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Sample records for cascaded nondegenerate four-wave

  1. Fundamentals of Highly Non-Degenerate Cascaded Four-Wave Mixing

    Directory of Open Access Journals (Sweden)

    Rosa Weigand

    2015-09-01

    Full Text Available By crossing two intense ultrashort laser pulses with different colors in a transparent medium, like a simple piece of glass, a fan of multicolored broadband light pulses can be simultaneously generated. These newly generated pulses are emitted in several well-defined directions and can cover a broad spectral range, from the infrared to the ultraviolet and beyond. This beautiful phenomenon, first observed and described 15 years ago, is due to highly-nondegenerate cascaded four-wave mixing (cascaded FWM, or CFWM. Here, we present a review of our work on the generation and measurement of multicolored light pulses based on third-order nonlinearities in transparent solids, from the discovery and first demonstration of highly-nondegenerate CFWM, to the coherent synthesis of single-cycle pulses by superposition of the multicolored light pulses produced by CFWM. We will also present the development and main results of a dedicated 2.5-D nonlinear propagation model, i.e., with propagation occurring along a two-dimensional plane while assuming cylindrically symmetric pump beam profiles, capable of adequately describing noncollinear FWM and CFWM processes. A new method for the generation of femtosecond pulses in the deep-ultraviolet (DUV based on FWM and CFWM will also be described. These experimental and theoretical results show that highly-nondegenerate third-order nonlinear optical processes are formally well understood and provide broader bandwidths than other nonlinear optical processes for the generation of ultrashort light pulses with wavelengths extending from the near-infrared to the deep-ultraviolet, which have many applications in science and technology.

  2. Non-Degenerate Four- Wave Mixing in Microstructure Fibres

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xia; REN Xiao-Min; WANG Zi-Nan; XU Yong-Zhao; ZHANG Rui-Rui; HUANG Yong-Qing; CHEN Xue

    2007-01-01

    Non-degenerate four wave mixing based on third-order susceptibility χ3 in high nonlinearity microstructure fibres is experimentally demonstrated. The Stokes and anti-Stokes peaks are observed simultaneously by launching 10-fs pulses from an 800nm Ti:sapphire laser into the fibre.

  3. Atomic coherence in nondegenerate four-wave mixing

    Institute of Scientific and Technical Information of China (English)

    Zuo Zhan-Chun; Sun Jiang; Liu Xia; Mi Xin; Yu Zu-He; Jiang Qian; Fu Pan-Ming; Wu Ling-An

    2007-01-01

    Two-photon resonant nondegenerate four-wave mixing (NFWM) with the addition of a coupling field in Ba atomic vapour has been studied. We find that coherence of the atomic level transitions leads to suppression of the NFWM signal, giving rise to a dip with a linewidth that is linearly proportional to the intensity of the coupling field.

  4. Phase-Sensitive Detection of Raman-Enhanced Nondegenerate Four-Wave Mixing by Polarization Interference

    Institute of Scientific and Technical Information of China (English)

    姜谦; 米辛; 俞祖和; 王延帮; 王利军; 傅盘铭

    2001-01-01

    We demonstrated a phase-sensitive method for studying the Raman-enhanced nondegenerate four-wave mixing (RENFWM). The reference beam is another four-wave mixing signal, which propagates along the same optical path as the RENFWM signal. This method is used for studying the phase dispersion of the third-ordersusceptibility X(3) and for the optical heterodyne detection of the RENFWM signal.

  5. Theory of nondegenerate four-wave mixing between pulses in a semiconductor waveguide

    DEFF Research Database (Denmark)

    Mørk, Jesper; Mecozzi, A.

    1997-01-01

    We develop a perturbation theory for calculating the effects of saturation on nondegenerate four-wave mixing between short optical pulses in a semiconductor optical amplifier. Saturation due to ultrafast intraband dynamics like carrier heating and spectral hole burning is found to be important...

  6. Ghost imaging with different frequencies through non-degenerated four-wave mixing.

    Science.gov (United States)

    Yu, Ya; Wang, Chengyuan; Liu, Jun; Wang, Jinwen; Cao, Mingtao; Wei, Dong; Gao, Hong; Li, Fuli

    2016-08-08

    As a novel imaging method, ghost imaging has been widely explored in various fields of research, such as lensless ghost imaging, computational ghost imaging, turbulence-free ghost imaging. Recently, ghost imaging in non-degenerated system with pseudo-thermal light has been discussed theoretically, however, to our best knowledge, no experimental evidence has been proven yet. In this paper, we propose a new approach to realize ghost imaging with different frequencies, which are generated through a non-degenerated four-wave mixing(FWM) process in Rb vapor. In our experiment, by employing pseudo-thermal light as the probe beam, we found that the generated FWM signal has a strong second-order correlation with the original thermal light. On basis of that, we successfully implement non-degenerate ghost imaging, and reconstruct highly similar images of objects.

  7. Field-Correlation Effects on Rayleigh-Enhanced Nondegenerate Four-Wave Mixing

    Institute of Scientific and Technical Information of China (English)

    王延帮; 姜谦; 米辛; 俞祖和; 傅盘铭

    2002-01-01

    We study Rayleigh-enhanced nondegenerate four-wave mixing (NFWM) with time-delayed, correlated fluctuating fields. The importance of the field correlation is revealed in the Rayleigh-enhanced NFWM spectrum when the time delay is varied. The Rayleigh-enhanced NFWM is employed to study the ultrafast processes in the frequency domain. A relaxation time as short as 220 fs was deduced in the Rayleigh-enhanced NFWM experiments in carbon disulphide.

  8. Broadband Polarization-Insensitive Wavelength Conversion Based on Non-Degenerate Four-Wave Mixing in a Silicon Nanowire

    DEFF Research Database (Denmark)

    Pu, Minhao; Hu, Hao; Ji, Hua

    2012-01-01

    We experimentally demonstrate broadband polarization-insensitive one-to-two wavelength conversion of a 10-Gb/s DPSK data signal based on non-degenerate four-wave mixing in a silicon nanowire with bit-error rate measurements.......We experimentally demonstrate broadband polarization-insensitive one-to-two wavelength conversion of a 10-Gb/s DPSK data signal based on non-degenerate four-wave mixing in a silicon nanowire with bit-error rate measurements....

  9. Spatially nondegenerate four-wave mixing in a broad area semiconductor laser: Modeling

    DEFF Research Database (Denmark)

    Jensen, Søren Blaaberg; Tromborg, Bjarne; Petersen, P. M.

    coupled equations for the field components in the cavity and a rate equation is used to describe the carrier density of the semiconductor material. The interference pattern of the four field components inside the cavity induces a periodic spatial modulation of the carrier density and thus of the complex......We present a numerical model of spatially nondegenerate four-wave mixing in a bulk broad area semiconductor laser with an external reflector and a spatial filter. The external reflector provides a feedback with an off-aixs direction of propagation. Such a configuration has experimentally been seen...

  10. Femtosecond Non-degenerate Four Wave Mixing Spectroscopy: The Two Color Photon Echo Peak Shift

    CERN Document Server

    Prall, B S

    2005-01-01

    The couplings between multiple electronic states and electronic and nuclear coordinates are examined for condensed phase systems by femtosecond degenerate and non-degenerate four wave mixing. The two-color photon echo peak shift experiment is developed which allows measurement of the correlation between transition frequencies in two different spectral regions. Two-color photon echo peak shift (2C3PEPS) experiments are used to study coupling between electronic states in the lutetium bisphthalocyanine anion, LuPc2−. Electronically induced mixing between exciton and charge resonance states leads to correlations in transition energies for the two observed transitions. This correlation generates non-zero 2C3PEPS which, when compared with 1C3PEPS, allows experimental determination of the degree of mixing, which was in good agreement with theoretical predictions. By exploiting a coherently excited nuclear wavepacket, the nuclear dependence on the electronic mixing between exciton and charge resonance state...

  11. Higher-Order Squeezing of Quantum Field and the Generalized Uncertainty Relations in Non-Degenerate Four-Wave Mixing

    Science.gov (United States)

    Li, Xi-Zeng; Su, Bao-Xia

    1996-01-01

    It is found that the field of the combined mode of the probe wave and the phase-conjugate wave in the process of non-degenerate four-wave mixing exhibits higher-order squeezing to all even orders. And the generalized uncertainty relations in this process are also presented.

  12. A theory for non-degenerate four-wave mixing in doped graphene

    Science.gov (United States)

    Margulis, Vl. A.; Muryumin, E. E.; Gaiduk, E. A.

    2017-03-01

    We present a theoretical study of the nonlinear optical (NLO) response of doped graphene to two coherent laser beams, of frequencies ω1 and ω2, resulting in the generation of radiation at frequency ωσ = 2ω1 -ω2 . The two main ingredients of the developed theory are the interplay of interband and intraband electron motion, induced by the incident light waves, and the finite lifetime of excited electronic states, caused by electron scattering. Adopting a tight-binding approximation for the π-electronic band structure of graphene and the Genkin-Mednis formalism of the nonlinear conductivity theory of semiconductors, we calculate the third-order NLO susceptibility χ (3) (-ωσ ;ω1 ,ω1 , -ω2) responsible for the non-degenerate four-wave mixing process under consideration. Our calculations show the resonant enhancement of the |χ (3) | (up to a value of 2.8 ×10-7 esu) when the frequencies ω1 and ω2 of the input beams are mat"ched to provide a resonance for the output photon energy ℏωσ with an effective optical gap of 2EF in the π-electronic band structure of doped graphene (EF is the Fermi energy of charge carriers in the graphene, tunable by an external gate voltage). The results obtained may be of practical interest for generating mid-infrared radiation from doped graphene pumped with two near-infrared laser beams.

  13. Observation of Rydberg Series in Sodium Vapour by Two-Photon Resonant Nondegenerate Four-Wave Mixing

    Institute of Scientific and Technical Information of China (English)

    王延帮; 姜谦; 李隆; 米辛; 俞祖和; 傅盘铭

    2001-01-01

    We apply two-photon resonant nondegenerate four-wave mixing with a resonant intermediate state for the obser- vation of Rydberg states in sodium vapour. The broadening and shift of the sodium 3S- 11D transition perturbed by argon are investigated. This technique can achieve Doppler-free resolution of narrow spectral structures of Rydberg levels if lasers with narrow bandwidths are employed.

  14. Continuous-wave anti-Stokes Raman laser based on phase-matched nondegenerate four-wave mixing.

    Science.gov (United States)

    Zaitsu, Shin-ichi; Imasaka, Totaro

    2015-01-01

    We demonstrate phase-matched nondegenerate four-wave mixing (FWM) in a high-finesse optical cavity using a gaseous Raman-active medium pumped by two independent continuous-wave lasers. Efficient upconversion is achieved for pump beams at different wavelengths under phase-matched conditions by optimizing the total dispersion of the hydrogen-filled optical cavity. The independent control of the pump-beam polarizations leads to further enhancement of the upconversion efficiency arising from a larger Raman gain than that in degenerate FWM. This approach offers a promising alternative for a narrow-linewidth tunable light source for highly precise laser spectroscopy.

  15. Enhancement of entanglement using cascaded four-wave mixing processes.

    Science.gov (United States)

    Xin, Jun; Qi, Jian; Jing, Jietai

    2017-01-15

    A maximal joint quadrature squeezing of -6.8±0.4  dB is experimentally obtained by a scheme of cascaded four-wave mixing (FWM) processes, which gives strong proof about the inseparability or entanglement between output of the twin beams from the system. Here joint quadrature is the difference between the two quadratures of the twin beam output from the cascaded FWM processes. This result is enhanced by about 3.1 dB, compared with the one of the single FWM process. We also study the gain dependence of the entanglement enhancement in this cascaded system. Theoretical predictions with the considerations of the losses in the experiment are also studied, and a similar trend in the low-gain regime can be found between the experimental results and the theoretical predictions. The scheme of cascaded FWM processes, which can be used to improve or even manipulate the degree of the entanglement between the output fields from the single FWM process, may find its applications in the continuous-variable quantum communication protocols.

  16. Suppression and Enhancement in Parametric Two-Photon Resonant Nondegenerate Four-Wave Mixing via Quantum Interference

    Institute of Scientific and Technical Information of China (English)

    SUN Jiang; MI Xin; YU Zu-He; JIANG Qian; ZUO Zhan-Chun; WANG Yan-Bang; WU Ling-An; FU Pan-Ming

    2004-01-01

    @@ Quantum interference may lead to suppression and enhancement of the two-photon resonant nondegenerate fourwave mixing signal in a cascade four-level system. Such phenomena are demonstrated in Ba through inducing atomic coherence between the ground state 6s2 and the doubly excited autoionizing Rydberg state 6pnd. This method can be used as a new spectroscopic tool for measuring the transition dipole moment between two highly excited atomic states.

  17. Quantum steering in cascaded four-wave mixing processes.

    Science.gov (United States)

    Wang, Li; Lv, Shuchao; Jing, Jietai

    2017-07-24

    Quantum steering is used to describe the "spooky action-at-a-distance" nonlocality raised in the Einstein-Podolsky-Rosen (EPR) paradox, which is important for understanding entanglement distribution and constructing quantum networks. Here, in this paper, we study an experimentally feasible scheme for generating quantum steering based on cascaded four-wave-mixing (FWM) processes in hot rubidium (Rb) vapor. Quantum steering, including bipartite steering and genuine tripartite steering among the output light fields, is theoretically analyzed. We find the corresponding gain regions in which the bipartite and tripartite steering exist. The results of bipartite steering can be used to establish a hierarchical steering model in which one beam can steer the other two beams in the whole gain region; however, the other two beams cannot steer the first beam simultaneously. Moreover, the other two beams cannot steer with each other in the whole gain region. More importantly, we investigate the gain dependence of the existence of the genuine tripartite steering and we find that the genuine tripartite steering exists in most of the whole gain region in the ideal case. Also we discuss the effect of losses on the genuine tripartite steering. Our results pave the way to experimental demonstration of quantum steering in cascaded FWM process.

  18. Optical encryption of parallel quadrature phase shift keying signals based on nondegenerate four-wave mixing in highly nonlinear fiber

    Science.gov (United States)

    Cui, Yue; Zhang, Min; Zhan, Yueying; Wang, Danshi; Huang, Shanguo

    2016-08-01

    A scheme for optical parallel encryption/decryption of quadrature phase shift keying (QPSK) signals is proposed, in which three QPSK signals at 10 Gb/s are encrypted and decrypted simultaneously in the optical domain through nondegenerate four-wave mixing in a highly nonlinear fiber. The results of theoretical analysis and simulations show that the scheme can perform high-speed wiretapping against the encryption of parallel signals and receiver sensitivities of encrypted signal and the decrypted signal are -25.9 and -23.8 dBm, respectively, at the forward error correction threshold. The results are useful for designing high-speed encryption/decryption of advanced modulated signals and thus enhancing the physical layer security of optical networks.

  19. Non-Degenerate Four-Wave Mixing in a Silicon Nanowire and its Application for One-to-Six WDM Multicasting

    DEFF Research Database (Denmark)

    Pu, Minhao; Hu, Hao; Ji, Hua

    2011-01-01

    We present WDM multicasting based on non-degenerate four-wave mixing in a silicon nanowire. A one-to-six phase-preserving wavelength multicasting of 10 Gb/s differential phase-shift-keying data is experimentally demonstrated with bit-error rate measurements.......We present WDM multicasting based on non-degenerate four-wave mixing in a silicon nanowire. A one-to-six phase-preserving wavelength multicasting of 10 Gb/s differential phase-shift-keying data is experimentally demonstrated with bit-error rate measurements....

  20. Nonlinear Pulse-reshaping of Sub-picosecond Pulses by Non-degenerate Four-wave Mixing

    DEFF Research Database (Denmark)

    Christensen, Jesper; Andersen, Lasse Mejling; Rottwitt, Karsten

    Four-wave mixing does according to various models allow for arbitrary pulse-reshaping of the generated idler. Using subpicosecond pulses, we investigate numerically whether nonlinear effects and dispersion broadening begin to prevent this ability.......Four-wave mixing does according to various models allow for arbitrary pulse-reshaping of the generated idler. Using subpicosecond pulses, we investigate numerically whether nonlinear effects and dispersion broadening begin to prevent this ability....

  1. Tunable Multicolored Femtosecond Pulse Generation Using Cascaded Four-Wave Mixing in Bulk Materials

    Directory of Open Access Journals (Sweden)

    Jinping He

    2014-09-01

    Full Text Available This paper introduces and discusses the main aspects of multicolored femtosecond pulse generation using cascaded four-wave mixing (CFWM in transparent bulk materials. Theoretical analysis and semi-quantitative calculations, based on the phase-matching condition of the four-wave mixing process, explain the phenomena well. Experimental studies, based on our experiments, have shown the main characteristics of the multicolored pulses, namely, broadband spectra with wide tunability, high stability, short pulse duration and relatively high pulse energy. Two-dimensional multicolored array generation in various materials are also introduced and discussed.

  2. Far-detuned cascaded intermodal four-wave mixing in a multimode fiber.

    Science.gov (United States)

    Dupiol, R; Bendahmane, A; Krupa, K; Tonello, A; Fabert, M; Kibler, B; Sylvestre, T; Barthelemy, A; Couderc, V; Wabnitz, S; Millot, G

    2017-04-01

    We demonstrate far-detuned parametric frequency conversion processes in a few mode graded-index optical fibers pumped by a Q-switched picosecond laser at 1064 nm. Through a detailed analytical and numerical analysis, we show that the multiple sidebands are generated through a complex cascaded process involving inter-modal four-wave mixing. The resulting parametric wavelength detuning spans in the visible down to 405 nm and in the near-infrared up to 1355 nm.

  3. Non-degenerate four-wave mixing in an optically injection-locked InAs/InP quantum dot Fabry–Perot laser

    Energy Technology Data Exchange (ETDEWEB)

    Huang, H.; Schires, K.; Grillot, F. [Télécom ParisTech, Ecole Nationale Supérieure des Télécommunications, CNRS LTCI, 46 rue Barrault, 75013 Paris Cedex (France); Poole, P. J. [National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6 (Canada)

    2015-04-06

    Non-degenerate four-wave mixing in an InAs/InP quantum dot Fabry–Perot laser is investigated with an optical injection-locking scheme. Wavelength conversion is obtained for frequency detunings ranging from +2.5 THz to −3.5 THz. The normalized conversion efficiency is maintained above −40 dB between −1.5 and +0.5 THz with an optical signal-to-noise ratio above 20 dB and a maximal third-order nonlinear susceptibility normalized to material gain of 2 × 10{sup −19} m{sup 3}/V{sup 2}. In addition, we show that injection-locking at different positions in the gain spectrum has an impact on the nonlinear conversion process and the symmetry between up- and down- converted signals.

  4. Superradiant cascade emissions in an atomic ensemble via four-wave mixing

    Energy Technology Data Exchange (ETDEWEB)

    Jen, H.H., E-mail: sappyjen@gmail.com

    2015-09-15

    We investigate superradiant cascade emissions from an atomic ensemble driven by two-color classical fields. The correlated pair of photons (signal and idler) is generated by adiabatically driving the system with large-detuned light fields via four-wave mixing. The signal photon from the upper transition of the diamond-type atomic levels is followed by the idler one which can be superradiant due to light-induced dipole–dipole interactions. We then calculate the cooperative Lamb shift (CLS) of the idler photon, which is a cumulative effect of interaction energy. We study its dependence on a cylindrical geometry, a conventional setup in cold atom experiments, and estimate the maximum CLS which can be significant and observable. Manipulating the CLS of cascade emissions enables frequency qubits that provide alternative robust elements in quantum network. - Highlights: • Superradiance from a cascade atomic transition. • Correlated photon pair generation via four-wave mixing. • Dynamical light–matter couplings in a phased symmetrical state. • Cooperative Lamb shift in a cylindrical atomic ensemble.

  5. Vortex algebra by multiply cascaded four-wave mixing of femtosecond optical beams.

    Science.gov (United States)

    Hansinger, Peter; Maleshkov, Georgi; Garanovich, Ivan L; Skryabin, Dmitry V; Neshev, Dragomir N; Dreischuh, Alexander; Paulus, Gerhard G

    2014-05-05

    Experiments performed with different vortex pump beams show for the first time the algebra of the vortex topological charge cascade, that evolves in the process of nonlinear wave mixing of optical vortex beams in Kerr media due to competition of four-wave mixing with self-and cross-phase modulation. This leads to the coherent generation of complex singular beams within a spectral bandwidth larger than 200nm. Our experimental results are in good agreement with frequency-domain numerical calculations that describe the newly generated spectral satellites.

  6. Generation of tripartite entanglement from cascaded four-wave mixing processes.

    Science.gov (United States)

    Wang, Hailong; Zheng, Zhan; Wang, Yaxian; Jing, Jietai

    2016-10-03

    We investigate the possibility of an experimentally feasible cascaded four-wave mixing (FWM) system [Phys. Rev. Lett. 113, 023602 (2014)] to generate tripartite entanglement. We verify that genuine tripartite entanglement is present in this system by calculating the covariances of three output beams and then considering the violations of the inequalities of the three-mode entanglement criteria, such as two-condition criterion, single-condition criterion, optimal single-condition criterion and the positivity under partial transposition (PPT) criterion. We also consider the possibilities of the bipartite entanglement of any pair of the three output beams using the Duan-Giedke-Cirac-Zoller criterion and PPT criterion. We find that the tripartite entanglement and the bipartite entanglement for the two pairs are present in the whole gain region. The entanglement characteristics under different entanglement criteria are also considered. Our results pave the way for the realization and application of multipartite entanglement based on the cascaded FWM processes.

  7. Cascaded four-wave mixing for broadband tunable laser sideband generation.

    Science.gov (United States)

    Liu, Weimin; Zhu, Liangdong; Wang, Liang; Fang, Chong

    2013-06-01

    We demonstrate the versatile broadband wavelength tunability of frequency upconverted multicolor cascaded four-wave-mixing (CFWM) signals spanning the continuous wavelength range from UV to near IR in a thin type-I BBO crystal using 35 fs, 800 nm fundamental and chirped IR supercontinuum white light pulses. Two sets of spatially dispersed CFWM laser sidebands are concomitantly generated from two incident pulses as well as their second-harmonic-generation and sum-frequency-generation pulses in a crossing geometry. The tunable cascaded signals with ultrabroad bandwidth can be readily achieved via spatially rotating the BBO crystal to different phase-matching conditions and temporally varying the time delay between the two incident near-IR pulses.

  8. Self-seeded four-wave mixing cascades with low power consumption

    Science.gov (United States)

    Cholan, N. A.; Al-Mansoori, M. H.; Noor, A. S. M.; Ismail, A.; Mahdi, M. A.

    2014-10-01

    The efficient generation of self-seeded four-wave mixing (FWM) cascades utilizing a double pass technique is demonstrated. To prove the efficiency of this technique, FWM cascades with a double-pass scheme are compared to their counterpart with a single-pass scheme. Experimental results indicate that the double-pass scheme consumes less power than the single-pass scheme. For the generation of ten spectral lines, the double-pass scheme requires an erbium-doped fiber amplifier (EDFA) output power of 114.02 mW, representing a 69% improvement over the single-pass scheme, which demands an EDFA output power of 366.32 mW. This is attributed to the use of the first-pass FWM cascades as seeds in the double-pass scheme, in contrast to two intracavity pumps as seeds in the single-pass scheme. The proposed scheme is not only free from external laser sources and phase modulators but also needs low power for operation, leading to the double-pass scheme being more cost effective than the single-pass scheme.

  9. Phase-sensitive cascaded four-wave mixing processes for generating continuous-variable entanglement.

    Science.gov (United States)

    Wang, Li; Jing, Jietai

    2017-03-20

    Quantum entanglement shared by different parties enhances their capabilities to communicate, which is the core content of continuous-variable quantum optics and quantum information science. Here, we study an experimentally feasible scheme for generating quantum entanglement of bipartite and tripartite cases based on phase-sensitive cascaded four-wave mixing processes in rubidium vapor. Quantum entanglement of bipartite and tripartite cases in our system, which can be manipulated by the phases and the intensity gains of the input beams, is predicted. We also find a sufficient optimal single-condition criterion to give a valid description for genuine tripartite quantum entanglement in our system. The sufficient optimal single-condition criterion is convenient and can be extended to genuine multipartite entanglement.

  10. Characterization of Pairwise Correlations from Multiple Quantum Correlated Beams Generated from Cascaded Four-Wave Mixing Processes.

    Science.gov (United States)

    Wang, Hailong; Cao, Leiming; Jing, Jietai

    2017-01-10

    We theoretically characterize the performance of the pairwise correlations (PCs) from multiple quantum correlated beams based on the cascaded four-wave mixing (FWM) processes. The presence of the PCs with quantum corre- lation in these systems can be verified by calculating the degree of intensity difference squeezing for any pair of all the output fields. The quantum correlation characteristics of all the PCs under different cascaded schemes are also discussed in detail and the repulsion effect between PCs in these cascaded FWM processes is theoretically predicted. Our results open the way for the classification and application of quantum states generated from the cascaded FWM processes.

