty-two equivalent DWDM signals across a 2.3 THz bandwidth portion of the C-band. The PI-FOPA employs a recently demonstrated diversity loop arrangement comprising two lengths of highly nonlinear fiber (HNLF) with the parametric pump being removed after the first HNLF in both directions about the loop. This arrangement is named the Half-Pass Loop FOPA or HPL-FOPA. In total, a record equivalent 2.3 Tb/s of data is amplified within the HPL-FOPA for three different pump power regimes producing net-gains of 10 dB, 15 dB and 20 dB (averaged over all signals). For the latter two regimes, the gain bandwidth is observed to extend considerably beyond the C-band, illustrating the potential for this design to amplify signals over bandwidths commensurate with the EDFA and beyond. Under the 15 dB gain condition, the average OSNR penalty to achieve 10-3 bit error rate for all twenty three signals was found to be 0.5 ± 0.3 dB. Worst case penalty was 0.8 ± 0.3 dB, verifying the use of the architecture for polarization insensitive operation. The growth of four-wave mixing signal-signal crosstalk is additionally characterized and found to be gain independent for a fixed output power per signal. A simple effective length model is developed which predicts this behavior and suggests a new configuration for significantly reduced crosstalk.

  10. Wide range operation of regenerative optical parametric wavelength converter using ASE-degraded 43-Gb/s RZ-DPSK signals.

    Science.gov (United States)

    Gao, Mingyi; Kurumida, Junya; Namiki, Shu

    2011-11-07

    For sustainable growth of the Internet, wavelength-tunable optical regeneration is the key to scaling up high energy-efficiency dynamic optical path networks while keeping the flexibility of the network. Wavelength-tunable optical parametric regenerator (T-OPR) based on the gain saturation effect of parametric amplification in a highly nonlinear fiber is promising for noise reduction in phase-shift keying signals. In this paper, we experimentally evaluated the T-OPR performance for ASE-degraded 43-Gb/s RZ-DPSK signals over a 20-nm input wavelength range between 1527 nm and 1547 nm. As a result, we achieved improved power penalty performance for the regenerated idler with a proper pump power range.

  11. Raw Knudsen Engineering 3260 CHIRP subbottom - CHIRP Subbottom Profiler data for the U.S. Atlantic margin.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Knudsen Engineering 3260 CHIRP subbottom - CHIRP Subbottom Profiler data were collected in Raw Knudsen SEG-Y Datagram format.

  12. Parametric diagram

    DEFF Research Database (Denmark)

    Hermund, Anders

    2010-01-01

    This paper will introduce the PhD research into applied 3d modeling and parametric design outlining the idea of a parametric diagram linked to philosophical and applied examples.......This paper will introduce the PhD research into applied 3d modeling and parametric design outlining the idea of a parametric diagram linked to philosophical and applied examples....

  13. Tunable chirped microwave photonic filter employing a dispersive Mach-Zehnder structure.

    Science.gov (United States)

    Xue, Xiaoxiao; Zheng, Xiaoping; Zhang, Hanyi; Zhou, Bingkun

    2011-09-01

    A Mach-Zehnder structure with modulation in one arm and dispersive time delay in the other is proposed to implement highly flexible single-bandpass chirped microwave photonic filters based on broadband optical sources. Both the amplitude response and the time delay slope can be fully reconfigured via control of the optical spectra and dispersion. The passband can also be widely tuned without changing the shape. A chirped filter with a bandwidth of ∼4 GHz, a delay slope of ∼-0.6 ns/GHz, and a tunability up to 40 GHz is demonstrated experimentally.

  14. Fiber-laser-based, green-pumped, picosecond optical parametric oscillator using fan-out grating PPKTP.

    Science.gov (United States)

    Chaitanya Kumar, S; Parsa, S; Ebrahim-Zadeh, M

    2016-01-01

    We report a stable, Yb-fiber-laser-based, green-pumped, picosecond optical parametric oscillator (OPO) for the near-infrared based on periodically poled potassium titanyl phosphate (PPKTP) nonlinear crystal, using fan-out grating design and operating near room temperature. The OPO is continuously tunable across 726-955 nm in the signal and 1201-1998 nm in the idler, resulting in a total signal plus idler wavelength coverage of 1026 nm by grating tuning at a fixed temperature. The device generates up to 580 mW of average power in the signal at 765 nm and 300 mW in the idler at 1338 nm, with an overall extraction efficiency of up to 52% and a pump depletion >76%. The extracted signal at 765 nm and idler at 1746 nm exhibit excellent passive power stability better than 0.5% and 0.8% rms, respectively, over 1 h with good beam quality in TEM00 mode profile. The output signal pulses have a Gaussian temporal duration of 13.2 ps, with a FWHM spectral bandwidth of 3.4 nm at 79.5 MHz repetition rate. Power scaling limitations of the OPO due to the material properties of PPKTP are studied.

  15. Cut-off scaling of high-harmonic generation driven by a femtosecond visible optical parametric amplifier

    International Nuclear Information System (INIS)

    Cirmi, Giovanni; Lai, Chien-Jen; Granados, Eduardo; Huang, Shu-Wei; Sell, Alexander; Hong, Kyung-Han; Moses, Jeffrey; Keathley, Phillip; Kärtner, Franz X

    2012-01-01

    We studied high-harmonic generation (HHG) in Ar, Ne and He gas jets using a broadly tunable, high-energy optical parametric amplifier (OPA) in the visible wavelength range. We optimized the noncollinear OPA to deliver tunable, femtosecond pulses with 200-500 µJ energy at the 1 kHz repetition rate with excellent spatiotemporal properties, suitable for HHG experiments. By tuning the central wavelength of the OPA while keeping other parameters (energy, duration and beam size) constant, we experimentally studied the scaling law of cut-off energy with the driver wavelength in helium. Our measurements show a λ 1.7+0.2 dependence of the HHG cut-off photon energy over the full visible range in agreement with previous experiments of near- and mid-IR wavelengths. By tuning the central wavelength of the driver source, the high-order harmonic spectra in the extreme ultraviolet cover the full range of photon energy between ∼25 and ∼100 eV. Due to the high coherence intrinsic in HHG, as well as the broad and continuous tunability in the extreme UV range, a high energy, high repetition rate version of this source might be an ideal seed for free electron lasers.

  16. High-power, continuous-wave, mid-infrared optical parametric oscillator based on MgO:sPPLT.

    Science.gov (United States)

    Chaitanya Kumar, S; Ebrahim-Zadeh, M

    2011-07-01

    We report a stable, high-power, cw, mid-IR optical parametric oscillator using MgO-doped stoichiometric periodically poled LiTaO₃ (MgO:sPPLT) pumped by a Yb fiber laser at 1064 nm. The singly resonant oscillator (SRO), based on a 30 mm long crystal, is tunable over 430 nm from 3032 to 3462 nm and can generate as much as 5.5 W of mid-IR output power, with >4 W of over 60% of the tuning range and under reduced thermal effects, enabling room temperature operation. Idler power scaling measurements at ~3.3 μm are compared with an MgO-doped periodically poled LiNbO₃ cw SRO, confirming that MgO:sPPLT is an attractive material for multiwatt mid-IR generation. The idler output at 3299 nm exhibits a peak-to-peak power stability better than 12.8% over 5 h and frequency stability of ~1 GHz, while operating close to room temperature, and has a linewidth of ~0.2 nm, limited by the resolution of the wavemeter. The corresponding signal linewidth at 1570 nm is ~21 MHz.

  17. A continuous-wave optical parametric oscillator around 5-μm wavelength for high-resolution spectroscopy.

    Science.gov (United States)

    Krieg, J; Klemann, A; Gottbehüt, I; Thorwirth, S; Giesen, T F; Schlemmer, S

    2011-06-01

    We present a continuous-wave optical parametric oscillator (OPO) capable of high resolution spectroscopy at wavelengths between 4.8 μm and 5.4 μm. It is based on periodically poled lithium niobate (PPLN) and is singly resonant for the signal radiation around 1.35 μm. Because of the strong absorption of PPLN at wavelengths longer than 4.5 μm, the OPO threshold rises to the scale of several watts, while it produces idler powers of more than 1 mW and offers continuous tuning over 15 GHz. A supersonic jet spectrometer is used in combination with the OPO to perform measurements of the transient linear molecule Si(2)C(3) at 1968.2 cm(-1). Fifty rovibrational transition frequencies of the ν(3) antisymmetric stretching mode have been determined with an accuracy on the order of 10(-4) cm(-1), and molecular parameters for the ground and the v(3) = 1 state have been determined most precisely. © 2011 American Institute of Physics

  18. Ultra-high-speed pumping of an optical parametric oscillator (OPO) for high-speed laser-induced fluorescence measurements

    Science.gov (United States)

    Sjöholm, Johan; Kristensson, Elias; Richter, Mattias; Aldén, Marcus; Göritz, Guido; Knebel, Kai

    2009-02-01

    The feasibility of pumping an optical parametric oscillator (OPO) with an ultra-high repetition rate multi:YAG laser system, producing a burst of up to eight high-energy pulses, has been investigated. For this investigation an OPO with a bandwidth around 5 cm-1, together with a frequency doubling crystal, was selected. In some laser-induced fluorescence measurements the large linewidth from the OPO can be advantageous as several lines can be excited simultaneously avoiding the saturation effects of individual lines. The energy output from the OPO as a function of pulse separation was measured down to pulse separations of 400 ns and was found to be completely independent of the pulse separation. The efficiency of the OPO unit, when optimized for single-pulse operation, was measured to be around 25% for all pulses, giving over 80 mJ at 585 nm output when pumped with ~350 mJ at 355 nm. This is similar to the specified efficiency for the OPO. The system was found to give a slightly lower efficiency when double pulsing the Nd:YAG lasers. This is attributed to a somewhat elongated pulse length from the Nd:YAG lasers giving a lower pump energy density. The system was applied for measuring high-speed planar laser-induced fluorescence images of OH radicals in a Bunsen burner.

  19. Multi-channel lock-in amplifier assisted femtosecond time-resolved fluorescence non-collinear optical parametric amplification spectroscopy with efficient rejection of superfluorescence background.

    Science.gov (United States)

    Mao, Pengcheng; Wang, Zhuan; Dang, Wei; Weng, Yuxiang

    2015-12-01

    Superfluorescence appears as an intense background in femtosecond time-resolved fluorescence noncollinear optical parametric amplification spectroscopy, which severely interferes the reliable acquisition of the time-resolved fluorescence spectra especially for an optically dilute sample. Superfluorescence originates from the optical amplification of the vacuum quantum noise, which would be inevitably concomitant with the amplified fluorescence photons during the optical parametric amplification process. Here, we report the development of a femtosecond time-resolved fluorescence non-collinear optical parametric amplification spectrometer assisted with a 32-channel lock-in amplifier for efficient rejection of the superfluorescence background. With this spectrometer, the superfluorescence background signal can be significantly reduced to 1/300-1/100 when the seeding fluorescence is modulated. An integrated 32-bundle optical fiber is used as a linear array light receiver connected to 32 photodiodes in one-to-one mode, and the photodiodes are further coupled to a home-built 32-channel synchronous digital lock-in amplifier. As an implementation, time-resolved fluorescence spectra for rhodamine 6G dye in ethanol solution at an optically dilute concentration of 10(-5)M excited at 510 nm with an excitation intensity of 70 nJ/pulse have been successfully recorded, and the detection limit at a pump intensity of 60 μJ/pulse was determined as about 13 photons/pulse. Concentration dependent redshift starting at 30 ps after the excitation in time-resolved fluorescence spectra of this dye has also been observed, which can be attributed to the formation of the excimer at a higher concentration, while the blueshift in the earlier time within 10 ps is attributed to the solvation process.

  20. Chirped-pulse manipulated carrier dynamics in low-temperature molecular-beam-epitaxy grown GaAs

    International Nuclear Information System (INIS)

    Lee, Chao-Kuei; Lin, Yuan-Yao; Lin, Sung-Hui; Lin, Gong-Ru; Pan, Ci-Ling

    2014-01-01

    Chirped pulse controlled carrier dynamics in low-temperature molecular-beam-epitaxy grown GaAs are investigated by degenerate pump-probe technique. Varying the chirped condition of excited pulse from negative to positive increases the carrier relaxation time so as to modify the dispersion and reshape current pulse in time domain. The spectral dependence of carrier dynamics is analytically derived and explained by Shockley-Read Hall model. This observation enables the new feasibility of controlling carrier dynamics in ultrafast optical devices via the chirped pulse excitations

  1. Adaptive Algorithm for Chirp-Rate Estimation

    Directory of Open Access Journals (Sweden)

    Igor Djurović

    2009-01-01

    Full Text Available Chirp-rate, as a second derivative of signal phase, is an important feature of nonstationary signals in numerous applications such as radar, sonar, and communications. In this paper, an adaptive algorithm for the chirp-rate estimation is proposed. It is based on the confidence intervals rule and the cubic-phase function. The window width is adaptively selected to achieve good tradeoff between bias and variance of the chirp-rate estimate. The proposed algorithm is verified by simulations and the results show that it outperforms the standard algorithm with fixed window width.

  2. Frequency chirp of harmonic and attosecond pulses

    International Nuclear Information System (INIS)

    Varju, K.; Johansson, P; L'Huillier, A.L.; Mairesse, Y.; Salieres, P.

    2005-01-01

    Full text: We have explored in detail the first- and second-order variations of the atomic phase as a function of the laser intensity and harmonic order. This unravels the similitudes and differences existing between the chirp of individual harmonic pulses and the chirp of the attosecond pulses. We show that the two techniques XFROG and RABITT used to characterize the two chirps (respectively) converge to give the same information, namely the values of the mixed partial derivatives of the atomic phase. This underlines the common physical origin of all these phenomena and provides a unified frame for their description and understanding. Ref. 1 (author)

  3. Study and realisation of a miniature optical parametric oscillator; Etude et realisation d`un oscillateur parametrique optique miniature

    Energy Technology Data Exchange (ETDEWEB)

    Fulop, L.

    1998-10-09

    We used micro-chip lasers developed in LETI to pump a miniature Optical Parametric Oscillator (OPO). The micro-chip lasers can be fabricated at very low cost, using collective fabrication processes. The micro-chip lasers we used are Nd:YAG lasers, passively Q-switched by a Cr{sup 4+}:YAG saturable absorber. They are pumped with 1 W standard laser diodes and emit pulses which characteristics are a few {mu}J energies and several kHz repetition rates. The main problem in pumping an OPO with such a micro-chip laser is to reach its oscillation threshold. We are calculated this threshold and showed that it will be impossible to pump an extra-cavity OPO with a micro-chip laser. We first worked with an extra-cavity OPO based on the non-critical-phase-matching conversion 1.064 {mu}m{yields}1.572 {mu}m + 3.293 {mu}m in a KTP crystal, pumped with a mJ energy laser. In spite of good results (low thresholds of 200 {mu}J) and as we have calculated, it was not be possible to pump such an OPO with our micro-chip lasers (10{mu}J maximum energies). We developed an intracavity micro-chip OPO (with the OPO inside the laser cavity). In this configuration, the OPO benefits from the intracavity laser intensity to reach the oscillation threshold. The micro-chip OPO emits about 10 ns pulses at 1.572 {mu}m with a few {mu}J energy at several kHz repetition rate. To our knowledge, we realised the first micro-chip-OPO using a 1 W standard diode pumped, passively Q-switched micro-chip laser. In order to improve the performances of the intracavity micro-chip-OPO, we developed a software for numerical modelling its operation. (author) 80 refs.

  4. Chirped pulse Raman amplification in plasma

    Energy Technology Data Exchange (ETDEWEB)

    Vieux, G; Lyachev, A; Yang, X; Ersfeld, B; Farmer, J P; Brunetti, E; Issac, R C; Raj, G; Welsh, G H; Wiggins, S M; Jaroszynski, D A, E-mail: d.a.jaroszynski@strath.ac.uk [Department of Physics, Scottish Universities Physics Alliance, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2011-06-15

    Raman amplification in plasma has been proposed to be a promising method of amplifying short radiation pulses. Here, we investigate chirped pulse Raman amplification (CPRA) where the pump pulse is chirped and leads to spatiotemporal distributed gain, which exhibits superradiant scaling in the linear regime, usually associated with the nonlinear pump depletion and Compton amplification regimes. CPRA has the potential to serve as a high-efficiency high-fidelity amplifier/compressor stage.

  5. Parametric generation of energetic short mid-infrared pulses for dielectric laser acceleration

    International Nuclear Information System (INIS)

    Wandel, S; Xu, G; Yin, Y; Jovanovic, I

    2014-01-01

    Laser-driven high-gradient electron acceleration in dielectric photonic structures is an enabling technology for compact and robust sources of tunable monochromatic x-rays. Such advanced x-ray sources are sought in medical imaging, security, industrial, and scientific applications. The use of long-wavelength pulses can mitigate the problem of laser-induced breakdown in dielectric structures at high optical intensities, relax the structure fabrication requirements, and allow greater pulse energy to be injected into the structure. We report on the design and construction of a simple and robust, short-pulse parametric source operating at a center wavelength 5 μm, to be used as a pump for a dielectric photonic structure for laser-driven acceleration. The source is based on a two-stage parametric downconversion design, consisting of a β-BaB 2 O 4 -based 2.05 μm optical parametric amplifier (OPA) and a ZnGeP 2 -based 5 μm OPA. The 2.05 μm OPA is presently pumped by a standard Ti:sapphire chirped-pulse amplified laser, which will be replaced with direct laser pumping at wavelengths >2 μm in the future. The design and performance of the constructed short-pulse mid-infrared source are described. The demonstrated architecture is also of interest for use in other applications, such as high harmonic generation and attosecond pulse production. (paper)

  6. Chirped self-similar waves for quadratic-cubic nonlinear Schrödinger equation

    Science.gov (United States)

    Pal, Ritu; Loomba, Shally; Kumar, C. N.

    2017-12-01

    We have constructed analytical self-similar wave solutions for quadratic-cubic Nonlinear Schrödinger equation (QC-NLSE) by means of similarity transformation method. Then, we have investigated the role of chirping on these self-similar waves as they propagate through the tapered graded index waveguide. We have revealed that the chirping leads to interesting features and allows us to control the propagation of self-similar waves. This has been demonstrated for two cases (i) periodically distributed system and (ii) constant choice of system parameters. We expect our results to be useful in designing high performance optical devices.

  7. Ultrashort pulse chirp measurement via transverse second-harmonic generation in strontium barium niobate crystal

    International Nuclear Information System (INIS)

    Trull, J.; Wang, B.; Parra, A.; Vilaseca, R.; Cojocaru, C.; Sola, I.; Krolikowski, W.; Sheng, Y.

    2015-01-01

    Pulse compression in dispersive strontium barium niobate crystal with a random size and distribution of the anti-parallel orientated nonlinear domains is observed via transverse second harmonic generation. The dependence of the transverse width of the second harmonic trace along the propagation direction allows for the determination of the initial chirp and duration of pulses in the femtosecond regime. This technique permits a real-time analysis of the pulse evolution and facilitates fast in-situ correction of pulse chirp acquired in the propagation through an optical system

  8. High-power Femtosecond Optical Parametric Amplification at 1 kHz in BiB(3)O(6) pumped at 800 nm.

    Science.gov (United States)

    Petrov, Valentin; Noack, Frank; Tzankov, Pancho; Ghotbi, Masood; Ebrahim-Zadeh, Majid; Nikolov, Ivailo; Buchvarov, Ivan

    2007-01-22

    Substantial power scaling of a travelling-wave femtosecond optical parametric amplifier, pumped near 800 nm by a 1 kHz Ti:sapphire laser amplifier, is demonstrated using monoclinic BiB(3)O(6) in a two stage scheme with continuum seeding. Total energy output (signal plus idler) exceeding 1 mJ is achieved, corresponding to an intrinsic conversion efficiency of approximately 32% for the second stage. The tunability extends from 1.1 to 2.9 microm. The high parametric gain and broad amplification bandwidth of this crystal allowed the maintenance of the pump pulse duration, leading to pulse lengths less than 140 fs, both for the signal and idler pulses, even at such high output levels.

  9. Ultrafast laser pulse chirp effects on laser-generated nanoacoustic strains in Silicon.

    Science.gov (United States)

    Bakarezos, M; Tzianaki, E; Petrakis, S; Tsibidis, G; Loukakos, P A; Dimitriou, V; Kosmidis, C; Tatarakis, M; Papadogiannis, N A

    2018-05-01

    Nanoacoustic strains are generated in Silicon by chirped femtosecond laser pulses using thin Titanium films as transducers. We investigate the effect that the generating laser pulse chirp has on the amplitude of the induced strains, manifested as Brillouin oscillations observed in degenerate femtosecond pump-probe transient reflectivity measurements. The strain amplitude is larger when negatively chirped pulses are used, which is attributed to the more efficient conversion of laser pulse light into acoustic strain in the Titanium transducer. Our present studies clearly show that the dependence of the Brillouin amplitude and the lattice strain is a non-monotonous function of the laser chirp parameter. An optimum negative laser pulse chirp is found for which the strain amplitude is maximized. A detailed thermomechanical model satisfactorily supports the experimental findings. In such a way, it is possible to suppress or enhance the induced nanoacoustic strain amplitude, thus all-optically controlling it by at least a factor of two. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. THz field engineering in two-color femtosecond filaments using chirped and delayed laser pulses

    Science.gov (United States)

    Nguyen, A.; González de Alaiza Martínez, P.; Thiele, I.; Skupin, S.; Bergé, L.

    2018-03-01

    We numerically study the influence of chirping and delaying several ionizing two-color light pulses in order to engineer terahertz (THz) wave generation in air. By means of comprehensive 3D simulations, it is shown that two chirped pulses can increase the THz yield when they are separated by a suitable time delay for the same laser energy in focused propagation geometry. To interpret these results, the local current theory is revisited and we propose an easy, accessible all-optical criterion that predicts the laser-to-THz conversion efficiencies given any input laser spectrum. In the filamentation regime, numerical simulations display evidence that a chirped pulse is able to produce more THz radiation due to propagation effects, which maintain the two colors of the laser field more efficiently coupled over long distances. A large delay between two pulses promotes multi-peaked THz spectra as well as conversion efficiencies above 10‑4.

  11. Frequency chirped light at large detuning with an injection-locked diode laser.

    Science.gov (United States)

    Teng, K; Disla, M; Dellatto, J; Limani, A; Kaufman, B; Wright, M J

    2015-04-01

    We have developed a laser system to generate frequency-chirped light at rapid modulation speeds (∼100 MHz) with a large frequency offset. Light from an external cavity diode laser with its frequency locked to an atomic resonance is passed through a lithium niobate electro-optical phase modulator. The phase modulator is driven by a ∼6 GHz signal whose frequency is itself modulated with a RF MHz signal (<200 MHz). A second injection locked diode laser is used to filter out all of the light except the frequency-chirped ±1 order by more than 30 dB. Using this system, it is possible to generate a 1 GHz frequency chirp in 5 ns.

  12. Frequency chirped light at large detuning with an injection-locked diode laser

    Energy Technology Data Exchange (ETDEWEB)

    Teng, K.; Disla, M.; Dellatto, J.; Limani, A.; Kaufman, B.; Wright, M. J., E-mail: mwright@adelphi.edu [Physics Department, Adelphi University, 1 South Ave., Garden City, New York 11530 (United States)

    2015-04-15

    We have developed a laser system to generate frequency-chirped light at rapid modulation speeds (∼100 MHz) with a large frequency offset. Light from an external cavity diode laser with its frequency locked to an atomic resonance is passed through a lithium niobate electro-optical phase modulator. The phase modulator is driven by a ∼6 GHz signal whose frequency is itself modulated with a RF MHz signal (<200 MHz). A second injection locked diode laser is used to filter out all of the light except the frequency-chirped ±1 order by more than 30 dB. Using this system, it is possible to generate a 1 GHz frequency chirp in 5 ns.

  13. Frequency chirped light at large detuning with an injection-locked diode laser

    International Nuclear Information System (INIS)

    Teng, K.; Disla, M.; Dellatto, J.; Limani, A.; Kaufman, B.; Wright, M. J.

    2015-01-01

    We have developed a laser system to generate frequency-chirped light at rapid modulation speeds (∼100 MHz) with a large frequency offset. Light from an external cavity diode laser with its frequency locked to an atomic resonance is passed through a lithium niobate electro-optical phase modulator. The phase modulator is driven by a ∼6 GHz signal whose frequency is itself modulated with a RF MHz signal (<200 MHz). A second injection locked diode laser is used to filter out all of the light except the frequency-chirped ±1 order by more than 30 dB. Using this system, it is possible to generate a 1 GHz frequency chirp in 5 ns

  14. Interaction of free charged particles with a chirped electromagnetic pulse

    International Nuclear Information System (INIS)

    Khachatryan, A.G.; Goor, F.A. van; Boller, K.-J.

    2004-01-01

    We study the effect of chirp on electromagnetic (EM) pulse interaction with a charged particle. Both the one-dimensional (1D) and 3D cases are considered. It is found that, in contrast to the case of a nonchirped pulse, the charged particle energy can be changed after the interaction with a 1D EM chirped pulse. Different types of chirp and pulse envelopes are considered. In the case of small chirp, an analytical expression is found for arbitrary temporal profiles of the chirp and the pulse envelope. In the 3D case, the interaction with a chirped pulse results in a polarization-dependent scattering of charged particles

  15. Efficient high-energy pulse generation from a diode-side-pumped passively Q-switched Nd:YAG laser and application for optical parametric oscillator

    International Nuclear Information System (INIS)

    Huang, Y P; Huang, Y J; Cho, C Y

    2014-01-01

    We employ a convex–concave resonator to develop a high-pulse-energy diode-side-pumped passively Q-switched Nd:YAG laser with high extraction efficiency. At a diode pump energy of 227 mJ, the output laser pulse reaches 30 mJ with a pulse width of 6 ns at a repetition rate of 20 Hz. The optical-to-optical conversion efficiency is up to 13.2%. Based on the developed Nd:YAG laser oscillator, we further employ a monolithic KTP crystal to perform the optical parametric oscillator (OPO). With the 1064 nm input energy of 30 mJ, the OPO energy at 1573 nm is found to be 13.3 mJ, corresponding to an OPO conversion efficiency as high as 44.3%. (letters)

  16. Paraxial propagation of the first-order chirped Airy vortex beams in a chiral medium.

    Science.gov (United States)

    Xie, Jintao; Zhang, Jianbin; Ye, Junran; Liu, Haowei; Liang, Zhuoying; Long, Shangjie; Zhou, Kangzhu; Deng, Dongmei

    2018-03-05

    We introduce the propagation of the first-order chirped Airy vortex beams (FCAiV) in a chiral medium analytically. Results show that the FCAiV beams split into the left circularly polarized vortex (LCPV) beams and the right circularly polarized vortex (RCPV) beams, which have totally different propagation trajectories in the chiral medium. In this paper, we investigate the effects of the first-order chirped parameter β, the chiral parameter γ and the optical vortex on the propagation process of the FCAiV beams. It is shown that the propagation trajectory of the FCAiV beams declines with the chirped parameter increasing. Besides, the increase of the chiral parameter acting on the LCPV beams makes the relative position between the main lobe and the optical vortex further while the effect on the RCPV beams is the opposite. Furthermore, the relative position between the main lobe and the optical vortex contributes to the position of the intensity focusing. Meanwhile, with the chiral parameter increasing, the maximum gradient and scattering forces of the LCPV beams decrease but those of the RCPV beams will increase during the propagation. It is significant that we can control the propagation trajectory, the intensity focusing position and the radiation forces of the FCAiV beams by varying the chirped parameter and the chiral parameter.

  17. Wide-band and fast wavelength-swept optical parametric oscillator with a photonic crystal fiber based on dispersion tuning technology at 1 μm

    Science.gov (United States)

    Chen, Jin; Yang, Sigang; Guo, Qiang; Chen, Hongwei; Chen, Minghua; Xie, Shizhong

    2016-03-01

    A wavelength-swept fiber optical parametric oscillator (FOPO) based on dispersion tuning technology at wavelength around 1 μm is demonstrated. A continuous wave single-longitudinal-mode ytterbium doped fiber laser with a line-width of 0.05 nm is modulated through a LiNbO3 Mach-Zehnder modulator to be a pulsed source with variable repetition rate. The pulsed source is amplified with a two-stage ytterbium doped fiber amplifier (YDFA) to a mediate power and a high power YDFA to peak power higher than 40 W. And a homemade 50-m photonic crystal fiber (PCF) which provides the optical parametric gain is pumped by the pulsed source. The optical modulator is driven by a frequency-swept electrical clock signal with frequency ranges from 107.24 MHz to 107.31 MHz. Thus the FOPO generates a wavelength-swept light source with a range of 80 nm centered at 1065.10 nm. Through careful customizing the sweeping rate of the driving clock signal, the sweeping rate of the parametric oscillator can be up to 10 kHz, which is limited by currently used electrical sweeping source. The generated pulses train are with pulse width of about 110 ps. For the electrical scan is used instead of the traditional mechanical scanning method in conventional wavelength-swept sources, it performs better stability under prolonged operation. The wavelength-swept FOPO is potential to be applied in OCT systems for its good stability and advantaged wavelength band.

  18. Fractional-length sync-pumped degenerate optical parametric oscillator for 500-MHz 3-μm mid-infrared frequency comb generation.

    Science.gov (United States)

    Ingold, Kirk A; Marandi, Alireza; Rudy, Charles W; Vodopyanov, Konstantin L; Byer, Robert L

    2014-02-15

    We demonstrate a mid-IR frequency comb centered at 3120 nm with 650-nm (20-THz) bandwidth at a comb-teeth spacing of 500 MHz. The generated comb is based on a compact ring-type synchronously pumped optical parametric oscillator (SPOPO) operating at degeneracy and pumped by a mode-locked Er-doped 1560 nm fiber laser at a repetition rate of 100 MHz. We achieve high-repetition rate by using a fractional-length cavity with a roundtrip length of 60 cm, which is one-fifth of the length dictated by conventional synchronous pumping.

  19. Cr:ZnS laser-pumped subharmonic GaAs optical parametric oscillator with the spectrum spanning 3.6-5.6  μm.

    Science.gov (United States)

    Smolski, V O; Vasilyev, S; Schunemann, P G; Mirov, S B; Vodopyanov, K L

    2015-06-15

    Using a subharmonic optical parametric oscillator (OPO) based on orientation-patterned GaAs, we produced a broadband instantaneous output that spans 3.6-5.6 μm at 50-dB level (4.4-5.2 μm at 3 dB level), has 110 mW of average power, and is suitable for producing wideband-frequency combs in the mid-infrared. The OPO was synchronously pumped by a compact Kerr-lens mode-locked femtosecond Cr:ZnS oscillator with the central wavelength 2.38 μm and pulse repetition frequency 175 MHz.

  20. Characteristics of optical parametric oscillator synchronously pumped by Yb:KGW laser and based on periodically poled potassium titanyl phosphate crystal

    Science.gov (United States)

    Vengelis, Julius; Tumas, Adomas; Pipinytė, Ieva; Kuliešaitė, Miglė; Tamulienė, Viktorija; Jarutis, Vygandas; Grigonis, Rimantas; Sirutkaitis, Valdas

    2018-03-01

    We present experimental data and numerical simulation results obtained during investigation of synchronously pumped optical parametric oscillator (SPOPO) pumped by femtosecond Yb:KGW laser (central wavelength at 1033 nm). The nonlinear medium for parametric generation was periodically poled potassium titanyl phosphate crystal (PPKTP). Maximum parametric light conversion efficiency from pump power to signal power was more than 37.5% at λs=1530 nm wavelength, whereas the achieved signal wave continuous tuning range was from 1470 nm to 1970 nm with signal pulse durations ranging from 91 fs to roughly 280 fs. We demonstrated wavelength tuning by changing cavity length and PPKTP crystal grating period and also discussed net cavity group delay dispersion (GDD) influence on SPOPO output radiation characteristics. The achieved high pump to signal conversion efficiency and easy wavelength tuning make this device a very promising alternative to Ti:sapphire based SPOPOs as a source of continuously tunable femtosecond laser radiation in the near and mid-IR range.

  1. Effects of Temperature and Axial Strain on Four-Wave Mixing Parametric Frequencies in Microstructured Optical Fibers Pumped in the Normal Dispersion Regime

    Directory of Open Access Journals (Sweden)

    Javier Abreu-Afonso

    2014-10-01

    Full Text Available A study of the effect of temperature and axial strain on the parametric wavelengths produced by four-wave mixing in microstructured optical fibers is presented. Degenerate four-wave mixing was generated in the fibers by pumping at normal dispersion, near the zero-dispersion wavelength, causing the appearance of two widely-spaced four-wave mixing spectral bands. Temperature changes, and/or axial strain applied to the fiber, affects the dispersion characteristics of the fiber, which can result in the shift of the parametric wavelengths. We show that the increase of temperature causes the signal and idler wavelengths to shift linearly towards shorter and longer wavelengths, respectively. For the specific fiber of the experiment, the band shift at rates ­–0.04 nm/ºC and 0.3 nm/ºC, respectively. Strain causes the parametric bands to shift in the opposite way. The signal band shifted 2.8 nm/me and the idler -5.4 nm/me. Experimental observations are backed by numerical simulations.

  2. Gain and bandwidth investigation in a near-zero ultra-flat dispersion PCF for optical parametric amplification around the communication wavelength.

    Science.gov (United States)

    Maji, Partha Sona; Chaudhuri, Partha Roy

    2015-04-10

    In this work, we explore the fiber optical parametric amplifiers (FOPAs) gain and bandwidth spectra of near-zero ultra-flattened photonic crystal fibers (PCFs) around the communication wavelength. The parametric gain and spectral bandwidth have been explored for all the three zero-dispersion wavelengths (ZDWs) of the near-zero ultra-flat fiber. Our numerical analysis establishes a dispersion profile with D=0±0.35  ps/nm/km for a bandwidth of 440 nm around the communication wavelength to fully exploit the four-wave mixing effect with three ZDWs for broadband applications. It has been observed that the broader gain spectrum of FOPAs can be achieved with the near-zero and ultra-flattened dispersion curve with proper tuning of the pumping condition. A broader bandwidth with sufficient peak gain value has been achieved with small negative anomalous dispersion (β2≤0) and positive value of fourth-order dispersion parameter (+ve  β4) around the pumping wavelength. Wider bandwidth of the parametric amplifier has been observed around the second ZDW with a negative slope of the dispersion curve. A total bandwidth ≈520  nm could be achieved with the ultra-flat dispersion nature of the optimized PCF. The design methodology of achieving wider gain by tuning the pumping wavelength for favorable higher-order dispersion parameters would be very useful for future dispersion engineered devices.

  3. Picosecond chirped pulse compression in single-mode fibers

    International Nuclear Information System (INIS)

    Wenhua Cao; Youwei Zhang

    1995-01-01

    In this paper, the nonlinear propagation of picosecond chirped pulses in single mode fibers has been investigated both analytically and numerically. Results show that downchirped pulses can be compressed owing to normal group-velocity dispersion. The compression ratio depends both on the initial peak power and on the initial frequency chirp of the input pulse. While the compression ratio depends both on the initial peak power and on the initial frequency chirp of the input pulse. While the compression ratio increases with the negative frequency chirp, it decreases with the initial peak power of the input pulse. This means that the self-phase modulation induced nonlinear frequency chirp which is linear and positive (up-chirp) over a large central region of the pulse and tends to cancel the initial negative chirp of the pulse. It is also shown that, as the negative chirped pulse compresses temporally, it synchronously experiences a spectral narrowing

  4. Numerical analysis of the optimal length and profile of a linearly chirped fiber Bragg grating for dispersion compensation.

    Science.gov (United States)

    Thibault, S; Lauzon, J; Cliche, J F; Martin, J; Duguay, M A; Têtu, M

    1995-03-15

    We propose a theoretical investigation of the length and coupling profile of a linearly chirped fiber Bragg grating for maximum dispersion compensation in a repeaterless optical communication system. The system consists of 100 km of standard optical fiber in which a 1550-nm signal, directly modulated at 2.5 Gbits/s, is launched. We discuss the results obtained with 6-, 4.33-, and 1-cm-long linearly chirped fiber Bragg gratings having Gaussian and uniform coupling profiles. We numerically show that a 4.33-cm-long chirped fiber Bragg grating having a uniform coupling profile is capable of compensating efficiently for the dispersion of our optical communication system.

  5. Optimizing chirped laser pulse parameters for electron acceleration in vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Akhyani, Mina; Jahangiri, Fazel; Niknam, Ali Reza; Massudi, Reza, E-mail: r-massudi@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, Tehran 1983969411 (Iran, Islamic Republic of)

    2015-11-14

    Electron dynamics in the field of a chirped linearly polarized laser pulse is investigated. Variations of electron energy gain versus chirp parameter, time duration, and initial phase of laser pulse are studied. Based on maximizing laser pulse asymmetry, a numerical optimization procedure is presented, which leads to the elimination of rapid fluctuations of gain versus the chirp parameter. Instead, a smooth variation is observed that considerably reduces the accuracy required for experimentally adjusting the chirp parameter.

  6. Raw Knudsen 320B/R CHIRP Subbottom Profiler - CHIRP Subbottom Profiler data for the Arctic Ocean ECS survey.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Knudsen 320B/R CHIRP Subbottom Profiler - CHIRP Subbottom Profiler data were collected in Raw Knudsen SEG-Y Datagram format.

  7. Efficient high-pulse-energy eye-safe laser generated by an intracavity Nd:YLF/KTP optical parametric oscillator: role of thermally induced polarization switching

    International Nuclear Information System (INIS)

    Huang, Y J; Tang, C Y; Huang, Y P; Cho, C Y; Su, K W; Chen, Y F

    2012-01-01

    A high-pulse-energy eye-safe laser at 1552 nm is effectually generated by an intracavity Nd:YLF/KTP optical parametric oscillator (OPO) with the help of the thermally induced polarization switching. The polarization characteristics of the c-cut Nd:YLF laser at 1053 nm in the continuous-wave (CW) and Q-switched operation are comprehensively investigated. We experimentally verify the thermally induced birefringence can lead to a polarization switching between the mutually orthogonal components of the fundamental pulses. Consequently, an efficient intracavity nonlinear frequency conversion can be achieved in an optically isotropic laser crystal without any additional polarization control. With this finding, the pulse energy and peak power of the compact Nd:YLF/KTP eye-safe laser under an incident pump power of 12.7 W and a pulse repetition rate of 5 kHz are up to 306 μJ and 4 kW, respectively

  8. Linearly chirped waveform generation with large time-bandwidth product using sweeping laser and dual-polarization modulator

    Science.gov (United States)

    Li, Xuan; Zhao, Shanghong; Li, Yongjun; Zhu, Zihang; Qu, Kun; Li, Tao; Hu, Dapeng

    2018-03-01

    A method for photonic generation of a linearly chirped microwave waveform using a frequency-sweeping laser and a dual-polarization modulator is proposed and investigated. A frequency-sweeping continuous-wave light is generated from the laser and then sent to the modulator. In the modulator, one part of the light is modulated with an RF signal to generate a frequency-shifting optical signal, while another part of the light is passed through a polarization rotator to rotate the polarization to an orthogonal direction. At the output of the modulator, the two optical signals are combined with orthogonal polarizations, and then injected into a polarization delay device to introduce a time delay. After combining the two optical signals for heterodyning, a linearly chirped waveform can be generated. The bandwidth, time duration, chirp rate and sign, central frequency of the generated waveform can be tuned independently and flexibly, furthermore, frequency doubling for the central frequency can be achieved in the waveform generation. A simulation is demonstrated to verify the proposed scheme, a linearly chirped microwave pulse with up or down chirp, central frequency of 20 or 40 GHz, bandwidth of 20 GHz, time duration of 500 ns, time-bandwidth product (TBWP) of 10000 is obtained.

  9. Raw ODEC Bathy2000 CHIRP subbottom profiler - CHIRP high-resolution Seismic Profile data for the Chukchi Cap and Arctic Ocean.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — ODEC Bathy2000 CHIRP subbottom profiler - CHIRP high-resolution Seismic Profile data were collected in Raw ODEC Bathy2000 CHIRP dat Datagram Format.

  10. Raw ODEC Bathy2000 CHIRP subbottom profiler - CHIRP high-resolution Seismic Profile data for the U.S. Arctic Continental Margin.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — ODEC Bathy2000 CHIRP subbottom profiler - CHIRP high-resolution Seismic Profile data were collected in Raw ODEC Bathy2000 CHIRP dat Datagram Format.

  11. Fiber transmission and generation of ultrawideband pulses by direct current modulation of semi-conductor lasers and chirp-to-intensity conversion

    DEFF Research Database (Denmark)

    Company Torres, Victor; Prince, Kamau; Tafur Monroy, Idelfonso

    2008-01-01

    Optical pulses generated by current modulation of semiconductor lasers are strongly frequency chirped. This effect has been considered pernicious for optical communications. We take advantage of this effect for the generation of ultrawideband microwave signals by using an optical filter to achieve...

  12. Review on Photonic Generation of Chirp Arbitrary Microwave Waveforms for Remote Sensing Application

    Science.gov (United States)

    Raghuwanshi, Sanjeev Kumar; Srivastav, Akash; Athokpam, Bidhanshel Singh

    2017-12-01

    A novel technique to generate an arbitrary chirped waveform by harnessing features of lithium niobate (LiNb O_3) Mach-Zehnder modulator is proposed and demonstrated. The most important application of chirped microwave waveform is that, it improves the range resolution of radar. Microwave photonics system provides high bandwidth capabilities of fiber-optic systems and also contains the ability to provide interconnect transmission properties, which are virtually independent of length. The low-loss wide bandwidth capability of optoelectronic systems makes them attractive for the transmission and processing of microwave signals, while the development of high-capacity optical communication systems has required the use of microwave techniques in optical transmitters and receivers. These two strands have led to the development of the research area of microwave photonics. So, it should be consider that microwave photonics as the field that studies the interaction between microwave and optical waves for applications such as communications, radars, sensors and instrumentations. In this paper, we have thoroughly reviewed the arbitrary chirped microwave generation techniques by using photonics technology.

  13. On the undesired frequency chirping in photonic time-stretch systems

    Science.gov (United States)

    Xu, Yuxiao; Chi, Hao; Jin, Tao; Zheng, Shilie; Jin, Xiaofeng; Zhang, Xianmin

    2017-12-01

    The technique of photonic time stretch (PTS) has been intensively investigated in the past decade due to its potential in the acquisition of ultra-high speed signals. The frequency-related RF power fading in the PTS systems with double sideband (DSB) modulation has been well-known, which limits the maximum modulation frequency. Some solutions have been proposed to solve this problem. In this paper, we report another effect, i.e., undesired frequency chirping, which also relates to the performance degradation of PTS systems with DSB modulation, for the first time to our knowledge. Distinct from the nonlinearities caused by nonlinear modulation and square-law photodetection, which is common in radio frequency analog optical links, this frequency chirping originates from the addition of two beating signals with a relative delay after photodetection. A theoretical model for exactly describing the frequency chirping is presented, and is then verified by simulations. Discussion on the method to avoid the frequency chirping is also presented.

  14. Comparison of Small-Scale Actively and Passively Q-Switched Eye-Safe Intracavity Optical Parametric Oscillators at 1.57 μm

    International Nuclear Information System (INIS)

    Miao Jie-Guang; Pan Yu-Zhai; Qu Shi-Liang

    2012-01-01

    The first experimental comparison between the actively and passively Q-switched intracavity optical parametric oscillators (IOPOs) at 1.57 μm driven by a small-scale diode-pumped Nd:YVO 4 laser are thoroughly presented. It is found that the performances of the two types of IOPOs are complementary. The actively Q-switched IOPO features a shorter pulse duration, a higher peak power, and a superior power and pulse stability. However, in terms of compactness, operation threshold and conversion efficiency, passively Q-switched IOPOs are more attractive. It is further indicated that the passively Q-switched IOPO at 1.57μm is a promising and cost-effective eye-safe laser source, especially at the low and moderate output levels. In addition, instructional improvement measures for the two types of IOPOs are also summarized. (fundamental areas of phenomenology(including applications))

  15. Continuous-wave pump-enhanced optical parametric oscillator with ring resonator for wide and continuous tuning of single-frequency radiation.

    Science.gov (United States)

    Stothard, David; Lindsay, Ian; Dunn, Malcolm

    2004-02-09

    We demonstrate a PPLN based pump-enhanced, singly-resonant optical parametric oscillator configured in a traveling wave geometry and pumped by a Ti:sapphire laser. The inclusion of a low finesse etalon within the OPO cavity stabilizes the signal frequency, and rotation of the etalon allows this frequency to be systematically hopped from axial mode to nearest neighbor axial mode over the entire free spectral range of the etalon (83GHz). Tuning of the pump frequency allows the signal frequency to be smoothly tuned over a cavity free spectral range. More than 35mW of single frequency idler power was generated in the spectral range 2800-3000nm for 600mW pump power. The superiority of traveling wave over standing wave geometries in these regards is discussed.

  16. Contextual realization of the universal quantum cloning machine and of the universal-NOT gate by quantum-injected optical parametric amplification

    International Nuclear Information System (INIS)

    Pelliccia, D.; Schettini, V.; Sciarrino, F.; Sias, C.; De Martini, F.

    2003-01-01

    A simultaneous, contextual experimental demonstration of the two processes of cloning an input qubit vertical bar Ψ> and of flipping it into the orthogonal qubit vertical bar Ψ perpendicular> is reported. The adopted experimental apparatus, a quantum-injected optical parametric amplifier is transformed simultaneously into a universal optimal quantum cloning machine and into a universal-NOT quantum-information gate. The two processes, indeed forbidden in their exact form for fundamental quantum limitations, were found to be universal and optimal, i.e., the measured fidelity of both processes F<1 was found close to the limit values evaluated by quantum theory. A contextual theoretical and experimental investigation of these processes, which may represent the basic difference between the classical and the quantum worlds, can reveal in a unifying manner the detailed structure of quantum information. It may also enlighten the yet little explored interconnections of fundamental axiomatic properties within the deep structure of quantum mechanics

  17. Longwave infrared, single-frequency, tunable, pulsed optical parametric oscillator based on orientation-patterned GaAs for gas sensing.

    Science.gov (United States)

    Clément, Q; Melkonian, J-M; Dherbecourt, J-B; Raybaut, M; Grisard, A; Lallier, E; Gérard, B; Faure, B; Souhaité, G; Godard, A

    2015-06-15

    We demonstrate a nanosecond single-frequency nested cavity optical parametric oscillator (NesCOPO) based on orientation-patterned GaAs (OP-GaAs). Its low threshold energy of 10 μJ enables to pump it with a pulsed single-frequency Tm:YAP microlaser. Stable single-longitudinal-mode emission is obtained owing to Vernier spectral filtering provided by the dual-cavity doubly-resonant NesCOPO scheme. Crystal temperature tuning covers the 10.3-10.9 μm range with a quasi-phase-matching period of 72.6 μm. A first step toward the implementation of this device in a differential absorption lidar is demonstrated by carrying out short-range standoff detection of ammonia vapor around 10.4 μm. Owing to the single-frequency emission, interferences due to absorption by atmospheric water vapor can be discriminated from the analyte signal.

  18. Application of mid-infrared cavity-ringdown spectroscopy to trace explosives vapor detection using a broadly tunable (6-8 μm) optical parametric oscillator

    Science.gov (United States)

    Todd, M. W.; Provencal, R. A.; Owano, T. G.; Paldus, B. A.; Kachanov, A.; Vodopyanov, K. L.; Hunter, M.; Coy, S. L.; Steinfeld, J. I.; Arnold, J. T.

    A novel instrument, based on cavity-ringdown spectroscopy (CRDS), has been developed for trace gas detection. The new instrument utilizes a widely tunable optical parametric oscillator (OPO), which incorporates a zinc-germanium-phosphide (ZGP) crystal that is pumped at 2.8 μm by a 25-Hz Er,Cr:YSGG laser. The resultant mid-IR beam profile is nearly Gaussian, with energies exceeding 200 μJ/pulse between 6 and 8 μm, corresponding to a quantum conversion efficiency of approximately 35%. Vapor-phase mid-infrared spectra of common explosives (TNT, TATP, RDX, PETN and Tetryl) were acquired using the CRDS technique. Parts-per-billion concentration levels were readily detected with no sample preconcentration. A collection/flash-heating sequence was implemented in order to enhance detection limits for ambient air sampling. Detection limits as low as 75 ppt for TNT are expected, with similar concentration levels for the other explosives.

  19. Widely tunable eye-safe laser by a passively Q-switched photonic crystal fiber laser and an external-cavity optical parametric oscillator

    International Nuclear Information System (INIS)

    Chang, H L; Zhuang, W Z; Huang, W C; Huang, J Y; Huang, K F; Chen, Y F

    2011-01-01

    We report on a widely tunable passively Q-switched photonic crystal fiber (PCF) laser with wavelength tuning range up to 80 nm. The PCF laser utilizes an AlGaInAs quantum well/barrier structure as a saturable absorber and incorporates an external-cavity optical parametric oscillator (OPO) to achieve wavelength conversion. Under a pump power of 13.1 W at 976 nm, the PCF laser generated 1029-nm radiation with maximum output energy of 750 μJ and was incident into an external-cavity OPO. The output energy and peak power of signal wave was found to be 138 μJ and 19 kW, respectively. By tuning the temperature of nonlinear crystal, periodically poled lithium niobate (PPLN), in the OPO, the signal wavelength in eye-safe regime from 1513 to 1593 nm was obtained

  20. Simultaneous intracavity optical parametric oscillation and stimulated Raman scattering pumped by a doubly passively Q-switched Nd:GGG laser

    Science.gov (United States)

    Chu, Hongwei; Zhao, Jia; Li, Yufei; Zhao, Shengzhi; Yang, Kejian; Li, Dechun; Li, Guiqiu; Li, Tao; Qiao, Wenchao

    2014-12-01

    By using a doubly passively Q-switched Nd:Gd3Ga5O12(Nd:GGG) laser with Cr4+:YAG and GaAs as saturable absorbers as pump laser, simultaneous intracavity optical parametric oscillation and stimulated Raman scattering based on a single X-cut KTiOPO4 (KTP) crystal have been realized. Under an incident diode pump power of 10.5 W, the output powers at the signal wave near 1,569 nm and the first Stokes emission near 1,094 nm were 218 and 72 mW, corresponding to the optical-to-optical conversion efficiencies of 2.08 and 0.69 %, respectively. The measured shortest pulse duration at the signal wave near 1,569 nm was 580 ps, generating a pulse peak power of 43.7 kW, while the minimum pulse duration at the first Stokes emission near 1,094 nm was 1.61 ns. By adjusting the tilt angle of the KTP crystal, up to the third Stokes scattering was also obtained.

  1. Relaxed damage threshold intensity conditions and nonlinear increase in the conversion efficiency of an optical parametric oscillator using a bi-directional pump geometry.