  11. Broadband Enhancement of Optical Frequency Comb Using Cascaded Four-Wave Mixing in Photonic Crystal Fiber

    Directory of Open Access Journals (Sweden)

    Tawfig Eltaif

    2017-01-01

    Full Text Available A cascaded intensity modulator (IM and phase modulator (PM are used to modulate a continuous-wave (CW laser and generate an optical frequency comb (OFC. Thus, the generated comb is utilized as an initial seed and combined with another CW-laser to generate four-wave mixing (FWM in photonic crystal fiber (PCF. Results show that an initial flat 30 GHz OFC of 29, 55 lines within power fluctuation of 0.8 dB and 2 dB, respectively, can be achieved by setting the ratio of the DC bias to amplitude of sinusoidal signal at 0.1 and setting the modulation indices of both IM and PM at 10. Moreover, the 1st order of FWM created through 14 m of PCF has over 68 and 94 lines with fluctuation of 0.8 dB and 2 dB, respectively. Hence, the generated wavelengths of 1st left and right order of FWM can be tuned in a range from ~1500 nm to ~1525 nm and ~1590 nm to ~1604 nm, respectively.

  12. Investigation of DWDM System Based on Cascaded Four-Wave Mixing

    OpenAIRE

    Spolītis, S; Lyashuk, I

    2011-01-01

    Four-wave mixing (FWM) in optical fibers refers to a nonlinear interaction among four different waves, in which the energy and wave-vector must be conserved. This requirement is often referred to as phase matching and depends strongly on the chromatic dispersion. FWM has received the attention in fiber optic parametric amplifiers due to the possibility to work in more optical regions than erbium doped fiber amplifier (EDFA) widely used in DWDM networks. This feature of FOPAs makes it poss...

  13. A Broadband, Spectrally Flat, High Rep-rate Frequency Comb: Bandwidth Scaling and Flatness Enhancement of Phase Modulated CW through Cascaded Four-Wave Mixing

    CERN Document Server

    Supradeepa, V R

    2010-01-01

    We demonstrate a scheme to scale the bandwidth by several times while enhancing spectral flatness of frequency combs generated by intensity and phase modulation of CW lasers using cascaded four-wave mixing in highly nonlinear fiber.

  14. Signal-Pressure Curves of Cascaded Four-Wave Mixing in Gas-Filled Capillary by fs Pulses

    Institute of Scientific and Technical Information of China (English)

    CHEN Bao-Zhen; HUANG Zu-Qia

    2005-01-01

    The theoretical framework for the cascaded four waves mixing (CFWM) in gas-filled capillary by fs pulses is constructed. Based on the theoretical framework, the signal-pressure curves (SPC) of the CFWM in gas-filled capillary by fs pulses are calculated. With a comparison between the theoretical and experimental SPC we have discussed the influence of the walk-off and Phase modulation on the SPC. At the same time, we have discussed the possible origin of the first three peaks of the SPC.

  15. Directional infrared emission resulting from cascade population inversion and four-wave mixing in Rb vapor.

    Science.gov (United States)

    Akulshin, Alexander; Budker, Dmitry; McLean, Russell

    2014-02-15

    Directional infrared emission at 1.37 and 5.23 μm is generated in Rb vapors that are stepwise excited by low-power cw resonant light. The radiation at 5.23 μm originating from amplified spontaneous emission on the 5D(5/2)→6P(3/2) transition and wave mixing consists of forward- and backward-directed components with distinctive spectral and spatial properties. Diffraction-limited light at 1.37 μm generated in the copropagating direction only is a product of parametric wave mixing around the 5P(3/2)→5D(5/2)→6P(3/2)→6S(1/2)→5P(3/2) transition loop. This highly nondegenerate mixing process involves one externally applied and two internally generated optical fields. Similarities between wave mixing generated blue and 1.37 μm light are demonstrated.

  16. Generation and Amplification of Tunable Multicolored Femtosecond Laser Pulses by Using Cascaded Four-Wave Mixing in Transparent Bulk Media

    Science.gov (United States)

    Liu, Jun; Kobayashi, Takayoshi

    2010-01-01

    We have reviewed the generation and amplification of wavelength-tunable multicolored femtosecond laser pulses using cascaded four-wave mixing (CFWM) in transparent bulk media, mainly concentrating on our recent work. Theoretical analysis and calculations based on the phase-matching condition could explain well the process semi-quantitatively. The experimental studies showed: (1) as many as fifteen spectral up-shifted and two spectral down-shifted sidebands were obtained simultaneously with spectral bandwidth broader than 1.8 octaves from near ultraviolet (360 nm) to near infrared (1.2 μm); (2) the obtained sidebands were spatially separated well and had extremely high beam quality with M2 factor better than 1.1; (3) the wavelengths of the generated multicolor sidebands could be conveniently tuned by changing the crossing angle or simply replacing with different media; (4) as short as 15-fs negatively chirped or nearly transform limited 20-fs multicolored femtosecond pulses were obtained when one of the two input beams was negatively chirped and the other was positively chirped; (5) the pulse energy of the sideband can reach a μJ level with power stability better than 1% RMS; (6) broadband two-dimensional (2-D) multicolored arrays with more than ten periodic columns and more than ten rows were generated in a sapphire plate; (7) the obtained sidebands could be simultaneously spectra broadened and power amplified in another bulk medium by using cross-phase modulation (XPM) in conjunction with four-wave optical parametric amplification (FOPA). The characterization showed that this is interesting and the CFWM sidebands generated by this novel method have good enough qualities in terms of power stability, beam quality, and temporal features suited to various experiments such as ultrafast multicolor time-resolved spectroscopy and multicolor-excitation nonlinear microscopy. PMID:22399882

  17. Generation and Amplification of Tunable Multicolored Femtosecond Laser Pulses by Using Cascaded Four-Wave Mixing in Transparent Bulk Media

    Directory of Open Access Journals (Sweden)

    Jun Liu

    2010-04-01

    Full Text Available We have reviewed the generation and amplification of wavelength-tunable multicolored femtosecond laser pulses using cascaded four-wave mixing (CFWM in transparent bulk media, mainly concentrating on our recent work. Theoretical analysis and calculations based on the phase-matching condition could explain well the process semi-quantitatively. The experimental studies showed: (1 as many as fifteen spectral up-shifted and two spectral down-shifted sidebands were obtained simultaneously with spectral bandwidth broader than 1.8 octaves from near ultraviolet (360 nm to near infrared (1.2 μm; (2 the obtained sidebands were spatially separated well and had extremely high beam quality with M2 factor better than 1.1; (3 the wavelengths of the generated multicolor sidebands could be conveniently tuned by changing the crossing angle or simply replacing with different media; (4 as short as 15-fs negatively chirped or nearly transform limited 20-fs multicolored femtosecond pulses were obtained when one of the two input beams was negatively chirped and the other was positively chirped; (5 the pulse energy of the sideband can reach a μJ level with power stability better than 1% RMS; (6 broadband two-dimensional (2-D multicolored arrays with more than ten periodic columns and more than ten rows were generated in a sapphire plate; (7 the obtained sidebands could be simultaneously spectra broadened and power amplified in another bulk medium by using cross-phase modulation (XPM in conjunction with four-wave optical parametric amplification (FOPA. The characterization showed that this is interesting and the CFWM sidebands generated by this novel method have good enough qualities in terms of power stability, beam quality, and temporal features suited to various experiments such as ultrafast multicolor time-resolved spectroscopy and multicolor-excitation nonlinear microscopy.

  18. Highly efficient non-degenerate four-wave mixing under dual-mode injection in InP/InAs quantum-dash and quantum-dot lasers at 1.55 μm

    Energy Technology Data Exchange (ETDEWEB)

    Sadeev, T., E-mail: tagir@mailbox.tu-berlin.de; Arsenijević, D. [Institut für Festkörperphysik, Technische Universität Berlin, Berlin 10623 (Germany); Huang, H.; Schires, K. [Télécom Paristech, Université Paris-Saclay, 46 rue Barrault, CNRS LTCI 75634 Paris Cedex 13 (France); Grillot, F. [Télécom Paristech, Université Paris-Saclay, 46 rue Barrault, CNRS LTCI 75634 Paris Cedex 13 (France); Center for High Technology Materials, University of New-Mexico, Albuquerque, New Mexico 1313 (United States); Bimberg, D. [Institut für Festkörperphysik, Technische Universität Berlin, Berlin 10623 (Germany); King Abdulaziz University, 22254 Jeddah (Saudi Arabia)

    2015-11-09

    This work reports on non-degenerate four-wave mixing under dual-mode injection in metalorganic vapor phase epitaxy grown InP/InAs quantum-dash and quantum dot Fabry-Perot laser operating at 1550 nm. High values of normalized conversion efficiency of −18.6 dB, optical signal-to-noise ratio of 37 dB, and third order optical susceptibility normalized to material gain χ{sup (3)}/g{sub 0} of ∼4 × 10{sup −19} m{sup 3}/V{sup 3} are measured for 1490 μm long quantum-dash lasers. These values are similar to those obtained with distributed-feedback lasers and semiconductor optical amplifiers, which are much more complicated to fabricate. On the other hand, due to the faster gain saturation and enhanced modulation of carrier populations, quantum-dot lasers demonstrate 12 dB lower conversion efficiency and 4 times lower χ{sup (3)}/g{sub 0} compared to quantum dash lasers.

  19. Spectrally-isolated violet to blue wavelength generation by cascaded degenerate four-wave mixing in a photonic crystal fiber.

    Science.gov (United States)

    Yuan, Jinhui; Kang, Zhe; Li, Feng; Zhang, Xianting; Zhou, Guiyao; Sang, Xinzhu; Wu, Qiang; Yan, Binbin; Zhou, Xian; Wang, Liang; Zhong, Kangping; Wang, Kuiru; Yu, Chongxiu; Tam, Hwa Yaw; Wai, P K A

    2016-06-01

    Generation of spectrally-isolated wavelengths in the violet to blue region based on cascaded degenerate four-wave mixing (FWM) is experimentally demonstrated for the first time in a tailor-made photonic crystal fiber, which has two adjacent zero dispersion wavelengths (ZDWs) at 696 and 852 nm in the fundamental mode. The influences of the wavelength λp and the input average power Pav of the femtosecond pump pulses on the phase-matched frequency conversion process are studied. When femtosecond pump pulses at λp of 880, 870, and 860 nm and Pav of 500 mW are coupled into the normal dispersion region close to the second ZDW, the first anti-Stokes waves generated near the first ZDW act as a secondary pump for the next FWM process. The conversion efficiency ηas2 of the second anti-Stokes waves, which are generated at the violet to blue wavelengths of 430, 456, and 472 nm, are 4.8, 6.48, and 9.66%, for λp equalling 880, 870, and 860 nm, respectively.

  20. Modeling and measurement of the noise figure of a cascaded non-degenerate phase-sensitive parametric amplifier.

    Science.gov (United States)

    Tong, Zhi; Bogris, Adonis; Lundström, Carl; McKinstrie, C J; Vasilyev, Michael; Karlsson, Magnus; Andrekson, Peter A

    2010-07-01

    Semi-classical noise characteristics are derived for the cascade of a non-degenerate phase-insensitive (PI) and a phase-sensitive (PS) fiber optical parametric amplifier (FOPA). The analysis is proved to be consistent with the quantum theory under the large-photon number assumption. Based on this, we show that the noise figure (NF) of the PS-FOPA at the second stage can be obtained via relative-intensity-noise (RIN) subtraction method after averaging the signal and idler NFs. Negative signal and idler NFs are measured, and 16 dB PS gain is estimated when considering the combined signal and idler input, which is believed to be the lowest measured NF of a non-degenerate PS amplifier to this date. The limitation of the RIN subtraction method attributed to pump transferred noise and Raman phonon induced noise is also discussed.

  1. Bandwidth scaling and spectral flatness enhancement of optical frequency combs from phase-modulated continuous-wave lasers using cascaded four-wave mixing.

    Science.gov (United States)

    Supradeepa, V R; Weiner, Andrew M

    2012-08-01

    We introduce a new cascaded four-wave mixing technique that scales up the bandwidth of frequency combs generated by phase modulation of a continuous-wave (CW) laser while simultaneously enhancing the spectral flatness. As a result, we demonstrate a 10 GHz frequency comb with over 100 lines in a 10 dB bandwidth in which a record 75 lines are within a flatness of 1 dB. The cascaded four-wave mixing process increases the bandwidth of the initial comb generated by the modulation of a CW laser by a factor of five. The broadband comb has approximately quadratic spectral phase, which is compensated upon propagation in single-mode fiber, resulting in a 10 GHz train of 940 fs pulses.

  2. Wideband multiwavelength output generation based on cascaded four-wave mixing in distributed Raman amplifier utilizing a Fabry-Pérot laser diode

    Science.gov (United States)

    Al-Alimi, A. W.; Cholan, N. A.; Yaacob, M. H.; Mahdi, M. A.

    2017-08-01

    Multiwavelength output generation based on cascaded four-wave mixing in a distributed Raman amplifier is demonstrated experimentally. The technique consists of launching a probe signal and Fabry-Pérot pump source in a co-propagating setup into a 2 km length of highly nonlinear fiber. In this configuration, the Fabry-Pérot laser diode plays two roles; as a Raman pump and as a source for multiple wavelengths generation. The output of multiple wavelengths with 27.8 GHz spacing centered around the probe signal is generated over 43 nm operation bandwidth. Besides, the bandwidth of the multiwavelength spectrum is also investigated at different wavelength ranges.

  3. Interplay of phase-sensitive amplification and cascaded four-wave mixing in dispersion-controlled waveguides

    Science.gov (United States)

    Martin, Aude; Combrié, Sylvain; Willinger, Amnon; Eisenstein, Gadi; de Rossi, Alfredo

    2016-08-01

    Phase-sensitive parametric interactions can selectively process the two complex quadratures of the optical field. We implement phase-sensitive amplification in a large band-gap semiconductor photonic crystal waveguide in order to avoid two-photon absorption and free-carrier-related effects. Experimentally, an extinction ratio of 15 dB is achieved in a 1.5-mm-long photonic crystal waveguide, at a peak pump power of about 600 mW. We show that cascaded parametric interaction has a strong impact on squeezing and phase-sensitive extinction ratio and that this depends on the dispersion profile of the waveguide.

  4. A comparative study of entanglement amplification in a nondegenerate three-level cascade laser employing various inseparability criteria

    Energy Technology Data Exchange (ETDEWEB)

    Tesfa, Sintayehu, E-mail: sint_tesfa@yahoo.co [Department of Physics, Dilla University, PO Box 419, Dilla (Ethiopia)

    2009-11-14

    A detailed comparison among the exhibited nature of entanglement of the cavity radiation of the nondegenerate three-level cascade laser when different inseparability criteria are employed is presented. Although the achievable degree of entanglement is generally found to vary with the applied inseparability criteria, there are cases for which more than two of the applied criteria lead to a significant degree of entanglement for certain parameters. Particularly, the procedures following from the criterion of Duan-Geidke-Cirac-Zoller and logarithmic negativity predict a similar pattern of entanglement except when the atoms are initially prepared in a maximum atomic coherent superposition. In the same manner, in relation to the absence of interatomic interaction, the Hillery-Zubairy and Cauchy-Schwarz inequalities virtually lead to a similar degree of entanglement. Since an appreciably large degree of entanglement is shown to be realizable using various criteria, there is no doubt that this quantum system can be utilized as a viable source of entangled light.

  5. Experimental generation of quadruple quantum-correlated beams from hot rubidium vapor by cascaded four-wave mixing using spatial multiplexing

    Science.gov (United States)

    Cao, Leiming; Qi, Jian; Du, Jinjian; Jing, Jietai

    2017-02-01

    Multimode quantum states, such as multipartite quantum entanglement or quantum correlations, are important for both fundamental science and the future development of quantum technologies. Here we theoretically propose and experimentally realize a scheme that can fully exploit the multi-spatial-mode nature of the four-wave-mixing (FWM) process, i.e., spatial multiplexing, and thus integrates multiple FWM processes into a single cell at each stage of the cascaded process. The number of generated quantum-correlated beams 2n is exponentially dependent on the number of vapor cells n . In addition, the quantum correlations between the multiple beams also increase as the number of vapor cell increases. For the case of n =2 , we experimentally show that the degree of intensity-difference squeezing between the four quantum-correlated beams in our scheme is enhanced to -8.2 ±0.2 dB from -5.6 ±0.3 and -6.5 ±0.2 dB of squeezing obtained with a single FWM process. Our system may find applications in quantum information and precision measurement.

  6. Quantum Frequency Conversion by Four-wave Mixing Using Bragg Scattering

    DEFF Research Database (Denmark)

    Andersen, Lasse Mejling; Rottwitt, Karsten; McKinstrie, C. J.

    2012-01-01

    Two theoretical models for frequency conversion (FC) using nondegenerate four-wave mixing are compared, and their range of validity are discussed. Quantum-statepreserving FC allows for arbitrary reshaping of states for an appropriate pump selection.......Two theoretical models for frequency conversion (FC) using nondegenerate four-wave mixing are compared, and their range of validity are discussed. Quantum-statepreserving FC allows for arbitrary reshaping of states for an appropriate pump selection....

  7. Effects of Atomic Coherence and Injected Classical Field on Chaotic Dynamics of Non-degenerate Cascade Two-Photon Lasers

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the cascade two-photon laser dynamic equation derived with the technique of quantum Langevin operators with the considerations of coherently prepared three-level atoms and the classical field injected into the cavity, we numerically study the effects of atomic coherence and classical field on the chaotic dynamics of a two-photon laser. Lyapunov exponent and bifurcation diagram calculations show that the Lorenz chaos and hyperchaos can be induced or inhibited by the atomic coherence and the classical field via crisis or Hopf bifurcations.

  8. Design of optical time-division multiplexed systems using the cascaded four-wave mixing in a highly nonlinear photonic crystal fiber for simultaneous time demultiplexing and wavelength multicasting

    Science.gov (United States)

    Hui, Zhan-Qiang; Zhang, Jian-Guo

    2015-07-01

    This paper reports a new design of optical time-division multiplexed (OTDM) systems that possess a functionality of simultaneous time demultiplexing and wavelength multicasting based on the cascaded four-wave mixing in a dispersion-flattened highly nonlinear photonic crystal fiber (DF-HNL-PCF). A module of OTDM demultiplexing and wavelength multicasting can be feasibly implemented by using a 3 dB optical coupler, a high-power erbium-doped fiber amplifier, a short-length DF-HNL-PCF, and a wavelength demultiplexer in the simple configuration. We also carry out an experiment on the proposed system to demonstrate the 100-10 Gbit s-1 OTDM demultiplexing with wavelength conversion simultaneously at 4 multicast wavelengths. It is shown that error-free wavelength multicasting is achieved on two wavelength channels with the minimum power penalty of 3.2 dB relative to the 10 Gbit s-1 back-to-back measurement, whereas the bit error rates of other two multicasting channels are measured to be about 10-6-10-5. Moreover, we propose the use of a proper error-correcting code to improve the multicasting performance of such an OTDM system, and our work reveals that the resulting system can theoretically support error-free multicasting of the OTDM-demultiplexed signal on four wavelength channels.

  9. Quantum-state-preserving optical frequency conversion and pulse reshaping by four-wave mixing

    DEFF Research Database (Denmark)

    McKinstrie, C. J.; Andersen, Lasse Mejling; Raymer, M. G.

    2012-01-01

    Nondegenerate four-wave mixing driven by two pulsed pumps transfers the quantum state of an input signal pulse to an output idler pulse, which is a frequency-converted and reshaped version of the signal. By varying the pump shapes appropriately, one can connect signal and idler pulses...

  10. Generation of Laser Light via Ultrasonic Four-wave Mixing

    Institute of Scientific and Technical Information of China (English)

    OU Fa; WU Fugen; HE Minggao

    2001-01-01

    On the basis of the interaction between phonons in ionic crystals with anharmonic lattice vibration, we present a laser model on acoustic nondegenerate four-wave mixing. Two beams of highfrequency ultrasound, incident on the acoustic cavity fulfilled with the medium of ionic crystal, play the role of pumping and one of the two side-band modes of the pumping frequency as an acoustic signal mode has a strong interaction with the optical cavity mode, the coupling-out of which wiIl be the light (far-infrared) output of a laser. The problem is treated with quantum-mechanics. The theory shows that there is the threshold phenomenon as usual lasers and a so called "phase-matching" condition is derived, which should be satisfied for stability of the system.

  11. Superresolution four-wave mixing microscopy.

    Science.gov (United States)

    Kim, Hyunmin; Bryant, Garnett W; Stranick, Stephan J

    2012-03-12

    We report on the development of a superresolution four-wave mixing microscope with spatial resolution approaching 130 nm which represents better than twice the diffraction limit at 800 nm while retaining the ability to acquire materials- and chemical- specific contrast. The resolution enhancement is achieved by narrowing the microscope's excitation volume in the focal plane through the combined use of a Toraldo-style pupil phase filter with the multiplicative nature of four-wave mixing.

  12. Efficiency of four-wave mixing in injection-locked InAs/GaAs quantum-dot lasers

    Directory of Open Access Journals (Sweden)

    H. Huang

    2016-12-01

    Full Text Available Frequency conversion using highly non-degenerate four-wave mixing is investigated in optically injection-locked InAs/GaAs quantum-dot Fabry-Perot lasers with different ridge waveguide dimensions. Conversion efficiencies up to -16 dB with a large optical signal-to-noise ratios of 36 dB are unveiled. The conversion bandwidth is extended to 4 THz with a quasi-symmetrical response between up- and down-converted signals.

  13. Diffraction manipulation by four-wave mixing

    CERN Document Server

    Katzir, Itay; Firstenberg, Ofer

    2014-01-01

    We suggest a scheme to manipulate paraxial diffraction by utilizing the dependency of a four-wave mixing process on the relative angle between the light fields. A microscopic model for four-wave mixing in a Lambda-type level structure is introduced and compared to recent experimental data. We show that images with feature size as low as 10 micrometers can propagate with very little or even negative diffraction. The inherent gain prevents loss and allows for operating at high optical depths. Our scheme does not rely on atomic motion and is thus applicable to both gaseous and solid media.

  14. Bichromatic field generation from double-four-wave mixing in a double-electromagnetically induced transparency system

    CERN Document Server

    Liu, Yang; Ding, Dongsheng; Shi, Baosen; Guo, Guangcan

    2012-01-01

    We demonstrate the double electromagnetically induced transparency (double-EIT) and double four-wave mixing (double-FWM) based on a new scheme of non-degenerate four-wave mixing (FWM) involving five levels of a cold 85Rb atomic ensemble, in which the double-EIT windows are used to transmit the probe field and enhance the third-order nonlinear susceptibility. The phase-matching conditions for both four-wave mixings could be satisfied simultaneously. The frequency of one component of the generated bichromatic field is less than the other by the ground-state hyperfine splitting (3GHz). This specially designed experimental scheme for simultaneously generating different nonlinear wave-mixing processes is expected to find applications in quantum information processing and cross phase modulation. Our results agree well with the theoretical simulation.

  15. Diffraction manipulation by four-wave mixing.

    Science.gov (United States)

    Katzir, Itay; Ron, Amiram; Firstenberg, Ofer

    2015-03-09

    We suggest a scheme to manipulate paraxial diffraction by utilizing the dependency of a four-wave mixing process on the relative angle between the light fields. A microscopic model for four-wave mixing in a Λ-type level structure is introduced and compared to recent experimental data. We show that images with feature size as low as 10 μm can propagate with very little or even negative diffraction. The mechanism is completely different from that conserving the shape of spatial solitons in nonlinear media, as here diffraction is suppressed for arbitrary spatial profiles. At the same time, the gain inherent to the nonlinear process prevents loss and allows for operating at high optical depths. Our scheme does not rely on atomic motion and is thus applicable to both gaseous and solid media.

  16. Coherent Control of Four-Wave Mixing

    CERN Document Server

    Zhang, Yanpeng; Xiao, Min

    2011-01-01

    "Coherent Control of Four-Wave Mixing" discusses the frequency, temporal and spatial domain interplays of four-wave mixing (FWM) processes induced by atomic coherence in multi-level atomic systems. It covers topics in five major areas: the ultrafast FWM polarization beats due to interactions between multi-color laser beams and multi-level media; coexisting Raman-Rayleigh-Brillouin-enhanced polarization beats due to color-locking noisy field correlations; FWM processes with different kinds of dual-dressed schemes in ultra-thin, micrometer and long atomic cells; temporal and spatial interference between FWM and six-wave mixing (SWM) signals in multi-level electromagnetically induced transparency (EIT) media; spatial displacements and splitting of the probe and generated FWM beams, as well as the observations of gap soliton trains, vortex solitons, and stable multicomponent vector solitons in the FWM signals. The book is intended for scientists, researchers, advanced undergraduate and graduate students in Nonlin...

  17. Low-noise on-chip frequency conversion by four-wave-mixing Bragg scattering in SiNx waveguides

    CERN Document Server

    Agha, Imad; Thurston, Bryce; Srinivasan, Kartik

    2012-01-01

    Low-noise, tunable wavelength-conversion through non-degenerate four-wave mixing Bragg scattering in SiNx waveguides is experimentally demonstrated. Finite element method simulations of waveguide dispersion are used with the split-step Fourier method to predict device performance, and indicate a strong dependence of the conversion efficiency on phase matching, which is controlled by the waveguide geometry. Two 1550 nm wavelength band pulsed pumps are used to achieve tunable conversion of a 980 nm signal over a range of 5 nm with a peak conversion efficiency of \\approx 5 %. The demonstrated Bragg scattering process is suitable for frequency conversion of quantum states of light.