    Science.gov (United States)

    Norris, G; McConnell, G

    2010-03-01

    A novel bi-directional pump geometry that nonlinearly increases the nonlinear optical conversion efficiency of a synchronously pumped optical parametric oscillator (OPO) is reported. This bi-directional pumping method synchronizes the circulating signal pulse with two counter-propagating pump pulses within a linear OPO resonator. Through this pump scheme, an increase in nonlinear optical conversion efficiency of 22% was achieved at the signal wavelength, corresponding to a 95% overall increase in average power. Given an almost unchanged measured pulse duration of 260 fs under optimal performance conditions, this related to a signal wavelength peak power output of 18.8 kW, compared with 10 kW using the traditional single-pass geometry. In this study, a total effective peak intensity pump-field of 7.11 GW/cm(2) (corresponding to 3.55 GW/cm(2) from each pump beam) was applied to a 3 mm long periodically poled lithium niobate crystal, which had a damage threshold intensity of 4 GW/cm(2), without impairing crystal integrity. We therefore prove the application of this novel pump geometry provides opportunities for power-scaling of synchronously pumped OPO systems together with enhanced nonlinear conversion efficiency through relaxed damage threshold intensity conditions.

  2. A general approach to optomechanical parametric instabilities

    International Nuclear Information System (INIS)

    Evans, M.; Barsotti, L.; Fritschel, P.

    2010-01-01

    We present a simple feedback description of parametric instabilities which can be applied to a variety of optical systems. Parametric instabilities are of particular interest to the field of gravitational-wave interferometry where high mechanical quality factors and a large amount of stored optical power have the potential for instability. In our use of Advanced LIGO as an example application, we find that parametric instabilities, if left unaddressed, present a potential threat to the stability of high-power operation.

  3. High-average-power, 50-fs parametric amplifier front-end at 1.55 μm.

    Science.gov (United States)

    Mero, Mark; Noack, Frank; Bach, Florian; Petrov, Valentin; Vrakking, Marc J J

    2015-12-28

    An average-power-scalable, two-stage optical parametric chirped pulse amplifier is presented providing 90-μJ signal pulses at 1.55 μm and 45-μJ idler pulses at 3.1 μm at a repetition rate of 100 kHz. The signal pulses were recompressible to within a few percent of their ~50-fs Fourier limit in anti-reflection coated fused silica at negligible losses. The overall energy conversion efficiency from the 1030-nm pump to the recompressed signal reached 19%, significantly reducing the cost per watt of pump power compared to similar systems. The two-stage source will serve as the front-end of a three-stage system permitting the development of novel experimental strategies towards laser-based imaging of molecular structures and chemical reactivity.

  4. High spatial and temporal resolution interrogation of fully distributed chirped fiber Bragg grating sensors

    OpenAIRE

    Ahmad, Eamonn J.; Wang, Chao; Feng, Dejun; Yan, Zhijun; Zhang, Lin

    2017-01-01

    A novel interrogation technique for fully distributed linearly chirped fiber Bragg grating (LCFBG) strain sensors with simultaneous high temporal and spatial resolution based on optical time-stretch frequency-domain reflectometry (OTS-FDR) is proposed and experimentally demonstrated. LCFBGs is a promising candidate for fully distributed sensors thanks to its longer grating length and broader reflection bandwidth compared to normal uniform FBGs. In the proposed system, two identical LCFBGs are...

  5. Generation of 1.024-Tb/s Nyquist-WDM phase-conjugated twin vector waves through polarization-insensitive optical parametric amplification enabling transmission over 4000-km dispersion-managed TWRS fiber

    DEFF Research Database (Denmark)

    Liu, Xiang; Hu, Hao; Chandrasekhar, S.

    2013-01-01

    We experimentally demonstrate the first Tb/s Nyquist-WDM phase-conjugated twin waves, consisting of eight 128-Gb/s PDM-QPSK signals and their idlers, by a broadband polarization-insensitive fiber optical parametric amplifier, enabling more than doubled reach in dispersion-managed transmission...

  6. Chirped Pulse Spectrometer Operating at 200 GHz

    Science.gov (United States)

    Hindle, Francis; Bray, Cédric; Hickson, Kevin; Fontanari, Daniele; Mouelhi, Meriem; Cuisset, Arnaud; Mouret, Gaël; Bocquet, Robin

    2018-01-01

    The combination of electronic sources operating at high frequencies and modern microwave instrumentation has enabled the recent development of chirped pulse spectrometers for the millimetre and THz bands. This type of instrument can operate at high resolution which is particularly suited to gas-phase rotational spectroscopy. The construction of a chirped pulse spectrometer operating at 200 GHz is described in detail while attention is paid to the phase stability and the data accumulation over many cycles. Validation using carbonyl sulphide has allowed the detection limit of the instrument to be established as function of the accumulation. A large number of OCS transitions were identified using a 10-GHz chirped pulse and include the six most abundant isotopologues, the weakest line corresponding to the fundamental R(17) transition of 16O13C33S with a line strength of 4.3 × 10-26 cm-1/(molecule cm-2). The linearity of the system response for different degrees of data accumulation and transition line strength was confirmed over four orders of magnitudes. A simple analysis of the time-domain data was demonstrated to provide the line-broadening coefficient without the need for conversion by a Fourier transform. Finally, the pulse duration is discussed and optimal values are given for both Doppler-limited and collisional regimes.

  7. SAR processing with stepped chirps and phased array antennas.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2006-09-01

    Wideband radar signals are problematic for phased array antennas. Wideband radar signals can be generated from series or groups of narrow-band signals centered at different frequencies. An equivalent wideband LFM chirp can be assembled from lesser-bandwidth chirp segments in the data processing. The chirp segments can be transmitted as separate narrow-band pulses, each with their own steering phase operation. This overcomes the problematic dilemma of steering wideband chirps with phase shifters alone, that is, without true time-delay elements.

  8. Femtosecond optical parametric amplification in BBO and KTA driven by a Ti:sapphire laser for LIDT testing and diagnostic development

    Science.gov (United States)

    Meadows, Alexander R.; Cupal, Josef; Hříbek, Petr; Durák, Michal; Kramer, Daniel; Rus, Bedřich

    2017-05-01

    We present the design of a collinear femtosecond optical parametric amplification (OPA) system producing a tunable output at wavelengths between 1030 nm and 1080 nm from a Ti:Sapphire pump laser at a wavelength of 795 nm. Generation of a supercontinuum seed pulse is followed by one stage of amplification in Beta Barium Borate (BBO) and two stages of amplification in Potassium Titanyle Arsenate (KTA), resulting in a 225 μJ output pulse with a duration of 90 fs. The output of the system has been measured by self-referenced spectral interferometry to yield the complete spectrum and spectral phase of the pulse. When compared to KTP, the greater transparency of KTA in the spectral range from 3 - 4 μm allows for reduced idler absorption and enhanced gain from the OPA process when it is pumped by the fundamental frequency of a Ti:sapphire laser. In turn, the use of the Ti:sapphire fundamental at 795 nm as a pump improves the efficiency with which light can be converted to wavelengths between 1030 nm and 1080 nm and subsequently used to test components for Nd-based laser systems. This OPA system is operated at 1 kHz for diagnostic development and laser-induced damage threshold testing of optical components for the ELI-Beamlines project.

  9. Generation of 1.024-Tb/s Nyquist-WDM phase-conjugated twin vector waves by a polarization-insensitive optical parametric amplifier for fiber-nonlinearity-tolerant transmission

    DEFF Research Database (Denmark)

    Liu, Xiang; Hu, Hao; Chandrasekhar, S.

    2014-01-01

    We experimentally demonstrate the generation of 1.024-Tb/s Nyquist-WDM phase-conjugated vector twin waves (PCTWs), consisting of eight 128-Gb/s polarization-division-multiplexed QPSK signals and their idlers, by a broadband polarization-insensitive fiber optic parametric amplifier. This novel all......-optical signal processing approach to generate WDM-PCTWs enables a 2-fold reduction in the needed optical transmitters as compared to the conventional approach where each idler is generated by a dedicated transmitter. Digital coherent superposition of the twin waves at the receiver enables more than doubled...

  10. Determining the parameters of chirp signals using cyclostationary ...

    African Journals Online (AJOL)

    This paper deals with the problems of detecting a chirp signal of motion target against a strong undesired signal from the transmitter in radar. We use Generalized Almost- Cyclostationary (GACS) signal processing method to determine the rate and initial frequency of the chirp signal in presence of the strong undesired ...

  11. Parameter estimation of linear and quadratic chirps by employing ...

    Indian Academy of Sciences (India)

    This paper discusses some analytical results of the GTFT. We identify the eigenfunctions and eigenvalues of the GTFT. The time shift property of the GTFT is discussed. The paper describes methods for estimation of parameters of individual chirp signals on receipt of a noisy mixture of chirps. A priori knowledge of the nature ...

  12. Pump to signal noise transfer in parametric fiber amplifiers

    DEFF Research Database (Denmark)

    Lund-Hansen, Toke; Rottwitt, Karsten; Peucheret, Christophe

    2010-01-01

    Fiber optic parametric amplifiers have been suggested due to their potential low spontaneous emission. However, by nature the parametric amplifier only work in a forward pumped configuration, which result in transfer of relative intensity noise in the pump to the signal.......Fiber optic parametric amplifiers have been suggested due to their potential low spontaneous emission. However, by nature the parametric amplifier only work in a forward pumped configuration, which result in transfer of relative intensity noise in the pump to the signal....

  13. Optical coherence tomography can assess skeletal muscle tissue from mouse models of muscular dystrophy by parametric imaging of the attenuation coefficient

    Science.gov (United States)

    Klyen, Blake R.; Scolaro, Loretta; Shavlakadze, Tea; Grounds, Miranda D.; Sampson, David D.

    2014-01-01

    We present the assessment of ex vivo mouse muscle tissue by quantitative parametric imaging of the near-infrared attenuation coefficient µt using optical coherence tomography. The resulting values of the local total attenuation coefficient µt (mean ± standard error) from necrotic lesions in the dystrophic skeletal muscle tissue of mdx mice are higher (9.6 ± 0.3 mm−1) than regions from the same tissue containing only necrotic myofibers (7.0 ± 0.6 mm−1), and significantly higher than values from intact myofibers, whether from an adjacent region of the same sample (4.8 ± 0.3 mm−1) or from healthy tissue of the wild-type C57 mouse (3.9 ± 0.2 mm−1) used as a control. Our results suggest that the attenuation coefficient could be used as a quantitative means to identify necrotic lesions and assess skeletal muscle tissue in mouse models of human Duchenne muscular dystrophy. PMID:24761302

  14. Tunable, high-repetition-rate, dual-signal-wavelength femtosecond optical parametric oscillator based on BiB3O6

    Science.gov (United States)

    Meng, Xianghao; Wang, Zhaohua; Tian, Wenlong; Fang, Shaobo; Wei, Zhiyi

    2018-01-01

    We have demonstrated a high-repetition-rate tunable femtosecond dual-signal-wavelength optical parametric oscillator (OPO) based on BiB3O6 (BiBO) crystal, synchronously pumped by a frequency-doubled mode-locked Yb:KGW laser. The cavity is simple since no dispersion compensators are used in the cavity. The wavelength range of dual-signal is widely tunable from 710 to 1000 nm. Tuning is accomplished by rotating phase-matching angle of BiBO, and optimizing cavity length and output coupler. Using a 3.75 W pump laser, the maximum average dual-signal output power is 760 mW at 707 and 750 nm, leading to a conversion efficiency of 20.3% not taking into account the idler power. Our experimental results show a non-critical phase-matching configuration pumped by a high peak power laser source. The operation of the dual-signal benefits from the balance of phase matching and group velocity mismatching between the two signals.

  15. Critically phase-matched Ti:sapphire-laser-pumped deep-infrared femtosecond optical parametric oscillator based on CdSiP2.

    Science.gov (United States)

    O'Donnell, Callum F; Kumar, S Chaitanya; Zawilski, K T; Schunemann, P G; Ebrahim-Zadeh, M

    2018-04-01

    We report a high-repetition-rate femtosecond optical parametric oscillator (OPO) for the deep-infrared (deep-IR) based on type-I critical phase-matching in CdSiP 2 (CSP), pumped directly by a Ti:sapphire laser. Using angle-tuning in the CSP crystal, the OPO can be continuously tuned across 7306-8329 nm (1201-1369  cm -1 ) in the deep-IR. It delivers up to 18 mW of idler average power at 7306 nm and >7  mW beyond 8000 nm at 80.5 MHz repetition rate, with the spectra exhibiting bandwidths of >150  nm across the tuning range. Moreover, the signal is tunable across 1128-1150 nm in the near-infrared, providing up to 35 mW of average power in ∼266  fs pulses at 1150 nm. Both beams exhibit single-peak Gaussian distribution in TEM 00 spatial profile. With an equivalent spectral brightness of ∼5.6×10 20 photons s -1  mm -2  sr -1 0.1% BW -1 , this OPO represents a viable alternative to synchrotron and supercontinuum sources for deep-IR applications in spectroscopy, metrology, and medical diagnostics.

  16. Improvement of stability and efficiency in diode-pumped passively Q-switched intracavity optical parametric oscillator with a monolithic cavity

    International Nuclear Information System (INIS)

    Huang, J Y; Zhuang, W Z; Huang, Y P; Huang, Y J; Su, K W; Chen, Y F

    2012-01-01

    We improve the performance of intracavity optical parametric oscillator (IOPO) pumped by a diode-pumped Q-switched Nd:YVO 4 /Cr 4+ :YAG laser. The IOPO cavity is formed independently by a monolithic KTP crystal that the mirrors are directly deposited on top of the nonlinear crystal. We study the performances of this IOPO cavity with different reflectivity of the output coupler at 1.5 μm (R s ) of 80 and 50%. The average power of 1.5 μm is up to 3.3 W at the maximum pump power of 16.8 W for both cases. The diode-to-signal conversion efficiency is up to 20%, which is the highest one for IOPOs to our best knowledge. At the maximum pump power, the pulse energies are 41 μJ with the pulse width of 3 ns at a pulse repetition rate (PRR) of 80 kHz for R s = 80% and 51 μJ with the pulse width of 1.2 ns at a PRR of 65 kHz for R s = 50%, respectively. The pulse amplitude fluctuations in standard deviation are 2.6% for R s = 80% and 4% for R s = 50%, respectively

  17. Fiber nonlinearity mitigation of WDM-PDM QPSK/16-QAM signals using fiber-optic parametric amplifiers based multiple optical phase conjugations

    DEFF Research Database (Denmark)

    Hu, Hao; Jopson, Robert M.; Gnauck, Alan H.

    2017-01-01

    We demonstrate fiber nonlinearity mitigation by using multiple optical phase conjugations (OPCs) in the WDM transmission systems of both 8 x 32-Gbaud PDM QPSK channels and 8 x 32-Gbaud PDM 16-QAM channels, showing improved performance over a single mid-span OPC and no OPC in terms of nonlinear...... threshold and a best achievable Q(2) factor after transmission. In addition, after an even number of OPCs, the signal wavelength can be preserved after transmission. The performance of multiple OPCs for fiber nonlinearity mitigation was evaluated independently for WDM PDM QPSK signals and WDM PDM 16QAM...... to 1 dB compared to the case of mid-span OPC. The improvements in the best achievable Q(2) factors were more modest, ranging from 0.2 dB to 1.1 dB for the results presented. (C) 2017 Optical Society of America...

  18. FY07 LDRD Final Report Precision, Split Beam, Chirped-Pulse, Seed Laser Technology

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, J W; Messerly, M J; Phan, H H; Crane, J K; Beach, R J; Siders, C W; Barty, C J

    2009-11-12

    The goal of this LDRD ER was to develop a robust and reliable technology to seed high-energy laser systems with chirped pulses that can be amplified to kilo-Joule energies and recompressed to sub-picosecond pulse widths creating extremely high peak powers suitable for petawatt class physics experiments. This LDRD project focused on the development of optical fiber laser technologies compatible with the current long pulse National Ignition Facility (NIF) seed laser. New technologies developed under this project include, high stability mode-locked fiber lasers, fiber based techniques for reduction of compressed pulse pedestals and prepulses, new compact stretchers based on chirped fiber Bragg gratings (CFBGs), new techniques for manipulation of chirped pulses prior to amplification and new high-energy fiber amplifiers. This project was highly successful and met virtually all of its goals. The National Ignition Campaign has found the results of this work to be very helpful. The LDRD developed system is being employed in experiments to engineer the Advanced Radiographic Capability (ARC) front end and the fully engineered version of the ARC Front End will employ much of the technology and techniques developed here.

  19. Generation of high-energy sub-20 fs pulses tunable in the 250-310 nm region by frequency doubling of a high-power noncollinear optical parametric amplifier.

    Science.gov (United States)

    Beutler, Marcus; Ghotbi, Masood; Noack, Frank; Brida, Daniele; Manzoni, Cristian; Cerullo, Giulio

    2009-03-15

    We report on the generation of powerful sub-20 fs deep UV pulses with 10 microJ level energy and broadly tunable in the 250-310 nm range. These pulses are produced by frequency doubling a high-power noncollinear optical parametric amplifier and compressed by a pair of MgF2 prisms to an almost transform-limited duration. Our results provide a power scaling by an order of magnitude with respect to previous works.

  20. Accuracy of CHIRPS Satellite-Rainfall Products over Mainland China

    Directory of Open Access Journals (Sweden)

    Lei Bai

    2018-02-01

    Full Text Available Precipitation is the main component of global water cycle. At present, satellite quantitative precipitation estimates (QPEs are widely applied in the scientific community. However, the evaluations of satellite QPEs have some limitations in terms of the deficiency in observation, evaluation methodology, the selection of time windows for evaluation and short periods for evaluation. The objective of this work is to make some improvements by evaluating the spatio-temporal pattern of the long-terms Climate Hazard Group InfraRed Precipitation Satellite’s (CHIRPS’s QPEs over mainland China. In this study, we compared the daily precipitation estimates from CHIRPS with 2480 rain gauges across China and gridded observation using several statistical metrics in the long-term period of 1981–2014. The results show that there is significant difference between point evaluation and grid evaluation for CHIRPS. CHIRPS has better performance for a large amount of precipitation than it does for arid and semi-arid land. The change in good performance zones has strong relationship with monsoon’s movement. Therefore, CHIRPS performs better in river basins of southern China and exhibits poor performance in river basins in northwestern and northern China. Moreover, CHIRPS exhibits better in warm season than in Winter, owing to its limited ability to detect snowfall. Nevertheless, CHIRPS is moderately sensitive to the precipitation from typhoon weather systems. The limitations for CHIRPS result from the Tropical Rainfall Measuring Mission (TRMM 3B42 estimates’ accuracy and valid spatial coverage.

  1. Tunable reflecting terahertz filter based on chirped metamaterial structure

    Science.gov (United States)

    Yang, Jing; Gong, Cheng; Sun, Lu; Chen, Ping; Lin, Lie; Liu, Weiwei

    2016-01-01

    Tunable reflecting terahertz bandstop filter based on chirped metamaterial structure is demonstrated by numerical simulation. In the metamaterial, the metal bars are concatenated to silicon bars with different lengths. By varying the conductivity of the silicon bars, the reflectivity, central frequency and bandwidth of the metamaterial could be tuned. Light illumination could be introduced to change the conductivity of the silicon bars. Numerical simulations also show that the chirped metamaterial structure is insensitive to the incident angle and polarization-dependent. The proposed chirped metamaterial structure can be operated as a tunable bandstop filter whose modulation depth, bandwidth, shape factor and center frequency can be controlled by light pumping. PMID:27941833

  2. Parametric Transverse Patterns in Broad Aperture Lasers

    DEFF Research Database (Denmark)

    Grigorieva, E.V.; Kashchenko, S.A.; Mosekilde, Erik

    1998-01-01

    Parametrically generated optical patterns are investigated for finite and large-scale transverse aperture lasers. Standing and rotating patterns as well as periodic and chaotic pattern alternations are described in the framework of the amplitude equation formalism. Sensitive dependence on the geo......Parametrically generated optical patterns are investigated for finite and large-scale transverse aperture lasers. Standing and rotating patterns as well as periodic and chaotic pattern alternations are described in the framework of the amplitude equation formalism. Sensitive dependence...

  3. In-line and cascaded DWDM transmission using a 15dB net-gain polarization-insensitive fiber optical parametric amplifier.

    Science.gov (United States)

    Stephens, M F C; Tan, M; Gordienko, V; Harper, P; Doran, N J

    2017-10-02

    We demonstrate and characterize polarization-division multiplexed (PDM) DWDM data transmission for the first time in a range of systems incorporating a net-gain polarization-insensitive fiber optical parametric amplifier (PI-FOPA) for loss compensation. The PI-FOPA comprises a modified diversity-loop architecture to achieve 15dB net-gain, and up to 2.3THz (~18nm) bandwidth. Three representative systems are characterized using a 100Gb/s PDM-QPSK signal in conjunction with emulated DWDM neighbouring channels: (a) a 4x75km in-line fiber transmission system incorporating multiple EDFAs and a single PI-FOPA (b) N cascaded PI-FOPA amplification stages in an unlevelled Nx25km recirculating loop arrangement, with no EDFAs used within the loop signal path, and (c) M cascaded PI-FOPA amplification stages as part of an Mx75.6km gain-flattened recirculating loop system with the FOPA compensating for the transmission fiber loss, and EDFA compensation for loop switching and levelling loss. For the 4x75km in-line system (a), we transmit 45x50GHz-spaced signals ('equivalent' data-rate of 4.5Tb/s) with average OSNR penalty of 1.3dB over the band at 10 -3 BER. For the unlevelled 'FOPA-only' 25.2km cascaded system (b), we report a maximum of eight recirculations for all 10x100GHz-spaced signals, and five recirculations for 20x50GHz-spaced signals. For the 75.6km levelled system (c), we achieve eight recirculations for all 20x50GHz signals resulting in a total transmission distance of 604.8km.

  4. Spin-torque switching and control using chirped AC currents

    Science.gov (United States)

    Klughertz, Guillaume; Friedland, Lazar; Hervieux, Paul-Antoine; Manfredi, Giovanni

    2017-10-01

    We propose to use oscillating spin currents with slowly varying frequency (chirp) to manipulate and control the magnetization dynamics in a nanomagnet. By recasting the Landau-Lifshitz-Slonczewski equation in a quantum-like two-level formalism, we show that a chirped spin current polarized in the direction normal to the anisotropy axis can induce a stable precession of the magnetic moment at any angle (up to 90^\\circ ) with respect to the anisotropy axis. The drive current can be modest (10^6~A~cm-2 or lower) provided the chirp rate is sufficiently slow. The induced precession is stable against thermal noise, even for small nano-objects at room temperature. Complete reversal of the magnetization can be achieved by adding a small external magnetic field antiparallel to the easy axis. Alternatively, a combination of chirped ac and dc currents with different polarization directions can also be used to trigger the reversal.

  5. Charged particle interaction with a chirped electromagnetic pulse

    NARCIS (Netherlands)

    Khachatryan, A.G.; Boller, Klaus J.; van Goor, F.A.

    2003-01-01

    It is found that a charged particle can get a net energy gain from the interaction with an electromagnetic chirped pulse. Theoretically, the energy gain increases with the pulse amplitude and with the relative frequency variation in the pulse.

  6. Dispersion measurement on chirped mirrors at arbitrary incidence angle and polarization state (Conference Presentation)

    Science.gov (United States)

    Kovacs, Mate; Somoskoi, Tamas; Seres, Imre; Borzsonyi, Adam; Sipos, Aron; Osvay, Károly

    2017-05-01

    The optical elements of femtosecond high peak power lasers have to fulfill more and more strict requirements in order to support pulses with high intensity and broad spectrum. In most cases chirped pulse amplification scheme is used to generate high peak power ultrashort laser pulses, where a very precise control of spectral intensity and spectral phase is required in reaching transform-limited temporal shape at the output. In the case of few cycle regime, the conventional bulk glass, prism-, grating- and their combination based compressors are not sufficient anymore, due to undesirable nonlinear effects in their material and proneness to optical damages. The chirped mirrors are also commonly used to complete the compression after a beam transport system just before the target. Moreover, the manufacturing technology requires quality checks right after production and over the lifetime of the mirror as well, since undesired deposition on the surface can lead alteration from the designed value over a large part of the aperture. For the high harmonic generation, polarization gating technology is used to generate single attosecond pulses [1]. In this case the pulse to be compressed has various polarization state falling to the chirped mirrors. For this reason, it is crucial to measure the dispersion of the mirrors for the different polarization states. In this presentation we demonstrate a simple technique to measure the dispersion of arbitrary mirror at angles of incidence from 0 to 55 degree, even for a 12" optics. A large aperture 4" mirror has been scanned over with micrometer accuracy and the dispersion property through the surface has been investigated with a stable interference fringes in that robust geometry. We used Spectrally Resolved Interferometry, which is based on a Michaelson interferometer and a combined visible and infrared spectrometer. Tungsten halogen lamp with 10 mW coupled optical power was used as a white-light source so with the selected

  7. High-power parametric amplification of 11.8-fs laser pulses with carrier-envelope phase control

    NARCIS (Netherlands)

    Zinkstok, R.T.; Witte, S.; Hogervorst, W.; Eikema, K.S.E.

    2005-01-01

    Phase-stable parametric chirped-pulse amplification of ultrashort pulses from a carrier-envelope phase-stabilized mode-locked Ti:sapphire oscillator (11.0 fs) to 0.25 mJ/pulse at 1 kHz is demonstrated. Compression with a grating compressor and a LCD shaper yields near-Fourier-limited 11.8-fs pulses

  8. Chirped Auger electron emission due to field-assisted post-collision interaction

    Directory of Open Access Journals (Sweden)

    Bonitz M.