  18. Theory of Pulsed Four-Wave-Mixing in One-dimensional Silicon Photonic Crystal Slab Waveguides

    CERN Document Server

    Lavdas, Spyros

    2015-01-01

    We present a comprehensive theoretical analysis and computational study of four-wave mixing (FWM) of optical pulses co-propagating in one-dimensional silicon photonic crystal waveguides (Si-PhCWGs). Our theoretical analysis describes a very general set-up of the interacting optical pulses, namely we consider nondegenerate FWM in a configuration in which at each frequency there exists a superposition of guiding modes. We incorporate in our theoretical model all relevant linear optical effects, including waveguide loss, free-carrier (FC) dispersion and FC absorption, nonlinear optical effects such as self- and cross-phase modulation (SPM, XPM), two-photon absorption (TPA), and cross-absorption modulation (XAM), as well as the coupled dynamics of FCs and optical field. In particular, our theoretical analysis based on the coupled-mode theory provides rigorously derived formulae for linear dispersion coefficients of the guiding modes, linear coupling coefficients between these modes, as well as the nonlinear waveg...

  19. Entangled State Representation for Four-Wave Mixing

    Institute of Scientific and Technical Information of China (English)

    MA Shan-Jun; LU Hai-Liang; FAN Hong-Yi

    2008-01-01

    We introduce the entangled state representation to describe the four-wave mixing. We find that the four-wave mixing operator, which engenders the correct input-output field transformation, has a natural representation in the entangled state representation. In this way, we see that the four-wave mixing process not only involves squeezing but also is an entanglement process. This analysis brings convenience to the calculation of quadrature-amplitude measurement for the output state of four-wave mixing process.

  20. Entangled State Representation for Four-Wave Mixing

    Science.gov (United States)

    Ma, Shan-Jun; Lu, Hai-Liang; Fan, Hong-Yi

    2008-08-01

    We introduce the entangled state representation to describe the four-wave mixing. We find that the four-wave mixing operator, which engenders the correct input-output field transformation, has a natural representation in the entangled state representation. In this way, we see that the four-wave mixing process not only involves squeezing but also is an entanglement process. This analysis brings convenience to the calculation of quadrature-amplitude measurement for the output state of four-wave mixing process.

  1. FOUR-WAVE MIXING STUDIES OF IONS IN SOLIDS

    OpenAIRE

    Powell, R.; Suchocki, A.; Durville, F.; Gilliland, G.; Behrens, E.; Quarles, G.; BOULON, G.

    1987-01-01

    The laser technique of four-wave mixing is useful in both optical device applications and for characterizing fundamental properties of optical materials. This paper gives an overview of the theory and experimental technique of four-wave mixing, and presents examples of using this technique as a spectroscopic tool and of forming optical devices.

  2. Parametric frequency fusion by inverse four-wave mixing

    CERN Document Server

    Sylvestre, Thibaut

    2015-01-01

    This work reports the experimental observation of a new type of four-wave mixing in which frequency-degenerate weak signal and idler waves are generated by mixing two pump waves of different frequencies in a normally dispersive birefringent optical fiber. This parametric frequency fusion is what we believed the first experimental evidence of inverse four-wave mixing.

  3. Optical frequency combs generated by four-wave mixing in a dual wavelength Brillouin laser cavity

    Directory of Open Access Journals (Sweden)

    Qing Li

    2017-07-01

    Full Text Available We propose and demonstrate the generation of optical frequency combs via four-wave mixing in a dual wavelength Brillouin laser cavity. When pumped by two continuous-wave lasers with a varied frequency separation, dual wavelength Brillouin lasers with reduced linewidth and improved optical signal to noise ratios are generated in a direction opposite to the pump laser. Simultaneously, cavity-enhanced cascaded four-wave mixing between dual wavelength Brillouin lasers occurs in the laser cavity, causing the generation of broadband optical frequency combs with step tunable mode spacing from 40 to 1300 GHz. Compared to the cavity-less case, the number of the comb lines generated in the dual wavelength Brillouin laser cavity is increased by ∼38 times.

  4. Four-Wave Mixing in Silicon-Rich Nitride Waveguides

    DEFF Research Database (Denmark)

    Mitrovic, Miranda; Guan, Xiaowei; Ji, Hua

    2015-01-01

    We demonstrate four-wave mixing wavelength conversion in silicon-rich nitride waveguides which are a promising alternative to silicon for nonlinear applications. The obtained conversion efficiency reaches -13.6 dB while showing no significant nonlinear loss.......We demonstrate four-wave mixing wavelength conversion in silicon-rich nitride waveguides which are a promising alternative to silicon for nonlinear applications. The obtained conversion efficiency reaches -13.6 dB while showing no significant nonlinear loss....

  5. Degenerate four wave mixing in solid core photonic bandgap fibers

    DEFF Research Database (Denmark)

    Rasmussen, Per Dalgaard; Lægsgaard, Jesper; Bang, Ole

    2008-01-01

    Degenerate four wave mixing in solid core photonic bandgap fibers is studied theoretically. We demonstrate the possibility of generating parametric gain across bandgaps, and propose a specific design suited for degenerate four wave mixing when pumping at 532nmm. the possibility of tuning the effi...... the efficency of the parametric gain by varying the temperature is also considered. The sults are verified by numerical simultations of pulse propagation....

  6. Observations of Autler-Townes spatial splitting of four-wave mixing image

    Science.gov (United States)

    Huang, Gaoping; Sun, Jia; Feng, Weikang; Yuan, Jiamin; Wu, Zhenkun; Qin, Mengzhe; Zhang, Yiqi; Zhang, Yanpeng

    2013-08-01

    We report the self- and external-dressed Autler-Townes (A-T) splittings of the images of the generated four-wave mixing signal (FWM) and electromagnetically induced transparency (EIT) of probe images in cascade three-level atomic system. Such spatial properties of probe and FWM signals are induced by the enhanced cross-Kerr nonlinearity. We demonstrate the controlled electromagnetically induced spatial dispersion (EISD), splitting and focusing of probe and FWM signals images by adjusting self- and external-dressing fields. Studies on such controllable A-T spatial splitting and spatial EIT effect can be very useful in applications of spatial signal processing and optical communication.

  7. Double-heralded generation of two-photon-states by spontaneous four-wave-mixing in the presence of noise.

    Science.gov (United States)

    Smith, Roger A; Reddy, Dileep V; Vitullo, Dashiell L P; Raymer, M G

    2016-03-21

    We present an experimental method for creating and verifying photon-number states created by non-degenerate, third-order nonlinear-optical photon-pair sources. By using spatially multiplexed, thresholding single-photon detectors and inverting a conditional probability matrix, we determine the photon-number probabilities created through heralded spontaneous four-wave-mixing. The deleterious effects of noise photons on reliable heralding are investigated and shown to degrade the conditional preparation of two-photon number states more than they degrade conditional single-photon states. We derive the equivalence between the presence of unwanted noise in the herald channel and loss in the signal channel of heralded experiments. A procedure for characterizing the noise-photon contributions, and a means of estimating the herald noise-free photon-number distribution is demonstrated.

  8. All-optical switching via four-wave mixing Bragg scattering in a silicon platform

    CERN Document Server

    Zhao, Yun; Mathews, Jay; Agha, Imad

    2016-01-01

    We employ the process of non-degenerate four-wave mixing Bragg scattering (FWM-BS) to demonstrate all-optical control in a silicon platform. In our configuration, a strong, non-information-carrying pump is mixed with a weak control pump and an input signal in a silicon-on-insulator waveguide. Through the optical nonlinearity of this highly-confining waveguide, the weak pump controls the wavelength conversion process from the signal to an idler, leading to a controlled depletion of the signal. The strong pump, on the other hand, plays the role of a constant bias. In this work, we show experimentally that it is possible to implement this low-power switching technique as a first step towards universal optical logic gates, and test the performance with random binary data. Even at very low powers, where the signal and control pump levels are almost equal, the eye-diagrams remain open, indicating a successful operation of the logic gates.

  9. Theory of pulsed four-wave mixing in one-dimensional silicon photonic crystal slab waveguides

    Science.gov (United States)

    Lavdas, Spyros; Panoiu, Nicolae C.

    2016-03-01

    We present a comprehensive theoretical analysis and computational study of four-wave mixing (FWM) of optical pulses co-propagating in one-dimensional silicon photonic crystal waveguides (Si-PhCWGs). Our theoretical analysis describes a very general setup of the interacting optical pulses, namely we consider nondegenerate FWM in a configuration in which at each frequency there exists a superposition of guiding modes. We incorporate in our theoretical model all relevant linear optical effects, including waveguide loss, free-carrier (FC) dispersion and FC absorption, nonlinear optical effects such as self- and cross-phase modulation (SPM, XPM), two-photon absorption (TPA), and cross-absorption modulation (XAM), as well as the coupled dynamics of free-carriers FCs and optical field. In particular, our theoretical analysis based on the coupled-mode theory provides rigorously derived formulas for linear dispersion coefficients of the guiding modes, linear coupling coefficients between these modes, as well as the nonlinear waveguide coefficients describing SPM, XPM, TPA, XAM, and FWM. In addition, our theoretical analysis and numerical simulations reveal key differences between the characteristics of FWM in the slow- and fast-light regimes, which could potentially have important implications to the design of ultracompact active photonic devices.

  10. All-optical switching via four-wave mixing Bragg scattering in a silicon platform

    Directory of Open Access Journals (Sweden)

    Yun Zhao

    2017-02-01

    Full Text Available We employ the process of non-degenerate four-wave mixing Bragg scattering to demonstrate all-optical control in a silicon platform. In our configuration, a strong, non-information-carrying pump is mixed with a weak control pump and an input signal in a silicon-on-insulator waveguide. Through the optical nonlinearity of this highly confining waveguide, the weak pump controls the wavelength conversion process from the signal to an idler, leading to a controlled depletion of the signal. The strong pump, on the other hand, plays the role of a constant bias. In this work, we show experimentally that it is possible to implement this low-power switching technique as a first step towards universal optical logic gates, and test the performance with random binary data. Even at very low powers, where the signal and control pump levels are almost equal, the eye-diagrams remain open, indicating a successful operation of the logic gates.

  11. Dressed Gain from the Parametrically Amplified Four-Wave Mixing Process in an Atomic Vapor

    Science.gov (United States)

    Zhang, Zhaoyang; Wen, Feng; Che, Junling; Zhang, Dan; Li, Changbiao; Zhang, Yanpeng; Xiao, Min

    2015-01-01

    With a forward cone emitting from the strong pump laser in a thermal rubidium atomic vapor, we investigate the non-degenerate parametrically amplified four-wave mixing (PA-FWM) process with dressing effects in a three-level “double-Λ” configuration both theoretically and experimentally. By seeding a weak probe field into the Stokes or anti-Stokes channel of the FWM, the gain processes are generated in the bright twin beams which are called conjugate and probe beams, respectively. However, the strong dressing effect of the pump beam will dramatically affect the gain factors both in the probe and conjugate channels, and can inevitably impose an influence on the quantum effects such as entangled degree and the quantum noise reduction between the two channels. We systematically investigate the intensity evolution of the dressed gain processes by manipulating the atomic density, the Rabi frequency and the frequency detuning. Such dressing effects are also visually evidenced by the observation of Autler-Townes splitting of the gain peaks. The investigation can contribute to the development of quantum information processing and quantum communications. PMID:26463588

  12. Phase-locking in Multi-Frequency Brillouin Oscillator via Four Wave Mixing

    CERN Document Server

    Buettner, Thomas F S; Hudson, Darren D; Pant, Ravi; Poulton, Christopher G; Judge, Alexander C; Eggleton, Benjamin J

    2014-01-01

    Stimulated Brillouin scattering (SBS) and Kerr-nonlinear four wave-mixing (FWM) are among the most important and widely studied nonlinear effects in optical fibres. At high powers SBS can be cascaded producing multiple Stokes waves spaced by the Brillouin frequency shift. Here, we investigate the complex nonlinear interaction of the cascade of Stokes waves, generated in a Fabry-Perot chalcogenide fibre resonator through the combined action of SBS and FWM. We demonstrate the existence of parameter regimes, in which pump and Stokes waves attain a phase-locked steady state. Real-time measurements of 40ps pulses with 8GHz repetition rate are presented, confirming short-and long-term stability. Numerical simulations qualitatively agree with experiments and show the significance of FWM in phase-locking of pump and Stokes waves. Our findings can be applied for the design of novel picosecond pulse sources with GHz repetition rate for optical communication systems.

  13. Broad bandwidth third-harmonic generation via four-wave mixing and stimulated Raman scattering in a microcavity.

    Science.gov (United States)

    Chen-Jinnai, Akitoshi; Kato, Takumi; Fujii, Shun; Nagano, Takuma; Kobatake, Tomoya; Tanabe, Takasumi

    2016-11-14

    We generate broad bandwidth visible light ranging from 498 to 611 nm via third-harmonic generation in a silica toroid microcavity. The silica toroid microcavity is fed with a continuous-wave input at a telecom wavelength, where third-harmonic generation follows the generation of an infrared Kerr comb via cascaded four-wave-mixing and stimulated Raman scattering effects. Thanks to these cascaded effects (four-wave mixing, stimulated Raman scattering, and third-harmonic generation) in an ultrahigh-Q microcavity, a broad bandwidth visible light is obtained. The visible light couples with the whispering gallery mode of the cavity by demonstrating the evanescent coupling of the generated visible light with a tapered fiber based on an add-drop configuration.

  14. Computing zeta functions of sparse nondegenerate hypersurfaces

    CERN Document Server

    Sperber, Steven

    2011-01-01

    Using the cohomology theory of Dwork, as developed by Adolphson and Sperber, we exhibit a deterministic algorithm to compute the zeta function of a nondegenerate hypersurface defined over a finite field. This algorithm is particularly well-suited to work with polynomials in small characteristic that have few monomials (relative to their dimension). Our method covers toric, affine, and projective hypersurfaces and also can be used to compute the L-function of an exponential sum.

  15. Frequency comb-based four-wave-mixing spectroscopy.

    Science.gov (United States)

    Lomsadze, Bachana; Cundiff, Steven T

    2017-06-15

    We experimentally demonstrate four-wave-mixing (FWM) spectroscopy using frequency combs. The experiment uses a geometry where excitation pulses and FWM signals generated by a sample co-propagate. We separate them in the radio frequency domain by heterodyne detection with a local oscillator comb that has a different repetition frequency.

  16. Continuum contribution to excitonic four-wave mixing

    DEFF Research Database (Denmark)

    Birkedal, Dan; Sayed, Karim El; Vadim, Lyssenko

    1996-01-01

    Summary form only given. We present an experimental and theoretical investigation of ultrafast transient four-wave mixing (TFWM) of GaAs-AlGaAs quantum wells for simultaneous excitation of exciton and continuum states. Recent TFWM experiments on semiconductors have shown unexpected results when...

  17. Spontaneous Four-Wave Mixing in an Irregular Nanofiber

    Directory of Open Access Journals (Sweden)

    Shukhin A.A.

    2015-01-01

    Full Text Available The features of biphotons states generated via spontaneous four-wave mixing in nanofibers with a variable cross-section are studied. The spectral amplitude of the biphoton field is calculated and the effects of interference and phase modulation of the biphoton field in such structures is discussed.

  18. Parametric four-wave mixing using a single cw laser

    CERN Document Server

    Brekke, E

    2013-01-01

    Four-wave mixing can be used to generate coherent output beams, with frequencies difficult to acquire in commercial lasers. Here a single narrow ECDL locked to the two photon 5s-5d transition in rubidium is combined with a tapered amplifier system to produce a high power cw beam at 778 nm and used to generate coherent light at 420 nm through parametric four-wave mixing. This process is analyzed in terms of the the intensity and frequency of the incoming beam as well as the atomic density of the sample. The efficiency of the process is currently limited when on resonance due to the absorption of the 420 nm beam, and modifications should allow a significant increase in output power.

  19. All Optical Signal-Processing Techniques Utilizing Four Wave Mixing

    Directory of Open Access Journals (Sweden)

    Refat Kibria

    2015-02-01

    Full Text Available Four Wave Mixing (FWM based optical signal-processing techniques are reviewed. The use of FWM in arithmetical operation like subtraction, wavelength conversion and pattern recognition are three key parts discussed in this paper after a brief introduction on FWM and its comparison with other nonlinear mixings. Two different approaches to achieve correlation are discussed, as well as a novel technique to realize all optical subtraction of two optical signals.

  20. Phase conjugation by four-wave mixing in inhomogeneous plasmas

    Science.gov (United States)

    Williams, Edward A.; Lininger, Diana M.; Goldman, Martin V.

    1989-01-01

    The effects of density, temperature, and velocity gradients on four-wave mixing (FWM) in a plasma are investigated. A fluid model is used in which the stimulated Brillouin terms are included, but pump depletion is neglected. The steady state phase conjugate reflectivity and signal transmission coefficients are calculated and discussed for both degenerate and resonant FWM. The substantial effects of inhomogeneity on the use of FWM as a plasma diagnostic are discussed.

  1. Four-Wave Mixing Aplication in Semiconductor Optical Amplifier

    Directory of Open Access Journals (Sweden)

    Radoslav Odrobinak

    2004-01-01

    Full Text Available Four-Wave Mixing (FWM in semiconductor optical amplifiers is an attrative mechanism for wavelenght coversion in wavelenght-division multiplexed (WDM systems since it provides modulation format and bit rate transparency over wide tuning ranges. A series of systems experiments evaluating several aspects of the performance of these devices at bit rates of 2.5 and 10 Gb/s are presented.

  2. Entanglement in a four-wave mixing process.

    Science.gov (United States)

    Zheng, Zhan; Wang, Hailong; Cheng, Bing; Jing, Jietai

    2017-07-15

    We investigate different kinds of entanglement in a four-wave mixing process with a degenerate pump. After analyses on means and quantum fluctuations of the three output beams (Stokes, anti-Stokes, and pump), we verify the existence of genuine tripartite entanglement, and quantify bipartite, two-mode, as well as tripartite entanglement with the covariance matrix. We find out that the input pump power and the nonlinear coupling strength are the physical origins to enhance entanglement at a given photon loss.

  3. Spatial Four Wave Mixing, Probe Images, and Fluorescence Signals in Dressed Three-Level System

    Science.gov (United States)

    Lan, Huayan; Sun, Jia; Wu, Zhenkun; Zhang, Dan; Zhang, Yiqi; Zheng, Huaibin; Zhang, Yanpeng

    2013-10-01

    We investigate the spatial images of the probe, generated four wave mixing (FWM) signal and the accompanying fluorescence spectrum signal simultaneously in FWM process in a cascade three-level atomic system for the first time. We experimentally observe and theoretically investigate the three spectrum signals versus the probe field as well as the dressing field frequency detunings. Utilizing the experimental results of spectrum signals, the cross phase modulation and the relative position between the weak and strong beams, we analyze the characteristics indicated in the spatial images of probe transmission and FWM, such as focusing or defocusing, shift and splitting in detail. Such studies can be used in all-optical controlled spatial signal transmission.

  4. Zero-voltage nondegenerate parametric mode in Josephson tunnel junctions

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig

    1976-01-01

    A new parametric mode in a Josephson tunnel junction biased in the zero-voltage mode is suggested. It is a nondegenerate parametric excitation where the junction plasma resonance represents the input circuit, and a junction geometrical resonance represents the idler circuit. This nondegenerate mo...... for such a coupling. Journal of Applied Physics is copyrighted by The American Institute of Physics....

  5. Spontaneous four-wave mixing in lossy microring resonators

    CERN Document Server

    Vernon, Z

    2015-01-01

    We develop a general Hamiltonian treatement of spontaneous four-wave mixing in a microring resonator side-coupled to a channel waveguide. The effect of scattering losses in the ring is included, as well as parasitic nonlinear effects including self- and cross-phase modulation. A procedure for computing the output of such a system for arbitrary parameters and pump states is presented. For the limit of weak pumping an expression for the joint spectral intensity of generated photon pairs, as well as the singles-to-coincidences ratio, is derived.

  6. Four wave mixing as a probe of the vacuum

    Science.gov (United States)

    Tennant, Daniel M.

    2016-06-01

    Much attention has been paid to the quantum structure of the vacuum. Higher order processes in quantum electrodynamics are strongly believed to cause polarization and even breakdown of the vacuum in the presence of strong fields soon to be accessible in high intensity laser experiments. Less explored consequences of strong field electrodynamics include effects from Born-Infeld type of electromagnetic theories, a nonlinear electrodynamics that follows from classical considerations as opposed to coupling to virtual fluctuations. In this article, I will demonstrate how vacuum four wave mixing has the possibility to differentiate between these two types of vacuum responses: quantum effects on one hand and nonlinear classical extensions on the other.

  7. Quantum temporal imaging by four-wave mixing.

    Science.gov (United States)

    Shi, Junheng; Patera, Giuseppe; Kolobov, Mikhail I; Han, Shensheng

    2017-08-15

    We investigate temporal imaging of broadband squeezed light by four-wave-mixing. We consider two possible imaging configurations: phase-conjugating (PC) and phase-preserving (PP). Both of these configurations have been successfully used for temporal imaging of classical temporal waveforms. We demonstrate that for quantum temporal imaging, precisely, temporal imaging of broadband squeezed light, these two schemes have very different behavior: the PC configuration deteriorates squeezing, while the PP configuration leaves it intact. These results are very important for the applications of temporal imaging for quantum communications and quantum information processing.

  8. Controllable azimuthons of four-wave mixing and their applications

    Science.gov (United States)

    Wang, R. M.; Che, J. L.; Wang, X. P.; Lan, H. Y.; Wu, Z. K.; Zhang, Y. Q.; Zhang, Y. P.

    2014-08-01

    We report controllable azimuthons of four-wave mixing (FWM), which can be modulated by several parameters in experiment. The spot number, splitting depth, rotation angular velocity and direction of such azimuthons can be controlled by the frequency and intensity of the FWM signal or the dressing field through the cross-phase modulation due to atomic coherence. The intensity gain of the azimuthons can be modulated by frequency detuning through quantum parametric amplification. The quantum correlated FWM vortex is observed in experiment. We also discuss the applications of such controllable azimuthons in all-optical circulators, multiplexers (demultiplexers), routers, cross-connects and optical amplifiers.

  9. ON INTERSECTIONS OF INDEPENDENT NONDEGENERATE DIFFUSION PROCESSES

    Institute of Scientific and Technical Information of China (English)

    Zhenlong CHEN

    2014-01-01

    Let X(1) = {X(1)(s), s ∈ R+} and X(2) = {X(2)(t), t ∈ R+} be two inde-pendent nondegenerate diffusion processes with values in Rd. The existence and fractal dimension of intersections of the sample paths of X (1) and X (2) are studied. More gener-ally, let E1, E2⊆(0,∞) and F ⊂Rd be Borel sets. A necessary condition and a suffcient condition for P{X(1)(E1)∩X(2)(E2)∩F 6=∅}>0 are proved in terms of the Bessel-Riesz type capacity and Hausdorff measure of E1 × E2 × F in the metric space (R+× R+× Rd,ρb), whereρb is an unsymmetric metric defined in R+× R+× Rd. Under reasonable conditions, results resembling those of Browian motion are obtained.

  10. Theoretical analysis of four wave mixing in quantum dot optical amplifiers

    DEFF Research Database (Denmark)

    Berg, Tommy Winther; Mørk, Jesper

    2003-01-01

    The four wave mixing properties of semiconductor quantum dot amplifiers have been investigated. The combination of strong non-equilibrium depletion of dot levels and a small linewidth enhancement factor results in efficient and symmetric four wave mixing....

  11. Enhanced four-wave mixing with nonlinear plasmonic metasurfaces

    CERN Document Server

    Jin, Boyuan

    2016-01-01

    Plasmonic metasurfaces provide an effective way to increase the efficiency of several nonlinear processes while maintaining nanoscale dimensions. In this work, nonlinear metasurfaces based on film-coupled silver nanostripes loaded with Kerr nonlinear material are proposed to achieve efficient four-wave mixing (FWM). Highly localized plasmon resonances are formed in the nanogap between the metallic film and nanostripes. The local electric field is dramatically enhanced in this subwavelength nanoregion. These properties combined with the relaxed phase matching condition due to the ultrathin area lead to a giant FWM efficiency, which is enhanced by nineteen orders of magnitude compared to a bare silver screen. In addition, efficient visible and low-THz sources can be constructed based on the proposed nonlinear metasurfaces. The FWM generated coherent wave has a directional radiation pattern and its output power is relatively insensitive to the incident angles of the excitation sources. This radiated power can be...

  12. Regenerative oscillation and four-wave mixing in graphene optoelectronics

    CERN Document Server

    Gu, Tingyi; Yang, Xiaodong; McMillian, James F; van der Zander, Arend; Yu, Min-bing; Lo, Guo-Qiang; Kwong, Dim-Lee; Hone, James; Wong, Chee-Wei

    2012-01-01

    The unique linear and massless band structure of graphene, in a purely two-dimensional Dirac fermionic structure, have led to intense research spanning from condensed matter physics to nanoscale device applications covering the electrical, thermal, mechanical and optical domains. Here we report three consecutive first-observations in graphene-silicon hybrid optoelectronic devices: (1) ultralow power resonant optical bistability; (2) self-induced regenerative oscillations; and (3) coherent four-wave mixing, all at a few femtojoule cavity recirculating energies. These observations, in comparison with control measurements with solely monolithic silicon cavities, are enabled only by the dramatically-large and chi(3) nonlinearities in graphene and the large Q/V ratios in wavelength-localized photonic crystal cavities. These results demonstrate the feasibility and versatility of hybrid two-dimensional graphene-silicon nanophotonic devices for next-generation chip-scale ultrafast optical communications, radio-freque...

  13. High conversion efficiency in resonant four-wave mixing processes.

    Science.gov (United States)

    Lee, Chin-Yuan; Wu, Bo-Han; Wang, Gang; Chen, Yong-Fang; Chen, Ying-Cheng; Yu, Ite A

    2016-01-25

    We propose a new scheme of the resonant four-wave mixing (FWM) for the frequency up or down conversion, which is more efficient than the commonly-used scheme of the non-resonant FWM. In this new scheme, two control fields are spatially varied such that a probe field at the input can be converted to a signal field at the output. The efficiency of probe-to-signal energy conversion can be 90% at medium's optical depth of about 100. Our proposed scheme works for both the continuous-wave and pulse cases, and is flexible in choosing the control field intensity. This work provides a very useful tool in the nonlinear frequency conversion.

  14. Four-Wave Mixing in Landau-Quantized Graphene.

    Science.gov (United States)

    König-Otto, Jacob C; Wang, Yongrui; Belyanin, Alexey; Berger, Claire; de Heer, Walter A; Orlita, Milan; Pashkin, Alexej; Schneider, Harald; Helm, Manfred; Winnerl, Stephan

    2017-04-12

    For Landau-quantized graphene, featuring an energy spectrum consisting of nonequidistant Landau levels, theory predicts a giant resonantly enhanced optical nonlinearity. We verify the nonlinearity in a time-integrated degenerate four-wave mixing (FWM) experiment in the mid-infrared spectral range, involving the Landau levels LL-1, LL0 and LL1. A rapid dephasing of the optically induced microscopic polarization on a time scale shorter than the pulse duration (∼4 ps) is observed, while a complementary pump-probe experiment under the same experimental conditions reveals a much longer lifetime of the induced population. The FWM signal shows the expected field dependence with respect to lowest order perturbation theory for low fields. Saturation sets in for fields above ∼6 kV/cm. Furthermore, the resonant behavior and the order of magnitude of the third-order susceptibility are in agreement with our theoretical calculations.

  15. Simultaneous multichannel wavelength multicasting and XOR logic gate multicasting for three DPSK signals based on four-wave mixing in quantum-dot semiconductor optical amplifier.

    Science.gov (United States)

    Qin, Jun; Lu, Guo-Wei; Sakamoto, Takahide; Akahane, Kouichi; Yamamoto, Naokatsu; Wang, Danshi; Wang, Cheng; Wang, Hongxiang; Zhang, Min; Kawanishi, Tetsuya; Ji, Yuefeng

    2014-12-01

    In this paper, we experimentally demonstrate simultaneous multichannel wavelength multicasting (MWM) and exclusive-OR logic gate multicasting (XOR-LGM) for three 10Gbps non-return-to-zero differential phase-shift-keying (NRZ-DPSK) signals in quantum-dot semiconductor optical amplifier (QD-SOA) by exploiting the four-wave mixing (FWM) process. No additional pump is needed in the scheme. Through the interaction of the input three 10Gbps DPSK signal lights in QD-SOA, each channel is successfully multicasted to three wavelengths (1-to-3 for each), totally 3-to-9 MWM, and at the same time, three-output XOR-LGM is obtained at three different wavelengths. All the new generated channels are with a power penalty less than 1.2dB at a BER of 10(-9). Degenerate and non-degenerate FWM components are fully used in the experiment for data and logic multicasting.

  16. Modeling interchannel four-wave mixing for 8-Ary modulated dense wavelength division multiplexing systems over dispersion map

    Science.gov (United States)

    Du, Jianxin; Shen, Ninghang; Xu, Yue

    2016-08-01

    Semianalytic models are developed to deterministically calculate the variances of degenerate and nondegenerate four-wave mixing (FWM) noises for dispersion-managed dense wavelength division multiplexing (DWDM) systems with 8-Ary modulations [i.e., 8-level amplitude- and differential phase-shift keying (8APSK) and constant-amplitude optical differential 8-level phase-shift keying (D8PSK)]. The semianalytic models include various important propagation effects for exact numerical results. A 5.28-Tb/s (40-Gs/s/ch) 100-GHz-spaced 33-channel DWDM system with a dispersion map is then numerically analyzed by using the newly derived semianalytic models. It is numerically validated that FWM impacts coming from 8APSK pump channels are more severe than those coming from D8PSK ones, where pump channels denote the channels whose energies are transferred to a probe channel through the FWM process. The numerical results show that although FWM tolerance of a central channel with 8APSK is worse than that with D8PSK, a central channel with 8APSK is still superior to that with D8PSK when some linear noises and FWM noise are simultaneously taken into account for our given system conditions, which is mainly attributed to a relatively larger minimum Euclidean distance for the 8APSK constellation than the D8PSK one.

  17. Geometric phases for non-degenerate and degenerate mixed states

    CERN Document Server

    Singh, K; Basu, K; Chen, J L; Du Jiang Feng

    2003-01-01

    This paper focuses on the geometric phase of general mixed states under unitary evolution. Here we analyze both non-degenerate as well as degenerate states. Starting with the non-degenerate case, we show that the usual procedure of subtracting the dynamical phase from the total phase to yield the geometric phase for pure states, does not hold for mixed states. To this end, we furnish an expression for the geometric phase that is gauge invariant. The parallelity conditions are shown to be easily derivable from this expression. We also extend our formalism to states that exhibit degeneracies. Here with the holonomy taking on a non-abelian character, we provide an expression for the geometric phase that is manifestly gauge invariant. As in the case of the non-degenerate case, the form also displays the parallelity conditions clearly. Finally, we furnish explicit examples of the geometric phases for both the non-degenerate as well as degenerate mixed states.

  18. Studies of nondegenerate, quasi-phase-matched optical parametric amplification

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence Livermore National Laboratory

    2004-03-18

    We have performed extensive numerical studies of quasi-phase-matched optical parametric amplification with the aim to improve its nondegenerate spectral bandwidth. Our multi-section fan-out design calculations indicate a 35-fold increase in spectral bandwidth.

  19. Enhanced four-wave mixing with nonlinear plasmonic metasurfaces.

    Science.gov (United States)

    Jin, Boyuan; Argyropoulos, Christos

    2016-06-27

    Plasmonic metasurfaces provide an effective way to increase the efficiency of several nonlinear processes while maintaining nanoscale dimensions. In this work, nonlinear metasurfaces based on film-coupled silver nanostripes loaded with Kerr nonlinear material are proposed to achieve efficient four-wave mixing (FWM). Highly localized plasmon resonances are formed in the nanogap between the metallic film and nanostripes. The local electric field is dramatically enhanced in this subwavelength nanoregion. These properties combined with the relaxed phase matching condition due to the ultrathin area lead to a giant FWM efficiency, which is enhanced by nineteen orders of magnitude compared to a bare silver screen. In addition, efficient visible and low-THz sources can be constructed based on the proposed nonlinear metasurfaces. The FWM generated coherent wave has a directional radiation pattern and its output power is relatively insensitive to the incident angles of the excitation sources. This radiated power can be further enhanced by increasing the excitation power. The dielectric nonlinear material placed in the nanogap is mainly responsible for the ultrastrong FWM response. Compact and efficient wave mixers and optical sources spanning different frequency ranges are envisioned to be designed based on the proposed nonlinear metasurface designs.

  20. Stimulated degenerate four-wave mixing in Si nanocrystal waveguides

    Science.gov (United States)

    Manna, Santanu; Bernard, Martino; Biasi, Stefano; Ramiro Manzano, Fernando; Mancinelli, Mattia; Ghulinyan, Mher; Pucker, George; Pavesi, Lorenzo

    2016-07-01

    Parametric frequency conversion via four-wave mixing (FWM) in silicon nanocrystal (Si NC) waveguides is observed at 1550 nm. To investigate the role of Si NC, different types of waveguides containing Si NC in a SiO2 matrix were fabricated. Owing to the increase of the dipole oscillator strength mediated by the quantum confinement effect, the non-linear refractive index ({n}2) of Si NCs is found to be more than one order of magnitude larger than the one of bulk Si. Coupled differential equations for the degenerate FWM process taking into account the role of Si NC were numerically solved to model the experimental data. The modeling yields an effective {n}2 for Si NCs in SiO2 waveguides which is similar to the one of Si waveguides. We also measured a large signal to idler conversion bandwidth of ∼22 nm. The large non-linear refractive index is joined with a large two photon absorption coefficient which makes the use of Si NC in non-linear optical devices mostly suitable for mid-infrared applications.

  1. Comparing the ecological relevance of four wave exposure models

    Science.gov (United States)

    Sundblad, G.; Bekkby, T.; Isæus, M.; Nikolopoulos, A.; Norderhaug, K. M.; Rinde, E.

    2014-03-01

    Wave exposure is one of the main structuring forces in the marine environment. Methods that enable large scale quantification of environmental variables have become increasingly important for predicting marine communities in the context of spatial planning and coastal zone management. Existing methods range from cartographic solutions to numerical hydrodynamic simulations, and differ in the scale and spatial coverage of their outputs. Using a biological exposure index we compared the performance of four wave exposure models ranging from simple to more advanced techniques. All models were found to be related to the biological exposure index and their performance, measured as bootstrapped R2 distributions, overlapped. Qualitatively, there were differences in the spatial patterns indicating higher complexity with more advanced techniques. In order to create complex spatial patterns wave exposure models should include diffraction, especially in coastal areas rich in islands. The inclusion of wind strength and frequency, in addition to wind direction and bathymetry, further tended to increase the amount of explained variation. The large potential of high-resolution numerical models to explain the observed patterns of species distribution in complex coastal areas provide exciting opportunities for future research. Easy access to relevant wave exposure models will aid large scale habitat classification systems and the continuously growing field of marine species distribution modelling, ultimately serving marine spatial management and planning.

  2. Four wave mixing experiments with extreme ultraviolet transient gratings

    Science.gov (United States)

    Bencivenga, F.; Cucini, R.; Capotondi, F.; Battistoni, A.; Mincigrucci, R.; Giangrisostomi, E.; Gessini, A.; Manfredda, M.; Nikolov, I. P.; Pedersoli, E.; Principi, E.; Svetina, C.; Parisse, P.; Casolari, F.; Danailov, M. B.; Kiskinova, M.; Masciovecchio, C.

    2015-01-01

    Four wave mixing (FWM) processes, based on third-order non-linear light-matter interactions, can combine ultrafast time resolution with energy and wavevector selectivity, and enables to explore dynamics inaccessible by linear methods.1-7 The coherent and multi-wave nature of FWM approach has been crucial in the development of cutting edge technologies, such as silicon photonics,8 sub-wavelength imaging9 and quantum communications.10 All these technologies operate with optical wavelengths, which limit the spatial resolution and do not allow probing excitations with energy in the eV range. The extension to shorter wavelengths, that is the extreme ultraviolet (EUV) and soft-x-ray (SXR) range, will allow to improve the spatial resolution and to expand the excitation energy range, as well as to achieve elemental selectivity by exploiting core resonances.5-7,11-14 So far FWM applications at these wavelengths have been prevented by the absence of coherent sources of sufficient brightness and suitable experimental setups. Our results show how transient gratings, generated by the interference of coherent EUV pulses delivered by the FERMI free electron laser (FEL),15 can be used to stimulate FWM processes at sub-optical wavelengths. Furthermore, we have demonstrated the possibility to read the time evolution of the FWM signal, which embodies the dynamics of coherent excitations as molecular vibrations. This result opens the perspective for FWM with nanometer spatial resolution and elemental selectivity, which, for example, would enable the investigation of charge-transfer dynamics.5-7 The theoretical possibility to realize these applications have already stimulated dedicated and ongoing FEL developments;16-20 today our results show that FWM at sub-optical wavelengths is feasible and would be the spark to the further advancements of the present and new sources. PMID:25855456

  3. Four-wave mixing experiments with extreme ultraviolet transient gratings.

    Science.gov (United States)

    Bencivenga, F; Cucini, R; Capotondi, F; Battistoni, A; Mincigrucci, R; Giangrisostomi, E; Gessini, A; Manfredda, M; Nikolov, I P; Pedersoli, E; Principi, E; Svetina, C; Parisse, P; Casolari, F; Danailov, M B; Kiskinova, M; Masciovecchio, C

    2015-04-09

    Four-wave mixing (FWM) processes, based on third-order nonlinear light-matter interactions, can combine ultrafast time resolution with energy and wavevector selectivity, and enable the exploration of dynamics inaccessible by linear methods. The coherent and multi-wave nature of the FWM approach has been crucial in the development of advanced technologies, such as silicon photonics, subwavelength imaging and quantum communications. All these technologies operate at optical wavelengths, which limits the spatial resolution and does not allow the probing of excitations with energy in the electronvolt range. Extension to shorter wavelengths--that is, the extreme ultraviolet and soft-X-ray ranges--would allow the spatial resolution to be improved and the excitation energy range to be expanded, as well as enabling elemental selectivity to be achieved by exploiting core resonances. So far, FWM applications at such wavelengths have been prevented by the absence of coherent sources of sufficient brightness and of suitable experimental set-ups. Here we show how transient gratings, generated by the interference of coherent extreme-ultraviolet pulses delivered by the FERMI free-electron laser, can be used to stimulate FWM processes at suboptical wavelengths. Furthermore, we have demonstrated the possibility of observing the time evolution of the FWM signal, which shows the dynamics of coherent excitations as molecular vibrations. This result opens the way to FWM with nanometre spatial resolution and elemental selectivity, which, for example, would enable the investigation of charge-transfer dynamics. The theoretical possibility of realizing these applications has already stimulated ongoing developments of free-electron lasers: our results show that FWM at suboptical wavelengths is feasible, and we hope that they will enable advances in present and future photon sources.

  4. Four-wave-mixing experiments with seeded free electron lasers.

    Science.gov (United States)

    Bencivenga, F; Calvi, A; Capotondi, F; Cucini, R; Mincigrucci, R; Simoncig, A; Manfredda, M; Pedersoli, E; Principi, E; Dallari, F; Duncan, R A; Izzo, M G; Knopp, G; Maznev, A A; Monaco, G; Di Mitri, S; Gessini, A; Giannessi, L; Mahne, N; Nikolov, I P; Passuello, R; Raimondi, L; Zangrando, M; Masciovecchio, C

    2016-12-16

    The development of free electron laser (FEL) sources has provided an unprecedented bridge between the scientific communities working with ultrafast lasers and extreme ultraviolet (XUV) and X-ray radiation. Indeed, in recent years an increasing number of FEL-based applications have exploited methods and concepts typical of advanced optical approaches. In this context, we recently used a seeded FEL to demonstrate a four-wave-mixing (FWM) process stimulated by coherent XUV radiation, namely the XUV transient grating (X-TG). We hereby report on X-TG measurements carried out on a sample of silicon nitride (Si3N4). The recorded data bears evidence for two distinct signal decay mechanisms: one occurring on a sub-ps timescale and one following slower dynamics extending throughout and beyond the probed timescale range (100 ps). The latter is compatible with a slower relaxation (time decay > ns), that may be interpreted as the signature of thermal diffusion modes. From the peak intensity of the X-TG signal we could estimate a value of the effective third-order susceptibility which is substantially larger than that found in SiO2, so far the only sample with available X-TG data. Furthermore, the intensity of the time-coincidence peak shows a linear dependence on the intensity of the three input beams, indicating that the measurements were performed in the weak field regime. However, the timescale of the ultrafast relaxation exhibits a dependence on the intensity of the XUV radiation. We interpreted the observed behaviour as the generation of a population grating of free-electrons and holes that, on the sub-ps timescale, relaxes to generate lattice excitations. The background free detection inherent to the X-TG approach allowed the determination of FEL-induced electron dynamics with a sensitivity largely exceeding that of transient reflectivity and transmissivity measurements, usually employed for this purpose.

  5. Sensitivity Enhancement for Fiber Bragg Grating Sensors by Four Wave Mixing

    Directory of Open Access Journals (Sweden)

    Jiangbing Du

    2015-04-01

    Full Text Available All-optical signal processing based on four wave mixing (FWM in a highly nonlinear fiber (HNLF to enhance the sensitivity of a fiber sensor is demonstrated and comprehensively reviewed in this paper. The principle is based on the frequency chirp magnification (FCM by FWM. Degenerated FWM, cascaded two-stage FWM and pump-pulsed FWM with optical parametric amplification (OPA are experimentally utilized for magnifying the frequency chirp. By using the pump pulse modulation to increase the peak power, OPA can be induced with the use of a dispersion-optimized HNLF. Therefore, ultra-highly efficient FWM can be realized due to the high peak power and OPA. By using the fiber Bragg grating (FBG laser as the FWM pump, the wavelength drift of the FBG can thus be magnified due to the FCM. We obtain a sensing performance of 13.3 pm/με strain sensitivity and 141.2 pm/°C temperature sensitivity for a conventional FBG, which has an intrinsic strain sensitivity of only ~1 pm/με and an intrinsic temperature sensitivity of only ~10 pm/°C, respectively.

  6. Phase-locking and Pulse Generation in Multi-Frequency Brillouin Oscillator via Four Wave Mixing

    Science.gov (United States)

    Büttner, Thomas F. S.; Kabakova, Irina V.; Hudson, Darren D.; Pant, Ravi; Poulton, Christopher G.; Judge, Alexander C.; Eggleton, Benjamin J.

    2014-01-01

    There is an increasing demand for pulsed all-fibre lasers with gigahertz repetition rates for applications in telecommunications and metrology. The repetition rate of conventional passively mode-locked fibre lasers is fundamentally linked to the laser cavity length and is therefore typically ~10–100 MHz, which is orders of magnitude lower than required. Cascading stimulated Brillouin scattering (SBS) in nonlinear resonators, however, enables the formation of Brillouin frequency combs (BFCs) with GHz line spacing, which is determined by the acoustic properties of the medium and is independent of the resonator length. Phase-locking of such combs therefore holds a promise to achieve gigahertz repetition rate lasers. The interplay of SBS and Kerr-nonlinear four-wave mixing (FWM) in nonlinear resonators has been previously investigated, yet the phase relationship of the waves has not been considered. Here, we present for the first time experimental and numerical results that demonstrate phase-locking of BFCs generated in a nonlinear waveguide cavity. Using real-time measurements we demonstrate stable 40 ps pulse trains with 8 GHz repetition rate based on a chalcogenide fibre cavity, without the aid of any additional phase-locking element. Detailed numerical modelling, which is in agreement with the experimental results, highlight the essential role of FWM in phase-locking of the BFC. PMID:24849053

  7. Phase-locking and Pulse Generation in Multi-Frequency Brillouin Oscillator via Four Wave Mixing

    Science.gov (United States)

    Büttner, Thomas F. S.; Kabakova, Irina V.; Hudson, Darren D.; Pant, Ravi; Poulton, Christopher G.; Judge, Alexander C.; Eggleton, Benjamin J.

    2014-05-01

    There is an increasing demand for pulsed all-fibre lasers with gigahertz repetition rates for applications in telecommunications and metrology. The repetition rate of conventional passively mode-locked fibre lasers is fundamentally linked to the laser cavity length and is therefore typically ~10-100 MHz, which is orders of magnitude lower than required. Cascading stimulated Brillouin scattering (SBS) in nonlinear resonators, however, enables the formation of Brillouin frequency combs (BFCs) with GHz line spacing, which is determined by the acoustic properties of the medium and is independent of the resonator length. Phase-locking of such combs therefore holds a promise to achieve gigahertz repetition rate lasers. The interplay of SBS and Kerr-nonlinear four-wave mixing (FWM) in nonlinear resonators has been previously investigated, yet the phase relationship of the waves has not been considered. Here, we present for the first time experimental and numerical results that demonstrate phase-locking of BFCs generated in a nonlinear waveguide cavity. Using real-time measurements we demonstrate stable 40 ps pulse trains with 8 GHz repetition rate based on a chalcogenide fibre cavity, without the aid of any additional phase-locking element. Detailed numerical modelling, which is in agreement with the experimental results, highlight the essential role of FWM in phase-locking of the BFC.

  8. Design of the Advanced Virgo non-degenerate recycling cavities

    Energy Technology Data Exchange (ETDEWEB)

    Granata, M; Barsuglia, M [Laboratoire Astroparticule et Cosmologie (APC) 10 rue Alice Domon et Leonie Duquet, 75013 Paris (France); Flaminio, R [Laboratoire des Materiaux Avances (LMA), IN2P3/CNRS F-69622 Villeurbanne, Lyon (France); Freise, A [School of Physics and Astronomy, University of Birmingham Birmingham, B15 2TT (United Kingdom); Hild, S [Institute for Gravitational Research, Department of Physics and Astronomy University of Glasgow, Glasgow, G12 8QQ (United Kingdom); Marque, J, E-mail: granata@apc.univ-paris7.f [European Gravitational Observatory (EGO) I-56021 Cascina (Italy)

    2010-05-01

    Advanced Virgo is the project to upgrade the interferometric gravitational wave detector Virgo, and it foresees the implementation of power and signal non-degenerate recycling cavities. Such cavities suppress the build-up of high order modes of the resonating sidebands, with some advantage for the commissioning of the detector and the build-up of the gravitational signal. Here we present the baseline design of the Advanced Virgo non-degenerate recycling cavities, giving some preliminary results of simulations about the tolerances of this design to astigmatism, mirror figure errors and thermal lensing.

  9. Mode-selective wavelength conversion based on four-wave mixing in a multimode silicon waveguide

    DEFF Research Database (Denmark)

    Ding, Yunhong; Xu, Jing; Ou, Haiyan;

    2014-01-01

    We propose and demonstrate all-optical mode-selective wavelength conversion in a silicon waveguide. The mode-selective wavelength conversion relies on strong four-wave mixing when pump and signal light are on the same spatial mode, while weak four-wave mixing is obtained between different modes due...

  10. Noise-like pulse based on dissipative four-wave-mixing with photonic crystal fiber filled by reduced graphene oxide

    CERN Document Server

    Gao, Lei; Huang, Wei

    2014-01-01

    A noise-like pulse based on dissipative four-wave-mixing in a fiber cavity with photonic crystal fiber filled by reduced graphene oxide is proposed. Due to large evanescent field provided by 3 cm photonic crystal fiber and ultrahigh nonlinearity of reduced graphene oxide, this mixed structure provides excellent saturable absorption and high nonlinearity, which are necessary for generating four-wave-mixing (FWM). We experimentally prove that the mode-locked laser transfers its energy from center wavelength to sidebands through degenerate FWM, and new frequencies are generated via cascaded FWM among those sidebands. During this process, the frequencies located in various orders of longitudinal modes of the ring cavity are supported, and others are suppressed due to destructive interference. As the longitudinal modes of the cavity with a spacing of 6.874 MHz are partially supported, the loosely fixed phase relationship results in noise-like pulse with a coherent peak of 530 fs locating on a pedestal of 730.693 p...

  11. Longitudinal dielectric permeability in quantum non-degenerate and maxwellian collisional plasma with constant collision frequency

    OpenAIRE

    Latyshev, A. V.; Yushkanov, A. A.

    2013-01-01

    The formula for dielectric function of non-degenerate and maxwellian collisional plasmas is transformed to the form, convenient for research. Graphic comparison of longitudinal dielectric functions of quantum and classical non-degenerate collisional plasmas is made.

  12. Gain-assisted superluminal microwave pulse propagation via four-wave mixing in superconducting phase quantum circuits

    CERN Document Server

    Sabegh, Z Amini; Maleki, M A; Mahmoudi, M

    2015-01-01

    We study the propagation and amplification of a microwave field in a four-level cascade quantum system which is realized in a superconducting phase quantum circuit. It is shown that by increasing the microwave pump tones feeding the system, the normal dispersion switches to the anomalous and the gain-assisted superluminal microwave propagation is obtained in this system. Moreover, it is demonstrated that the stimulated microwave field is generated via four-wave mixing without any inversion population in the energy levels of the system (amplification without inversion) and the group velocity of the generated pulse can be controlled by the external oscillating magnetic fluxes. We also show that in some special set of parameters, the absorption-free superluminal generated microwave propagation is obtained in superconducting phase quantum circuit system.

  13. Properties of dual codes defined by nondegenerate forms

    Directory of Open Access Journals (Sweden)

    Steve Szabo

    2017-01-01

    Full Text Available Dual codes are defined with respect to non-degenerate sesquilinear or bilinear forms over a finite Frobenius ring. These dual codes have the properties one expects from a dual code: they satisfy a double-dual property, they have cardinality complementary to that of the primal code, and they satisfy the MacWilliams identities for the Hamming weight.