    2013-03-01

    Full Text Available We have investigated the Auger decay in the temporal domain by applying a terahertz streaking light field. Xenon and krypton atoms were studied by implementing the free-electron laser in Hamburg (FLASH as well as a source of high-order harmonic radiation combined with terahertz pulses from an optical rectification source. The observed linewidth asymmetries in the streaked spectra suggest a chirped Auger electron emission which is understood in terms of field-assisted post-collision interaction. The experimentally obtained results agree well with model calculations.

  9. Influence of transmitter chirp and receiver imperfections on RF gain in short-range ROMMF systems

    DEFF Research Database (Denmark)

    Petersen, Martin Nordal; Tartarini, Giovanni; Visani, Davide

    2011-01-01

    Two important effects that can lead to extensive detrimental effects on short-range radio-over-multimode-fiber systems are presented. The work experimentally shows how transmitter chirp and receiver imperfections determine the degree of both small signal RF variations as well as optical power...... variations. Both theoretical and experimental results conclude that without taking proper precautions in designing even short-range links, the potential power variations can reach more than 5 dB over just 150m multimode-fiber....

  10. Parameter estimation of linear and quadratic chirps by employing ...

    Indian Academy of Sciences (India)

    Multiplication of the above function in u with a quadratic chirp ejψu3 . 4. Multiplication by a complex amplification factor. As in the case of LFM chirps, where we do not evaluate FrFT of all values for α but only over a restricted range given by Eq. (23), here too we evaluate FrFT for a restricted range of φ given by Equation (46) ...

  11. Chirp of monolithic colliding pulse mode-locked diode lasers

    DEFF Research Database (Denmark)

    Hofmann, M.; Bischoff, S.; Franck, Thorkild

    1997-01-01

    Spectrally resolved streak camera measurements of picosecond pulses emitted by hybridly colliding pulse mode-locked (CPM) laser diodes are presented in this letter. Depending on the modulation frequency both blue-chirped (upchirped) and red-chirped (downchirped) pulses can be observed. The two...... different regimes and the transition between them are characterized experimentally and the behavior is explained on the basis of our model for the CPM laser dynamics. (C) 1997 American Institute of Physics....

  12. Effects of laser frequency chirp on modal noise in short-range radio over multimode fiber links

    DEFF Research Database (Denmark)

    Visani, Davide; Tartarini, Giovanni; Petersen, Martin Nordal

    2010-01-01

    An important effect of the frequency chirp of the optical transmitter in radio over multimode fiber links is put into evidence experimentally and modeled theoretically for the first time, to our knowledge. This effect can have an important impact in short-range connections, where, although...... intermodal dispersion does not generally cause unacceptable limitations to the transmittable bandwidth, the presence of modal noise must be accurately kept under control, since it determines undesired real-time fluctuations of the link....

  13. Generation of 1.024-Tb/s Nyquist-WDM phase-conjugated twin vector waves by a polarization-insensitive optical parametric amplifier for fiber-nonlinearity-tolerant transmission.

    Science.gov (United States)

    Liu, Xiang; Hu, Hao; Chandrasekhar, S; Jopson, R M; Gnauck, A H; Dinu, M; Xie, C; Winzer, P J

    2014-03-24

    We experimentally demonstrate the generation of 1.024-Tb/s Nyquist-WDM phase-conjugated vector twin waves (PCTWs), consisting of eight 128-Gb/s polarization-division-multiplexed QPSK signals and their idlers, by a broadband polarization-insensitive fiber optic parametric amplifier. This novel all-optical signal processing approach to generate WDM-PCTWs enables a 2-fold reduction in the needed optical transmitters as compared to the conventional approach where each idler is generated by a dedicated transmitter. Digital coherent superposition of the twin waves at the receiver enables more than doubled reach in a dispersion-managed transmission link. We further study the impact of polarization-mode dispersion on the performance gain brought by the phase-conjugated twin waves, showing a gain of ~3.8 dB in signal quality factors.

  14. Development and applications of femtosecond monolithic Yb-doped fiber chirped-pulse amplifiers

    International Nuclear Information System (INIS)

    Zhu, L.

    2011-01-01

    In the past few years, compact and environmentally stable high-energy ultrashort pulse laser sources have been broadly utilized in many different applications. Fiber lasers offer big practical advantages over bulk solid-state laser systems in terms of flexibility, compactness, reliability, cost effectiveness and turn-key operability. Moreover, thermal effects are dramatically reduced due to the large surface-to-volume ratio of an optical fiber, and good spatial mode quality can be ensured by its waveguiding property. Therefore, a fiber-based laser system is considered to be the preferred laser architecture. The main theme of this thesis is the development of various femtosecond monolithic Yb-doped fiber chirped-pulse-amplification (FCPA) system and their applications. We demonstrate an ultrafast high-energy monolithic Yb-doped FCPA system in which the pulse fidelity is preserved by weakening the nonlinear effects via a substantial level of temporal stretching of the seed pulses and by using highly doped active fibers as amplifying media. The presented monolithic FCPA delivers up to ∼ 25 μJ diffraction-limited pulses that can be recompressed to sub-200 fs duration, and the pulse quality has been confirmed through the second-harmonic-generation (SHG) conversion efficiency of over 52%. Improved dispersion and nonlinearity management schemes of the FCPA system allowing substantial pulse energy scaling in the monolithic format as well as methods for overcoming a series of technological challenges are reported. Three different types of Yb-doped fiber oscillators have been developed and built in the course of this PhD work. First, we compare two oscillator types that are based on the all-normal-dispersion (ANDi) regime and the dispersion-managed (DM) regime. Both of them have been tested as the seed-pulse source of the monolithic Yb-doped FCPA system. Then we introduce another novel design based on higher-order-mode (HOM) dispersion management that competes with a

  15. Democratizing science with the aid of parametric design and additive manufacturing: Design and fabrication of a versatile and low-cost optical instrument for scattering measurement.

    Science.gov (United States)

    Nadal-Serrano, Jose M; Nadal-Serrano, Adolfo; Lopez-Vallejo, Marisa

    2017-01-01

    This paper focuses on the application of rapid prototyping techniques using additive manufacturing in combination with parametric design to create low-cost, yet accurate and reliable instruments. The methodology followed makes it possible to make instruments with a degree of customization until now available only to a narrow audience, helping democratize science. The proposal discusses a holistic design-for-manufacturing approach that comprises advanced modeling techniques, open-source design strategies, and an optimization algorithm using free parametric software for both professional and educational purposes. The design and fabrication of an instrument for scattering measurement is used as a case of study to present the previous concepts.

  16. Multiuser chirp modulation for underwater acoustic channel based on VTRM

    Directory of Open Access Journals (Sweden)

    Fei Yuan

    2017-05-01

    Full Text Available In this paper, an ascheme is proposed for multiuser underwater acoustic communication by using the multi-chirp rate signals. It differs from the well known TDMA (Time Division Multiple Access, FDMA (Frequency Division Multiple Access or CDMA (Code Division Multiple Access, by assigning each users with different chirp-rate carriers instead of the time, frequency or PN code. Multi-chirp rate signals can be separated from each other by FrFT (Fractional Fourier Transform, which can be regarded as the chirp-based decomposing, and superior to the match filter in the underwater acoustic channel. VTRM (Virtual Time Reverse Mirror is applied into the system to alleviate the ISI caused by the multipatch and make the equalization more simple. Results of computer simulations and pool experiments prove that the proposed multiuser underwater acoustic communication based on the multi-chirp rate exhibit well performance. Outfield experments carrie out in Xiamen Port show that using about 10 kHz bandwidth, four users could communicate at the same time with 425 bps with low BER and can match the UAC application.

  17. Propagation of frequency-chirped laser pulses in a medium of atoms with a Λ-level scheme

    International Nuclear Information System (INIS)

    Demeter, G.; Dzsotjan, D.; Djotyan, G. P.

    2007-01-01

    We study the propagation of frequency-chirped laser pulses in optically thick media. We consider a medium of atoms with a Λ level-scheme (Lambda atoms) and also, for comparison, a medium of two-level atoms. Frequency-chirped laser pulses that induce adiabatic population transfer between the atomic levels are considered. They induce transitions between the two lower (metastable) levels of the Λ-atoms and between the ground and excited states of the two-level atoms. We show that associated with this adiabatic population transfer in Λ-atoms, there is a regime of enhanced transparency of the medium--the pulses are distorted much less than in the medium of two-level atoms and retain their ability to transfer the atomic population much longer during propagation

  18. High efficiency, monolithic fiber chirped pulse amplification system for high energy femtosecond pulse generation.

    Science.gov (United States)

    Peng, Xiang; Kim, Kyungbum; Mielke, Michael; Jennings, Stephen; Masor, Gordon; Stohl, Dave; Chavez-Pirson, Arturo; Nguyen, Dan T; Rhonehouse, Dan; Zong, Jie; Churin, Dmitriy; Peyghambarian, N

    2013-10-21

    A novel monolithic fiber-optic chirped pulse amplification (CPA) system for high energy, femtosecond pulse generation is proposed and experimentally demonstrated. By employing a high gain amplifier comprising merely 20 cm of high efficiency media (HEM) gain fiber, an optimal balance of output pulse energy, optical efficiency, and B-integral is achieved. The HEM amplifier is fabricated from erbium-doped phosphate glass fiber and yields gain of 1.443 dB/cm with slope efficiency >45%. We experimentally demonstrate near diffraction-limited beam quality and near transform-limited femtosecond pulse quality at 1.55 µm wavelength. With pulse energy >100 µJ and pulse duration of 636 fs (FWHM), the peak power is estimated to be ~160 MW. NAVAIR Public Release Distribution Statement A-"Approved for Public release; distribution is unlimited".

  19. Randomly spaced chirped grating-based random fiber laser

    Science.gov (United States)

    Guo, Ziyang; Song, Jingxuan; Liu, Yimin; Liu, Zhaoxin; Shum, Ping; Dong, Xinyong

    2018-03-01

    A random fiber laser is demonstrated using a randomly spaced chirped-fiber Bragg grating (CFBG) array, which was fabricated along a 1-m-long erbium-doped fiber using a UV laser with a random separation ranging from 30 to 100 mm. Random distributed feedback is effectively realized through reflection of the CFBGs and further enhanced by changing chirp directions of the gratings. When pumped with a 980-nm laser diode, laser with multi-wavelength output was achieved with a pump threshold of 15 mW. Laser performance was studied as a function of pump power and time.

  20. Multiple Frequency Parametric Sonar

    Science.gov (United States)

    2015-09-28

    300003 1 MULTIPLE FREQUENCY PARAMETRIC SONAR STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and...a method for increasing the bandwidth of a parametric sonar system by using multiple primary frequencies rather than only two primary frequencies...2) Description of Prior Art [0004] Parametric sonar generates narrow beams at low frequencies by projecting sound at two distinct primary

  1. Cascaded chirped narrow bandpass filter with flat-top based on two-dimensional photonic crystals.

    Science.gov (United States)

    Zhuang, Yuyang; Chen, Heming; Ji, Ke

    2017-05-10

    We propose a structure of a cascaded chirped narrow bandpass filter with a flat-top based on two-dimensional (2D) photonic crystals (PhCs). The filter discussed here consists of three filter units, each with a resonator and two reflectors. Coupled mode theory and transfer matrix method are methodologies applied in the analysis of the features. The calculations show that the bandwidth of the filter can be adjusted by changing the distances between resonators and reflectors, and based on this, a flat-top response can be achieved by chirped-cascading the filter units. According to the theoretical model, we design a narrow bandpass filter based on 2D PhCs with a triangular lattice of air holes, the parameters of which are calculated using the finite element method. The simulation results show that the filter has a center frequency of 193.40 THz, an insertion loss of 0.18 dB, a flat bandwidth of 40 GHz, and ripples of about 0.2 dB in the passband. The filter is suitable for dense-wavelength-division-multiplexed optical communication systems with 100 GHz channel spacing.

  2. Parametric Instability in Advanced Laser Interferometer Gravitational Wave Detectors

    International Nuclear Information System (INIS)

    Ju, L; Grass, S; Zhao, C; Degallaix, J; Blair, D G

    2006-01-01

    High frequency parametric instabilities in optical cavities are radiation pressure induced interactions between test mass mechanical modes and cavity optical modes. The parametric gain depends on the cavity power and the quality factor of the test mass internal modes (usually in ultrasonic frequency range), as well as the overlap integral for the mechanical and optical modes. In advanced laser interferometers which require high optical power and very low acoustic loss test masses, parametric instabilities could prevent interferometer operation if not suppressed. Here we review the problem of parametric instabilities in advanced detector configurations for different combinations of sapphire and fused silica test masses, and compare three methods for control or suppression of parametric instabilities-thermal tuning, surface damping and active feedback

  3. Measurement and control of the frequency chirp rate of high-order harmonic pulses

    International Nuclear Information System (INIS)

    Mauritsson, J.; Johnsson, P.; Lopez-Martens, R.; Varju, K.; L'Huillier, A.; Kornelis, W.; Biegert, J.; Keller, U.; Gaarde, M.B.; Schafer, K.J.

    2004-01-01

    We measure the chirp rate of harmonics 13 to 23 in argon by cross correlation with a 12 femtosecond probe pulse. Under low ionization conditions, we directly measure the negative chirp due to the atomic dipole phase, and show that an additional chirp on the pump pulse is transferred to the qth harmonic as q times the fundamental chirp. Our results are in accord with simulations using the experimentally measured 815 nm pump and probe pulses. The ability to measure and manipulate the harmonic chirp rate is essential for the characterization and optimization of attosecond pulse trains

  4. Electron heating enhancement by frequency-chirped laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Yazdani, E.; Afarideh, H., E-mail: hafarideh@aut.ac.ir [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Sadighi-Bonabi, R., E-mail: Sadighi@sharif.ir [Department of Physics, Sharif University of Technology, P.O. Box 11365-9567, Tehran (Iran, Islamic Republic of); Riazi, Z. [Physics and Accelerator School, Tehran (Iran, Islamic Republic of); Hora, H. [Department of Theoretical Physics, University of New South Wales, Sydney 2052 (Australia)

    2014-09-14

    Propagation of a chirped laser pulse with a circular polarization through an uprising plasma density profile is studied by using 1D-3V particle-in-cell simulation. The laser penetration depth is increased in an overdense plasma compared to an unchirped pulse. The induced transparency due to the laser frequency chirp results in an enhanced heating of hot electrons as well as increased maximum longitudinal electrostatic field at the back side of the solid target, which is very essential in target normal sheath acceleration regime of proton acceleration. For an applied chirp parameter between 0.008 and 0.01, the maximum amount of the electrostatic field is improved by a factor of 2. Furthermore, it is noticed that for a chirped laser pulse with a₀=5, because of increasing the plasma transparency length, the laser pulse can penetrate up to about n{sub e}≈6n{sub c}, where n{sub c} is plasma critical density. It shows 63% increase in the effective critical density compared to the relativistic induced transparency regime for an unchirped condition.

  5. Effects of temperature on chirp rates of tree crickets (Orthoptera ...

    African Journals Online (AJOL)

    1991-10-02

    Oct 2, 1991 ... The relationship between temperature and chirp rate is described for three African tree crickets, Oecanthus capensis, 0. karschi and O. ... Finally, the animal should sing from an elevated position, such as a tree, shrub or ... incorrectly referred to as O. burmeisteri, is known for its baffle-making behaviour.

  6. Decoherence control in quantum computing with simple chirped ...

    Indian Academy of Sciences (India)

    We show how the use of optimally shaped pulses to guide the time evolution of a system ('coherent control') can be an effective approach towards quantum computation logic. We demonstrate this with selective control of decoherence for a multilevel system with a simple linearly chirped pulse. We use a multiphoton ...

  7. Decoherence control in quantum computing with simple chirped ...

    Indian Academy of Sciences (India)

    Abstract. We show how the use of optimally shaped pulses to guide the time evolution of a system. ('coherent control') can be an effective approach towards quantum computation logic. We demon- strate this with selective control of decoherence for a multilevel system with a simple linearly chirped pulse. We use a ...

  8. Optimal control of quantum systems by chirped pulses

    DEFF Research Database (Denmark)

    Amstrup, Bjarne; Doll, J. D.; Sauerbrey, R. A.

    1993-01-01

    Research on optimal control of quantum systems has been severely restricted by the lack of experimentally feasible control pulses. Here, to overcome this obstacle, optimal control is considered with the help of chirped pulses. Simulated annealing is used as the optimizing procedure. The examples ...

  9. Ultrafast geometric control of a single qubit using chirped pulses

    International Nuclear Information System (INIS)

    Hawkins, Patrick E; Malinovskaya, Svetlana A; Malinovsky, Vladimir S

    2012-01-01

    We propose a control strategy to perform arbitrary unitary operations on a single qubit based solely on the geometrical phase that the qubit state acquires after cyclic evolution in the parameter space. The scheme uses ultrafast linearly chirped pulses and provides the possibility of reducing the duration of a single-qubit operation to a few picoseconds.

  10. Parameter estimation of linear and quadratic chirps by employing ...

    Indian Academy of Sciences (India)

    dependent i.e. they require a priori knowledge about the nature of the chirp signal – linear or quadratic relation- ship between the time and instantaneous frequency. Most of them use techniques like Fractional. Fourier Transform (FrFT), Wigner Ville ...

  11. Ultra-Compact linear chirped microwave signal generator

    DEFF Research Database (Denmark)

    Yan, Siqi; Zhou, Feng; Dong, Jianji

    2017-01-01

    A novel concept to generate linear chirped microwave signal is proposed and experimentally verified. The frequency to time mapping method is used while the Mach-Zehnder interferometer based on the photonic crystal waveguide is employed as the key device with its significant advantages of the ultra...

  12. Decoherence control in quantum computing with simple chirped ...

    Indian Academy of Sciences (India)

    Decoherence control in quantum computing with simple chirped pulses. DEBABRATA GOSWAMI. Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India. Abstract. We show how the use of optimally shaped pulses to guide the time evolution of a system. ('coherent control') can be an effective ...

  13. Interaction of free charged particles with a chirped electromagnetic pulse

    NARCIS (Netherlands)

    Khachatryan, A.G.; van Goor, F.A.; Boller, Klaus J.

    2004-01-01

    We study the effect of chirp on electromagnetic (EM) pulse interaction with a charged particle. Both the one-dimensional (1D) and 3D cases are considered. It is found that, in contrast to the case of a nonchirped pulse, the charged particle energy can be changed after the interaction with a 1D EM

  14. On Parametric (and Non-Parametric Variation

    Directory of Open Access Journals (Sweden)

    Neil Smith

    2009-11-01

    Full Text Available This article raises the issue of the correct characterization of ‘Parametric Variation’ in syntax and phonology. After specifying their theoretical commitments, the authors outline the relevant parts of the Principles–and–Parameters framework, and draw a three-way distinction among Universal Principles, Parameters, and Accidents. The core of the contribution then consists of an attempt to provide identity criteria for parametric, as opposed to non-parametric, variation. Parametric choices must be antecedently known, and it is suggested that they must also satisfy seven individually necessary and jointly sufficient criteria. These are that they be cognitively represented, systematic, dependent on the input, deterministic, discrete, mutually exclusive, and irreversible.

  15. Reference hearing threshold levels for chirp signals delivered by an ER-3A insert earphone

    DEFF Research Database (Denmark)

    Gøtsche-Rasmussen, Kristian; Poulsen, Torben; Elberling, Claus

    2012-01-01

    Objective: To establish reference hearing threshold levels for chirps and frequency-specific chirps. Design: Hearing thresholds were determined monaurally for broad-band chirps and octave-band chirps using the Etymotic Research, ER-3A insert earphone. The chirps were presented using two repetition...... back from a Tucker Davies Technologies System II, and a Matlab program controlled the test setup. The results are specified in dB peak-to-peak equivalent threshold sound pressure levels (dB peETSPL). Study sample: The test group consisted of 25 otologically-normal young adults (age 18–25 years......). Results: The results are in good agreement with the results from another investigation of hearing thresholds using the same chirp stimuli, and the values for the octave-band chirps are in line with the standardized reference values for corresponding tone bursts (ISO 389-6, 2007). Conclusions: The results...

  16. MGL1109 Chirp - US Extended Continental Shelf Project: Gulf of Alaska CHIRP high-resolution Seismic Profile data.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Knudsen 2620 acquired sub-bottom profiles continuously throughout the cruise. The Knudsen was operated in 3.5 kHz Chirp mode, emitting a 1.5 kHz to 5 kHz (3 kHz...

  17. Optical model parametrization between 10keV and 20MeV. Application to the spherical nuclei 89Y and 93Nb

    International Nuclear Information System (INIS)

    Lagrange, C.

    1975-01-01

    Fast neutron cross sections for 89 Y and 93 Nb were calculated in the energy range 10keV-20MeV with the spherical optical model. The optical potential parameters used were obtained from a comparison theory-experiment using strength functions, potential scattering radius, total cross sections and differential elastic scattering data [fr

  18. Electron acceleration from rest to GeV energy by chirped axicon Gaussian laser pulse in vacuum in the presence of wiggler magnetic field

    Science.gov (United States)

    Kant, Niti; Rajput, Jyoti; Singh, Arvinder

    2018-03-01

    This paper presents a scheme of electron energy enhancement by employing frequency - chirped lowest order axicon focussed radially polarised (RP) laser pulse in vacuum under the influence of wiggler magnetic field. Terawatt RP laser can be focussed down to ∼5μm by an axicon optical element, which produces an intense longitudinal electric field. This unique property of axicon focused Gaussian RP laser pulse is employed for direct electron acceleration in vacuum. A linear frequency chirp increases the time duration of laser-electron interaction, whereas, the applied magnetic wiggler helps in improving the strength of ponderomotive force v→ ×B→ and periodically deflects electron in order to keep it traversing in the accelerating phase up to longer distance. Numerical simulations have been carried out to investigate the influence of laser, frequency chirp and magnetic field parameters on electron energy enhancement. It is noticed that an electron from rest can be accelerated up to GeV energy under optimized laser and magnetic field parameters. Significant enhancement in the electron energy gain of the order of 11.2 GeV is observed with intense chirped laser pulse in the presence of wiggler magnetic field of strength 96.2 kG.

  19. Distribution profiling of a transverse load using the DGD spectrum of chirped FBGs.

    Science.gov (United States)

    Descamps, Frédéric; Caucheteur, Christophe; Mégret, Patrice; Bette, Sébastien

    2015-07-13

    In this paper, we propose a new method to determine the longitudinal distribution of a non-uniform transverse force applied to an optical fiber. For that purpose, we use a chirped fiber Bragg grating (CFBG) for which we monitor the polarization parameters in reflection. In particular, we demonstrate that the differential group delay (DGD) spectrum of the CFBG is an imprint of the load profile so that it can be used for the shape determination of an applied load. Thereafter, we discuss the influence of the CFBG parameters on the achievable accuracy and resolution of our technique. An experimental validation is finally reported with two 48 mm long CFBGs subject to step transverse load profiles.

  20. Role of third-order dispersion in chirped Airy pulse propagation in single-mode fibers

    Science.gov (United States)

    Cai, Wangyang; Wang, Lei; Wen, Shuangchun

    2018-04-01

    The dynamic propagation of the initial chirped Airy pulse in single-mode fibers is studied numerically, special attention being paid to the role of the third-order dispersion (TOD). It is shown that for the positive TOD, the Airy pulse experiences inversion irrespective of the sign of initial chirp. The role of TOD in the dynamic propagation of the initial chirped Airy pulse depends on the combined sign of the group-velocity dispersion (GVD) and the initial chirp. If the GVD and chirp have the opposite signs, the chirped Airy pulse compresses first and passes through a breakdown area, then reconstructs a new Airy pattern with opposite acceleration, with the breakdown area becoming small and the main peak of the new Airy pattern becoming asymmetric with an oscillatory structure due to the positive TOD. If the GVD and chirp have the same signs, the finite-energy Airy pulse compresses to a focal point and then inverses its acceleration, in the case of positive TOD, the distance to the focal point becoming smaller. At zero-dispersion point, the finite-energy Airy pulse inverses to the opposite acceleration at a focal point, with the tight-focusing effect being reduced by initial chirp. Under the effect of negative TOD, the initial chirped Airy pulse disperses and the lobes split. In addition, in the anomalous dispersion region, for strong nonlinearity, the initial chirped Airy pulse splits and enters a soliton shedding regime.

  1. Photonic linear chirped microwave signal generation based on the ultra-compact spectral shaper using the slow light effect

    DEFF Research Database (Denmark)

    Yan, Siqi; Gao, Shengqian; Zhou, Feng

    2017-01-01

    A novel concept to generate a linear chirped microwave signal is proposed and experimentally demonstrated. The frequency to time mapping method is employed, where the photonic crystal waveguide Mach-Zehnder interferometer structure acts as the spectral shaper thanks to the slow light effect. By o....... The utilization of the slow light effect brings in significant advantages, including the ultra-small footprint of 0.096 mm(2) and simple structure to our scheme, which may be of great importance towards its potential applications. (C) 2017 Optical Society of America...

  2. Optically controlled tunable dispersion compensators based on pumped fiber gratings.

    Science.gov (United States)

    Shu, Xuewen; Sugden, Kate; Bennion, Ian

    2011-08-01

    We demonstrate optically tunable dispersion compensators based on pumping fiber Bragg gratings made in Er/Yb codoped fiber. The tunable dispersion for a chirped grating and also a uniform-period grating was successfully demonstrated in the experiment. The dispersion of the chirped grating was tuned from 900 to 1990 ps/nm and also from -600 to -950 ps/nm in the experiment. © 2011 Optical Society of America

  3. Electromagnetic Chirps from Neutron Star–Black Hole Mergers

    Science.gov (United States)

    Schnittman, Jeremy D.; Dal Canton, Tito; Camp, Jordan; Tsang, David; Kelly, Bernard J.

    2018-02-01

    We calculate the electromagnetic signal of a gamma-ray flare coming from the surface of a neutron star shortly before merger with a black hole companion. Using a new version of the Monte Carlo radiation transport code Pandurata that incorporates dynamic spacetimes, we integrate photon geodesics from the neutron star surface until they reach a distant observer or are captured by the black hole. The gamma-ray light curve is modulated by a number of relativistic effects, including Doppler beaming and gravitational lensing. Because the photons originate from the inspiraling neutron star, the light curve closely resembles the corresponding gravitational waveform: a chirp signal characterized by a steadily increasing frequency and amplitude. We propose to search for these electromagnetic chirps using matched filtering algorithms similar to those used in LIGO data analysis.

  4. Description of a New 400MHz Bandwidth Chirp Transform Spectrometer

    Science.gov (United States)

    Paganini, Lucas; Hartogh, Paul

    A new chirp transform spectrometer (CTS) with a bandwidth of 400MHz and a spectral resolution of 100 kHz has been developed. The CTS is deviced using a digital chirp generator and a preprocessing unit based on a Complementary Metal Oxide Semiconductor (CMOS) and an Application-Specific Integrated Circuit (ASIC). A build in PC 104 computer handles the process control and the external communication via Ethernet and a Transistor-Transistor Logic (TTL) interface. The CTS has been applied to atmospheric science, i.e., a 25-K noise temperature, 22-GHz water vapor, and a 142-GHz ozone system. Astronomical observations have been performed using the Heinrich Hertz submillimeter telescope. In this paper, we describe the function of the CTS and provide information about its functional performance.

  5. Parametric Transverse Patterns in Broad Aperture Lasers

    DEFF Research Database (Denmark)

    Grigorieva, E.V.; Kashchenko, S.A.; Mosekilde, Erik

    1998-01-01

    Parametrically generated optical patterns are investigated for finite and large-scale transverse aperture lasers. Standing and rotating patterns as well as periodic and chaotic pattern alternations are described in the framework of the amplitude equation formalism. Sensitive dependence...... on the geometrical size of the system is demonstrated even in the case of large-scale systems....

  6. Surface spontaneous parametric down-conversion

    Czech Academy of Sciences Publication Activity Database

    Peřina ml., Jan; Lukš, A.; Haderka, Ondřej

    2009-01-01

    Roč. 103, č. 6 (2009), 063902/1-063902/4 ISSN 0031-9007 R&D Projects: GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : parametric down-conversion * surface Subject RIV: BH - Optics, Masers, Lasers Impact factor: 7.328, year: 2009

  7. Parametrics in Urban Design

    DEFF Research Database (Denmark)

    Steinø, Nicolai; Obeling, Esben

    2013-01-01

    by the “Twitter revolution” and other social media phenomena in recent years – may also form the basis of this approach, adding a different reach to it. While different parametric design tools have different strengths and weaknesses, the CityEngine software programme is dedicated to parametric simulation...

  8. Parametrization of translational surfaces

    OpenAIRE

    Perez-Diaz, Sonia; Shen, Liyong

    2014-01-01

    The algebraic translational surface is a typical modeling surface in computer aided design and architecture industry. In this paper, we give a necessary and sufficient condition for that algebraic surface having a standard parametric representation and our proof is constructive. If the given algebraic surface is translational, then we can compute a standard parametric representation for the surface.

  9. Superharmonic imaging with chirp coded excitation: filtering spectrally overlapped harmonics.

    Science.gov (United States)

    Harput, Sevan; McLaughlan, James; Cowell, David M J; Freear, Steven

    2014-11-01

    Superharmonic imaging improves the spatial resolution by using the higher order harmonics generated in tissue. The superharmonic component is formed by combining the third, fourth, and fifth harmonics, which have low energy content and therefore poor SNR. This study uses coded excitation to increase the excitation energy. The SNR improvement is achieved on the receiver side by performing pulse compression with harmonic matched filters. The use of coded signals also introduces new filtering capabilities that are not possible with pulsed excitation. This is especially important when using wideband signals. For narrowband signals, the spectral boundaries of the harmonics are clearly separated and thus easy to filter; however, the available imaging bandwidth is underused. Wideband excitation is preferable for harmonic imaging applications to preserve axial resolution, but it generates spectrally overlapping harmonics that are not possible to filter in time and frequency domains. After pulse compression, this overlap increases the range side lobes, which appear as imaging artifacts and reduce the Bmode image quality. In this study, the isolation of higher order harmonics was achieved in another domain by using the fan chirp transform (FChT). To show the effect of excitation bandwidth in superharmonic imaging, measurements were performed by using linear frequency modulated chirp excitation with varying bandwidths of 10% to 50%. Superharmonic imaging was performed on a wire phantom using a wideband chirp excitation. Results were presented with and without applying the FChT filtering technique by comparing the spatial resolution and side lobe levels. Wideband excitation signals achieved a better resolution as expected, however range side lobes as high as -23 dB were observed for the superharmonic component of chirp excitation with 50% fractional bandwidth. The proposed filtering technique achieved >50 dB range side lobe suppression and improved the image quality without

  10. Short-range harmonic radar: chirp waveform, electronic targets

    Science.gov (United States)

    Mazzaro, Gregory J.; Gallagher, Kyle A.; Martone, Anthony F.; Sherbondy, Kelly D.; Narayanan, Ram M.

    2015-05-01

    Radio-frequency (RF) electronic targets, such as man-portable electronics, cannot be detected by traditional linear radar because the radar cross section of those targets is much smaller than that of nearby clutter. One technology that is capable of separating RF electronic targets from naturally-occurring clutter is nonlinear radar. Presented in this paper is the evolution of nonlinear radar at the United States Army Research Laboratory (ARL) and recent results of short-range over-the-air harmonic radar tests there. For the present implementation of ARL's nonlinear radar, the transmit waveform is a chirp which sweeps one frequency at constant amplitude over an ultra-wide bandwidth (UWB). The receiver captures a single harmonic of this entire chirp. From the UWB received harmonic, a nonlinear frequency response of the radar environment is constructed. An inverse Fourier Transform of this nonlinear frequency response reveals the range to the nonlinear target within the environment. The chirped harmonic radar concept is validated experimentally using a wideband horn antenna and commercial off-the-shelf electronic targets.

  11. Chirp Z-transform spectral zoom optimization with MATLAB.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Grant D.

    2005-11-01

    The MATLAB language has become a standard for rapid prototyping throughout all disciplines of engineering because the environment is easy to understand and use. Many of the basic functions included in MATLAB are those operations that are necessary to carry out larger algorithms such as the chirp z-transform spectral zoom. These functions include, but are not limited to mathematical operators, logical operators, array indexing, and the Fast Fourier Transform (FFT). However, despite its ease of use, MATLAB's technical computing language is interpreted and thus is not always capable of the memory management and performance of a compiled language. There are however, several optimizations that can be made within the chirp z-transform spectral zoom algorithm itself, and also to the MATLAB implementation in order to take full advantage of the computing environment and lower processing time and improve memory usage. To that end, this document's purpose is two-fold. The first demonstrates how to perform a chirp z-transform spectral zoom as well as an optimization within the algorithm that improves performance and memory usage. The second demonstrates a minor MATLAB language usage technique that can reduce overhead memory costs and improve performance.

  12. Effect of frequency chirping on supercontinuum generation in dispersion flatted and dispersion decreasing fiber

    International Nuclear Information System (INIS)

    Jin Wei; Xu Wencheng; Chen Zhaoxi; Xu Yongzhao; Yu Bingtao; Cui Hu; Liu Songhao

    2004-01-01

    The effect of frequency chirping on supercontinuum (SC) generation in dispersion flatted and dispersion decreasing fiber has been studied by numerical simulation based on the total field nonlinear Schroedinger equation. Our results show that a positive initial frequency chirp can significantly broaden the supercontinuum spectrum by up to approximate 80 nm, and the SC intensity increase about 5 dB. A range of optimal positive frequency chirps is identified to obtain the maximized supercontinuum bandwidth. The mechanism of this enhancement is also discussed detailedly through the evolutions of temporal and spectral width related to different pre-chirped pulses

  13. Parametric amplification in MoS2drum resonator.

    Science.gov (United States)

    Prasad, Parmeshwar; Arora, Nishta; Naik, A K

    2017-11-30

    Parametric amplification is widely used in diverse areas from optics to electronic circuits to enhance low level signals by varying relevant system parameters. Parametric amplification has also been performed in several micro-nano resonators including nano-electromechanical system (NEMS) resonators based on a two-dimensional (2D) material. Here, we report the enhancement of mechanical response in a MoS 2 drum resonator using degenerate parametric amplification. We use parametric pumping to modulate the spring constant of the MoS 2 resonator and achieve a 10 dB amplitude gain. We also demonstrate quality factor enhancement in the resonator with parametric amplification. We investigate the effect of cubic nonlinearity on parametric amplification and show that it limits the gain of the mechanical resonator. Amplifying ultra-small displacements at room temperature and understanding the limitations of the amplification in these devices is key for using these devices for practical applications.

  14. Multiharmonic Frequency-Chirped Transducers for Surface-Acoustic-Wave Optomechanics

    Science.gov (United States)

    Weiß, Matthias; Hörner, Andreas L.; Zallo, Eugenio; Atkinson, Paola; Rastelli, Armando; Schmidt, Oliver G.; Wixforth, Achim; Krenner, Hubert J.

    2018-01-01

    Wide-passband interdigital transducers are employed to establish a stable phase lock between a train of laser pulses emitted by a mode-locked laser and a surface acoustic wave generated electrically by the transducer. The transducer design is based on a multiharmonic split-finger architecture for the excitation of a fundamental surface acoustic wave and a discrete number of its overtones. Simply by introducing a variation of the transducer's periodicity p , a frequency chirp is added. This combination results in wide frequency bands for each harmonic. The transducer's conversion efficiency from the electrical to the acoustic domain is characterized optomechanically using single quantum dots acting as nanoscale pressure sensors. The ability to generate surface acoustic waves over a wide band of frequencies enables advanced acousto-optic spectroscopy using mode-locked lasers with fixed repetition rate. Stable phase locking between the electrically generated acoustic wave and the train of laser pulses is confirmed by performing stroboscopic spectroscopy on a single quantum dot at a frequency of 320 MHz. Finally, the dynamic spectral modulation of the quantum dot is directly monitored in the time domain combining stable phase-locked optical excitation and time-correlated single-photon counting. The demonstrated scheme will be particularly useful for the experimental implementation of surface-acoustic-wave-driven quantum gates of optically addressable qubits or collective quantum states or for multicomponent Fourier synthesis of tailored nanomechanical waveforms.

  15. Parametric and Non-Parametric System Modelling

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg

    1999-01-01

    considered. It is shown that adaptive estimation in conditional parametric models can be performed by combining the well known methods of local polynomial regression and recursive least squares with exponential forgetting. The approach used for estimation in conditional parametric models also highlights how...... of a linear model are estimated as functions of some explanatory variable(s). Also, software for handling the estimation is presented. The software runs under S-PLUS and R and contains also a number of tools useful when doing model diagnostics or interpreting the results. Adaptive estimation is also...... networks is included. In this paper, neural networks are used for predicting the electricity production of a wind farm. The results are compared with results obtained using an adaptively estimated ARX-model. Finally, two papers on stochastic differential equations are included. In the first paper, among...

  16. Overhead Transmission Line Sag Estimation Using a Simple Optomechanical System with Chirped Fiber Bragg Gratings. Part 1: Preliminary Measurements.

    Science.gov (United States)

    Wydra, Michal; Kisala, Piotr; Harasim, Damian; Kacejko, Piotr

    2018-01-20

    A method of measuring the power line wire sag using optical sensors that are insensitive to high electromagnetic fields was proposed. The advantage of this technique is that it is a non-invasive measurement of power line wire elongation using a unique optomechanical system. The proposed method replaces the sag of the power line wire with an extension of the control sample and then an expansion of the attached chirped fiber Bragg grating. This paper presents the results of the first measurements made on real aluminum-conducting steel-reinforced wire, frequently used for power line construction. It has been shown that the proper selection of the CFBG (chirped fiber Bragg grating) transducer and the appropriate choice of optical parameters of such a sensor will allow for high sensitivity of the line wire elongation and sag while reducing the sensitivity to the temperature. It has been shown that with a simple optomechanical system, a non-invasive measurement of the power line wire sag that is insensitive to temperature changes and the influence of high electromagnetic fields can be achieved.

  17. parametric nonlinear quasivariational inequalities

    Directory of Open Access Journals (Sweden)

    Zeqing Liu

    2005-01-01

    uniqueness results and sensitivity analysis of solutions are also established for the system of generalized nonlinear parametric quasivariational inequalities and some convergence results of iterative sequence generated by the algorithm with errors are proved.

  18. Controlling Parametric Resonance

    DEFF Research Database (Denmark)

    Galeazzi, Roberto; Pettersen, Kristin Ytterstad

    2012-01-01

    if the system undergoing it could transform the large amplitude motion into, for example, energy. Therefore the development of control strategies to induce parametric resonance into a system can be as valuable as those which aim at stabilizing the resonant oscillations. By means of a mechanical equivalent......Parametric resonance is a resonant phenomenon which takes place in systems characterized by periodic variations of some parameters. While seen as a threatening condition, whose onset can drive a system into instability, this chapter advocates that parametric resonance may become an advantage...... the authors review the conditions for the onset of parametric resonance, and propose a nonlinear control strategy in order to both induce the resonant oscillations and to stabilize the unstable motion. Lagrange’s theory is used to derive the dynamics of the system and input–output feedback linearization...

  19. Summary Report on A Seamap-C Chirp Deconvolution Algorithm With Demonstrations Using Synthetic and Field Data

    National Research Council Canada - National Science Library

    Lindwall, Dennis

    2004-01-01

    This report describes several ways to generate a chirp signal for the Seamap-C side-scan sonar system and then to remove the chirp signal from the field data to produce high-resolution sea floor images...

  20. Capacity Building with CHIRPS Amidst a Station-Recording Crisis

    Science.gov (United States)

    Peterson, P.

    2016-12-01

    Station data are essential for improving the accuracy of satellite-derived rainfall products. However we face a severe reporting crisis as the number of available stations observations has declined precipitously. For example there were 2400 monthly stations available in Africa (excluding South Africa) in the 1980's, while at present there are about 500 stations (Figure 1). In this talk we describe how partnerships with regional and national collaborators can improve our collective ability to monitor food production and inform decision making. A high quality, long-term, high-resolution precipitation dataset is key for supporting agricultural drought monitoring, food security and early warning. Here we present the Climate Hazards group InfraRed Precipitation with Stations (CHIRPS) v2.0, developed by scientists at the University of California, Santa Barbara and the U.S. Geological Survey Earth Resources Observation and Science Center under the direction of Famine Early Warning Systems Network (FEWS NET). This quasi-global precipitation product is available at daily to seasonal time scales with a spatial resolution of 0.05° and a 1981 to near real-time period of record. The Climate Hazards Group (CHG) has developed an extensive database of in situ daily, pentadal, and monthly precipitation totals with over a billion daily observations worldwide. Under support from the USAID FEWS NET, CHG/USGS has developed a two way strategy for incorporating contributed station data while providing web-based visualization tools to partners in developing nations. For example, we are currently working with partners in Mexico (Conagua), Southern Africa (SASSCAL), Colombia (IDEAM), Somalia (SWALIM) and Ethiopia (NMA). These institutions provide in situ observations which enhance the CHIRPS. The CHIRPS is then placed in a web accessible geospatial database. Partners in these countries can then access and display this information using web based mapping tools. This provides a win

  1. Plasma absorption evidence via chirped pulse spectral transmission measurements

    Energy Technology Data Exchange (ETDEWEB)

    Jedrkiewicz, Ottavia, E-mail: ottavia.jedrkiewicz@ifn.cnr.it [Istituto di Fotonica e Nanotecnologie, CNR and CNISM UdR Como, Via Valleggio 11, I-22100 Como (Italy); Minardi, Stefano [Institute of Applied Physics, Friedrich-Schiller-University Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Couairon, Arnaud; Jukna, Vytautas [Centre de Physique Theorique, CNRS, Ecole Polytechnique, F-91128 Palaiseau (France); Selva, Marco; Di Trapani, Paolo [Dipartimento di Scienza e Alta Tecnologia, University of Insubria and CNISM UdR Como, Via Valleggio 11, I-22100 Como (Italy)

    2015-06-08

    This work aims at highlighting the plasma generation dynamics and absorption when a Bessel beam propagates in glass. We developed a simple diagnostics allowing us to retrieve clear indications of the formation of the plasma in the material, thanks to transmission measurements in the angular and wavelength domains. This technique featured by the use of a single chirped pulse having the role of pump and probe simultaneously leads to results showing the plasma nonlinear absorption effect on the trailing part of the pulse, thanks to the spectral-temporal correspondence in the measured signal, which is also confirmed by numerical simulations.

  2. Superimposed chirped pulse parameter estimation based on the extended Kalman filter (EKF)

    CSIR Research Space (South Africa)

    Olivier, JC

    2009-05-01

    Full Text Available An extended Kalman filter (EKF) is proposed to estimate the frequencies and chirp rate of multiple superimposed chirped pulses. The estimation problem is a difficult one, where maximum likelyhood methods are very complex especially if more than two...

  3. Low-frequency versus high-frequency synchronisation in chirp-evoked auditory brainstem responses

    DEFF Research Database (Denmark)

    Rønne, Filip Munch; Gøtsche-Rasmussen, Kristian

    2011-01-01

    This study investigates the frequency specific contribution to the auditory brainstem response (ABR) of chirp stimuli. Frequency rising chirps were designed to compensate for the cochlear traveling wave delay, and lead to larger wave-V amplitudes than for click stimuli as more auditory nerve fibres...

  4. Propagation and reflection of chirped pulses in the nonuniform ionospheric plasma

    International Nuclear Information System (INIS)

    Levitsky, S.M.

    2009-01-01

    By passing of a chirped pulse in a inhomogeneous ionospheric plasma this pulses due to the dispersion futures of the plasma becomes deformed and can be strongly compressed. The chirped pulse can be compressed also being reflected by the ionosphere. This can give some advantage using such pulses in the experiments of ionospheric zoning.

  5. Backward Raman amplification in plasmas with chirped wideband pump and seed pulses

    Science.gov (United States)

    Wu, Zhao-Hui; Wei, Xiao-Feng; Zuo, Yan-Lei; Liu, Lan-Qin; Zhang, Zhi-Meng; Li, Min; Zhou, Yu-Liang; Su, Jing-Qin

    2015-01-01

    Chirped wideband pump and seed pulses are usually considered for backward Raman amplification (BRA) in plasmas to achieve an extremely high-power laser pulse. However, current theoretical models only contain either a chirped pump or a chirped seed. In this paper, modified three-wave coupling equations are proposed for the BRA in the plasmas with both chirped wideband pump and seed. The simulation results can more precisely describe the experiments, such as the Princeton University experiment. The optimized chirp and bandwidth are determined based on the simulation to enhance the output intensity and efficiency. Project supported by the National Natural Science Foundation of China (Grant No. 11305157) and the Development Foundation of China Academy of Engineering Physics Laboratory (CAEPL) (Grant No. 2013A0401019).

  6. Laser chirp effect on femtosecond laser filamentation generated for pulse compression.

    Science.gov (United States)

    Park, Juyun; Lee, Jae-Hwan; Nam, Chang H

    2008-03-31

    The influence of laser chirp on the formation of femtosecond laser filamentation in Ar was investigated for the generation of few-cycle high-power laser pulses. The condition for the formation of a single filament has been carefully examined using 28-fs laser pulses with energy over 3 mJ. The filament formation and output spectrum changed very sensitively to the initial laser chirp and gas pressure. Much larger spectral broadening was obtained with positively chirped pulses, compared to the case of negatively chirped pulses that generated much longer filament, and compressed pulses of 5.5 fs with energy of 0.5 mJ were obtained from the filamentation of positively chirped 30-fs laser pulses in a single Ar cell.

  7. Female house crickets, Acheta domesticus, prefer the chirps of large males.

    Science.gov (United States)

    Gray

    1997-12-01

    This study demonstrates that invertebrate acoustic signals can provide information about male phenotypic attributes, and that females can use this acoustic information in mate choice to select a phenotypically superior mate. I investigated the relationships between a male acoustic sexual signal, the phenotype of the signaller, and the female response to signal variation. I recorded and analysed the calling songs of male house crickets, Acheta domesticus. The analyses showed that chirps convey information about male size. With the exception of amplitude, the mean number of pulses per chirp was the best predictor of male size. I performed a laboratory tape-playback experiment to determine female preference during phonotaxis. Females preferred tapes playing the chirps of large males, specifically chirps with a greater number of pulses per chirp. Selection on the female preference is discussed.Copyright 1997 The Association for the Study of Animal Behaviour

  8. Transverse-to-longitudinal Emittance-exchange with an Energy Chirped Beam

    Energy Technology Data Exchange (ETDEWEB)

    Thangaraj, J.; Ruan, J.; Johnson, A.S.; Thurman-Keup, R.; Lumpkin, A.H.; Santucci, J.; Sun, Y.-E; Maxwell, T.; Edwards, H.; /Fermilab

    2012-05-01

    Emittance exchange has been proposed to increase the performance of free electron lasers by tailoring the phase space of an electron beam. The principle of emittance exchange - where the transverse phase space of the electron beam is exchanged with the longitudinal phase space - has been demonstrated recently at the A0 photoinjector. The experiment used a low charge bunch (250 pC) with no energy chirp. Theory predicts an improvement in the emittance exchange scheme when the incoming beam has an energy chirp imparted on it. The energy chirp helps to overcome the thick lens effect of the deflecting mode cavity and other second order effects that might lead to an incomplete emittance exchange at higher charges. In this work, we report experimental and simulation results from operating the emittance exchange beam line using an energy chirped beam with higher charge (500 pC) at different RF-chirp settings.

  9. Extension of supercontinuum spectrum, generated in polarization-maintaining photonic crystal fiber, using chirped femtosecond pulses

    Science.gov (United States)

    Vengelis, Julius; Jarutis, Vygandas; Sirutkaitis, Valdas

    2018-01-01

    We present results of experimental and numerical investigation of supercontinuum (SC) generation in polarization-maintaining photonic crystal fiber (PCF) using chirped femtosecond pulses. The initial unchirped pump pulse source was a mode-locked Yb:KGW laser generating 52-nJ energy, 110-fs duration pulses at 1030 nm with a 76-MHz repetition rate. The nonlinear medium was a 32-cm-long polarization-maintaining PCF manufactured by NKT Photonics A/S. We demonstrated the influence of pump pulse chirp on spectral characteristics of a SC. We showed that by chirping pump pulses positively or negatively one can obtain a broader SC spectrum than in the case of unchirped pump pulses at the same peak power. Moreover, the extension can be controlled by changing the amount of pump pulse chirp. Numerical simulation results also indicated that pump pulse chirp yields an extension of SC spectrum.

  10. Parametric Powder Diffraction

    Science.gov (United States)

    David, William I. F.; Evans, John S. O.

    The rapidity with which powder diffraction data may be collected, not only at neutron and X-ray synchrotron facilities but also in the laboratory, means that the collection of a single diffraction pattern is now the exception rather than the rule. Many experiments involve the collection of hundreds and perhaps many thousands of datasets where a parameter such as temperature or pressure is varied or where time is the variable and life-cycle, synthesis or decomposition processes are monitored or three-dimensional space is scanned and the three-dimensional internal structure of an object is elucidated. In this paper, the origins of parametric diffraction are discussed and the techniques and challenges of parametric powder diffraction analysis are presented. The first parametric measurements were performed around 50 years ago with the development of a modified Guinier camera but it was the automation afforded by neutron diffraction combined with increases in computer speed and memory that established parametric diffraction on a strong footing initially at the ILL, Grenoble in France. The theoretical parameterisation of quantities such as lattice constants and atomic displacement parameters will be discussed and selected examples of parametric diffraction over the past 20 years will be reviewed that highlight the power of the technique.

  11. Chirp echo Fourier transform EPR-detected NMR

    Science.gov (United States)

    Wili, Nino; Jeschke, Gunnar

    2018-04-01

    A new ultra-wide band (UWB) pulse EPR method is introduced for observing all nuclear frequencies of a paramagnetic center in a single shot. It is based on burning spectral holes with a high turning angle (HTA) pulse that excites forbidden transitions and subsequent detection of the hole pattern by a chirp echo. We term this method Chirp Echo Epr SpectroscopY (CHEESY)-detected NMR. The approach is a revival of FT EPR-detected NMR. It yields similar spectra and the same type of information as electron-electron double resonance (ELDOR)-detected NMR, but with a multiplex advantage. We apply CHEESY-detected NMR in Q band to nitroxides and correlate the hyperfine spectrum to the EPR spectrum by varying the frequency of the HTA pulse. Furthermore, a selective π pulse before the HTA pulse allows for detecting hyperfine sublevel correlations between transitions of one nucleus and for elucidating the coupling regime, the same information as revealed by the HYSCORE experiment. This is demonstrated on hexaaquamanganese(II). We expect that CHEESY-detected NMR is generally applicable to disordered systems and that our results further motivate the development of EPR spectrometers capable of coherent UWB excitation and detection, especially at higher fields and frequencies.