  14. Observation of non-degenerate photorefractive parametric amplification

    DEFF Research Database (Denmark)

    Pedersen, H.C.; Johansen, P.M.

    1996-01-01

    We report on the first experimental observation of so-called nondegenerate photorefractive parametric amplification. We show that due to this effect it is possible for a weakly modulated photoinduced grating to be parametrically amplified via nonlinear interaction with a strongly modulated...

  15. Four-wave parametric amplification in semiconductor quantum dot-metallic nanoparticle hybrid molecules.

    Science.gov (United States)

    Li, Jian-Bo; He, Meng-Dong; Chen, Li-Qun

    2014-10-06

    We study theoretically four-wave parametric amplification arising from the nonlinear optical response of hybrid molecules composed of semiconductor quantum dots and metallic nanoparticles. It is shown that highly efficient four-wave parametric amplification can be achieved by adjusting the frequency and intensity of the pump field and the distance between the quantum dot and the metallic nanoparticle. Specifically, the induced probe-wave gain is tunable in a large range from 1 to 1.43 × 10⁵. This gain reaches its maximum at the position of three-photon resonance. Our findings hold great promise for developing four-wave parametric oscillators.

  16. Intermodal parametric gain of degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    OpenAIRE

    Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2013-01-01

    Intermodal degenerate four wave mixing (FWM) is investigated numerically in large mode area hybrid photonic crystal fibers. The dispersion is controlled independently of core size, and thus allows for power scaling of the FWM process.

  17. Frequency conversion through spontaneous degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Olausson, Christina Bjarnal Thulin;

    2014-01-01

    Frequency conversion through spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers. Different FWM processes are observed, phasematching between fiber modes of orthogonal polarization, intermodal phasematching across bandgaps, and intramodal...

  18. Performance Optimization of Dispersion-Managed WDM Systems Based on Four-Wave Mixing

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    We systemically investigate the interchannel four-wave mixing (FWM) in dispersion-managed WDM systems with arbitrary launch position. We optimize the number of fiber sections, and the dispersion ratio for the system performance.

  19. Observation of Optical Undular Bores in Multiple Four-Wave Mixing

    National Research Council Canada - National Science Library

    Fatome, J; Finot, C; Millot, G; Armaroli, A; Trillo, S

    2014-01-01

    ... (strong multiple four-wave mixing). In particular, by exploiting an all-optical-fiber platform, we show that input modulations propagating in standard telecom fibers in the regime of weak normal dispersion lead to the formation of undular bores...

  20. Investigation of Four wave mixing effects using different modulation formats in optical communication system

    Directory of Open Access Journals (Sweden)

    Prabhpreet Kaur,

    2014-01-01

    Full Text Available In this paper, the four wave mixing effect on sixteen channel wavelength divison multiplexing has been compared for different modulation formats at various values of dispersion, core effective area, channel spacing.The performance of system has been evaluated in terms of four wave mixing power, BER and Q-factor.This paper simulates that with increase in the channel spacing,core effective area of fiber, signal interference between input signals decreases hence four wave mixing effect also decreases. It has been observed that for duobinary FWM decreases 1dBm more than NRZ. So duobinary modulation format is best suitable technique to reduce four wave mixing power by varying dispersion from 0 to 4 ps/nm.km, core effective area and channel spacing.

  1. A High Efficiency Wavelength Conversion Scheme Based on Four Wave Minxing in a Semiconductor Optical Amplifier

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new approach of all optical wavelength converter based on four wave mixing (FWM) in a semiconductor optical amplifier (SOA) with the conjugate wave reflected by a fiber Bragg grating (FBG) and then amplified by the SOA is reported. By adjusting the pump power, the conversion efficiency could be improved 7~10dB with signal-to-background-noise-ratio (SBR) deteriorated 1~2dB, compared with traditional single pump four wave mixing.

  2. Intermodal parametric gain of degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2013-01-01

    Intermodal degenerate four wave mixing (FWM) is investigated numerically in large mode area hybrid photonic crystal fibers. The dispersion is controlled independently of core size, and thus allows for power scaling of the FWM process.......Intermodal degenerate four wave mixing (FWM) is investigated numerically in large mode area hybrid photonic crystal fibers. The dispersion is controlled independently of core size, and thus allows for power scaling of the FWM process....

  3. Boundaries of Parametric Gain due to Four-wave Mixing in Hybrid Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Lægsgaard, Jesper; Alkeskjold, Thomas Tanggaard

    2014-01-01

    Parametric gain by four-wave mixing is considered in photonic crystal fibers for an undepleted pump. The mode distributions are wavelength dependent, thus field overlap integrals cannot be simplified, and an extended gain region is observed......Parametric gain by four-wave mixing is considered in photonic crystal fibers for an undepleted pump. The mode distributions are wavelength dependent, thus field overlap integrals cannot be simplified, and an extended gain region is observed...

  4. Polarization switch of four-wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Olausson, Christina Bjarnal Thulin;

    2015-01-01

    Degenerate spontaneous four-wave mixing is considered in a large mode area hybrid photonic crystal fiber. Numerical and experimental results show birefringence assisted four-wave mixing for a certain polarization state of the pump field. The parametric gain can be turned on and off by switching...... the polarization state of the pump field between the two principal axis of the hybrid photonic crystal fiber. (C) 2015 Optical Society of America...

  5. Polarization switch of four-wave mixing in large mode area hybrid photonic crystal fibers.

    Science.gov (United States)

    Petersen, Sidsel R; Alkeskjold, Thomas T; Olausson, Christina B; Lægsgaard, Jesper

    2015-02-15

    Degenerate spontaneous four-wave mixing is considered in a large mode area hybrid photonic crystal fiber. Numerical and experimental results show birefringence assisted four-wave mixing for a certain polarization state of the pump field. The parametric gain can be turned on and off by switching the polarization state of the pump field between the two principal axis of the hybrid photonic crystal fiber.

  6. 320 Gbit/s DQPSK all-optical wavelength conversion using four wave mixing

    DEFF Research Database (Denmark)

    Galili, Michael; Huettl, B.; Schmidt-Langhorst, C.

    2007-01-01

    In this paper we demonstrate wavelength conversion of 320 Gbit/s DQPSK and 160 Gbit/s DPSK data signals by four wave mixing in highly nonlinear fibre. Error free operation is shown for conversion of both DPSK and DQPSK......In this paper we demonstrate wavelength conversion of 320 Gbit/s DQPSK and 160 Gbit/s DPSK data signals by four wave mixing in highly nonlinear fibre. Error free operation is shown for conversion of both DPSK and DQPSK...

  7. Saturation properties of four-wave mixing between short optical pulses in semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Mørk, Jesper; Mecozzi, A.; Diez, S.

    1999-01-01

    Summary form only given. The authors report the first comparison between theory and experiment on the four wave mixing between trains of short pulses in semiconductor optical amplifiers. The theory is able to explain all qualitative features seen in the experiment.......Summary form only given. The authors report the first comparison between theory and experiment on the four wave mixing between trains of short pulses in semiconductor optical amplifiers. The theory is able to explain all qualitative features seen in the experiment....

  8. Polarization Insensitive Wavelength Conversion Based on Four-Wave Mixing in a Silicon Nanowire

    DEFF Research Database (Denmark)

    Pu, Minhao; Hu, Hao; Peucheret, Christophe

    2012-01-01

    We experimentally demonstrate, for the first time, polarization-insensitive wavelength conversion of a 10 Gb/s NRZ-OOK data signal based on four-wave mixing in a silicon nanowire with bit-error rate measurements.......We experimentally demonstrate, for the first time, polarization-insensitive wavelength conversion of a 10 Gb/s NRZ-OOK data signal based on four-wave mixing in a silicon nanowire with bit-error rate measurements....

  9. Quantum Frequency Conversion of Single-Photon States by Three and Four-Wave Mixing

    DEFF Research Database (Denmark)

    Raymer, Michael G.; Reddy, Dileep V.; Andersen, Lasse Mejling

    2013-01-01

    Three- or four-wave mixing can convert a single-photon wave packet to a new frequency. By tailoring the shapes of the pump(s), one can achieve add/drop functionality for different temporally orthogonal wave packets.......Three- or four-wave mixing can convert a single-photon wave packet to a new frequency. By tailoring the shapes of the pump(s), one can achieve add/drop functionality for different temporally orthogonal wave packets....

  10. Mode Selectivity with Quantum-state-preserving Frequency Conversion Using Four-wave Mixing

    DEFF Research Database (Denmark)

    Andersen, Lasse Mejling; Reddy, Dileep V.; McKinstrie, Colin J.

    2013-01-01

    We consider quantum frequency conversion using four-wave mixing Bragg scattering and the prospects for multiplexing using the temporal modes.We find that there is an optimal strength parameter, but that the fiber length is less critical.......We consider quantum frequency conversion using four-wave mixing Bragg scattering and the prospects for multiplexing using the temporal modes.We find that there is an optimal strength parameter, but that the fiber length is less critical....

  11. Influence of thermal effects induced by nonlinear absorption on four-wave mixing in silicon waveguides

    DEFF Research Database (Denmark)

    Pu, Minhao; Chen, Yaohui; Yvind, Kresten

    2014-01-01

    Influence of thermal effects induced by nonlinear absorption on four-wave mixing in silicon waveguides is investigated. A conversion bandwidth reduction up to 63% is observed in simulation due to the thermal effects.......Influence of thermal effects induced by nonlinear absorption on four-wave mixing in silicon waveguides is investigated. A conversion bandwidth reduction up to 63% is observed in simulation due to the thermal effects....

  12. Measuring the correlation of two optical frequencies using four-wave mixing.

    Science.gov (United States)

    Anthur, Aravind P; Watts, Regan T; Huynh, Tam N; Venkitesh, Deepa; Barry, Liam P

    2014-11-10

    We use the physics of four-wave mixing to study the decorrelation of two optical frequencies as they propagate through different fiber delays. The phase noise relationship between the four-wave mixing components is used to quantify and measure the correlation between the two optical frequencies using the correlation coefficient. We show the difference in the evolution of decorrelation between frequency-dependent and frequency-independent components of phase noise.

  13. Quantum-state-preserving Frequency Conversion Using Four-wave Mixing

    DEFF Research Database (Denmark)

    Andersen, Lasse Mejling; Reddy, Dileep V.; McKinstrie, Colin J.

    2013-01-01

    We investigate the applicability of temporal multiplexing using four-wave mixing Bragg scattering for quantum frequency conversion. Various pump shapes are considered and we find that a large selectivity is possible for all the pump shapes.......We investigate the applicability of temporal multiplexing using four-wave mixing Bragg scattering for quantum frequency conversion. Various pump shapes are considered and we find that a large selectivity is possible for all the pump shapes....

  14. [Study on phase-matching of four-wave mixing spectrum in photonic crystal fiber].

    Science.gov (United States)

    Liu, Xiao-xu; Wang, Shu-tao; Zhao, Xing-tao; Chen, Shuang; Zhou, Gui-yao; Wu, Xi-jun; Li, Shu-guang; Hou, Lan-Tian

    2014-06-01

    In the present paper, the four-wave mixing principle of fiber was analyzed, and the high-gain phase-matching conditions were shown. The nonlinear coefficient and dispersion characteristics of photonic crystal fibers were calculated by multipole method. The phase mismatch characteristics of fibers with multiple zero-dispersion wavelengths were analyzed for the first time. The changing rules of phase matching wavelength with the pump wavelength and the pump power were obtained, and the phase matching curves were shown. The characteristics of phase matching wavelengths for different dispersion curves were analyzed. There are four new excitation wavelengths of four-wave mixing spectrum in two zero-dispersion wavelength photonic crystal fiers. Four-wave mixing spectroscopy of photonic crystal fibers with two zero-dispersion wavelengths was obtained in the experi-ent, which is consistent with the theoretical analysis, and verified the reliability of the phase matching theory. The fiber with multiple zero-dispersion wavelengths can create a ricbhphase-matching topology, excite more four-wave mixing wavelengths, ena-ling enhanced control over the spectral locations of the four-wave mixing and resonant-radiation bands emitted by solitons and short pulses. These provide theoretical guidance for photonic crystal fiber wavelength conversion and supercontinoum generation based on four-wave mixing.

  15. Broad optical bandwidth based on nonlinear effect of intensity and phase modulators through intense four-wave mixing in photonic crystal fiber

    Science.gov (United States)

    Eltaif, Tawfig

    2017-05-01

    This work investigates the advantages of nonlinear optics of a cascaded intensity modulator (IM) and phase modulator (PM) to generate an initial optical frequency comb. The results show that when the direct current bias to amplitude ratio, α=0.1, and the IM and PM have the same modulation index and are equal 10, seed comb is achieved; it is generated by the modulation of two continuous wave lasers. Hence, based on these parameters, an intense four-wave mixing is created through 9 m of photonic crystal fiber. Moreover, a broadband spectrum was achieved, spaced by a 30-GHz microwave frequency.

  16. Nonlinear Optical Properties in Molecular Systems with Non-Zero Permanent Dipole Moments in Four-Wave Mixing Under Stochastic Considerations

    Science.gov (United States)

    Paz, J. L.; Mastrodomenico, A.; Cardenas-Garcia, Jaime F.; Rodriguez, Luis G.; Vera, Cesar Costa

    2016-07-01

    The solvent effects over nonlinear optical properties of a two-level molecular system in presence of a classical electromagnetic field were modeled in this work. The collective effects proper of the thermal reservoir are modeled as a random Bohr frequency, whose manifestation is the broadening of the upper level according to a prescribed random function. A technique of work, based in the use of the cumulant expansions to obtain the average in the Fourier components associated with the coherence and populations, evaluated by the use of the Optical Stochastic Bloch Equations (OSBE), is employed. Analytical expressions for susceptibility, optical properties and non-degenerate Four-Wave Mixing (nd-FWM) signal intensity, were obtained. Numerical calculations were carried out to construct surfaces corresponding to these magnitudes as a function of the pump-probe frequency detuning, values of the permanent dipole moments (PDM), noise parameters and relationships between the longitudinal and transversal relaxation times. Our results show that it is necessary to neglect the Rotating-Wave approximation (RWA) in order to measure the effect of the permanent dipole moments and that the inclusion of these favors two-photon transitions over those with one-photon. In general, the effect of non-zero permanent dipole moments, are reflected in the appearance of new and more complex signals associated with new multiphoton processes.

  17. Wavelength Conversion by Cascaded FWM in a Fiber Optical Parametric Oscillator

    DEFF Research Database (Denmark)

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

    2011-01-01

    We report on a continuous-wave fiber optical parametric oscillator utilizing selective filtering on cascade four wave mixing (CFWM). Oscillations of distinct CFWM terms are obtained, extending wavelength conversion outside the parametric gain region.......We report on a continuous-wave fiber optical parametric oscillator utilizing selective filtering on cascade four wave mixing (CFWM). Oscillations of distinct CFWM terms are obtained, extending wavelength conversion outside the parametric gain region....

  18. Four-wave mixing instabilities in photonic-crystal and tapered fibers.

    Science.gov (United States)

    Biancalana, F; Skryabin, D V; Russell, P St J

    2003-10-01

    Four-wave mixing instabilities are theoretically studied for continuous wave propagation in ultrasmall core photonic-crystal and tapered fibers. The waveguide, or geometrical, contribution to the overall dispersion of these structures is much stronger than in conventional fibers. This leads to the appearance of unstable frequency bands that are qualitatively and quantitatively different from those seen in conventional fibers. The four-wave mixing theory developed here is based on the full wave equation, which allows rigorous study of the unstable bands even when the detunings are of the order of the pump frequency itself. Solutions obtained using the generalized nonlinear Schrödinger equation, which is an approximate version of the full wave equation, reveal that it suffers from several deficiencies when used to describe four-wave mixing processes.

  19. Enhanced continuous-wave four-wave mixing efficiency in nonlinear AlGaAs waveguides.

    Science.gov (United States)

    Apiratikul, Paveen; Wathen, Jeremiah J; Porkolab, Gyorgy A; Wang, Bohan; He, Lei; Murphy, Thomas E; Richardson, Christopher J K

    2014-11-03

    Enhancements of the continuous-wave four-wave mixing conversion efficiency and bandwidth are accomplished through the application of plasma-assisted photoresist reflow to reduce the sidewall roughness of sub-square-micron-modal area waveguides. Nonlinear AlGaAs optical waveguides with a propagation loss of 0.56 dB/cm demonstrate continuous-wave four-wave mixing conversion efficiency of -7.8 dB. Narrow waveguides that are fabricated with engineered processing produce waveguides with uncoated sidewalls and anti-reflection coatings that show group velocity dispersion of +0.22 ps²/m. Waveguides that are 5-mm long demonstrate broadband four-wave mixing conversion efficiencies with a half-width 3-dB bandwidth of 63.8-nm.

  20. Entangled photon generation using four-wave mixing in azimuthally symmetric microresonators.

    Science.gov (United States)

    Camacho, Ryan M

    2012-09-24

    A novel quantum mechanical formulation of the bi-photon wavefunction and spectra resulting from four-wave mixing is developed for azimuthally symmetric systems. Numerical calculations are performed verifying the use of the angular group velocity and angular group velocity dispersion in such systems, as opposed their commonly used linear counterparts. The dispersion profile and bi-photon spectra of two illustrative examples are given, emphasizing the physical origin of the effects leading to the conditions for angular momentum and energy conservation. A scheme is proposed in which widely spaced narrowband entangled photons may be produced through a four-wave mixing process in a chip-scale ring resonator. The entangled photon pairs are found to conserve energy and momentum in the four-wave mixing interaction, even though both photon modes lie in spectral regions of steep angular group velocity dispersion.

  1. Adaptive defect and pattern detection in amplitude and phase structures via photorefractive four-wave mixing.

    Science.gov (United States)

    Nehmetallah, George; Banerjee, Partha; Khoury, Jed

    2015-11-10

    This work comprises the theoretical and numerical validations of experimental work on pattern and defect detection of periodic amplitude and phase structures using four-wave mixing in photorefractive materials. The four-wave mixing optical processor uses intensity filtering in the Fourier domain. Specifically, the nonlinear transfer function describing four-wave mixing is modeled, and the theory for detection of amplitude and phase defects and dislocations are developed. Furthermore, numerical simulations are performed for these cases. The results show that this technique successfully detects the slightest defects clearly even with no prior enhancement. This technique should prove to be useful in quality control systems, production-line defect inspection, and e-beam lithography.

  2. Enhancing four-wave-mixing processes by nanowire arrays coupled to a gold film.

    Science.gov (United States)

    Poutrina, Ekaterina; Ciracì, Cristian; Gauthier, Daniel J; Smith, David R

    2012-05-07

    We consider the process of four-wave mixing in an array of gold nanowires strongly coupled to a gold film. Using full-wave simulations, we perform a quantitative comparison of the four-wave mixing efficiency associated with a bare film and films with nanowire arrays. We find that the strongly localized surface plasmon resonances of the coupled nanowires provide an additional local field enhancement that, along with the delocalized surface plasmon of the film, produces an overall four-wave mixing efficiency enhancement of up to six orders of magnitude over that of the bare film. The enhancement occurs over a wide range of excitation angles. The film-coupled nanowire array is easily amenable to nanofabrication, and could find application as an ultra-compact component for integrated photonic and quantum optic systems.

  3. 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.

  4. Four-wave mixing analysis of quantum dot semiconductor lasers for linewidth enhancement factor extraction.

    Science.gov (United States)

    Lin, Chih-Hao; Lin, Hung-Hsin; Lin, Fan-Yi

    2012-01-02

    We apply a four-wave mixing analysis on a quantum dot laser to simultaneously obtain the linewidth enhancement factor α and other intrinsic laser parameters. By fitting the experimentally obtained regenerative signals and power spectra at different detuning frequencies with the respective curves analytically calculated from the rate equations, parameters including the linewidth enhancement factor, the carrier decay rate in the dots, the differential gain, and the photon decay rate can be determined all at once under the same operating conditions. In this paper, a theoretical model for the four-wave mixing analysis of the QD lasers is derived and verified. The sensitivity and accuracy of the parameter extraction using the four-wave mixing method are presented. Moreover, how each each parameters alter the shapes of the regenerative signals and the power spectra are also discussed.

  5. Spectral signatures of x((5)) processes in four-wave mixing of homogeneously broadened excitons

    DEFF Research Database (Denmark)

    Langbein, W.; Meier, T.; Koch, S.W.;

    2001-01-01

    The influence of fifth-order coherences on the spectrally resolved four-wave mixing response of predominantly homogeneously broadened quasi-two-dimensional excitons is studied. Fifth-order signatures are discussed as a function of spectral position and excitation polarization. An exciton-biexcito...... of one- and two-exciton resonances up to the fifth order in the optical field.......The influence of fifth-order coherences on the spectrally resolved four-wave mixing response of predominantly homogeneously broadened quasi-two-dimensional excitons is studied. Fifth-order signatures are discussed as a function of spectral position and excitation polarization. An exciton...

  6. Enhanced four-wave mixing in graphene-silicon slow-light photonic crystal waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Hao, E-mail: hz2299@columbia.edu, E-mail: tg2342@columbia.edu, E-mail: cww2104@columbia.edu [College of Electronic Information, Sichuan University, Chengdu 610064 (China); Optical Nanostructures Laboratory, Columbia University, New York, New York 10027 (United States); Gu, Tingyi, E-mail: hz2299@columbia.edu, E-mail: tg2342@columbia.edu, E-mail: cww2104@columbia.edu; McMillan, James F.; Wong, Chee Wei, E-mail: hz2299@columbia.edu, E-mail: tg2342@columbia.edu, E-mail: cww2104@columbia.edu [Optical Nanostructures Laboratory, Columbia University, New York, New York 10027 (United States); Petrone, Nicholas; Zande, Arend van der; Hone, James C. [Mechanical Engineering, Columbia University, New York, New York 10027 (United States); Yu, Mingbin; Lo, Guoqiang; Kwong, Dim-Lee [The Institute of Microelectronics, Singapore 117685 (Singapore); Feng, Guoying [College of Electronic Information, Sichuan University, Chengdu 610064 (China); Zhou, Shouhuan [College of Electronic Information, Sichuan University, Chengdu 610064 (China); North China Research Institute of Electro-Optics, Beijing 100015 (China)

    2014-09-01

    We demonstrate the enhanced four-wave mixing of monolayer graphene on slow-light silicon photonic crystal waveguides. 200-μm interaction length, a four-wave mixing conversion efficiency of −23 dB is achieved in the graphene-silicon slow-light hybrid, with an enhanced 3-dB conversion bandwidth of about 17 nm. Our measurements match well with nonlinear coupled-mode theory simulations based on the measured waveguide dispersion, and provide an effective way for all-optical signal processing in chip-scale integrated optics.

  7. Enhanced four-wave mixing via photonic bandgap coupled defect resonances.

    Science.gov (United States)

    Blair, S

    2005-05-16

    Frequency conversion efficiency via four-wave mixing in coupled 1-D photonic crystal defect structures is studied numerically. In structures where all interacting frequencies coincide with intraband defect resonances, energy conversion efficiencies greater than 5% are predicted. Because the frequency spacings are determined by the free-spectral range, thereby requiring long defects for small spacings using intraband resonances, four-wave mixing using coupled-defect miniband resonances in more compact structures is also studied. Conversion efficiencies of greater than 1% are obtained in this case.

  8. Characterizing gold nanorods in aqueous solution by acoustic vibrations probed with four-wave mixing.

    Science.gov (United States)

    Wu, Jian; Xiang, Dao; Gordon, Reuven

    2016-06-13

    We demonstrate continuous-wave four-wave mixing to probe the acoustic vibrations of gold nanorods in aqueous solution. The nonlinear optical response of gold nanorods, resonantly enhanced by electrostriction coupling to the acoustic vibration modes, shows an extensional vibration which combines an expansion along the long axis with a contraction along the short axis. We also observed the extensional vibration of gold nanospheres as byproducts of the gold nanorod synthesis. Theoretical calculation of the nanoparticle size and distribution based on the vibrational frequency agrees well with the experimental results obtained from the scanning electron microscopic examination, indicating the four-wave mixing technique can provide in situ nanoparticle characterization.

  9. Continuous-wave four-wave mixing in cm-long Chalcogenide microstructured fiber.

    Science.gov (United States)

    Brès, Camille-Sophie; Zlatanovic, Sanja; Wiberg, Andreas O J; Radic, Stojan

    2011-12-12

    We present the experimental demonstration of broadband four-wave mixing in a 2.5 cm-long segment of AsSe Chalcogenide microstructured fiber. The parametric mixing was driven by a continuous-wave pump compatible with data signal wavelength conversion. Four-wave mixing products over more than 70 nm on the anti-stoke side of the pump were measured for 345 mW of pump power and 1.5 dBm of signal power. The ultrafast signal processing capability was verified through wavelength conversion of 1.4 ps pulses at 8 GHz repetition rate. © 2011 Optical Society of America

  10. Degeneration of Four Wave Mixing in 500 m Step Index Two Mode Fiber

    Directory of Open Access Journals (Sweden)

    J. Jamaludin

    2016-12-01

    Full Text Available Four wave mixing (FWM in two-mode fiber was experimentally demonstrated at 24.7 dBm of output Erbium doped fiber amplifier (EDFA. The 0.5 km two mode fiber in laser cavity enhances the performance of four wave mixing by suppressing the homogenous broadening effect in erbium-doped fiber and perform a stable oscillation. At output EDFA approaches to 24.7 dBm, FWM is generated and the increasing of output EDFA induced the optical signal to noise ratio (OSNR of all laser peaks.

  11. Frequency translation via four-wave mixing Bragg scattering in Rb filled photonic bandgap fibers.

    Science.gov (United States)

    Donvalkar, Prathamesh S; Venkataraman, Vivek; Clemmen, Stéphane; Saha, Kasturi; Gaeta, Alexander L

    2014-03-15

    We demonstrate frequency translation at microwatt pump power levels in Rubidium vapor confined to a hollow-core photonic bandgap fiber using four-wave mixing Bragg scattering. The 5S(1/2)→5D(3/2) two-photon transition in 85Rb is employed for the four-wave mixing process. Using continuous-wave pump beams at 780 and 795 nm, a weak signal beam at 776 nm is translated to a wavelength of 762 nm with a 21% conversion efficiency at pump powers of 300 μW.

  12. Mode-selective wavelength conversion based on four-wave mixing in a multimode silicon waveguide.

    Science.gov (United States)

    Ding, Yunhong; Xu, Jing; Ou, Haiyan; Peucheret, Christophe

    2014-01-13

    We propose and demonstrate all-optical mode-selective wavelength conversion in a silicon waveguide. The mode-selective wavelength conversion relies on strong four-wave mixing when pump and signal light are on the same spatial mode, while weak four-wave mixing is obtained between different modes due to phase mismatch. A two-mode division multiplexing circuit with tapered directional coupler based (de)multiplexers and a multimode waveguide is designed and fabricated for this application. Experimental results show clear eye-diagrams and moderate power penalties for the wavelength conversion of both modes.

  13. Coexisting Raman- and Rayleigh-Enhanced Four-Wave Mixing in Femtosecond Polarization Beats

    Institute of Scientific and Technical Information of China (English)

    NIE Zhi-Qiang; ZHAO Yan; ZHANG Yan-Peng; GAN Chen-Li; ZHENG Huai-Sin; LI Chang-Biao; LU Ke-Qing

    2009-01-01

    Based on the polarization interference of Raman- and Rayleigh-enhanced four-wave mixing processes,heterodyne detection of the Raman,Rayleigh and coexisting Raman and Rayleigh femtosecond difference-frequency polarization beats is investigated in the cw and the three Markovian stochastic models,respectively.These two processes exhibit asymmetric and symmetric spectra,respectively,and the thermal effect in them can be suppressed by a field-correlation method.Such studies of coexisting Raman- and Rayleigh-enhanced four-wave mixing processes can have important applications in coherence quantum control,and quantum information processing.

  14. Determination of the threshold for instability in four-wave mixing mediated by Brillouin scattering

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, D.E. (Los Alamos National Lab., NM (United States)); Scott, A.M.; Ridley, K.D. (Royal Signals and Radar Establishment, Malvern (United Kingdom))

    1990-12-01

    The threshold for instability in Brillouin-enhanced four-wave mixing has been experimentally determined as a function of both the phase mismatch and the ratio of the pump beam intensities, and is shown to agree with theoretical modeling. The effective input noise intensity for four-wave mixing in the unstable regime is compared to the noise in a stimulated Brillouin scattering amplifier and is found to be higher by a factor of three in the forward direction. Competition between two input signals has been investigated and it is shown that the signal which arrives first dominates the interaction in the unstable regime.

  15. Dispersion-Flattened Composite Highly Nonlinear Fibre Optimised for Broadband Pulsed Four-Wave Mixing

    DEFF Research Database (Denmark)

    Lillieholm, Mads; Galili, Michael; Oxenløwe, Leif Katsuo

    2016-01-01

    We present a segmented composite HNLF optimised for mitigation of dispersion-fluctuation impairments for broadband pulsed four-wave mixing. The HNLF-segmentation allows for pulsed FWMprocessing of a 13-nm wide input WDM-signal with -4.6-dB conversion efficiency...

  16. Correlation coefficient measurement of the mode-locked laser tones using four-wave mixing.

    Science.gov (United States)

    Anthur, Aravind P; Panapakkam, Vivek; Vujicic, Vidak; Merghem, Kamel; Lelarge, Francois; Ramdane, Abderrahim; Barry, Liam P

    2016-06-01

    We use four-wave mixing to measure the correlation coefficient of comb tones in a quantum-dash mode-locked laser under passive and active locked regimes. We study the uncertainty in the measurement of the correlation coefficient of the proposed method.

  17. A Novel All-optical Wavelength Converter Based on Self-pump Four-wave Mixing

    Institute of Scientific and Technical Information of China (English)

    CHEN Jianxiao; CHEN Zhangyuan; TAO Zhenning; WU Deming; XU Anshi; WANG Ziyu

    2002-01-01

    A novel scheme of all-optical wavelength converter(AOWC) based on dual pump four-wave mixing(DP-FWM) was demonstrated. To suppress the ASE noise of the semiconductor optical amplifier (SOA), one of the two pumps was generated interiorly from a loop laser constructed mainly by tunable optical filter and SOA. The theoretical model and some experimental results were presented.

  18. Multiple four-wave mixing and Kerr combs in a bichromatically pumped nonlinear fiber ring cavity.

    Science.gov (United States)

    Ceoldo, D; Bendahmane, A; Fatome, J; Millot, G; Hansson, T; Modotto, D; Wabnitz, S; Kibler, B

    2016-12-01

    We report numerical and experimental studies of multiple four-wave mixing processes emerging from dual-frequency pumping of a passive nonlinear fiber ring cavity. We observe the formation of a periodic train of nearly background-free soliton pulses associated with Kerr frequency combs. The generation of resonant dispersive waves is also reported.

  19. Transient four-wave mixing in T-shaped GaAs quantum wires

    DEFF Research Database (Denmark)

    Langbein, Wolfgang Werner; Gislason, Hannes; Hvam, Jørn Märcher

    1999-01-01

    The binding energy of excitons and biexcitons and the exciton dephasing in T-shaped GaAs quantum wires is investigated by transient four-wave mixing. The T-shaped structure is fabricated by cleaved-edge overgrowth, and its geometry is engineered to optimize the one-dimensional confinement...

  20. Polarisation independent bi-directional four wave mixing for mid span spectral inversion

    DEFF Research Database (Denmark)

    Clausen, Anders; Buxens, Alvaro A.; Poulsen, Henrik Nørskov

    1999-01-01

    Polarisation independent Four Wave Mixing in a Semiconductor Optical Amplifier used for Mid Span Spectral Inversion (MSSI) is implemented and introduce only 0.9 dB penalty compared to polarisation dependent MSSI. The polarisation dependence in receiver sensitivity is 1 dB....

  1. Nonlinear fiber-optic strain sensor based on four-wave mixing in microstructured optical fiber

    DEFF Research Database (Denmark)

    Gu, Bobo; Yuan, Scott Wu; Frosz, Michael H.

    2012-01-01

    We demonstrate a nonlinear fiber-optic strain sensor, which uses the shifts of four-wave mixing Stokes and anti-Stokes peaks caused by the strain-induced changes in the structure and refractive index of a microstructured optical fiber. The sensor thus uses the inherent nonlinearity of the fiber...

  2. Mode-Selective Wavelength Conversion Based on Four-Wave Mixing in a Multimode Silicon Waveguide

    DEFF Research Database (Denmark)

    Ding, Yunhong; Xu, Jing; Ou, Haiyan

    2013-01-01

    We report all-optical mode-selective wavelength conversion based on four-wave mixing in a multimode Si waveguide. A two-mode division multiplexing circuit using tapered directional coupler based (de)multiplexers is used for the application. Experimental results show clear eye-diagrams and moderate...

  3. Spectrally resolved four-wave mixing in semiconductors: Influence of inhomogeneous broadening

    DEFF Research Database (Denmark)

    Erland, J.; Pantke, K.-H.; Mizeikis, V.

    1994-01-01

    We study the influence of inhomogeneous broadening on results obtained from spectrally resolved transient four-wave mixing. In particular, we study the case where more resonances are coherently excited, leading to polarization interference or quantum beats, depending on the microscopic nature...

  4. Temporally uncorrelated photon-pair generation by dual-pump four-wave mixing

    DEFF Research Database (Denmark)

    Christensen, Jesper Bjerge; McKinstrie, C. J.; Rottwitt, Karsten

    2016-01-01

    We study the preparation of heralded single-photon states using dual-pump spontaneous four-wave mixing. The dual-pump configuration, which in our case employs cross-polarized pumps, allows for a gradual variation of the nonlinear interaction strength enabled by a birefringence-induced walk...

  5. Discussion of a “coherent artifact” in four-wave mixing experiments

    NARCIS (Netherlands)

    Ferwerda, Hedzer A.; Terpstra, Jacob; Wiersma, Douwe A.

    1989-01-01

    In this paper, we discuss the nonlinear optical effects that arise when stochastic light waves, with different correlation times, interfere in an absorbing medium. It is shown that four-wave mixing signals are generated in several directions that spectrally track the incoming light fields. This effe

  6. Coherent control over Liouville-space pathways interference in transient four-wave mixing spectroscopy

    NARCIS (Netherlands)

    Pshenichnikov, M.S; de Boeij, W.P.; Wiersma, D. A.

    1996-01-01

    A novel interference effect in transient four-wave mixing is demonstrated. The phenomenon is based on phase-controlled Liouville-space pathways interference and observed in the heterodyne-detected stimulated photon echo. Changing the phase difference between the first two excitation pulses from pi/2

  7. Solution dynamics by line shape analysis, resonance light scattering and femtosecond four-wave mixing

    NARCIS (Netherlands)

    Nibbering, Erik T.J.; Duppen, Koos; Wiersma, Douwe A.

    1992-01-01

    The results of line shape analysis, resonance light scattering and femtosecond four-wave mixing measurements are reported on several organic molecules in solution. It is shown that a Brownian oscillator model for line broadening provides a full description for the optical dynamics in aprotic solutio

  8. Delayed four-wave-mixing spectroscopy in molecular crystals : A nonperturbative approach

    NARCIS (Netherlands)

    Weitekamp, D.P.; Duppen, Koos; Wiersma, Douwe A.

    1983-01-01

    The delayed or time-domain four-wave-mixing experiment is treated in the regime of intense near-resonant pulses. The interaction with the radiation during both pump and probe pulses is considered to all powers of the electric field amplitude. Analytical results are obtained for an effective four-lev

  9. Four-wave mixing Bragg scattering in hydrogenated amorphous silicon waveguides.

    Science.gov (United States)

    Li, Kangmei; Sun, Hongcheng; Foster, Amy C

    2017-04-15

    We demonstrate 15% on-chip conversion efficiency of four-wave mixing Bragg scattering in a hydrogenated amorphous silicon waveguide with only 55 and 194 mW peak pump powers in the waveguide. The lightwaves can be maintained in the telecommunication band, and the operational bandwidth is measured to be larger than 4 nm.

  10. Continuum contribution to excitonic four-wave mixing due to interaction-induced nonlinearities

    DEFF Research Database (Denmark)

    Birkedal, Dan; Vadim, Lyssenko; Hvam, Jørn Märcher

    1996-01-01

    We present an experimental and theoretical investigation of ultrafast transient four-wave mixing of GaAs/AlxGa1-xAs quantum wells for coherent excitation of exciton and continuum states. The signal appears at the exciton resonance and is shown to consist of two contributions: an intense spectrally...

  11. Image processing by four-wave mixing in photorefractive GaAs

    Science.gov (United States)

    Gheen, Gregory; Cheng, Li-Jen

    1987-01-01

    Three image processing experiments were performed by degenerate four-wave mixing in photorefractive GaAs. The experiments were imaging by phase conjugation, edge enhancement, and autocorrelation. The results show that undoped, semiinsulating, liquid-encapsulated Czochralski-grown GaAs crystals can be used as effective optical processing media despite their small electrooptic coefficient.

  12. Discussion of a “coherent artifact” in four-wave mixing experiments

    NARCIS (Netherlands)

    Ferwerda, Hedzer A.; Terpstra, Jacob; Wiersma, Douwe A.

    1989-01-01

    In this paper, we discuss the nonlinear optical effects that arise when stochastic light waves, with different correlation times, interfere in an absorbing medium. It is shown that four-wave mixing signals are generated in several directions that spectrally track the incoming light fields. This effe

  13. Delayed four-wave-mixing spectroscopy in molecular crystals : A nonperturbative approach

    NARCIS (Netherlands)

    Weitekamp, D.P.; Duppen, Koos; Wiersma, Douwe A.

    1983-01-01

    The delayed or time-domain four-wave-mixing experiment is treated in the regime of intense near-resonant pulses. The interaction with the radiation during both pump and probe pulses is considered to all powers of the electric field amplitude. Analytical results are obtained for an effective four-lev

  14. Non-degenerate parametric amplification and filtering in biomimetic hair flow sensors

    NARCIS (Netherlands)

    Droogendijk, H.; Bruinink, C.M.; Sanders, R.G.P.; Krijnen, G.J.M.

    2011-01-01

    We report non-degenerate parametric amplification in our biomimetic MEMS hair-based flow-sensors with improved responsivity and sharp filtering through AC-biasing. To the best of our knowledge, this is the first flow sensor with tunable filtering by non-degenerate electromechanical parametric amplif

  15. Deformation quantization of a Kaehler-Poisson structure vanishing on a Levi nondegenerate hypersurface

    OpenAIRE

    Karabegov, Alexander V.

    2006-01-01

    We give an elementary proof of the result by Leichtnam, Tang, and Weinstein that there exists a deformation quantization with separation of variables on a complex manifold endowed with a Kaehler-Poisson structure vanishing on a Levi nondegenerate hypersurface and nondegenerate on its complement.

  16. Intermodal and cross-polarization four-wave mixing in large-core hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Olausson, Christina Bjarnal Thulin;

    2015-01-01

    Degenerate four-wave mixing is considered in large mode area hybrid photonic crystal fibers, combining photonic bandgap guidance and index guidance. Co- and orthogonally polarized pump, signal and idler fields are considered numerically by calculating the parametric gain and experimentally...... by spontaneous degenerate four-wave mixing. Intermodal and birefringence assisted intramodal phase matching is observed. Good agreement between calculations and experimental observations is obtained. Intermodal four-wave mixing is achieved experimentally with a conversion efficiency of 17%. (C) 2015 Optical...

  17. Intermodal and cross-polarization four-wave mixing in large-core hybrid photonic crystal fibers.

    Science.gov (United States)

    Petersen, Sidsel R; Alkeskjold, Thomas T; Olausson, Christina B; Lægsgaard, Jesper

    2015-03-09

    Degenerate four-wave mixing is considered in large mode area hybrid photonic crystal fibers, combining photonic bandgap guidance and index guidance. Co- and orthogonally polarized pump, signal and idler fields are considered numerically by calculating the parametric gain and experimentally by spontaneous degenerate four-wave mixing. Intermodal and birefringence assisted intramodal phase matching is observed. Good agreement between calculations and experimental observations is obtained. Intermodal four-wave mixing is achieved experimentally with a conversion efficiency of 17%.

  18. Mixing Angles and Non-Degenerate Systems of Particles

    CERN Document Server

    Duret, Q; Duret, Quentin; Machet, Bruno

    2006-01-01

    Defining, in the framework of quantum field theory, their mass eigenstates through their matricial propagator, we show why the mixing matrices of non-degenerate coupled systems should not be parametrized as unitary. This is how, for leptonic binary systems, two-angles solutions with discrete values pi/4 [pi/2] and pi/2 [pi] arise when weak leptonic currents of mass eigenstates approximately satisfy the two properties of universality and vanishing of their non-diagonal neutral components. Charged weak currents are also discussed, which leads to a few remarks concerning oscillations. We argue that quarks, which cannot be defined on shell because of the confinement property, are instead more naturally endowed with unitary Cabibbo-like mixing matrices, involving a single unconstrained mixing angle. The similarity between neutrinos and neutral kaons is outlined, together with the role of the symmetry by exchange of families.

  19. Observation of Quantum Beat in Rb by Parametric Four-Wave Mixing

    Institute of Scientific and Technical Information of China (English)

    ZHU Chang-Jun; HE Jun-Fang; XUE Bing; ZHAI Xue-Jun

    2007-01-01

    @@ Two coupled parametric four-wave-mixing processes in Rb atoms are studied using perturbation theory, which reveals clear evidence of the appearance of quantum beat at 608cm-1, corresponding to the energy difference of the 7s - 5d states of Rb atoms, in the parametric four-wave-mixing signals. A pump-probe technique is utilized to observe the quantum beat. Time-varying characteristics of the quantum beat are investigated using time-dependent Fourier transform. The results show that the time-varying characteristics of the quantum beat not only offers a sensitive detecting method for observing the decay of atomic wave packets, but also provides a potential tool for monitoring the dissociation of molecules.

  20. Double-lambda microscopic model for entangled light generation by four-wave-mixing

    CERN Document Server

    Glorieux, Q; Guibal, S; Guidoni, L; Likforman, J -P; Coudreau, T; Arimondo, E

    2010-01-01

    Motivated by recent experiments, we study four-wave-mixing in an atomic double-{\\Lambda} system driven by a far-detuned pump. Using the Heisenberg-Langevin formalism, and based on the microscopic properties of the medium, we calculate the classical and quantum properties of seed and conju- gate beams beyond the linear amplifier approximation. A continuous variable approach gives us access to relative-intensity noise spectra that can be directly compared to experiments. Restricting ourselves to the cold-atom regime, we predict the generation of quantum-correlated beams with a relative-intensity noise spectrum well below the standard quantum limit (down to -6 dB). Moreover entanglement between seed and conjugate beams measured by an inseparability down to 0.25 is expected. This work opens the way to the generation of entangled beams by four-wave mixing in a cold atomic sample.

  1. High-efficiency degenerate four wave-mixing in triply resonant nanobeam cavities

    CERN Document Server

    Lin, Zin; Loncar, Marko; Johnson, Steven G; Rodriguez, Alejandro W

    2013-01-01

    We demonstrate high-efficiency, degenerate four-wave mixing in triply resonant Kerr $\\chi^(3)$ photonic crystal (PhC) nanobeam cavities. Using a combination of temporal coupled mode theory and nonlinear finite-difference time-domain (FDTD) simulations, we study the nonlinear dynamics of resonant four-wave mixing processes and demonstrate the possibility of observing high-efficiency limit cycles and steady-state conversion corresponding to $\\approx 100$% depletion of the pump light at low powers, even including effects due to losses, self- and cross-phase modulation, and imperfect frequency matching. Assuming operation in the telecom range, we predict close to perfect quantum efficiencies at reasonably low $\\sim$ 50 mW input powers in silicon micrometer-scale cavities.

  2. Coherent Fano resonances in a plasmonic nanocluster enhance optical four-wave mixing

    Science.gov (United States)

    Zhang, Yu; Wen, Fangfang; Zhen, Yu-Rong; Nordlander, Peter; Halas, Naomi J.

    2013-01-01

    Plasmonic nanoclusters, an ordered assembly of coupled metallic nanoparticles, support unique spectral features known as Fano resonances due to the coupling between their subradiant and superradiant plasmon modes. Within the Fano resonance, absorption is significantly enhanced, giving rise to highly localized, intense near fields with the potential to enhance nonlinear optical processes. Here, we report a structure supporting the coherent oscillation of two distinct Fano resonances within an individual plasmonic nanocluster. We show how this coherence enhances the optical four-wave mixing process in comparison with other double-resonant plasmonic clusters that lack this property. A model that explains the observed four-wave mixing features is proposed, which is generally applicable to any third-order process in plasmonic nanostructures. With a larger effective susceptibility χ(3) relative to existing nonlinear optical materials, this coherent double-resonant nanocluster offers a strategy for designing high-performance third-order nonlinear optical media. PMID:23690571

  3. Metal-free flat lens using negative refraction by nonlinear four-wave mixing.

    Science.gov (United States)

    Cao, Jianjun; Zheng, Yuanlin; Feng, Yaming; Chen, Xianfeng; Wan, Wenjie

    2014-11-21

    A perfect lens with unlimited resolution has always posed a challenge to both theoretical and experimental physicists. Recent developments in optical metamaterials promise an attractive approach towards perfect lenses using negative refraction to overcome the diffraction limit, improving resolution. However, those artificially engineered metamaterials are usually accompanied by high losses from metals and are extremely difficult to fabricate. An alternative proposal using negative refraction by four-wave mixing has attracted much interest recently, though most existing experiments still require metals and none of them have been implemented for an optical lens. Here, we experimentally demonstrate a metal-free flat lens for the first time using negative refraction by degenerate four-wave mixing with a thin glass slide. We realize an optical lensing effect utilizing a nonlinear refraction law, which may have potential applications in microscopy.

  4. All-optical mode conversion via spatially-multimode four-wave mixing

    CERN Document Server

    Danaci, Onur; Glasser, Ryan T

    2016-01-01

    We experimentally demonstrate the conversion of a Gaussian beam to an approximate Bessel-Gauss mode by making use of a non-collinear four-wave mixing process in hot atomic vapor. The presence of a strong, spatially non-Gaussian pump both converts the probe beam into a non-Gaussian mode, and generates a conjugate beam that is in a similar non-Gaussian mode. The resulting probe and conjugate modes are compared to the output of a Gaussian beam incident on an annular aperture that is then spatially filtered according to the phase-matching conditions imposed by the four-wave mixing process. We find that the resulting experimental data agrees well with both numerical simulations, as well as analytical formulae describing the effects of annular apertures on Gaussian modes. These results show that spatially-multimode gain platforms may be used as a new method of mode conversion.

  5. Classical-to-quantum transition with broadband four-wave mixing.

    Science.gov (United States)

    Vered, Rafi Z; Shaked, Yaakov; Ben-Or, Yelena; Rosenbluh, Michael; Pe'er, Avi

    2015-02-13

    A key question of quantum optics is how nonclassical biphoton correlations at low power evolve into classical coherence at high power. Direct observation of the crossover from quantum to classical behavior is desirable, but difficult due to the lack of adequate experimental techniques that cover the ultrawide dynamic range in photon flux from the single photon regime to the classical level. We investigate biphoton correlations within the spectrum of light generated by broadband four-wave mixing over a large dynamic range of ∼80  dB in photon flux across the classical-to-quantum transition using a two-photon interference effect that distinguishes between classical and quantum behavior. We explore the quantum-classical nature of the light by observing the interference contrast dependence on internal loss and demonstrate quantum collapse and revival of the interference when the four-wave mixing gain in the fiber becomes imaginary.

  6. Suppression of the four-wave mixing amplification via Raman absorption

    CERN Document Server

    Romanov, Gleb; Novikova, I

    2015-01-01

    We propose a method to controllably suppress the effect of the four-wave mixing caused by the coupling of the strong control optical field to both optical transitions in the $\\Lambda$ system under the conditions of electromagnetically induced transparency. At sufficiently high atomic density, this process leads to amplification of a weak optical signal field, that is detrimental for the fidelity of any EIT-based quantum information applications. Here we show that an additional absorption resonance centered around the idler field frequency, generated in such a four-wave mixing process, may efficiently suppress the unwanted signal amplification without affecting properties of the EIT interaction. We discuss the possibility of creating such tunable absorption using two-photon Raman absorption resonances in the other Rb isotope, and present some preliminary experimental results.

  7. Monitoring Gold Nanoparticle Growth in Situ via the Acoustic Vibrations Probed by Four-Wave Mixing.

    Science.gov (United States)

    Wu, Jian; Xiang, Dao; Gordon, Reuven

    2017-02-21

    We monitor in situ gold nanoparticle growth in aqueous solution by probing the acoustic vibrations with four-wave mixing. We observe two acoustic vibrational modes of gold nanoparticles from the nonlinear optical response: an extensional mode with longitudinal expansion and transverse contraction and a breathing mode with radial expansion and contraction. The mode frequencies, which show an inverse dependence on the nanoparticle diameter, allow one to monitor the nanoparticle size and size distribution during synthesis. The information about the nanoparticle size and size distribution calculated on the basis of the mode frequencies agrees well with the results obtained from the electron microscopy analysis, validating the four-wave mixing technique as an accurate and effective tool for in situ monitoring of colloidal growth.

  8. The influence of velocity-changing collisions on resonant degenerate four-wave mixing

    Science.gov (United States)

    Richardson, W. H.; Maleki, L.; Garmire, Elsa

    1989-01-01

    The phase-conjugate signal observed in resonant degenerate four-wave mixing on the 6 3P2 to 7 3S1 transition of atomic Hg in an Hg-Ar discharge is investigated. At a fixed Ar pressure the variation of the signal with pump powers is explained by a model that includes the effects of velocity-changing collisions (VCCs). As the Ar pressure was varied from 0 to 1 torr, an increase in the phase-conjugate signal was observed and is ascribed to a change in the discharge dynamics with Ar pressure and to the influence of VCCs. To further clarify the role of collisions and optical pumping, degenerate four-wave mixing spectra are examined as a function of pump power. Line shapes are briefly discussed.