  12. Parametric Amplification of a Superconducting Plasma Wave.

    Science.gov (United States)

    Rajasekaran, S; Casandruc, E; Laplace, Y; Nicoletti, D; Gu, G D; Clark, S R; Jaksch, D; Cavalleri, A

    2016-11-01

    Many applications in photonics require all-optical manipulation of plasma waves1, which can concentrate electromagnetic energy on sub-wavelength length scales. This is difficult in metallic plasmas because of their small optical nonlinearities. Some layered superconductors support Josephson plasma waves (JPWs)2,3, involving oscillatory tunneling of the superfluid between capacitively coupled planes. Josephson plasma waves are also highly nonlinear4, and exhibit striking phenomena like cooperative emission of coherent terahertz radiation5,6, superconductor-metal oscillations7 and soliton formation8. We show here that terahertz JPWs can be parametrically amplified through the cubic tunneling nonlinearity in a cuprate superconductor. Parametric amplification is sensitive to the relative phase between pump and seed waves and may be optimized to achieve squeezing of the order parameter phase fluctuations9 or single terahertz-photon devices.

  13. Parametric autoresonant excitation of the nonlinear Schrödinger equation.

    Science.gov (United States)

    Friedland, L; Shagalov, A G

    2016-10-01

    Parametric excitation of autoresonant solutions of the nonlinear Schrodinger (NLS) equation by a chirped frequency traveling wave is discussed. Fully nonlinear theory of the process is developed based on Whitham's averaged variational principle and its predictions verified in numerical simulations. The weakly nonlinear limit of the theory is used to find the threshold on the amplitude of the driving wave for entering the autoresonant regime. It is shown that above the threshold, a flat (spatially independent) NLS solution can be fully converted into a traveling wave. A simplified, few spatial harmonics expansion approach is also developed for studying this nonlinear mode conversion process, allowing interpretation as autoresonant interaction within triads of spatial harmonics.

  14. Solitary-wave emission fronts, spectral chirping, and coupling to beam acoustic modes in RPIC simulation of SRS backscatter.

    Energy Technology Data Exchange (ETDEWEB)

    DuBois, D. F. (Donald F.); Yin, L. (Lin); Daughton, W. S. (William S.); Bezzerides, B. (Bandel); Dodd, E. S. (Evan S.); Vu, H. X. (Hoanh X.)

    2004-01-01

    Detailed diagnostics of quasi-2D RPIC simulations of backward stimulated Raman scattering (BSRS), from single speckles under putative NIF conditions, reveal a complex spatio-temporal behavior. The scattered light consists of localized packets, tens of microns in width, traveling toward the laser at an appreciable fraction of the speed of light. Sub pico-second reflectivity pulses occur as these packets leave the system. The LW activity consists of a front traveling with the light packets with a wake of free LWs traveling in the laser direction. The parametric coupling occurs in the front where the scattered light and LW overlap and are strongest. As the light leaves the plasma the LW quickly decays, liberating its trapped electrons. The high frequency part of the |n{sub e}(k,{omega})|{sup 2} spectrum, where n{sub e} is the electron density fluctuation, consists of a narrow streak or straight line with a slope that is the velocity of the parametric front. The time dependence of |n{sub e}(k,t)|{sup 2}, shows that during each pulse the most intense value of k also 'chirps' to higher values, consistent with the k excursions seen in the |n{sub e}(k,{omega})|{sup 2} spectrum. But k does not always return, in the subsequent pulses, to the original parametrically matched value, indicating that, in spite of side loss, the electron distribution function does not return to its original Maxwellian form. Liberated pulses of hot electrons result in down-stream, bump on tail distributions that excite LWs and beam acoustic modes deeper in the plasma. The frequency broadened spectra are consistent with Thomson scatter spectra observed in TRIDENT single-hot-spot experiments in the high k{lambda}{sub D}, trapping regime. Further details including a comparison of results from full PIC simulations, and movies of the spatio-temporal behavior, will be given in the poster by L Yin et al.

  15. PARAMETRIC DRAWINGS VS. AUTOLISP

    Directory of Open Access Journals (Sweden)

    PRUNĂ Liviu

    2015-06-01

    Full Text Available In this paper the authors make a critical analysis of the advantages offered by the parametric drawing use by comparison with the AutoLISP computer programs used when it comes about the parametric design. Studying and analysing these two work models the authors have got to some ideas and conclusions which should be considered in the moment in that someone must to decide if it is the case to elaborate a software, using the AutoLISP language, or to establish the base rules that must be followed by the drawing, in the idea to construct outlines or blocks which can be used in the projection process.

  16. PARAMETRIC DRAWINGS VS. AUTOLISP

    OpenAIRE

    PRUNĂ Liviu; SLONOVSCHI Andrei

    2015-01-01

    In this paper the authors make a critical analysis of the advantages offered by the parametric drawing use by comparison with the AutoLISP computer programs used when it comes about the parametric design. Studying and analysing these two work models the authors have got to some ideas and conclusions which should be considered in the moment in that someone must to decide if it is the case to elaborate a software, using the AutoLISP language, or to establish the base rules that must be followed...

  17. Marine substrate response from the analysis of seismic attributes in CHIRP sub-bottom profiles

    Directory of Open Access Journals (Sweden)

    Larissa Felicidade Werkhauser Demarco

    Full Text Available Abstract This paper presents an evaluation of the response of seismic reflection attributes in different types of marine substrate (rock, shallow gas, sediments using seafloor samples for ground-truth statistical comparisons. The data analyzed include seismic reflection profiles collected using two CHIRP subbottom profilers (Edgetech Model 3100 SB-216S, with frequency ranging between 2 and 16 kHz, and a number (38 of sediment samples collected from the seafloor. The statistical method used to discriminate between different substratum responses was the non-parametric Kruskal-Wallis analysis, carried out in two steps: 1 comparison of Seismic Attributes between different marine substrates (unconsolidated sediments, rock and shallow gas; 2 comparison of Seismic Attributes between different sediment classes in seafloors characterized by unconsolidated sediments (subdivided according to sorting. These analyses suggest that amplitude-related attributes were effective in discriminating between sediment and gassy/rocky substratum, but did not differentiate between rocks and shallow gas. On the other hand, the Instantaneous Frequency attribute was effective in differentiating sediments, rocks and shallow gas, with sediment showing higher frequency range, rock an intermediate range, and shallow gas the lowest response. Regarding grain-size classes and sorting, statistical analysis discriminated between two distinct groups of samples, the SVFS (silt and very fine sand and the SFMC (fine, medium and coarse sand groups. Using a Spearman coefficient, it was found that the Instantaneous Amplitude was more efficient in distinguishing between the two groups. None of the attributes was able to distinguish between the closest grain size classes such as those of silt and very fine sand.

  18. Parametric Human Movements

    DEFF Research Database (Denmark)

    Herzog, Dennis

    with an investigation of PHMM training methods and structures to utilize the PHMM as a unified representation of parametric primitives, which is adequate for recognition and for synthesis. This is evaluated on a large motion data set. Main contributions of the thesis are the development and evaluation of approaches...

  19. Parametric modal transition systems

    DEFF Research Database (Denmark)

    Beneš, Nikola; Křetínský, Jan; Larsen, Kim Guldstrand

    2011-01-01

    in the refinement process like exclusive, conditional and persistent choices. We introduce a new model called parametric modal transition systems (PMTS) together with a general modal refinement notion that overcome many of the limitations and we investigate the computational complexity of modal refinement checking....

  20. Optics

    CERN Document Server

    Mathieu, Jean Paul

    1975-01-01

    Optics, Parts 1 and 2 covers electromagnetic optics and quantum optics. The first part of the book examines the various of the important properties common to all electromagnetic radiation. This part also studies electromagnetic waves; electromagnetic optics of transparent isotropic and anisotropic media; diffraction; and two-wave and multi-wave interference. The polarization states of light, the velocity of light, and the special theory of relativity are also examined in this part. The second part is devoted to quantum optics, specifically discussing the classical molecular theory of optical p

  1. Influence of laser frequency chirp on deuteron energy from laser-driven deuterated methane cluster expansion

    Energy Technology Data Exchange (ETDEWEB)

    Li, H.Y. [College of Physics and Electronic Information, Tianjin Normal University, Tianjin, P.R. (China); Liu, J.S. [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, P.R. (China)

    2010-06-15

    The simulations of three-dimensional particle dynamics are carried out to investigate the Coulomb explosion dynamics of deuterated methane clusters under the irradiation of an ultrashort intense laser pulse. The final kinetic energy of deuterons produced from the cluster explosion is calculated as a function of the pulse width, the laser intensity and the pulse chirp. It is found that the deuteron energy obtained in an intense laser pulse with negative chirp is higher than that with positive chirp, which agrees qualitatively with the experimental results reported by Fukuda et al. [Y. Fukuda et al., Phys. Rev. A 67, 061201 (2003)]. (authors)

  2. Influence of laser frequency chirp on deuteron energy from laser-driven deuterated methane cluster expansion

    Science.gov (United States)

    Li, H. Y.; Liu, J. S.

    2010-06-01

    The simulations of three-dimensional particle dynamics are carried out to investigate the Coulomb explosion dynamics of deuterated methane clusters under the irradiation of an ultrashort intense laser pulse. The final kinetic energy of deuterons produced from the cluster explosion is calculated as a function of the pulse width, the laser intensity and the pulse chirp. It is found that the deuteron energy obtained in an intense laser pulse with negative chirp is higher than that with positive chirp, which agrees qualitatively with the experimental results reported by Fukuda et al. [Y. Fukuda et al., Phys. Rev. A 67, 061201 (2003)].

  3. Explanation of the JET n=0 chirping mode

    International Nuclear Information System (INIS)

    Berk, H.L.; Boswell, C.J.; Borba, D.; Figueiredo, A.C.A.; Nave, M.F.F.; Johnson, T.; Pinches, S.D.; Sharapov, S.E.

    2006-01-01

    Persistent rapid up and down frequency chirping modes with a toroidal mode number of zero (n=0) are observed in the JET tokomak when energetic ions, in the range of several hundred keV, are created by high field side ion cyclotron resonance frequency heating. Fokker-Planck calculations demonstrate that the heating method enables the formation of an energetically inverted ion distribution which supplies the free energy for the ions to excite a mode related to the geodesic acoustic mode (GAM). The large frequency shifts of this mode are attributed to the formation of phase space structures whose frequencies, which are locked to an ion orbit bounce resonance frequency, are forced to continually shift so that energetic particle energy can be released to counterbalance the energy dissipation present in the background plasma. (author)

  4. Parametric instabilities in advanced gravitational wave detectors

    International Nuclear Information System (INIS)

    Gras, S; Zhao, C; Blair, D G; Ju, L

    2010-01-01

    As the LIGO interferometric gravitational wave detectors have finished gathering a large observational data set, an intense effort is underway to upgrade these observatories to improve their sensitivity by a factor of ∼10. High circulating power in the arm cavities is required, which leads to the possibility of parametric instability due to three-mode opto-acoustic resonant interactions between the carrier, transverse optical modes and acoustic modes. Here, we present detailed numerical analysis of parametric instability in a configuration that is similar to Advanced LIGO. After examining parametric instability for a single three-mode interaction in detail, we examine instability for the best and worst cases, as determined by the resonance condition of transverse modes in the power and signal recycling cavities. We find that, in the best case, the dual recycling detector is substantially less susceptible to instability than a single cavity, but its susceptibility is dependent on the signal recycling cavity design, and on tuning for narrow band operation. In all cases considered, the interferometer will experience parametric instability at full power operation, but the gain varies from 3 to 1000, and the number of unstable modes varies between 7 and 30 per test mass. The analysis focuses on understanding the detector complexity in relation to opto-acoustic interactions, on providing insights that can enable predictions of the detector response to transient disturbances, and of variations in thermal compensation conditions.

  5. Pulsed single-photon spectrometer by frequency-to-time mapping using chirped fiber Bragg gratings.

    Science.gov (United States)

    Davis, Alex O C; Saulnier, Paul M; Karpiński, Michał; Smith, Brian J

    2017-05-29

    A fiber-integrated spectrometer for single-photon pulses outside the telecommunications wavelength range based upon frequency-to-time mapping, implemented by chromatic group delay dispersion (GDD), and precise temporally-resolved single-photon counting, is presented. A chirped fiber Bragg grating provides low-loss GDD, mapping the frequency distribution of an input pulse onto the temporal envelope of the output pulse. Time-resolved detection with fast single-photon-counting modules enables monitoring of a wavelength range from 825 nm to 835 nm with nearly uniform efficiency at 55 pm resolution (24 GHz at 830 nm). To demonstrate the versatility of this technique, spectral interference of heralded single photons and the joint spectral intensity distribution of a photon-pair source are measured. This approach to single-photon-level spectral measurements provides a route to realize applications of time-frequency quantum optics at visible and near-infrared wavelengths, where multiple spectral channels must be simultaneously monitored.

  6. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  7. MEMS digital parametric loudspeaker

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2016-03-23

    This paper reports on the design and fabrication of MEMS actuator arrays suitable for Digital Sound reconstruction and Parametric Directional Loudspeakers. Two distinct versions of the device were fabricated: one using the electrostatic principle actuation and the other one, the piezoelectric principle. Both versions used similar membrane dimensions, with a diameter of 500 μm. These devices are the smallest Micro-Machined Ultrasound Transducer (MUT) arrays that can be operated for both modes: Digital Sound Reconstruction and Parametric Loudspeaker. The chips consist of an array with 256 transducers, in a footprint of 12 mm by 12 mm. The total single chip size is: 2.3 cm by 2.3 cm, including the contact pads. © 2016 IEEE.

  8. Macromechanical Parametric Amplification

    DEFF Research Database (Denmark)

    Neumeyer, Stefan

    between the two peaks can be altered. The first experimental bistable amplified steady-state responses are also reported. The derived analytical models and experimental setups can readily be extended to investigate other factors. Some of the results are also applicable to the more general field of systems...... for energy harvesting. Using analytical, numerical, and experimental methods, the thesis focuses on superthreshold pumping (above the systems parametric instability threshold), nonlinear effects, frequency response backbones, and frequency detuning effects for parametric amplifiers. Part one of the thesis...... covers superthreshold pumping and nonlinear effects. Superthresh-old pumping produces some useful characteristics. For instance, strong superthreshold pumping yields a high gain even though nonlinear effects tend to reduce it. In addition, a narrower excitation phase range is realized for which...

  9. Parametric Explosion Spectral Model

    Energy Technology Data Exchange (ETDEWEB)

    Ford, S R; Walter, W R

    2012-01-19

    Small underground nuclear explosions need to be confidently detected, identified, and characterized in regions of the world where they have never before occurred. We develop a parametric model of the nuclear explosion seismic source spectrum derived from regional phases that is compatible with earthquake-based geometrical spreading and attenuation. Earthquake spectra are fit with a generalized version of the Brune spectrum, which is a three-parameter model that describes the long-period level, corner-frequency, and spectral slope at high-frequencies. Explosion spectra can be fit with similar spectral models whose parameters are then correlated with near-source geology and containment conditions. We observe a correlation of high gas-porosity (low-strength) with increased spectral slope. The relationship between the parametric equations and the geologic and containment conditions will assist in our physical understanding of the nuclear explosion source.

  10. A multi-wavelength fiber laser based on superimposed fiber grating and chirp fiber Bragg grating for wavelength selection

    Science.gov (United States)

    Wang, Feng; Bi, Wei-hong; Fu, Xing-hu; Jiang, Peng; Wu, Yang

    2015-11-01

    In this paper, a new type of multi-wavelength fiber laser is proposed and demonstrated experimentally. Superimposed fiber grating (SIFG) and chirp fiber Bragg grating (CFBG) are used for wavelength selection. Based on gain equalization technology, by finely adjusting the stress device in the cavity, the gain and loss are equal, so as to suppress the modal competition and achieve multi-wavelength lasing at room temperature. The experimental results show that the laser can output stable multi-wavelength lasers simultaneously. The laser coupling loss is small, the structure is simple, and it is convenient for integration, so it can be widely used in dense wavelength division multiplexing (DWDM) system and optical fiber sensors.

  11. Towards Stabilizing Parametric Active Contours

    DEFF Research Database (Denmark)

    Liu, Jinchao; Fan, Zhun; Olsen, Søren Ingvor

    2014-01-01

    to a parametrization that is proportional to the natural parametrization which implies that the control points of the contour are uniformly distributed. We theoretically prove that this tangential diffusion term is bounded and therefore numerically stable. Several experiments were conducted and verified......Numerical instability often occurs in evolving of parametric active contours. This is mainly due to the undesired change of parametrization during evolution. In this paper, we propose a new tangential diffusion term to compensate this undesired change. As a result, the parametrization will converge...

  12. Meta-Parametric Design

    OpenAIRE

    Harding, John E.; Shepherd, Paul

    2017-01-01

    Parametric modelling software often maintains an explicit history of design development in the form of a graph. However, as the graph increases in complexity it quickly becomes inflexible and unsuitable for exploring a wide design space. By contrast, implicit low-level rule systems can offer wide design exploration due to their lack of structure, but often act as black boxes to human observers with only initial conditions and final designs cognisable. In response to these two extremes, the au...

  13. Propagation properties of the chirped Airy beams through the gradient-index medium

    Science.gov (United States)

    Feng, Liyan; Zhang, Jianbin; Pang, Zihao; Wang, Linyi; Zhong, Tianfen; Yang, Xiangbo; Deng, Dongmei

    2017-11-01

    Through analytical derivation and numerical analysis, the propagation properties of the chirped Airy(CAi) beams in the gradient-index medium are investigated. The intensity and the phase distributions, the propagation trajectory and the Poynting vector of the CAi beams are demonstrated to investigate the propagation properties. Owing to the special and symmetrical refractive index profile of the gradient-index medium, the CAi beams propagate periodically. The effects of the distribution factor and the chirped parameter on the propagation of the CAi beams are analyzed. As the increasing of the distribution factor, the intensity distribution of the CAi beams is more scattering. However, with the chirped parameter increasing, the focusing property of the CAi beams strengthens. The variation of the chirped parameter can change the position of the peak intensity maximum, but it cannot alter the period of the peak intensity. The variations of the initial phase and the energy of the beams in the transverse plane expedite accordingly.

  14. Fabry-Pérot cavity based on chirped sampled fiber Bragg gratings.

    Science.gov (United States)

    Zheng, Jilin; Wang, Rong; Pu, Tao; Lu, Lin; Fang, Tao; Li, Weichun; Xiong, Jintian; Chen, Yingfang; Zhu, Huatao; Chen, Dalei; Chen, Xiangfei

    2014-02-10

    A novel kind of Fabry-Pérot (FP) structure based on chirped sampled fiber Bragg grating (CSFBG) is proposed and demonstrated. In this structure, the regular chirped FBG (CFBG) that functions as reflecting mirror in the FP cavity is replaced by CSFBG, which is realized by chirping the sampling periods of a sampled FBG having uniform local grating period. The realization of such CSFBG-FPs having diverse properties just needs a single uniform pitch phase mask and sub-micrometer precision moving stage. Compared with the conventional CFBG-FP, it becomes more flexible to design CSFBG-FPs of diverse functions, and the fabrication process gets simpler. As a demonstration, based on the same experimental facilities, FPs with uniform FSR (~73 pm) and chirped FSR (varying from 28 pm to 405 pm) are fabricated respectively, which shows good agreement with simulation results.

  15. Parametric Resonance in Dynamical Systems

    CERN Document Server

    Nijmeijer, Henk

    2012-01-01

    Parametric Resonance in Dynamical Systems discusses the phenomenon of parametric resonance and its occurrence in mechanical systems,vehicles, motorcycles, aircraft and marine craft, and micro-electro-mechanical systems. The contributors provide an introduction to the root causes of this phenomenon and its mathematical equivalent, the Mathieu-Hill equation. Also included is a discussion of how parametric resonance occurs on ships and offshore systems and its frequency in mechanical and electrical systems. This book also: Presents the theory and principles behind parametric resonance Provides a unique collection of the different fields where parametric resonance appears including ships and offshore structures, automotive vehicles and mechanical systems Discusses ways to combat, cope with and prevent parametric resonance including passive design measures and active control methods Parametric Resonance in Dynamical Systems is ideal for researchers and mechanical engineers working in application fields such as MEM...

  16. Comparing auditory brainstem responses (ABRs) to toneburst and narrow band CE-chirp in young infants.

    Science.gov (United States)

    Rodrigues, Gabriela Ribeiro Ivo; Ramos, Natália; Lewis, Doris Ruthi

    2013-09-01

    The difference of characteristics (latency and amplitude) between toneburst and narrow CE-chirp stimuli on ABR recording was analyzed in normal hearing infants. 500, 1000, 2000 and 4000 Hz toneburst and narrow band CE-chirp auditory brainstem responses (ABRs) were recorded in 40 normal-hearing infants. The amplitude and latency parameters of the ABR were collected for each of the four stimulus levels: 80, 60, 40, and 20 dB nHL. Both stimuli started from 80 dB nHL using alternating polarity and the rates were both 27.1/s. The toneburst latencies are greater than narrow band CE-chirp latencies for all intensities at 500, 1000 and 2000 Hz (p Hz this difference was not significant. At 500 Hz, wave V amplitude is larger for toneburst than narrow CE-chirp (p Hz there is no difference between the wave V toneburst and narrow band CE-chirp amplitudes at 80 dB nHL (p = 0.940; p = 0.776 and p = 0.217 respectively). On the other hand, in the levels to 60, 40 and 20 dB nHL, narrow band CE-chirp amplitudes are larger than toneburst amplitude (p < 0.001). Narrow band CE-chirp ABRs generates shorter latencies than the toneburst ABRs, especially to low frequencies. Higher amplitudes were found with narrow band CE-chirp stimuli for all frequencies tested, except to high levels. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  17. LS CE-Chirp® vs. Click in the neuroaudiological diagnosis by ABR.

    Science.gov (United States)

    Cargnelutti, Michelle; Cóser, Pedro Luis; Biaggio, Eliara Pinto Vieira

    The chirp stimulus was developed seeking to counterbalance the delay of the sound wave on its journey through the cochlea, allowing the hair cells to depolarize at the same time. The result is a simultaneous stimulation providing better neural synchrony and, consequently, the recording of responses with greater amplitudes. To compare the absolute latency of waves I, III and V, the interpeak intervals I-III, III-V and I-V, amplitude values of wave V and its association with the amplitude of wave I, and the interaural difference V-V in the auditory brainstem response (ABR) using Click and LS CE-Chirp ® stimuli to determine whether the responses evoked by LS CE-Chirp ® could be applied to neuroaudiological diagnosis. Cross-sectional study with 30 normal-hearing individuals. The parameters used were: intensity of 85dBnHL, alternating polarity; 17.1 stimuli/s and 100-3000Hz filters. The absolute latencies of waves I, III and V observed with LS CE-Chirp ® and click did not show significant differences. Significantly higher amplitudes of wave V were observed with the LS CE-Chirp ® . The interaural difference between the wave V latencies between stimuli showed no significant difference. The LS CE-Chirp ® stimulus was shown to be as efficient as the click to capture ABR at high levels of stimulation, with the advantage of producing greater-amplitude V waves. Copyright © 2016. Published by Elsevier Editora Ltda.

  18. Optical parametric amplification beyond the slowly varying ...

    Indian Academy of Sciences (India)

    Here, the effect of the backward waves is equivalent to keeping the second spatial derivatives of the fields in the coupled-wave equations, as was originally shown by Shen ([1],. §3.3). The periodic behavior of the signal (idler) intensity distribution within the medium about the corresponding SVA distribution, resulted from the ...

  19. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  20. Parametric Trace Slicing

    Science.gov (United States)

    Rosu, Grigore (Inventor); Chen, Feng (Inventor); Chen, Guo-fang; Wu, Yamei; Meredith, Patrick O. (Inventor)

    2014-01-01

    A program trace is obtained and events of the program trace are traversed. For each event identified in traversing the program trace, a trace slice of which the identified event is a part is identified based on the parameter instance of the identified event. For each trace slice of which the identified event is a part, the identified event is added to an end of a record of the trace slice. These parametric trace slices can be used in a variety of different manners, such as for monitoring, mining, and predicting.