  9. Observation of four-wave mixing in caesium atoms using a noncycling transition

    Institute of Scientific and Technical Information of China (English)

    Wang Li-Rong; Ma Jie; Zhao Jian-Ming; Xiao Lian-Tuan; Jia Suo-Tang

    2006-01-01

    In this paper the generation of four-wave mixing (FWM) signal using a noncycling transition of caesium atoms is investigated when the pumping laser is locked to the transition 6S1/2F = 4 → 6P3/2F' = 4, and meanwhile the probe frequency is scanned across the 6S1/2F = 4 → 6P3/2 transition. The efficiency of the four-wave mixing signal as a function of the intensity of the pumping beams and the detuning of the pumping beams is also studied. In order to increase the detection efficiency, a repumping laser which is resonant with 6S1/2F = 3 → 6P3/2F' = 4 transition is used. A theoretical model is also introduced, and the theoretical results are in qualitative agreement with experimental ones.

  10. Spectral anti-broadening due to four-wave mixing in optical fibers

    CERN Document Server

    Balk, Alexander M

    2015-01-01

    We show that the four-wave mixing can restrict spectral broadening. This is a general physical phenomenon that occurs in one-dimensional systems of four wave packets that resonantly interact "2-to-2": $ \\omega_1+\\omega_2=\\omega_3+\\omega_4,\\; k_1+k_2=k_3+k_4$, when an annihilation of one pair of waves results in the creation of another pair. In addition, for this phenomenon to occur, the group velocities $C_1,C_2,C_3,C_4$ of the packets should be in a certain order: The extreme value (max or min) of the four group velocities should be in the same pair with the middle value of the remaining three, e.g. $C_1

  11. Numerical simulation of four-wave mixing efficiency and its induced relative intensity noise

    Institute of Scientific and Technical Information of China (English)

    Chen Wei; Meng Zhou; Zhou Hui-Juan; Luo Hong

    2012-01-01

    Four-wave mixing,as well as its induced intensity noise,is harmful to wavelength division multiplexing systems.The efficiency and the relative intensity noise of four-wave mixing are numerically simulated for the two-wave and the three-wave fiber transmissions.It is found that the efficiency decreases with the increase of both the frequency spacing and the fiber length,which can be explained using the quasi-phase-matching condition.Furthermore,the relative intensity noise decreases with the increase of frequency spacing,while it increases with the increase of fiber length,which is due to the considerable power loss of the pump light.This investigation presents a good reference for the practical application of wavelength division multiplexing systems.

  12. Metal-Free Flat Lens Using Negative Refraction by Nonlinear Four-wave Mixing

    CERN Document Server

    Cao, Jianjun; Feng, Yaming; Chen, Xianfeng; Wan, Wenjie

    2014-01-01

    A perfect lens with unlimited resolution has always posed a challenge to both theoretical and experimental physicists. Recent developments in optical meta-materials promise an attractive approach towards perfect lenses using negative refraction to overcome the diffraction limit, improving resolution. However, those artificially engineered meta-materials usually company by high losses from metals and are extremely difficult to fabricate. An alternative proposal on using negative refraction by four-wave mixing has attracted much interests recently, though most of existing experiments still require metals and none of them has been implemented for an optical lens. Here we experimentally demonstrate a metal-free flat lens for the first time using negative refraction by degenerate four-wave mixing with a simple thin glass slide. We realize optical lensing utilizing a nonlinear refraction law, which may have potential applications in infrared microscopy and super-resolution imaging.

  13. Effects of ``atomic depletion'' on four-wave mixing in potassium

    Science.gov (United States)

    Mehendale, S. C.; Gupta, P. K.; Rustagi, K. C.

    1983-12-01

    Theoretical and experimental results are presented for a four-wave mixing process involving two photons generated internally by stimulated electronic Raman scattering. Effects of saturation of the Stokes wave due to loss of population in the ground state are analyzed in some detail. It is shown that phase mismatch and the absorption of the generated wave play an important role in determining the efficiency of the mixing process.

  14. Silicon-on-Sapphire Waveguides: Mode-converting Couplers and Four-wave Mixing

    Science.gov (United States)

    2014-09-01

    width of the waveguides was between 1600 and 1900 nm . Figure 1 shows gain bands for a waveguide with 500- nm height and 1700 - nm width, demonstrating...1. Calculated conversion efficiency of four-wave mixing in 1700 - nm wide silicon-on-sapphire waveguide. Color bar indicates conversion efficiency in...dominance. Previous investigations show that this spectral range is of interest for applications that include free-space communications, laser radar

  15. Experimental demonstration of optical switching and routing via four-wave mixing spatial shift.

    Science.gov (United States)

    Nie, Zhiqiang; Zheng, Huaibin; Zhang, Yanpeng; Zhao, Yan; Zuo, Cuicui; Li, Changbiao; Chang, Hong; Xiao, Min

    2010-01-18

    We demonstrate the shift characteristics of four-wave mixing (FWM) beam spots which are controlled by the strong laser fields via the large cross-Kerr nonlinearity. The shift distances and directions are determined by the nonlinear dispersions. Based on such spatial displacements of the FWM beams, as well as the probe beam, we experimentally demonstrate spatial optical switching for one beam or multiple optical beams, which can be used for all-optical switching, switching arrays and routers.

  16. Carbon nanotube/polymer composite coated tapered fiber for four wave mixing based wavelength conversion.

    Science.gov (United States)

    Xu, Bo; Omura, Mika; Takiguchi, Masato; Martinez, Amos; Ishigure, Takaaki; Yamashita, Shinji; Kuga, Takahiro

    2013-02-11

    In this paper, we demonstrate a nonlinear optical device based on a fiber taper coated with a carbon nanotube (CNT)/polymer composite. Using this device, four wave mixing (FWM) based wavelength conversion of 10 Gb/s Non-return-to-zero signal is achieved. In addition, we investigate wavelength tuning, two photon absorption and estimate the effective nonlinear coefficient of the CNTs embedded in the tapered fiber to be 1816.8 W(-1)km(-1).

  17. Observation of four-wave mixing in slow-light silicon photonic crystal waveguides.

    Science.gov (United States)

    McMillan, James F; Yu, Mingbin; Kwong, Dim-Lee; Wong, Chee Wei

    2010-07-19

    Four-wave mixing is observed in a silicon W1 photonic crystal waveguide. The dispersion dependence of the idler conversion efficiency is measured and shown to be enhanced at wavelengths exhibiting slow group velocities. A 12-dB increase in the conversion efficiency is observed. Concurrently, a decrease in the conversion bandwidth is observed due to the increase in group velocity dispersion in the slow-light regime. The experimentally observed conversion efficiencies agree with the numerically modeled results.

  18. Observations of four-wave mixing in slow-light silicon photonic crystal waveguides

    CERN Document Server

    McMillan, James F; Kwong, Dim-Lee; Wong, Chee Wei

    2010-01-01

    Four-wave mixing is observed in a silicon W1 photonic crystal waveguide. The dispersion dependence of the idler conversion efficiency is measured and shown to be enhanced at wavelengths exhibiting slow group velocities. A 12-dB increase in the conversion efficiency is observed. Concurrently, a decrease in the conversion bandwidth is observed due to the increase in group velocity dispersion in the slow-light regime. The experimentally observed conversion efficiencies agree with the numerically modeled results.

  19. Four-wave mixing instabilities in tapered and photonic crystal fibers

    OpenAIRE

    Biancalana, Fabio; Skryabin, Dmitry V.; Ortigosa-Blanch, Arturo

    2002-01-01

    We present an analytical study of four-wave mixing instabilities in tapered fibers and photonic crystal fibers. Our approach avoids the use of Taylor expansion for the linear susceptibility and the slowly-varying envelope approximation. This allows us to describe the generation of sidebands strongly detuned from the pump wave with simultaneous account for the entire dispersion characteristic of a fiber, which is found to be important for describing properly the key role of the parametric inst...

  20. Theory of slow light enhanced four-wave mixing in photonic crystal waveguides

    OpenAIRE

    Santagiustina M.; Someda C.G.; Vadala G.; Combrie S.; Rossi A.

    2010-01-01

    The equations for Four-Wave-Mixing in a Photonic Crystal waveguide are derived accurately. The dispersive nature of slow-light enhancement, the impact of Bloch mode reshaping in the nonlinear overlap integrals and the tensor nature of the third order polarization are therefore taken into account. Numerical calculations reveal substantial differences with simpler models, which increase with decreasing group velocity. We predict that the gain for a 1.3 mm long, unoptimized GaInP waveguide will ...

  1. The 3rd-order nonlinearity of bacteriorhodopsin by four-wave mixing

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The 3rd-order nonlinear optical susceptibility X(3) and the response time of the light-transducing biomolecule bacteriorhodopsin were measured with the four-wave mixing technique and a picosecond frequency-doubled Nd:YAG laser(532nm).The X(3) and the response time measured are 10-9 esu and 20 ps,respectively.The possible mechanism for generating the 3rd-order nonlinear optical susceptibility X(3) and response time were discussed.

  2. Numerical analysis of multiwavelength erbium-doped fiber ring laser exploiting four-wave mixing.

    Science.gov (United States)

    Xu, Xiaochuan; Yao, Yong; Chen, Deying

    2008-08-04

    In this paper, a model is proposed to study the behavior of four-wave mixing assisted multiwavelength erbium doped fiber ring laser based on the theoretical model of the multiple FWM processes and Gile's theory of erbium-doped fiber. It is demonstrated that the mode competition can be effectively suppressed through FWM. The effect of phase matching, the nonlinear coefficient, the power in the cavity and the length of the nonlinear medium on output spectrum uniformity are also investigated.

  3. Detailed characterization of CW- and pulsed-pump four-wave mixing in highly nonlinear fibers

    DEFF Research Database (Denmark)

    Lillieholm, Mads; Galili, Michael; Grüner-Nielsen, L.

    2016-01-01

    We present a quantitative comparison of continuouswave- (CW) and pulsed-pump four-wave mixing (FWM) in commercially available highly nonlinear fibers (HNLFs), and suggest properties for which the CW and pulsed FWM bandwidths are limited in practice. The CWand pulsed-pump parametric gain...... bandwidth. However, an inverse scaling of the TOD with the dispersion fluctuations, leads to different CW-optimized fibers, which depend only on the even dispersion-orders....

  4. Four-wave mixing at maximum coherence and eliminated Doppler broadening controlled with the driving fields

    CERN Document Server

    Popov, A K; George, T F; Shalaev, V M; Bayev, Alexander S.; George, Thomas F.; Shalaev, Vladimir M.

    2000-01-01

    New feasibity of coherent quantum control of four-wave mixing processes in a resonant Doppler-broadened medium are studied. We propose a technique which enables one to enhance the quantum efficiency of nonlinear optical conversion. At the same time, it allows one to decrease the required intensities of the fundamental beams compared to those necessary in the approach based on coherent population trapping. The major outcomes of the analysis are illustrated with numerical simulation addressed within a practical medium.

  5. Effect of signal frequency on four-wave mixing through stimulated Brillouin scattering

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, D.E. (Los Alamos National Laboratory, P. O. Box 1663, Los Alamos, NM (USA)); Scott, A.M.; Ridley, K.D. (Royal Signals and Radar Establishment, Great Malvern, Worcestershire (England))

    1990-11-15

    We present measurements of the dependence of the phase-conjugate reflectivity on signal frequency for Brillouin-enhanced four-wave mixing at pump intensities above the threshold instability. The measurements were made in TiCl{sub 4} at {lambda}=1 {mu}m and are consistent with a computer model of the reflectivity. We have observed that the frequency of the conjugate beam is independent of the frequency of the input signal beam in the unstable regime.

  6. Measurement of coherence decay in GaMnAs using femtosecond four-wave mixing.

    Science.gov (United States)

    Webber, Daniel; de Boer, Tristan; Yildirim, Murat; March, Sam; Mathew, Reuble; Gamouras, Angela; Liu, Xinyu; Dobrowolska, Margaret; Furdyna, Jacek; Hall, Kimberley

    2013-12-03

    The application of femtosecond four-wave mixing to the study of fundamental properties of diluted magnetic semiconductors ((s,p)-d hybridization, spin-flip scattering) is described, using experiments on GaMnAs as a prototype III-Mn-V system.  Spectrally-resolved and time-resolved experimental configurations are described, including the use of zero-background autocorrelation techniques for pulse optimization.  The etching process used to prepare GaMnAs samples for four-wave mixing experiments is also highlighted.  The high temporal resolution of this technique, afforded by the use of short (20 fsec) optical pulses, permits the rapid spin-flip scattering process in this system to be studied directly in the time domain, providing new insight into the strong exchange coupling responsible for carrier-mediated ferromagnetism.  We also show that spectral resolution of the four-wave mixing signal allows one to extract clear signatures of (s,p)-d hybridization in this system, unlike linear spectroscopy techniques.   This increased sensitivity is due to the nonlinearity of the technique, which suppresses defect-related contributions to the optical response. This method may be used to measure the time scale for coherence decay (tied to the fastest scattering processes) in a wide variety of semiconductor systems of interest for next generation electronics and optoelectronics.

  7. A Compact Source for Quantum Image Processing with Four-wave Mixing in Rubidium-85

    CERN Document Server

    Vogl, Ulrich; Lett, Paul D; 10.1117/12.907333

    2012-01-01

    We have built a compact light source for bright squeezed twin-beams at 795\\,nm based on four-wave-mixing in atomic $^{85}$Rb vapor. With a total optical power of 400\\,mW derived from a free running diode laser and a tapered amplifier to pump the four-wave-mixing process, we achieve 2.1\\,dB intensity difference squeezing of the twin beams below the standard quantum limit, without accounting for losses. Squeezed twin beams generated by the type of source presented here could be used as reference for the precise calibration of photodetectors. Transferring the quantum correlations from the light to atoms in order to generate correlated atom beams is another interesting prospect. In this work we investigate the dispersion that is generated by the employed four-wave-mixing process with respect to bandwidth and dependence on probe detuning. We are currently using this squeezed light source to test the transfer of spatial information and quantum correlations through media of anomalous dispersion.

  8. Useful models of four-wave mixing in Bose Einstein condensates

    Science.gov (United States)

    Infeld, E.; Trippenbach, M.

    2003-11-01

    A recent experiment demonstrated four-wave mixing of wavepackets in a sodium Bose-Einstein condensate (Deng et al 1999 Nature 398 218). This was followed by a theoretical and numerical treatment of the experiment (Trippenbach et al 2000 Phys. Rev. A 62 02368). In the experiment, a short period of free expansion of the condensate, after release from the magnetic trap, was followed by a set of two Bragg pulses which created moving wavepackets. These wavepackets, due to nonlinear interaction and under phase-matching conditions, created a new momentum component in a four-wave mixing process. We propose simple mathematical models for this process. Next we suggest that, instead of exactly matching the frequencies as in the abovementioned experiments, we introduce a small mismatch in the energies, and therefore the frequencies Dgrohgr. We show that such a small mismatch can compensate for the initial phases that are built on the condensate during free expansion. A physical explanation is offered. This compensation can improve the efficiency of four-wave mixing; in some cases even increasing it by a factor of 2. We also deal with the situation where two strong wavepackets are accompanied by a weak input beam applied as a seed both with and without a mismatch. Here the influence of the mismatch is less obviously beneficial. We also comment on recent work by Ketterle's group (Vogels et al 2002 Phys. Rev. Lett. 89 020401).

  9. Influence of Four-Wave Mixing and Walk-Off on the Self-Focusing of Coupled Waves

    DEFF Research Database (Denmark)

    Bergé, L.; Bang, Ole; Krolikowski, W.

    2000-01-01

    Four-wave mixing and walk-off between two optical beams are! investigated For focusing Kerr media. It is shown that four-wave mixing reinforces the self-focusing of mutually trapped waves by lowering their power threshold for collapse, only when their phase mismatch is small. On the contrary, walk...

  10. Detailed phase matching characterization of inter-modal four-wave mixing in a two-mode fiber

    DEFF Research Database (Denmark)

    Friis, Søren Michael Mørk; Jung, Y.; Begleris, I.

    2016-01-01

    We experimentally characterize the phase matching properties of two inter-modal four-wave mixing processes in a graded index fiber guiding the LP01 and LP11 mode-groups.......We experimentally characterize the phase matching properties of two inter-modal four-wave mixing processes in a graded index fiber guiding the LP01 and LP11 mode-groups....

  11. Broadband receiver-based distortion elimination in phase-modulated analog optical links using four-wave mixing

    Science.gov (United States)

    Bhatia, Amit; Ting, Hong-Fu; Foster, Mark A.

    2015-03-01

    We present a method for full distortion elimination in phase-modulated analog optical links using the nonlinear optical process of four-wave mixing (FWM). Phase-modulated links consist of a laser and phase modulator in the transmitter and an interferometer (or local oscillator) and photodiode in the receiver. Phase modulation is a linear process, so distortion is introduced in the interferometric detection process. Quadrature biasing eliminates even-order distortion products, leaving only odd-order distortion. Here we introduce a method for eliminating these odd-order distortion products in the receiver. A small portion of the phase-modulated signal is tapped and combined with an unmodulated CW laser to seed a cascaded FWM comb source. This process generates an array of lightwaves with integer multiples of the signal's phase modulation. By suitably scaling and combining these lightwaves with the original signal the overall transfer function of the interferometric receiver can be linearized (or given another tailored shape) through a Fourier synthesis approach. By combining a single lightwave from the generated comb with the original signal, we demonstrate the complete elimination of third-order distortion from the phase-modulated link leaving fifth-order distortion as the dominate source of distortion. We show a 17.6-dB SFDR improvement (1-Hz bandwidth) for a 6 GHz link operating at 5-mA total photocurrent and a 16.4-dB SFDR improvement (1-Hz bandwidth) for a 15 GHz link operating at 10-mA total photocurrent. By appropriately combining additional lightwaves from the generated comb, higher-order distortion products can be eliminated to produce an ideal linear (or custom shaped) transfer function.

  12. Effects of noninstantaneous nonlinear processes on photon-pair generation by spontaneous four-wave mixing

    DEFF Research Database (Denmark)

    Koefoed, Jacob Gade; Christensen, Jesper Bjerge; Rottwitt, Karsten

    2017-01-01

    We present a general model, based on a Hamiltonian approach, for the joint quantum state of photon pairs generated through pulsed spontaneous four-wave mixing, including nonlinear phase modulation and a finite material response time. For the case of a silica fiber, it is found that the pair......-dependent change in quantum-mechanical purity may be observed in silica. This shows that Raman scattering not only introduces noise, but can also drastically change the spectral correlations in photon pairs when pumped with short pulses....

  13. Full-band quantum-dynamical theory of saturation and four-wave mixing in graphene.

    Science.gov (United States)

    Zhang, Zheshen; Voss, Paul L

    2011-12-01

    The linear and nonlinear optical response of graphene are studied within a quantum-mechanical, full-band, steady-state density-matrix model. This nonpurtabative method predicts the saturatable absorption and saturable four-wave mixing of graphene. The model includes τ(1) and τ(2) time constants that denote carrier relaxation and quantum decoherence, respectively. Fits to existing experimental data yield τ(2) < 1 fs due to carrier-carrier scattering. τ(1) is found to be on the timescale from 250 fs to 550 fs, showing agreement with experimental data obtained by differential transmission measurements. © 2011 Optical Society of America

  14. Theory of slow light enhanced four-wave mixing in photonic crystal waveguides.

    Science.gov (United States)

    Santagiustina, M; Someda, C G; Vadalà, G; Combrié, S; De Rossi, A

    2010-09-27

    The equations for Four-Wave-Mixing in a Photonic Crystal waveguide are derived accurately. The dispersive nature of slow-light enhancement, the impact of Bloch mode reshaping in the nonlinear overlap integrals and the tensor nature of the third order polarization are therefore taken into account. Numerical calculations reveal substantial differences with simpler models, which increase with decreasing group velocity. We predict that the gain for a 1.3 mm long, unoptimized GaInP waveguide will exceed 10 dB if the pump power exceeds 1 W.

  15. Four-wave mixing stability in hybrid photonic crystal fibers with two zero-dispersion wavelengths.

    Science.gov (United States)

    Sévigny, Benoit; Vanvincq, Olivier; Valentin, Constance; Chen, Na; Quiquempois, Yves; Bouwmans, Géraud

    2013-12-16

    The four-wave mixing process in optical fibers is generally sensitive to dispersion uniformity along the fiber length. However, some specific phase matching conditions show increased robustness to longitudinal fluctuations in fiber dimensions, which affect the dispersion, even for signal and idler wavelengths far from the pump. In this paper, we present the method by which this point is found, how the fiber design characteristics impact on the stable point and demonstrate the stability through propagation simulations using the non-linear Schrödinger equation.

  16. Theory of Slow Light Enhanced Four-Wave Mixing in Photonic Crystal Waveguides

    CERN Document Server

    Santagiustina, M; Vadalà, G; Combrié, S; De Rossi, A

    2010-01-01

    The equations for Four-Wave-Mixing in a Photonic Crystal waveguide are derived accurately. The dispersive nature of slow-light enhancement, the impact of Bloch mode reshaping in the nonlinear overlap integrals and the tensor nature of the third order polarization are therefore taken into account. Numerical calculations reveal substantial differences with simpler models, which increase with decreasing group velocity. We predict that the gain for a 1.3 mm long, unoptimized GaInP waveguide will exceed 10 dB if the pump power exceeds 1 W.

  17. Designing slow-light photonic crystal waveguides for four-wave mixing applications.

    Science.gov (United States)

    Kanakis, Panagiotis; Kamalakis, Thomas; Sphicopoulos, Thomas

    2014-02-15

    We discuss the optimization of photonic crystal waveguides for four-wave mixing (FWM) applications, taking into account linear loss and free-carrier effects. Suitable figures of merit are introduced in order to guide us through the choice of practical, high-efficiency designs requiring relatively low pump power and small waveguide length. In order to realistically perform the waveguide optimization process, we propose and validate an approximate expression for the FWM efficiency, which significantly alleviates our numerical calculations. Promising waveguide designs are identified by means of an exhaustive search, altering some structural parameters. Our approach aims to optimize the waveguides for nonlinear signal-processing applications based on the FWM.

  18. Intermodal four-wave mixing from femtosecond pulse-pumped photonic crystal fiber.

    Science.gov (United States)

    Tu, H; Jiang, Z; Marks, D L; Boppart, S A

    2009-03-09

    Large Stokes-shift ( approximately 4700 cm(-1)) four-wave mixing is generated in a deeply normal dispersion regime from a 20 cm commercial large-mode-area photonic crystal fiber pumped by amplified approximately 800 nm femtosecond pulses. The phase-matching condition is realized through an intermodal scheme involving two pump photons in the fundamental fiber mode and a pair of Stokesanti-Stokes photons in a higher-order fiber mode. Over 7% conversion efficiency from the pump input to 586 nm anti-Stokes signal has been attained.

  19. Stimulated Brillouin scattering and Brillouin-coupled four-wave-mixing in a silica microbottle resonator

    CERN Document Server

    Asano, Motoki; Özdemir, Şahin Kaya; Ikuta, Rikizo; Yang, Lan; Imoto, Nobuyuki; Yamamoto, Takashi

    2016-01-01

    We report the first observation of stimulated Brillouin scattering (SBS) with Brillouin lasing, and Brillouin-coupled four-wave-mixing (FWM) in an ultra-high-Q silica microbottle resonator. The Brillouin lasing was observed at the frequency of $\\Omega_B=2\\pi\\times10.4$ GHz with a threshold power of $0.45$ mW. Coupling between Brillouin and FWM was observed in both backward and forward scattering directions with separations of $2\\Omega_B$. At a pump power of $10$ mW, FWM spacing reached to 7th and 9th order anti-Stokes and Stokes, respectively.

  20. Wavelength multicasting through four-wave mixing with an optical comb source.

    Science.gov (United States)

    Ting, Hong-Fu; Wang, Ke-Yao; Stroud, Jasper R; Petrillo, Keith G; Sun, Hongcheng; Foster, Amy C; Foster, Mark A

    2017-04-17

    Based on four-wave mixing (FWM) with an optical comb source (OCS), we experimentally demonstrate 26-way or 15-way wavelength multicasting of 10-Gb/s differential phase-shift keying (DPSK) data in a highly-nonlinear fiber (HNLF) or a silicon waveguide, respectively. The OCS provides multiple spectrally equidistant pump waves leading to a multitude of FWM products after mixing with the signal. We achieve error-free operation with power penalties less than 5.7 dB for the HNLF and 4.2 dB for the silicon waveguide, respectively.

  1. Four-wave mixing and nonlinear losses in thick silicon waveguides.

    Science.gov (United States)

    Morrison, Blair; Zhang, Yanbing; Pagani, Mattia; Eggleton, Benjamin; Marpaung, David

    2016-06-01

    We experimentally investigate four-wave mixing and nonlinear losses in low-loss 3 μm thick silicon strip waveguides. Adiabatic bends allow for single-mode operation in an ultra-compact 35 cm long spiral. The waveguides exhibited reduced nonlinear losses due to the large mode area of 2.75  μm2. The nonlinear coefficient γ was measured as 5.5  m-1  W-1. These features, along with the low propagation loss of 0.17 dB/cm, enable large idler power generation at 1550 nm.