  1. Investigation of Non-linear Chirp Coding for Improved Second Harmonic Pulse Compression.

    Science.gov (United States)

    Arif, Muhammad; Ali, Muhammad Asim; Shaikh, Muhammad Mujtaba; Freear, Steven

    2017-08-01

    Non-linear frequency-modulated (NLFM) chirp coding was investigated to improve the pulse compression of the second harmonic chirp signal by reducing the range side lobe level. The problem of spectral overlap between the fundamental component and second harmonic component (SHC) was also investigated. Therefore, two methods were proposed: method I for the non-overlap condition and method II with the pulse inversion technique for the overlap harmonic condition. In both methods, the performance of the NLFM chirp was compared with that of the reference LFM chirp signals. Experiments were performed using a 2.25 MHz transducer mounted coaxially at a distance of 5 cm with a 1 mm hydrophone in a water tank, and the peak negative pressure of 300 kPa was set at the receiver. Both simulations and experimental results revealed that the peak side lobe level (PSL) of the compressed SHC of the NLFM chirp was improved by at least 13 dB in method I and 5 dB in method II when compared with the PSL of LFM chirps. Similarly, the integrated side lobe level (ISL) of the compressed SHC of the NLFM chirp was improved by at least 8 dB when compared with the ISL of LFM chirps. In both methods, the axial main lobe width of the compressed NLFM chirp was comparable to that of the LFM signals. The signal-to-noise ratio of the SHC of NLFM was improved by as much as 0.8 dB, when compared with the SHC of the LFM signal having the same energy level. The results also revealed the robustness of the NLFM chirp under a frequency-dependent attenuation of 0.5 dB/cm·MHz up to a penetration depth of 5 cm and a Doppler shift up to 12 kHz. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  2. Stimulated Brillouin Scattering (SBS) Suppression and Long Delivery Fibers at the Multikilowatt Level with Chirped Seed Lasers

    Science.gov (United States)

    2017-03-16

    the Multikilowatt Level with Chirped Seed Lasers by Jeffrey O White, Mark Harfouche, John Edgecumbe, Naresh Satyan, George Rakuljic, and Amnon...Suppression and Long Delivery Fibers at the Multikilowatt Level with Chirped Seed Lasers by Jeffrey O White Sensors and Electron Devices Directorate, ARL...Fibers at the Multikilowatt Level with Chirped Seed Lasers 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S

  3. Combining parametric, semi-parametric, and non-parametric survival models with stacked survival models.

    Science.gov (United States)

    Wey, Andrew; Connett, John; Rudser, Kyle

    2015-07-01

    For estimating conditional survival functions, non-parametric estimators can be preferred to parametric and semi-parametric estimators due to relaxed assumptions that enable robust estimation. Yet, even when misspecified, parametric and semi-parametric estimators can possess better operating characteristics in small sample sizes due to smaller variance than non-parametric estimators. Fundamentally, this is a bias-variance trade-off situation in that the sample size is not large enough to take advantage of the low bias of non-parametric estimation. Stacked survival models estimate an optimally weighted combination of models that can span parametric, semi-parametric, and non-parametric models by minimizing prediction error. An extensive simulation study demonstrates that stacked survival models consistently perform well across a wide range of scenarios by adaptively balancing the strengths and weaknesses of individual candidate survival models. In addition, stacked survival models perform as well as or better than the model selected through cross-validation. Finally, stacked survival models are applied to a well-known German breast cancer study. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Parametric Linear Dynamic Logic

    Directory of Open Access Journals (Sweden)

    Peter Faymonville

    2014-08-01

    Full Text Available We introduce Parametric Linear Dynamic Logic (PLDL, which extends Linear Dynamic Logic (LDL by temporal operators equipped with parameters that bound their scope. LDL was proposed as an extension of Linear Temporal Logic (LTL that is able to express all ω-regular specifications while still maintaining many of LTL's desirable properties like an intuitive syntax and a translation into non-deterministic Büchi automata of exponential size. But LDL lacks capabilities to express timing constraints. By adding parameterized operators to LDL, we obtain a logic that is able to express all ω-regular properties and that subsumes parameterized extensions of LTL like Parametric LTL and PROMPT-LTL. Our main technical contribution is a translation of PLDL formulas into non-deterministic Büchi word automata of exponential size via alternating automata. This yields a PSPACE model checking algorithm and a realizability algorithm with doubly-exponential running time. Furthermore, we give tight upper and lower bounds on optimal parameter values for both problems. These results show that PLDL model checking and realizability are not harder than LTL model checking and realizability.

  5. Thermally tunable dispersion compensator in 40-Gb/s system using FBG fabricated with linearly chirped phase mask.

    Science.gov (United States)

    Sun, Jie; Dai, Yitang; Chen, Xiangfei; Zhang, Yejin; Xie, Shizhong

    2006-01-09

    An improved design and fabrication method of nonlinearly chirped fiber Bragg gratings is demonstrated. Based on reconstruction-equivalent- chirp method, the nonlinearly chirped fiber Bragg grating is realized with a linearly chirped phase mask instead of a uniform one, which improves the performance of the device. Coated with uniform thin metal film, the obtained grating works as a tunable dispersion compensator with a tuning range ~200ps/nm, peak-to-peak group delay ripple fiber using carrier suppressed return-to-zero format is less than 0.7dB at a BER=10-10.

  6. A Study of Mexican Free-Tailed Bat Chirp Syllables: Bayesian Functional Mixed Models for Nonstationary Acoustic Time Series

    KAUST Repository

    Martinez, Josue G.

    2013-06-01

    We describe a new approach to analyze chirp syllables of free-tailed bats from two regions of Texas in which they are predominant: Austin and College Station. Our goal is to characterize any systematic regional differences in the mating chirps and assess whether individual bats have signature chirps. The data are analyzed by modeling spectrograms of the chirps as responses in a Bayesian functional mixed model. Given the variable chirp lengths, we compute the spectrograms on a relative time scale interpretable as the relative chirp position, using a variable window overlap based on chirp length. We use 2D wavelet transforms to capture correlation within the spectrogram in our modeling and obtain adaptive regularization of the estimates and inference for the regions-specific spectrograms. Our model includes random effect spectrograms at the bat level to account for correlation among chirps from the same bat, and to assess relative variability in chirp spectrograms within and between bats. The modeling of spectrograms using functional mixed models is a general approach for the analysis of replicated nonstationary time series, such as our acoustical signals, to relate aspects of the signals to various predictors, while accounting for between-signal structure. This can be done on raw spectrograms when all signals are of the same length, and can be done using spectrograms defined on a relative time scale for signals of variable length in settings where the idea of defining correspondence across signals based on relative position is sensible.

  7. The effect of a laser beam displacement on parametric oscillatory instabilities for Advanced LIGO

    International Nuclear Information System (INIS)

    Heinert, D.; Strigin, S.E.

    2011-01-01

    The arm cavities of real gravitational wave detectors can show small deviations like a tilt or a spatial shift between the cavity mirrors. These deviations lead to a separation of the optical mode centres with respect to the mirror's centre. In this Letter we perform the computation of parametric instable modes considering the described displacement. We further analyse the possibility of parametric oscillatory instability in the Advanced LIGO interferometer for the case of a displaced arm cavity. Our results reveal an additional number of optical and elastic mode combinations due to a displacement that can give rise to the undesirable effect of parametric oscillatory instability. -- Highlights: → We analyse the possibility of parametric oscillatory instability in the Advanced LIGO interferometer. → We perform the computation of parametric instable modes considering the mirror displacement. → Our results reveal an additional number of optical and elastic mode unstable combinations.

  8. Classification rates: non‐parametric verses parametric models using ...

    African Journals Online (AJOL)

    The local likelihood technique was used to model fit the data sets. The same sets of data were modeled using parametric logit and the abilities of the two models to correctly predict the binary outcome compared. The results obtained showed that non‐parametric estimation gives a better prediction rate (classification ratio) for ...

  9. Use of parametric and non-parametric survival analysis techniques ...

    African Journals Online (AJOL)

    This paper presents parametric and non-parametric survival analysis procedures that can be used to compare acaricides. The effectiveness of Delta Tick Pour On and Delta Tick Spray in knocking down tsetse flies were determined. The two formulations were supplied by Chemplex. The comparison was based on data ...

  10. Versatile engineering of multimode squeezed states by optimizing the pump spectral profile in spontaneous parametric down-conversion

    Science.gov (United States)

    Arzani, Francesco; Fabre, Claude; Treps, Nicolas

    2018-03-01

    We study the quantum correlations induced by spontaneous parametric down-conversion of a frequency comb. We derive a theoretical method to find the output state corresponding to a pump with an arbitrary spectral profile. After applying it to the relevant example of a spectrally chirped pump, we run an optimization algorithm to numerically find the pump profiles maximizing some target functions. These include the number of independently squeezed modes and the variances of nullifiers defining cluster states used in many continuous-variable quantum information protocols. To assess the advantages of pump shaping in real experiments, we take into account the physical limitations of the pulse shaper.

  11. Investigation of Chirped InAs/InGaAlAs/InP Quantum Dash Lasers as Broadband Emitters

    KAUST Repository

    Khan, Mohammed Zahed Mustafa

    2014-02-01

    In this paper, we assessed the effect of additionally broadened quantum dash (Qdash) optical transitions in the multi-stack dash-in-a-well laser structure at both, material and device level. A broad photoluminescence linewidth of ?150 nm demonstrates the formation of highly inhomogeneous InAs-dashes across the stacks. The transmission electron microscopy revealed small (large) average dash height from the Qdash stack with thick (thin) over grown barrier layer. The Fabry-Perot laser diodes fabricated from this chirped structure exhibits unique device physics under the short pulsewidth (SPW) and quasi-continuous wave (QCW) operation. Varying the ridge-width W from 2 to 4 ?rm showed quenching of ultrabroad lasing signature in the SPW operation, and consistent even for a wide 15 ?rm oxide strip laser diode. A lasing spectral split with reduced intensity gap in the center is observed in the QCW operation with the gap decreasing with increasing ridge-width. Such atypical lasing operation, influenced by the waveguiding mechanism is qualitatively realized by associating to the reduced vertical coupling effect of the Qdash stacks in the operation of small ridge-width lasers compared with large ridge-width and oxide stripe lasers, and leading to varying non-uniform distribution of carriers among the inhomogeneously broadened Qdash stacks in each case. Our chirped 2 × 830 ?rm ridge laser demonstrated marked improvement in the internal quantum efficiency (?80) and -3 dB lasing bandwidth, >50 nm centered at ?1.61 ?m. © 2013 IEEE.

  12. Basic consideration on identification of objects using chirped ultrasonic wave; Chirp choonpa wo mochiita keijo hanbetsu no kisoteki kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Jitsumori, A. [Mitsubishi Electric Corp., Tokyo (Japan)] Ando, S. [Tokyo Univ. (Japan)

    1998-11-30

    Regarding identification of geometrical features of objects using echoes of ultrasonic pulses, there are generally two ways. One is the way that a beam of ultrasonic waves having sharp directivity scan on a object, and the other is the way that ultrasonic waves, irradiating a object so as to cover the whole of it, capture the features of all the object at a time. In this paper, the theoretical basis about the latter were investigated. A mathematical model with which lumpiness of a object can be dealed as the sum of echoes from relatively small number of certain particular points (stationary points) was derived. The stationary points meaning local maximal points, saddle points, etc., it was investigated what is the optimum waveform that can separate and identify echoes from other portions. It being difficult to supply high energy in short time, if temporal width of a pulse is made larger, resolution of echoes come to fall. As a measure for solution, contraction of pulse width was attempted using chirped ultrasonic wave (modulated carrier frequency). The pulse of AM (amplitude modification) or LFM (linear frequency modulation) being selected, experimental results agreed fairly well the simulations. 10 refs., 13 figs.

  13. Ionization Cooling using Parametric Resonances

    International Nuclear Information System (INIS)

    Johnson, Rolland P.

    2008-01-01

    Ionization Cooling using Parametric Resonances was an SBIR project begun in July 2004 and ended in January 2008 with Muons, Inc., (Dr. Rolland Johnson, PI), and Thomas Jefferson National Accelerator Facility (JLab) (Dr. Yaroslav Derbenev, Subcontract PI). The project was to develop the theory and simulations of Parametric-resonance Ionization Cooling (PIC) so that it could be used to provide the extra transverse cooling needed for muon colliders in order to relax the requirements on the proton driver, reduce the site boundary radiation, and provide a better environment for experiments. During the course of the project, the theoretical understanding of PIC was developed and a final exposition is ready for publication. Workshops were sponsored by Muons, Inc. in May and September of 2007 that were devoted to the PIC technique. One outcome of the workshops was the interesting and somewhat unexpected realization that the beam emittances using the PIC technique can get small enough that space charge forces can be important. A parallel effort to develop our G4beamline simulation program to include space charge effects was initiated to address this problem. A method of compensating for chromatic aberrations by employing synchrotron motion was developed and simulated. A method of compensating for spherical aberrations using beamline symmetry was also developed and simulated. Different optics designs have been developed using the OptiM program in preparation for applying our G4beamline simulation program, which contains all the power of the Geant4 toolkit. However, no PIC channel design that has been developed has had the desired cooling performance when subjected to the complete G4beamline simulation program. This is believed to be the consequence of the difficulties of correcting the aberrations associated with the naturally large beam angles and beam sizes of the PIC method that are exacerbated by the fringe fields of the rather complicated channel designs that have been

  14. Radiation parametric generation in non-linear crystals

    International Nuclear Information System (INIS)

    Pacheco, M.T.; Pereira, M.A.C.Q.

    1983-01-01

    A short historical development review is presented on the optical parametric oscillators. Analysis on behaviour of the simple resonant oscillators (SRO), double resonant oscillators (DRO) and ring resonant oscillators (RRO), in the plane wave pumping approximation is shown. Comparision between the three oscillators types is given. (Author) [pt

  15. Parametric binary dissection

    Science.gov (United States)

    Bokhari, Shahid H.; Crockett, Thomas W.; Nicol, David M.

    1993-01-01

    Binary dissection is widely used to partition non-uniform domains over parallel computers. This algorithm does not consider the perimeter, surface area, or aspect ratio of the regions being generated and can yield decompositions that have poor communication to computation ratio. Parametric Binary Dissection (PBD) is a new algorithm in which each cut is chosen to minimize load + lambda x(shape). In a 2 (or 3) dimensional problem, load is the amount of computation to be performed in a subregion and shape could refer to the perimeter (respectively surface) of that subregion. Shape is a measure of communication overhead and the parameter permits us to trade off load imbalance against communication overhead. When A is zero, the algorithm reduces to plain binary dissection. This algorithm can be used to partition graphs embedded in 2 or 3-d. Load is the number of nodes in a subregion, shape the number of edges that leave that subregion, and lambda the ratio of time to communicate over an edge to the time to compute at a node. An algorithm is presented that finds the depth d parametric dissection of an embedded graph with n vertices and e edges in O(max(n log n, de)) time, which is an improvement over the O(dn log n) time of plain binary dissection. Parallel versions of this algorithm are also presented; the best of these requires O((n/p) log(sup 3)p) time on a p processor hypercube, assuming graphs of bounded degree. How PBD is applied to 3-d unstructured meshes and yields partitions that are better than those obtained by plain dissection is described. Its application to the color image quantization problem is also discussed, in which samples in a high-resolution color space are mapped onto a lower resolution space in a way that minimizes the color error.

  16. CHIRP-Like Signals: Estimation, Detection and Processing A Sequential Model-Based Approach

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J. V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-08-04

    Chirp signals have evolved primarily from radar/sonar signal processing applications specifically attempting to estimate the location of a target in surveillance/tracking volume. The chirp, which is essentially a sinusoidal signal whose phase changes instantaneously at each time sample, has an interesting property in that its correlation approximates an impulse function. It is well-known that a matched-filter detector in radar/sonar estimates the target range by cross-correlating a replicant of the transmitted chirp with the measurement data reflected from the target back to the radar/sonar receiver yielding a maximum peak corresponding to the echo time and therefore enabling the desired range estimate. In this application, we perform the same operation as a radar or sonar system, that is, we transmit a “chirp-like pulse” into the target medium and attempt to first detect its presence and second estimate its location or range. Our problem is complicated by the presence of disturbance signals from surrounding broadcast stations as well as extraneous sources of interference in our frequency bands and of course the ever present random noise from instrumentation. First, we discuss the chirp signal itself and illustrate its inherent properties and then develop a model-based processing scheme enabling both the detection and estimation of the signal from noisy measurement data.

  17. Extension of supercontinuum spectrum generated in photonic crystal fiber by using chirped femtosecond pulses

    Science.gov (United States)

    Vengelis, Julius; Jarutis, Vygandas; Sirutkaitis, Valdas

    2017-08-01

    We present results of experimental and numerical investigation of supercontinuum generation in polarization maintaining photonic crystal fiber (PCF) using chirped femtosecond pulses. The initial unchirped pump pulse source was a mode-locked Yb:KGW laser generating 52 nJ energy 110 fs duration pulses at 1030 nm with 76 MHz repetition rate. The nonlinear medium was a 32 cm long polarization maintaining PCF manufactured by NKT Photonics A/S. We demonstrated the influence of pump pulse chirp on spectral characteristics of supercontinuum. We showed that by chirping pump pulses positively or negatively one can obtain broader supercontinuum spectrum than in case of unchirped pump pulses at the same peak power. Moreover, the extension can be controlled by changing the amount of pump pulse chirp. In our case the supercontinuum spectrum width was extended by up to 115 nm (at maximum chirp value of +10500 fs2 that we could achieve in our setup) compared to the case of unchirped pump at the same peak power.

  18. Mechanical Parametric Oscillations and Waves

    Science.gov (United States)

    Dittrich, William; Minkin, Leonid; Shapovalov, Alexander S.

    2013-01-01

    Usually parametric oscillations are not the topic of general physics courses. Probably it is because the mathematical theory of this phenomenon is relatively complicated, and until quite recently laboratory experiments for students were difficult to implement. However parametric oscillations are good illustrations of the laws of physics and can be…

  19. Segmented Chirped-Pulse Millimeter-Wave Spectroscopy for Astrochemistry

    Science.gov (United States)

    Arenas, Benjamin E.; Steber, Amanda; Gruet, Sébastien; Schnell, Melanie

    2016-06-01

    The ability to detect molecules in the interstellar medium (ISM) is afforded to us by the collaboration of state-of-the-art observations, like from the Atacama Large Millimeter/submillimeter Array (ALMA), and high-resolution laboratory spectra. Here, we present our use of a commercial segmented chirped-pulse Fourier transform millimeter-wave rotational spectrometer to study simple oxygen-containing organic molecules. Our spectrometer operates in the region 75 - 110 GHz, providing an overlap with ALMA's Band 3 and allowing direct comparison of our laboratory spectra with observational data. We have measured rotational spectra of 1,2-propanediol[1, 2, 3] and methyl acetate[4, 5] in this spectral range at room temperature - both have been previously studied in the microwave and millimeter-wave regions. The rotational spectrum of the former in the 3 mm region shows eight different conformers to date. Spectral bandwidth overlap with ALMA Band 3 will allow for easier detection of new chemicals in the ISM. [1] Caminati, W., J. Mol. Spectrosc., 86(1), 193-201, 1981. [2] Lovas, F. J., Plusquellic, D. F., Pate, B. H., Neill, J. T., Muckle, M. T. and Remijan, A. J., J. Mol. Spectrosc., 257(1), 82-93, 2009. [3] Bossa, J. -B., Ordu, M. H., Müller, H. S. P., Lewen, F. and Schlemmer, S., Astron. Astrophys., 570, A12, 2014. [4] Tudorie, M., Kleiner, I., Hougen, J. T., Melandri, S., Sutikdja, L. W. and Stahl, W., J. Mol. Spectrosc., 269, 211-225, 2011. [5] Nguyen, H. V. L., Kleiner, I., Shipman, S. T., Mae, Y., Hirose, K., Hatanaka, S. and Kobayashi, K., J. Mol. Spectrosc., 299, 17-21, 2014.

  20. Numerical studies of driven, chirped Bernstein, Greene, and Kruskal modes

    International Nuclear Information System (INIS)

    Peinetti, F.; Bertsche, W.; Fajans, J.; Wurtele, J.; Friedland, L.

    2005-01-01

    Recent experiments showed the possibility of creating long-lived, nonlinear kinetic structures in a pure-electron plasma. These structures, responsible for large-amplitude periodic density fluctuations, were induced by driving the plasma with a weak oscillating drive, whose frequency was adiabatically decreased in time [W. Bertsche, J. Fajans, and L. Friedland, Phys. Rev. Lett. 91, 265003 (2003)]. A one-dimensional analytical model of the system was developed [L. Friedland, F. Peinetti, W. Bertsche, J. Fajans, and J. Wurtele, Phys. Plasmas 11, 4305 (2004)], which pointed out the phenomenon responsible for the modifications induced by the weak drive in the phase-space distribution of the plasma (initially Maxwellian). In order to validate the theory and to perform quantitative comparisons with the experiments, a more accurate description of the system is developed and presented here. The new detailed analysis of the geometry under consideration allows for more precise simulations of the excitation process, in which important physical and geometrical parameters (such as the length of the plasma column) are evaluated accurately. The numerical investigations probe properties and features of the modes not accessible to direct measurement. Due to the presence of two distinct time scales (because of the adiabatic chirp of the drive frequency), a fully two-dimensional numerical study of the system is expected to be rather time consuming. This becomes particularly important when, as here, a large number of comparisons (covering a wide range of drive parameters) are performed. For this reason, a coupled one-dimensional, radially averaged model is derived and implemented in a particle-in-cell code

  1. Direct generation of 81 nJ pulses and external compression to a subpicosecond regime with a 4.9 MHz chirped-pulse multipass-cavity Cr⁴⁺:forsterite oscillator.

    Science.gov (United States)

    Cankaya, Huseyin; Akturk, Selcuk; Sennaroglu, Alphan

    2011-05-01

    We report direct generation of 81 nJ chirped pulses from a room-temperature, Kerr lens mode-locked Cr⁴⁺:forsterite oscillator operating at 1258 nm. To increase the pulse energy, the pulse repetition rate of the short x-type resonator was lowered from 143 to 4.9 MHz by the addition of a q-preserving multipass cavity, which provided an additional effective optical path length of 59.4 m. The duration of the chirped pulses was around 5.5 ps with a spectral width of 21 nm. The pulses were externally compressed to 607 fs by using a diffraction grating pair. To our knowledge, this is the highest reported pulse energy directly generated from a room-temperature mode-locked Cr⁴⁺:forsterite laser.

  2. Toward a compact fibered squeezing parametric source.

    Science.gov (United States)

    Brieussel, Alexandre; Ott, Konstantin; Joos, Maxime; Treps, Nicolas; Fabre, Claude

    2018-03-15

    In this work, we investigate three different compact fibered systems generating vacuum squeezing that involve optical cavities limited by the end surface of a fiber and by a curved mirror and containing a thin parametric crystal. These systems have the advantage to couple squeezed states directly to a fiber, allowing the user to benefit from the flexibility of fibers in the use of squeezing. Three types of fibers are investigated: standard single-mode fibers, photonic-crystal large-mode-area single-mode fibers, and short multimode fibers taped to a single-mode fiber. The observed squeezing is modest (-0.56  dB, -0.9  dB, -1  dB), but these experiments open the way for miniaturized squeezing devices that could be a very interesting advantage in scaling up quantum systems for quantum processing, opening new perspectives in the domain of integrated quantum optics.

  3. Femtosecond X-ray Pulses from a Spatially Chirped Electron Bunch in a SASE FEL

    Energy Technology Data Exchange (ETDEWEB)

    Emma, P.

    2003-01-14

    We propose a simple method to produce short x-ray pulses using a spatially chirped electron bunch in a SASE FEL. The spatial chirp is generated using an rf deflector which produces a transverse offset (in y and/or y') correlated with the longitudinal bunch position. Since the FEL gain is very sensitive to an initial offset in the transverse phase space at the entrance of the undulator, only a small portion of the electron bunch with relatively small transverse offset will interact significantly with the radiation, resulting in an x-ray pulse length much shorter than the electron bunch length. The x-ray pulse is also naturally phase locked to the rf deflector and so allows high precision timing synchronization. We discuss the generation and transport of such a spatially chirped electron beam and show that tens of femtosecond long pulse can be generated for the linac coherent light source (LCLS).

  4. A 400ch SCPC signal demodulator using chirp transform and correlation detection scheme

    Science.gov (United States)

    Kohri, Takeharu; Morikura, Masahiro; Kato, Shuzo

    A group demodulator for PSK-FDMA (phase-shift-keyed frequency-division multiple access) signals using a chirp transform is proposed for hardware and power consumption reduction of demodulators at a hub station. The proposed demodulator uses a chirp filter for FDM/TDM transform of received PSK-FDMA signals and demodulates TDM transform signals by recovering each channel carrier and clock. Since the chirp filter works as an analog correlator, the transform TDM signals have the maximum S/N (signal-to-noise) ratio at the sampling instant, achieving 2 b/s/Hz frequency utilization efficiency with a QPSK (quadrature phase-shift keyed) modulation scheme. The feasibility test results on the prototype 400-channel demodulator show a good agreement with theory. The proposed group demodulator can contribute to reduce significantly hardware size and power consumption of hub stations.

  5. Evaluation of chirp reversal power modulation sequence for contrast agent imaging

    Science.gov (United States)

    Novell, A.; Sennoga, CA; Escoffre, JM; Chaline, J.; Bouakaz, A.

    2014-09-01

    Over the last decade, significant research effort has been focused on the use of chirp for contrast agent imaging because chirps are known to significantly increase imaging contrast-to-noise ratio (CNR). New imaging schemes, such as chirp reversal (CR), have been developed to improve contrast detection by increasing non-linear microbubble responses. In this study we evaluated the contrast enhancement efficiency of various chirped imaging sequences in combination with well-established imaging schemes such as power modulation (PM) and pulse inversion (PI). The imaging schemes tested were implemented on a fully programmable open scanner and evaluated by ultrasonically scanning (excitation frequency of 2.5 MHz amplitude of 350 kPa) a tissue-mimicking flow phantom comprising a 4 mm diameter tube through which aqueous dispersions (dilution fraction of 1/2000) of the commercial ultrasound contrast agent, SonoVue® were continuously circulated. The recovery of non-linear microbubble responses after chirp compression requires the development and the optimization of a specific filter. A compression filter was therefore designed and used to compress and extract several non-linear components from the received microbubble responses. The results showed that using chirps increased the image CNR by approximately 10 dB, as compared to conventional Gaussian apodized sine burst excitation but degraded the axial resolution by a factor of 1.4, at -3 dB. We demonstrated that the highest CNR and contrast-to-noise ratio (CTR) were achievable when CR was combined with PM as compared to other imaging schemes such as PI.

  6. Spectral tuning of the diameter-dependent-chirped Bragg gratings written in microfibers.

    Science.gov (United States)

    Xiao, Peng; Liu, Tong; Feng, Fu-Rong; Sun, Li-Peng; Liang, Hao; Ran, Yang; Jin, Long; Guan, Bai-Ou

    2016-12-26

    Chirped fiber Bragg gratings can straightforwardly and efficiently be fabricated onto microfibers with a uniform phase mask. Due to the variation of the propagating constant, which depends on the fiber diameter, the broadband spectrum of the grating can be formed. Depending on the different responses to the ambient refractive index in different parts of the grating, the bandwidth of the grating can be tuned by changing the surrounding solution. In addition, by being partly immersed in a liquid, the diameter-chirped Bragg grating can act as a broadband Fabry-Perot interferometer, whose spectrum can be tuned by means of controlling the liquid level and ambient refractive index.

  7. Study on time-varying velocity measurement with self-mixing laser diode based on Discrete Chirp-Fourier Transform

    International Nuclear Information System (INIS)

    Zhang Zhaoyun; Gao Yang; Zhao Xinghai; Zhao Xiang

    2011-01-01

    Laser's optical output power and frequency are modulated when the optical beam is back-scattered into the active cavity of the laser. By signal processing, the Doppler frequency can be acquired, and the target's velocity can be calculated. Based on these properties, an interferometry velocity sensor can be designed. When target move in time-varying velocity mode, it is difficult to extract the target's velocity. Time-varying velocity measurement by self-mixing laser diode is explored. A mathematics model was proposed for the time-varying velocity (invariable acceleration) measurement by self-mixing laser diode. Based on this model, a Discrete Chirp-Fourier Transform (DCFT) method was applied, DCFT is analogous to DFT. We show that when the signal length N is prime, the magnitudes of all the side lobes are 1, whereas the magnitudes of the main lobe is √N, And the coordinates of the main lobe shows the target's velocity and acceleration information. The simulation results prove the validity of the algorithm even in the situation of low SNR when N is prime.

  8. Parametric Verification of Weighted Systems

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Hansen, Mikkel; Mariegaard, Anders

    2015-01-01

    This paper addresses the problem of parametric model checking for weighted transition systems. We consider transition systems labelled with linear equations over a set of parameters and we use them to provide semantics for a parametric version of weighted CTL where the until and next operators...... are themselves indexed with linear equations. The parameters change the model-checking problem into a problem of computing a linear system of inequalities that characterizes the parameters that guarantee the satisfiability. To address this problem, we use parametric dependency graphs (PDGs) and we propose...

  9. Parametric Mass Reliability Study

    Science.gov (United States)

    Holt, James P.

    2014-01-01

    The International Space Station (ISS) systems are designed based upon having redundant systems with replaceable orbital replacement units (ORUs). These ORUs are designed to be swapped out fairly quickly, but some are very large, and some are made up of many components. When an ORU fails, it is replaced on orbit with a spare; the failed unit is sometimes returned to Earth to be serviced and re-launched. Such a system is not feasible for a 500+ day long-duration mission beyond low Earth orbit. The components that make up these ORUs have mixed reliabilities. Components that make up the most mass-such as computer housings, pump casings, and the silicon board of PCBs-typically are the most reliable. Meanwhile components that tend to fail the earliest-such as seals or gaskets-typically have a small mass. To better understand the problem, my project is to create a parametric model that relates both the mass of ORUs to reliability, as well as the mass of ORU subcomponents to reliability.

  10. Non-parametric versus parametric methods in environmental sciences

    Directory of Open Access Journals (Sweden)

    Muhammad Riaz

    2017-06-01

    Full Text Available This current report intends to highlight the importance of considering background assumptions required for the analysis of real datasets in different disciplines. We will provide comparative discussion of parametric methods (that depends on distributional assumptions (like normality relative to non-parametric methods (that are free from many distributional assumptions. We have chosen a real dataset from environmental sciences (one of the application areas. The findings may be extended to the other disciplines following the same spirit.

  11. Parametrization of contrails in a comprehensive climate model

    Energy Technology Data Exchange (ETDEWEB)

    Ponater, M.; Brinkop, S.; Sausen, R.; Schumann, U. [Deutsche Forschungs- und Versuchsanstalt fuer Luft- und Raumfahrt e.V., Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere

    1997-12-31

    A contrail parametrization scheme for a general circulation model (GCM) is presented. Guidelines for its development were that it should be based on the thermodynamic theory of contrail formation and that it should be consistent with the cloud parametrization scheme of the GCM. Results of a six-year test integration indicate reasonable results concerning the spatial and temporal development of both contrail coverage and contrail optical properties. Hence, the scheme forms a promising basis for the quantitative estimation of the contrail climatic impact. (author) 9 refs.

  12. Parametric Optimization of Hospital Design

    DEFF Research Database (Denmark)

    Holst, Malene Kirstine; Kirkegaard, Poul Henning; Christoffersen, L.D.

    2013-01-01

    Present paper presents a parametric performancebased design model for optimizing hospital design. The design model operates with geometric input parameters defining the functional requirements of the hospital and input parameters in terms of performance objectives defining the design requirements...

  13. Planar Parametrization in Isogeometric Analysis

    DEFF Research Database (Denmark)

    Gravesen, Jens; Evgrafov, Anton; Nguyen, Dang-Manh

    2012-01-01

    Before isogeometric analysis can be applied to solving a partial differential equation posed over some physical domain, one needs to construct a valid parametrization of the geometry. The accuracy of the analysis is affected by the quality of the parametrization. The challenge of computing...... and maintaining a valid geometry parametrization is particularly relevant in applications of isogemetric analysis to shape optimization, where the geometry varies from one optimization iteration to another. We propose a general framework for handling the geometry parametrization in isogeometric analysis and shape...... are suitable for our framework. The non-linear methods we consider are based on solving a constrained optimization problem numerically, and are divided into two classes, geometry-oriented methods and analysis-oriented methods. Their performance is illustrated through a few numerical examples....

  14. Role of volume and surface spontaneous parametric down-conversion in the generation of photon pairs in layered media

    Czech Academy of Sciences Publication Activity Database

    Javůrek, D.; Peřina ml., Jan

    2017-01-01

    Roč. 95, č. 4 (2017), s. 1-13, č. článku 043828. ISSN 2469-9926 Institutional support: RVO:68378271 Keywords : surface spontaneous * parametric down-conversion * photon pairs * layered media Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 2.925, year: 2016

  15. Self-designing parametric geometries

    OpenAIRE

    Sobester, Andras

    2015-01-01

    The thesis of this paper is that script-based geometry modelling offers the possibility of building `self-designing' intelligence into parametric airframe geometries. We show how sophisticated heuristics (such as optimizers and complex decision structures) can be readily integrated into the parametric geometry model itself using a script-driven modelling architecture. The result is an opportunity for optimization with the scope of conceptual design and the fidelity of preliminary design. Addi...

  16. Parametric Coding of Stereo Audio

    Directory of Open Access Journals (Sweden)

    Erik Schuijers

    2005-06-01

    Full Text Available Parametric-stereo coding is a technique to efficiently code a stereo audio signal as a monaural signal plus a small amount of parametric overhead to describe the stereo image. The stereo properties are analyzed, encoded, and reinstated in a decoder according to spatial psychoacoustical principles. The monaural signal can be encoded using any (conventional audio coder. Experiments show that the parameterized description of spatial properties enables a highly efficient, high-quality stereo audio representation.

  17. Thermal modulation for suppression of parametric instability in advanced gravitational wave detectors

    Science.gov (United States)

    Ma, Y. B.; Liu, J.; Ma, Y. Q.; Zhao, C.; Ju, L.; Blair, D. G.; Zhu, Z. H.

    2017-07-01

    Three-mode parametric instability is a threat to attaining design power levels in advanced gravitational wave detectors. The first observation of three-mode parametric instability in a long optical cavity revealed that instabilities could be suppressed by time variation of the mirror radius of curvature. In this paper, we present three dimensional finite element analysis of this thermo-acousto-optics system to determine whether thermal modulation could provide sufficient instability suppression without degrading time averaged optical performance. It is shown that deformations due to the time averaged heating profile on the mirror surface can be compensated by rear surface heating of the test mass. Results show that a heating source with a modulation amplitude of 1 W at 0.01 Hz is sufficient to stabilize an acoustic mode with parametric gain up to 3. The parametric gain suppression factor is linearly proportional to the peak modulation power.

  18. Parametric excitation of a SiN membrane via piezoelectricity

    Science.gov (United States)

    Wu, Shuhui; Sheng, Jiteng; Zhang, Xiaotian; Wu, Yuelong; Wu, Haibin

    2018-01-01

    We develop a stoichiometric silicon nitride (SiN) membrane-based electromechanical system, in which the spring constant of the mechanical resonator can be dynamically controlled via piezoelectric actuation. The degenerate parametric amplifier is studied in this configuration. We observe the splitting of mechanical mode in the response spectra of a phase-sensitive parametric amplifier. In addition, we demonstrate that the quality factor Q of the membrane oscillator can be significantly enhanced by more than two orders of magnitude due to the coherent amplification, reaching an effective Q factor of ˜3 × 108 at room temperature. The nonlinear effect on the parametric amplification is also investigated, as well as the thermomechanical noise squeezing. This system offers the possibility to integrate electrical, optical and mechanical degrees of freedom without compromising the exceptional material properties of SiN membranes, and can be a useful platform for studying cavity optoelectromechanics.

  19. Parametric excitation of a SiN membrane via piezoelectricity

    Directory of Open Access Journals (Sweden)

    Shuhui Wu

    2018-01-01

    Full Text Available We develop a stoichiometric silicon nitride (SiN membrane-based electromechanical system, in which the spring constant of the mechanical resonator can be dynamically controlled via piezoelectric actuation. The degenerate parametric amplifier is studied in this configuration. We observe the splitting of mechanical mode in the response spectra of a phase-sensitive parametric amplifier. In addition, we demonstrate that the quality factor Q of the membrane oscillator can be significantly enhanced by more than two orders of magnitude due to the coherent amplification, reaching an effective Q factor of ∼3 × 108 at room temperature. The nonlinear effect on the parametric amplification is also investigated, as well as the thermomechanical noise squeezing. This system offers the possibility to integrate electrical, optical and mechanical degrees of freedom without compromising the exceptional material properties of SiN membranes, and can be a useful platform for studying cavity optoelectromechanics.

  20. Imaging of human tooth using ultrasound based chirp-coded nonlinear time reversal acoustics

    Czech Academy of Sciences Publication Activity Database

    Dos Santos, S.; Převorovský, Zdeněk

    2011-01-01

    Roč. 51, č. 6 (2011), s. 667-674 ISSN 0041-624X Institutional research plan: CEZ:AV0Z20760514 Keywords : TR-NEWS * chirp-coded excitation * echodentography * ultrasonic imaging Subject RIV: BI - Acoustics Impact factor: 1.838, year: 2011 http://www.sciencedirect.com/science/article/pii/S0041624X11000229

  1. Flashlamp pumped Ti-sapphire laser for ytterbium glass chirped pulse amplification

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Akihiko; Ohzu, Akira; Sugiyama, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1998-03-01

    A flashlamp pumped Ti:sapphire laser is designed for ytterbium glass chirped pulse amplification. A high quality Ti:sapphire rod and a high energy long pulse discharging power supply are key components. The primary step is to produce the output power of 10 J per pulse at 920 nm. (author)

  2. Diffraction characteristics of chirped femtosecond laser pulse by rectangle reflection grating

    Science.gov (United States)

    Liu, Guohua; Xu, Rongrong; Wu, Hanping; Yu, Wenbing

    2012-06-01

    The spectral and temporal intensity distribution expression for the chirped femtosecond laser pulse diffracted by a rectangle reflection grating is derived. The effects of the chirped coefficient on the spatiotemporal and spectral characteristics are theoretically investigated in detail, and a criterion for judging whether or not the diffraction pulse is just split into two independent pulses in the temporal domain is obtained. The results show that the envelope curve of spectral intensity on the diffraction axis is more blue-shift, and its full width at e- 1 maximum is wider for bigger chirped coefficient. The principal maximum on the temporal axis can split into two independent principal maximums for enough height from the upper and the nether reflection surface of the grating. Each principal maximum splits into two smooth pulses, namely one principal pulse and one secondary pulse, and the secondary pulse gradually increases with the increasing of the chirped coefficient; the duration of two principal pulses increases with the increasing of the height of the upper and the nether reflection surface of the grating.

  3. Ultra-high temperature chirped fiber Bragg gratings produced by gradient stretching of viscoelastic silica.

    Science.gov (United States)

    Gao, Shaorui; Canning, John; Cook, Kevin

    2013-12-15

    By applying a suitable quadratic temperature distribution at a temperature within the viscoelastic softening region for silica, a regenerated chirped grating with bandwidth of 9.8 nm is produced from a uniform grating using post strain-tuning under load. Simulated and experimental results are in good agreement.

  4. A Fast Algorithm for Maximum Likelihood Estimation of Harmonic Chirp Parameters

    DEFF Research Database (Denmark)

    Jensen, Tobias Lindstrøm; Nielsen, Jesper Kjær; Jensen, Jesper Rindom

    2017-01-01

    . A statistically efficient estimator for extracting the parameters of the harmonic chirp model in additive white Gaussian noise is the maximum likelihood (ML) estimator which recently has been demonstrated to be robust to noise and accurate --- even when the model order is unknown. The main drawback of the ML...

  5. Helium in chirped laser fields as a time-asymmetric atomic switch

    Czech Academy of Sciences Publication Activity Database

    Kaprálová-Žďánská, Petra Ruth; Moiseyev, N.

    2014-01-01

    Roč. 141, č. 1 (2014), "014307-1"-"014307-14" ISSN 0021-9606 R&D Projects: GA ČR GAP205/11/0571 Institutional support: RVO:68378271 Keywords : laser excitation * chirped pulses * non-hermitian quantum mechanics * time-asymmetry Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.952, year: 2014

  6. Parametric design using IGRIP

    International Nuclear Information System (INIS)

    Baker, C.

    1994-10-01

    The Department of Energy's (DOE) Hanford site near Richland, Washington is being cleaned up after 50 years of nuclear materials production. One of the most serious problems at the site is the waste stored in single-shell underground storage tanks. There are 149 of these tanks containing the spent fuel residue remaining after the fuel is dissolved in acid and the desired materials (primarily plutonium and uranium) are separated out. The tanks are upright cylinders 75 ft. in diameter with domed tops. They are made of reinforced concrete, have steel liners, and each tank is buried under 7--12 ft. of overburden. The tanks are up to 40-ft. high, and have capacities of 500,000, 750,000, or 1,000,000 gallons of waste. As many as one-third of these tanks are known or suspected to leak. The waste form contained in the tanks varies in consistency from liquid supernatant to peanut-butter-like gels and sludges to hard salt cake (perhaps as hard as low-grade concrete). The current waste retrieval plan is to insert a large long-reach manipulator through a hole cut in the top of the tank, and use a variety of end-effectors to mobilize the waste and remove it from the tank. PNL has, with the assistance of Deneb robotics employees, developed a means of using the IGRIP code to perform parametric design of mechanical systems. This method requires no modifications to the IGRIP code, and all design data are stored in the IGRIP workcell. The method is presented in the context of development of a passive articulated mechanism that is used to deliver down-arm services to a gantry robot. The method is completely general, however, and could be used to design a fully articulated manipulator. Briefly, the method involves using IGCALC expressions to control manipulator joint angles, and IGCALC variables to allow user control of link lengths and offsets. This paper presents the method in detail, with examples drawn from PNL's experience with the gantry robot service-providing mechanism

  7. Noncollinear SHG with compensation of phase mismatch by controlling frequency chirp and tilted pulse fronts of femtosecond laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Aoyama, Makoto; Nakano, Fumihiko; Akahane, Yutaka; Yamakawa, Koichi [Japan Atomic Energy Research Inst., Kizu, Kyoto (Japan). Kansai Research Establishment; Harimoto, Tetsuo [Yamanashi Univ., Faculty of Engineering, Yamanashi (Japan)

    2001-10-01

    In order to achieve efficient second-harmonic generation with femtosecond laser pulses, we studied noncollinear second-harmonic generation with tilted pulse fronts and a suitable frequency chirp of fundamental pulses. We discussed the compensation of a phase-mismatch by controlling the frequency chirp of fundamental pulses and an improvement of the energy conversion efficiency using our method. When the energy conversion efficiency was less than 0.4% under a phase-mismatch condition, we experimentally obtained a 30% energy conversion efficiency with a proper frequency chirp of fundamental pulses. (author)

  8. Multi-resonance effects within a single chirp in broadband rotational spectroscopy: The rapid adiabatic passage regime for benzonitrile

    Science.gov (United States)

    Schmitz, David; Alvin Shubert, V.; Betz, Thomas; Schnell, Melanie

    2012-10-01

    We report here pronounced, stepwise multi-resonance excitations in benzonitrile arising from a single 1 μs broadband 2-8.3 GHz microwave chirp, observed with our new chirped-pulse broadband rotational spectrometer, COMPACT. Such multi-resonance excitations significantly alter the relative intensity patterns and are a strong indication that, for the given experimental conditions and using benzonitrile as a polar test molecule (μA = 4.5152 D), the rapid adiabatic passage (RAP) regime for strong coupling must be applied. This finding is contrary to previous discussions of chirped-pulse rotational spectroscopy, where the linear fast passage regime of weak coupling has been assumed.

  9. Ionospheric modification and parametric instabilities

    International Nuclear Information System (INIS)

    Fejer, J.A.

    1979-01-01

    Thresholds and linear growth rates for stimulated Brillouin and Raman scattering and for the parametric decay instability are derived by using arguments of energy transfer. For this purpose an expression for the ponderomotive force is derived. Conditions under which the partial pressure force due to differential dissipation exceeds the ponderomotive force are also discussed. Stimulated Brillouin and Raman scattering are weakly excited by existing incoherent backscatter radars. The parametric decay instability is strongly excited in ionospheric heating experiments. Saturation theories of the parametric decay instability are therefore described. After a brief discussion of the purely growing instability the effect of using several pumps is discussed as well as the effects of inhomogenicity. Turning to detailed theories of ionospheric heating, artificial spread F is discussed in terms of a purely growing instability where the nonlinearity is due to dissipation. Field-aligned short-scale striations are explained in terms of dissipation of the parametrically excited Langmuir waves (plasma oscillations): they might be further amplified by an explosive instability (except the magnetic equator). Broadband absorption is probably responsible for the 'overshoot' effect: the initially observed level of parametrically excited Langmuir waves is much higher than the steady state level

  10. Parametric functional principal component analysis.

    Science.gov (United States)

    Sang, Peijun; Wang, Liangliang; Cao, Jiguo

    2017-09-01

    Functional principal component analysis (FPCA) is a popular approach in functional data analysis to explore major sources of variation in a sample of random curves. These major sources of variation are represented by functional principal components (FPCs). Most existing FPCA approaches use a set of flexible basis functions such as B-spline basis to represent the FPCs, and control the smoothness of the FPCs by adding roughness penalties. However, the flexible representations pose difficulties for users to understand and interpret the FPCs. In this article, we consider a variety of applications of FPCA and find that, in many situations, the shapes of top FPCs are simple enough to be approximated using simple parametric functions. We propose a parametric approach to estimate the top FPCs to enhance their interpretability for users. Our parametric approach can also circumvent the smoothing parameter selecting process in conventional nonparametric FPCA methods. In addition, our simulation study shows that the proposed parametric FPCA is more robust when outlier curves exist. The parametric FPCA method is demonstrated by analyzing several datasets from a variety of applications. © 2017, The International Biometric Society.

  11. Dense wavelength-division multiplexing dispersion compensators based on chirped and apodized Fibonacci structures: CA-FC(j,n).

    Science.gov (United States)

    Golmohammadi, Saeed; Moravvej-Farshi, Mohammad Kazem; Rostami, Ali; Zarifkar, Abbas

    2008-12-10

    Chromatic dispersion compensation is an essential feature of high speed dense wavelength-division multiplexing (DWDM) systems. We propose a dispersion compensator structure whose characteristics meet the optical DWDM system requirements. The proposed structure is based on Fibonacci quasi-periodic multilayer structures composed of layers with large index differences. Studying the dispersive properties of Fibonacci structures with generation numbers j=3 and 4, and calculating group delay (GD) and group velocity dispersion (GVD) of their reflection bands, we have demonstrated that to have a smooth GD and almost a constant GVD in each band of a DWDM system, one needs not only to suitably chirp the structure refractive index profile, but also must properly apodize it. We also demonstrate the possibility of achieving high slope GDs and large GVDs by means of high order Fibonacci structures with thicker layers. Finally, by varying the layer dimensions and refractive indices as well as Fibonacci's order, one can design DWDM dispersion compensators suitable for distances as long as 220 km.

  12. Nonlinear optical interactions in silicon waveguides

    Directory of Open Access Journals (Sweden)

    Kuyken B.

    2017-03-01

    Full Text Available The strong nonlinear response of silicon photonic nanowire waveguides allows for the integration of nonlinear optical functions on a chip. However, the detrimental nonlinear optical absorption in silicon at telecom wavelengths limits the efficiency of many such experiments. In this review, several approaches are proposed and demonstrated to overcome this fundamental issue. By using the proposed methods, we demonstrate amongst others supercontinuum generation, frequency comb generation, a parametric optical amplifier, and a parametric optical oscillator.

  13. Variance in parametric images: direct estimation from parametric projections

    International Nuclear Information System (INIS)

    Maguire, R.P.; Leenders, K.L.; Spyrou, N.M.

    2000-01-01

    Recent work has shown that it is possible to apply linear kinetic models to dynamic projection data in PET in order to calculate parameter projections. These can subsequently be back-projected to form parametric images - maps of parameters of physiological interest. Critical to the application of these maps, to test for significant changes between normal and pathophysiology, is an assessment of the statistical uncertainty. In this context, parametric images also include simple integral images from, e.g., [O-15]-water used to calculate statistical parametric maps (SPMs). This paper revisits the concept of parameter projections and presents a more general formulation of the parameter projection derivation as well as a method to estimate parameter variance in projection space, showing which analysis methods (models) can be used. Using simulated pharmacokinetic image data we show that a method based on an analysis in projection space inherently calculates the mathematically rigorous pixel variance. This results in an estimation which is as accurate as either estimating variance in image space during model fitting, or estimation by comparison across sets of parametric images - as might be done between individuals in a group pharmacokinetic PET study. The method based on projections has, however, a higher computational efficiency, and is also shown to be more precise, as reflected in smooth variance distribution images when compared to the other methods. (author)

  14. Schroedinger cat states and optimum universal quantum cloning by entangled parametric amplification

    Science.gov (United States)

    De Martini, Francesco; Mussi, Valentina; Bovino, Fabio

    2000-05-01

    The new process of quantum-injection by a single-photon in a pure quantum superposition state into an optical parametric amplifier operating in entangled configuration is adopted to generate an all optical multiphoton Schroedinger-cat state which is largely detectable against the squeezed-vacuum noise. The invariance properties of the OPA interaction hamiltonian show that, under certain conditions, the device may act as a universal quantum cloning machine (UQCM) of the input qubits. Preliminary results here reported show the first experimental realization of such a device based on stimulated emission process in an optical parametric amplifier.

  15. Atom-resonant squeezed light from a tunable monolithic ppRKTP parametric amplifier.

    Science.gov (United States)

    Zielińska, Joanna A; Mitchell, Morgan W

    2018-02-15

    We demonstrate vacuum squeezing at the D 1 line of atomic rubidium (795 nm) with a tunable, doubly-resonant, monolithic subthreshold optical parametric oscillator in periodically-poled Rb-doped potassium titanyl phosphate (ppRKTP). The squeezing appears to be undiminished by a strong dispersive optical nonlinearity recently observed in this material.

  16. Raw Knudsen Chirp 320BR subbottom profiler - Knudsen subbottom profile data for the Chukchi Cap and Arctic Ocean.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Knudsen Chirp 320BR subbottom profiler - Knudsen subbottom profile data were collected in Raw Knudsen SEG-Y Datagram format.

  17. Parametric Processes for Generation and Low Noise Detection of Infrared Light

    DEFF Research Database (Denmark)

    Høgstedt, Lasse

    . The first chapter of the thesis introduces and motivates the work with frequency conversion, sketching the potential of the noise properties for upconversion based detection systems and the increased wavelength availability for parametric light sources. A selection of prior work is presented to give...... an overview of the focus in the field and to place the thesis in a general context. The second chapter introduces the basic concepts of nonlinear parametric interaction in the context of this work, where phasematching is a key factor in the work on both light sources and detection systems. Third chapter...... presents the work on infrared light sources. An optical parametric generator was constructed, and worked as an optical parametric amplifier for both a near- and a mid-infrared seed. The setups are analyzed spectrally and temporally, and discussed with respect to spectroscopic applications. It is concluded...

  18. Parametric programming of industrial robots

    Directory of Open Access Journals (Sweden)

    Szulczyński Paweł

    2015-06-01

    Full Text Available This article proposes the use of parametric design software, commonly used by architects, in order to obtain complex trajectory and program code for industrial robots. The paper describes the drawbacks of existing solutions and proposes a new script to obtain a correct program. The result of the algorithm was verified experimentally.

  19. Graphical functions in parametric space

    Science.gov (United States)

    Golz, Marcel; Panzer, Erik; Schnetz, Oliver

    2017-06-01

    Graphical functions are positive functions on the punctured complex plane C{\\setminus }{0,1} which arise in quantum field theory. We generalize a parametric integral representation for graphical functions due to Lam, Lebrun and Nakanishi, which implies the real analyticity of graphical functions. Moreover, we prove a formula that relates graphical functions of planar dual graphs.

  20. PARAMETRIC MODEL OF LUMBAR VERTEBRA

    Directory of Open Access Journals (Sweden)

    CAPPETTI Nicola

    2010-11-01

    Full Text Available The present work proposes the realization of a parametric/variational CAD model of a normotype lumbar vertebra, which could be used for improving the effectiveness of actual imaging techniques in informational augmentation of the orthopaedic and traumatological diagnosis. In addition it could be used for ergonomic static and dynamical analysis of the lumbar region and vertebral column.