  2. Efficient calculation of time- and frequency-resolved four-wave-mixing signals.

    Science.gov (United States)

    Gelin, Maxim F; Egorova, Dassia; Domcke, Wolfgang

    2009-09-15

    "Four-wave-mixing" is the generic name for a family of nonlinear electronic and vibrational spectroscopies. These techniques are widely used to explore dissipation, dephasing, solvation, and interstate coupling mechanisms in various material systems. Four-wave-mixing spectroscopy needs a firm theoretical support, because it delivers information on material systems indirectly, through certain transients, which are measured as functions of carrier frequencies, durations, and relative time delays of the laser pulses. The observed transients are uniquely determined by the three-pulse-induced third-order polarization. There exist two conceptually different approaches to the calculation of the nonlinear polarization. In the standard perturbative approach to nonlinear spectroscopy, the third-order polarization is expressed in terms of the nonlinear response functions. As the material systems become more complex, the evaluation of the response functions becomes cumbersome and the calculation of the signals necessitates a number of approximations. Herein, we review alternative methods for the calculation of four-wave-mixing signals, in which the relevant laser pulses are incorporated into the system Hamiltonian and the driven system dynamics is simulated numerically exactly. The emphasis is on the recently developed equation-of-motion phase-matching approach (EOM-PMA), which allows us to calculate the three-pulse-induced third-order polarization in any phase-matching direction by performing three (with the rotating wave approximation) or seven (without the rotating wave approximation) independent propagations of the density matrix. The EOM-PMA is limited to weak laser fields (its domain of validity is equivalent to the approach based on the third-order response functions) but allows for arbitrary pulse durations and automatically accounts for pulse-overlap effects. As an illustration, we apply the EOM-PMA to the calculation of optical three-pulse photon-echo two

  3. Stimulated Brillouin scattering and Brillouin-coupled four-wave-mixing in a silica microbottle resonator.

    Science.gov (United States)

    Asano, Motoki; Takeuchi, Yuki; Ozdemir, Sahin Kaya; Ikuta, Rikizo; Yang, Lan; Imoto, Nobuyuki; Yamamoto, Takashi

    2016-05-30

    We report the first observation of stimulated Brillouin scattering (SBS) with Brillouin lasing, and Brillouin-coupled four-wave-mixing (FWM) in an ultra-high-Q silica microbottle resonator. The Brillouin lasing was observed at the frequency of ΩB = 2π × 10.4 GHz with a threshold power of 0.45 mW. Coupling between Brillouin and FWM was observed in both backward and forward scattering directions with separations of 2ΩB. At a pump power of 10 mW, FWM spacing reached to 7th and 9th order anti-Stokes and Stokes, respectively.

  4. Polarization properties of degenerate four-wave mixing in GaAs

    Science.gov (United States)

    Liu, Duncan T.; Cheng, Li-Jen

    1989-01-01

    The effect of an applied dc electric field on beam-polarization properties of degenerate four-wave mixing in GaAs is investigated. The results can be interpreted in terms of the phase retardation arising from the applied electric field and the light-induced periodic space-charge field. The conditions for attaining a cross-polarized diffracted beam and read beam are discussed. The experimental results agree reasonably well with the theoretical calculations for an applied voltage of 6 kV.

  5. Quantum frequency translation by four-wave mixing in a fiber: low-conversion regime

    DEFF Research Database (Denmark)

    Andersen, Lasse Mejling; McKinstrie, C. J.; Raymer, M. G.

    2012-01-01

    In this paper we consider frequency translation enabled by Bragg scattering, a four-wave mixing process. First we introduce the theoretical background of the Green function formalism and the Schmidt decomposition. Next the Green functions for the low-conversion regime are derived perturbatively...... in the frequency domain, using the methods developed for three-wave mixing, then transformed to the time domain. These results are also derived and verified using an alternative time-domain method, the results of which are more general. For the first time we include the effects of convecting pumps, a more...

  6. Raman enhanced polarization-insensitive wavelength conversion based on two-pump four-wave mixing.

    Science.gov (United States)

    Guo, Xiaojie; Shu, Chester

    2016-12-12

    Backward Raman amplification is applied to improve the conversion efficiency of two-orthogonal-pump four-wave mixing (FWM) with polarization insensitivity. Wavelength conversion with ~0dB efficiency and negligible polarization dependency is demonstrated by using a common highly nonlinear fiber without pump dithering. The conversion efficiency is increased by ~29dB with Raman enhancement. We also discuss the impact of the Raman pump power and the FWM pump powers on the performance of wavelength conversion. The results indicate that moderate pump powers without inducing significant spontaneous noise and stimulated Brillouin scattering are favorable to ensure high conversion efficiency and low excess noise for performance optimization.

  7. Optical precursor with four-wave mixing and storage based on a cold-atom ensemble.

    Science.gov (United States)

    Ding, Dong-Sheng; Jiang, Yun Kun; Zhang, Wei; Zhou, Zhi-Yuan; Shi, Bao-Sen; Guo, Guang-Can

    2015-03-06

    We observed optical precursors in four-wave mixing based on a cold-atom gas. Optical precursors appear at the edges of pulses of the generated optical field, and propagate through the atomic medium without absorption. Theoretical analysis suggests that these precursors correspond to high-frequency components of the signal pulse, which means the atoms cannot respond quickly to rapid changes in the electromagnetic field. In contrast, the low-frequency signal components are absorbed by the atoms during transmission. We also showed experimentally that the backward precursor can be stored using a Raman transition of the atomic ensemble and retrieved later.

  8. NUMEREICAL ANALYSIS OF FOUR WAVE MIXING AND EXTRACTION OF DISPERSION PARAMETERS OF THE FIBRE

    Directory of Open Access Journals (Sweden)

    S.Sugumaran

    2013-04-01

    Full Text Available Four wave mixing generally occurs when two or more different wavelengths from two or more sources are launched into the fibre, resulting in a new wavelength known as idler (different from thegiven wavelengths. Here in this paper the efficiency of the generation of idler and the power of idler will be numerically simulated for two wave fibre transmissions. From this simulation, a curve will be obtained between power of idler and wavelength separation between signal and pump source, which will be used topropose a power independent method for extraction of dispersion parameters of a fibre.

  9. Relative-intensity squeezing at audio frequencies using four-wave mixing in an atomic vapor

    CERN Document Server

    McCormick, C F; Lett, P D; Marino, A M

    2007-01-01

    We demonstrate the use of four-wave mixing in hot atomic vapor to generate up to -7.1 dB of measured relative-intensity squeezing. Due to its intrinsic simplicity, our system is strongly decoupled from environmental noise, and we observe more than -4 dB of squeezing down to frequencies as low as 5 kHz. This robust source of narrowband squeezed light may be useful for a variety of applications, such as coupling to atomic ensembles and enhancing the sensitivity of photothermal spectroscopy.

  10. Degenerate Four-Wave Mixing in SO2 in Free Jets

    Institute of Scientific and Technical Information of China (English)

    CHEN De-Ying; FAN Rong-Wei; YANG Xin-Ju; ZHENG Qi-Ke; QIN Qi-Zong

    2004-01-01

    @@ A rotational excitation spectrum of SO2 [A 1A2(511) ← X 1A1(000)] at about 33331cm-1 in free jets was observed by using the forward degenerate four-wave mixing (DFWM). Twelve lines of the G band and 11 ones of the E band were marked based on the rotational constants according to Hamada's result [Can. J. Phys. 53(1975) 2555]. The relation between the DFWM signal intensity and the pressure of the buffer gas in free-jets was experimentally investigated.

  11. Observation of multi-component spatial vector solitons of four-wave mixing.

    Science.gov (United States)

    Wang, Ruimin; Wu, Zhenkun; Zhang, Yiqi; Zhang, Zhaoyang; Yuan, Chenzhi; Zheng, Huaibin; Li, Yuanyuan; Zhang, Jinhai; Zhang, Yanpeng

    2012-06-18

    We report the observation of multi-component dipole and vortex vector solitons composed of eight coexisting four-wave mixing (FWM) signals in two-level atomic system. The formation and stability of the multi-component dipole and vortex vector solitons are observed via changing the experiment parameters, including the frequency detuning, powers, and spatial configuration of the involved beams and the temperature of the medium. The transformation between modulated vortex solitons and rotating dipole solitons is observed at different frequency detunings. The interaction forces between different components of vector solitons are also investigated.

  12. Enhanced four-wave mixing via crossover resonance in cesium vapor

    CERN Document Server

    de Silans, T Passerat; Felinto, D; Tabosa, J W R

    2011-01-01

    We report on the observation of enhanced four-wave mixing via crossover resonance in a Doppler broadened cesium vapor. Using a single laser frequency, a resonant parametric process in a double-$\\Lambda$ level configuration is directly excited for a specific velocity class. We investigate this process in different saturation regimes and demonstrate the possibility of generating intensity correlation and anti-correlation between the probe and conjugate beams. A simple theoretical model is developed that accounts qualitatively well to the observed results.

  13. Intermodal four-wave mixing in a higher-order-mode fiber

    OpenAIRE

    Cheng, Ji; Pedersen, Martin E. V.; Charan, Kriti; Wang, Ke; Xu, Chris; Grüner-Nielsen, Lars; Jakobsen, Dan

    2012-01-01

    We demonstrate a high-efficiency intermodal four-wave-mixing process in an all-fiber system, comprising a picosecond fiber laser and a high-order-mode (HOM) fiber. Two pump photons in the LP01 mode of the fiber can generate an anti-Stokes photon in the LP01 mode and a Stokes photon in the LP02 mode. The wavelength dependent mode profiles of the HOM fiber produce significant spatial overlap between the modes involved. The anti-Stokes wave at 941 nm is generated with 20% conversion efficiency w...

  14. Polarization enhancement and suppression of four-wave mixing in multi-Zeeman levels

    Institute of Scientific and Technical Information of China (English)

    Zhiguo Wang; Yuxin Fu; Yue Song; Guoxian Dai; Feng Wen; Jinyan Zhao; Yanpeng Zhang

    2011-01-01

    Polarization dependence of the enhancement and suppression of four-wave mixing(FWM) in a multiZeeman level atomic system is investigated both theoretically and experimentally.A dressing field applied to the adjacent transition can cause energy level splitting.Therefore,it can control the enhancement and suppression of the FWM processes in the system due to the effect of electromagnetically induced transparency.The results show that the pumping beams with different polarizations select the transitions between different Zeeman levels that,in turn,affect the enhancement and suppression efficiencies of FWM.

  15. Four-wave mixing in InAlGaAs quantum dots

    DEFF Research Database (Denmark)

    Leosson, Kristjan; Birkedal, Dan; Hvam, Jørn Märcher

    2001-01-01

    The nonlinear optical properties of semiconductor quantum dots are of interest, both fundamentally and for potential device applications. Large optical nonlinearities are predicted due to the three dimensional confinement but the small active volume of the dots and their large inhomogeneous...... broadening strongly reduce the interaction with the electromagnetic field. Until now, four-wave mixing (FWM) in III-V quantum dots has only been reported in optical amplifiers at room temperature, where the interaction length is increased by waveguiding in the quantum dot plane. We have carried out...

  16. Graphene Near-Degenerate Four-Wave Mixing for Phase Characterization of Broadband Pulses in Ultrafast Microscopy.

    Science.gov (United States)

    Ciesielski, Richard; Comin, Alberto; Handloser, Matthias; Donkers, Kevin; Piredda, Giovanni; Lombardo, Antonio; Ferrari, Andrea C; Hartschuh, Achim

    2015-08-12

    We investigate near-degenerate four-wave mixing in graphene using femtosecond laser pulse shaping microscopy. Intense near-degenerate four-wave mixing signals on either side of the exciting laser spectrum are controlled by amplitude and phase shaping. Quantitative signal modeling for the input pulse parameters shows a spectrally flat phase response of the near-degenerate four-wave mixing due to the linear dispersion of the massless Dirac Fermions in graphene. Exploiting these properties we demonstrate that graphene is uniquely suited for the intrafocus phase characterization and compression of broadband laser pulses, circumventing disadvantages of common methods utilizing second or third harmonic light.

  17. Non-degenerate solutions of universal Whitham hierarchy

    CERN Document Server

    Takasaki, Kanehisa; Teo, Lee Peng

    2010-01-01

    The notion of non-degenerate solutions for the dispersionless Toda hierarchy is generalized to the universal Whitham hierarchy of genus zero with $M+1$ marked points. These solutions are characterized by a Riemann-Hilbert problem (generalized string equations) with respect to two-dimensional canonical transformations, and may be thought of as a kind of general solutions of the hierarchy. The Riemann-Hilbert problem contains $M$ arbitrary functions $H_a(z_0,z_a)$, $a = 1,...,M$, which play the role of generating functions of two-dimensional canonical transformations. The solution of the Riemann-Hilbert problem is described by period maps on the space of $(M+1)$-tuples $(z_\\alpha(p) : \\alpha = 0,1,...,M)$ of conformal maps from $M$ disks of the Riemann sphere and their complements to the Riemann sphere. The period maps are defined by an infinite number of contour integrals that generalize the notion of harmonic moments. The $F$-function (free energy) of these solutions is also shown to have a contour integral r...

  18. Quantum correlations by four-wave-mixing in atomic vapor. Theory and Experiments

    CERN Document Server

    Glorieux, Quentin

    2011-01-01

    We study both theoretically and experimentally the generation of quantum correlations in the continuous variable regime by way of four-wave mixing in a hot atomic vapor. Two theoretical approaches have been developed. On one side, we study the four-wave mixing under the "classical" non-linear optics point of view. In such a way we obtain the evolution equation for an ideal linear amplifier in a {\\chi}^(3) medium. On the other side, we present a microscopic model with 4 levels in the double-{\\Lambda} configuration to calculate the {\\chi}^(3) coefficient in a atomic vapor dressed with a laser. This calculation allows us to derive the spectra of intensity noise for interesting parameters. The experimental part of this work describes the demonstration of this effect on the D1 line of rubidium 85. We present a measurement of relative intensity squeezing as high as -9.2dB below the standard quantum limit, and an original regime where quantum correlations have been measured without amplification.These results have b...

  19. Numerical analysis to four-wave mixing induced spectral broadening in high power fiber lasers

    Science.gov (United States)

    Feng, Yujun; Wang, Xiaojun; Ke, Weiwei; Sun, Yinhong; Zhang, Kai; Ma, Yi; Li, Tenglong; Wang, Yanshan; Wu, Juan

    2015-02-01

    For powers exceeding a threshold the spectral broadening in fiber amplifiers becomes a significant challenge for the development of high power narrow bandwidth fiber lasers. In this letter, we show that the spectral broadening can be partly caused by four-wave mixing(FWM) process in which the power of the central wavelength would transfer to the side ones. A practical FWM induced spectral broadening theory has been derived from the early works. A numerical model of fiber amplifier has been established and FWM process has been added to the model. During the simulation process, we find that when a 10 GHz, several watts narrow bandwidth laser is seeded into a few modes fiber laser amplifier, the FWM induced spectral broadening effect might continually increase the FWHM of the spectra of the continuum laser to 100 GHz within the amplification process to several hundred watts which has been convinced by our experiments. Some other results have also been analyzed in this paper to complete the four-wave mixing induced spectral broadening theory in fiber amplifiers.

  20. Highly efficient four wave mixing in GaInP photonic crystal waveguides.

    Science.gov (United States)

    Eckhouse, V; Cestier, I; Eisenstein, G; Combrié, S; Colman, P; De Rossi, A; Santagiustina, M; Someda, C G; Vadalà, G

    2010-05-01

    We report highly efficient four wave mixing in a GaInP photonic crystal waveguide. Owing to its large bandgap, the ultrafast Kerr nonlinearity of GaInP is not diminished by two photon absorption and related carrier effects for photons in the 1550 nm range. A four-wave-mixing efficiency of -49 dB was demonstrated for cw pump and probe signals in the milliwatt range, while for pulsed pumps with a peak power of 25 mW the conversion efficiency increased to -36 dB. Measured conversion efficiency dependencies on pump probe detuning and on pump power are in excellent agreement with a simple analytical model from which the nonlinear parameter gamma is extracted. Gamma scales approximately with the square of the slow down factor and varies from 800 W(-1) m(-1) at a pump wavelength lambda(p)=1532 nm to 2900 W(-1) m(-1) at lambda(p)=1550 nm. These values are consistent with those obtained from self phase modulation experiments in similar devices.

  1. Four-wave mixing in a parity-time (PT)-symmetric coupler.

    Science.gov (United States)

    Wasak, T; Szańkowski, P; Konotop, V V; Trippenbach, M

    2015-11-15

    Parity-time (PT) symmetry allows for implementing controllable matching conditions for the four-wave mixing in 1D coupled waveguides. Different types of the process involving energy transition between slow and fast modes are established. In the case of defocusing Kerr media, the degenerated four-wave mixing is studied in detail. It is shown that unbroken PT symmetry supports the process existing in the conservative limit and, at the same time, originates new types of matching conditions, which cannot exist in the conservative system. In the former case, a slow beam splits into two fast beams, with nearly conserved total power, while in the latter case, one slow beam and one fast beam are generated. In the last process, the energy of the input primary slow beam is not changed and growth of the energy of the generated slow beam varies due to gain and loss of the medium. The appreciable generation of the fifth mode, i.e., the effect of the secondary resonant interactions, is observed.

  2. Photon pair generation by intermodal spontaneous four wave mixing in birefringent, weakly guiding optical fibers

    CERN Document Server

    Garay-Palmett, K; Dominguez-Serna, F; Ortiz-Ricardo, E; Monroy-Ruz, J; Ramirez, H Cruz; Ramirez-Alarcon, R; U'Ren, A B

    2016-01-01

    We present a theoretical and experimental study of the generation of photon pairs through the process of spontaneous four wave mixing (SFWM) in a few-mode, birefringent fiber. Under these conditions, multiple SFWM processes are in fact possible, each associated with a different combination of transverse modes for the four waves involved. We show that in the weakly guiding regime, for which the propagation modes may be well approximated by linearly polarized modes, the departure from circular symmetry due to the fiber birefringence translates into conservation rules which retain elements from azimuthal and rectangular symmetries: both OAM and parity must be conserved for a process to be viable. We have implemented a SFWM source based on a "bow-tie" birefringent fiber, and have measured for a collection of pump wavelengths the SFWM spectra of each of the signal and idler photons in coincidence with its partner photon. We have used this information, together with knowledge of the transverse modes into which the ...

  3. Terahertz-wave generation by surface-emitted four-wave mixing in optical fiber

    Institute of Scientific and Technical Information of China (English)

    Ping Zhou; Dianyuan Fan

    2011-01-01

    We propose a novel terahertz-wave source through the four-wave mixing effect in a conventional singlemode optical fiber pumped by a dual-wavelength laser whose difference frequency lies in the terahertz range.Surface-emitted geometry is employed to decrease absorption loss.A detailed derivation of the terahertz-wave power expression is presented using the coupled-wave theory.This is a promising way for realizing a reasonable narrow-band terahert-wave source.%@@ We propose a novel terahertz-wave source through the four-wave mixing effect in a conventional singlemode optical fiber pumped by a dual-wavelength laser whose difference frequency lies in the terahertz range.Surface-emitted geometry is employed to decrease absorption loss.A detailed derivation of the terahertz-wave power expression is presented using the coupled-wave theory.This is a promising way for realizing a reasonable narrow-band terahertz-wave source.

  4. Polarized Spatial Splitting of Four-Wave Mixing Signal in Multi-Level Atomic Systems

    Institute of Scientific and Technical Information of China (English)

    FU Yu-Xin; ZHAO Jin-Yan; SONG Yue; DAI Guo-Xian; HUO Shu-Li; ZHANG Yan-Peng

    2011-01-01

    @@ We illustrate our experimental observation of the periodic changes of spatial splitting of the generated four-wave mixing(FWM)signal induced by different polarization states of one of the dressing beams.It is pointed out that the changes of intensity of the dressing beam and the FWM signal have influences on the spatial splitting and their influences compete with each other.The differences between p- and s-polarized FWM beams are demonstrated.The influences of the dressing beams, which lead to the larger spatial splitting with different polarization states or frequency detuning, are observed as well.%We illustrate our experimental observation of the periodic changes of spatial splitting of the generated four-wave mixing (FWM) signal induced by different polarization states of one of the dressing beams. It is pointed out that the changes of intensity of the dressing beam and the FWM signal have influences on the spatial splitting and their influences compete with each other. The differences between p- and s-polarized FWM beams are demonstrated.The influences of the dressing beams, which lead to the larger spatial splitting with different polarization states or frequency detuning, are observed as well.

  5. Quasi-phase-matched DC-induced three wave mixing versus four wave mixing: a simulated comparison.

    Science.gov (United States)

    Sapiano, Christopher A; Aitchison, J Stewart; Qian, Li

    2012-04-01

    A comparison is made between DC-induced three-wave mixing under an on-off quasi-phase-matching scheme and a perfectly phase-matched four wave mixing process. It is shown that the DC-induced process is capable of producing a significantly larger conversion efficiency than the four wave mixing process. Despite the fact that it suffers greater effects of dispersion, the enhanced growth rate of the DC-induced process provides a conversion efficiency roughly 300× larger than that of four wave mixing. Over a sample length of 20 cm the DC-induced process is able to generate idler power more than 270 times greater than that produced by the equivalent four wave mixing process.

  6. Improving efficiency of supercontinuum generation in photonic crystal|fibers by direct degenerate four-wave-mixing

    DEFF Research Database (Denmark)

    Nikolov, Nikola Ivanov; Bang, Ole; Bjarklev, Anders Overgaard

    2002-01-01

    The efficiency of supercontinuum generation in photonic crystal fibers is significantly improved by designing the dispersion to allow widely separated spectral lines generated by degenerate four-wave-mixing directly from the pump to broaden and merge.......The efficiency of supercontinuum generation in photonic crystal fibers is significantly improved by designing the dispersion to allow widely separated spectral lines generated by degenerate four-wave-mixing directly from the pump to broaden and merge....

  7. On-chip wavelength switch based on thermally tunable discrete four-wave mixing in a silicon waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Chen, Yaohui; Hu, Hao

    2014-01-01

    An on-chip wavelength switch is proposed based on discrete four-wave mixing in a silicon waveguide. Switching operation can be realized by thermal tuning the waveguide dispersion. We also discuss optimal dimension design concerning device performances.......An on-chip wavelength switch is proposed based on discrete four-wave mixing in a silicon waveguide. Switching operation can be realized by thermal tuning the waveguide dispersion. We also discuss optimal dimension design concerning device performances....

  8. Modified gravitational instability of degenerate and non-degenerate dusty plasma

    Science.gov (United States)

    Jain, Shweta; Sharma, Prerana

    2016-09-01

    The gravitational instability of strongly coupled dusty plasma (SCDP) is studied considering degenerate and non-degenerate dusty plasma situations. The SCDP system is assumed to be composed of the electrons, ions, neutrals, and strongly coupled dust grains. First, in the high density regime, due to small interparticle distance, the electrons are considered degenerate, whereas the neutrals, dust grains, and ions are treated non-degenerate. In this case, the dynamics of inertialess electrons are managed by Fermi pressure and Bohm potential, while the inertialess ions are by only thermal pressure. Second, in the non-degenerate regime, both the electrons and ions are governed by the thermal pressure. The generalized hydrodynamic model and the normal mode analysis technique are employed to examine the low frequency waves and gravitational instability in both degenerate and non-degenerate cases. The general dispersion relation is discussed for a characteristic timescale which provides two regimes of frequency, i.e., hydrodynamic regime and kinetic regime. Analytical solutions reveal that the collisions reduce the growth rate and have a strong impact on structure formation in both degenerate and non-degenerate circumstances. Numerical estimation on the basis of observed parameters for the degenerate and non-degenerate cases is presented to show the effects of dust-neutral collisions and dust effective velocity in the presence of polarization force. The values of Jeans length and Jeans mass have been estimated for degenerate white dwarfs as Jeans length L J = 1.3 × 10 5 cm and Jeans mass M J = 0.75 × 10 - 3 M⊙ and for non-degenerate laboratory plasma Jeans length L J = 6.86 × 10 16 cm and Jeans mass M J = 0.68 × 10 10 M⊙. The stability of the SCDP system is discussed using the Routh-Hurwitz criterion.

  9. Continuous-wave four-wave mixing with linear growth based on electromagnetically dual induced transparency

    Institute of Scientific and Technical Information of China (English)

    Jiahua Li(李家华); Wenxing Yang(杨文星); Jucun Peng(彭菊村)

    2004-01-01

    Using Schrodinger-Maxwell formalism, we propose and analyze a continuous-wave four-wave mixing (FWM) scheme for the generation of coherent light in a six-level atomic system based on electromagnetically dual induced transparency. We derive the corresponding explicit analytical expressions for the generated mixing field. We find that the scheme greatly enhances FWM production efficiency and is also capable of inhibiting and delaying the onset of the detrimental three-photon destructive interference by choosing the proper decay rate in the second electromagnetically induced transparency (EIT) process.In addition, such an optical process also provides possibilities for producing short-wave-length coherent radiation at low pump intensities.

  10. Optical cavity for enhanced parametric four-wave mixing in rubidium

    CERN Document Server

    Brekke, E

    2016-01-01

    We demonstrate the implementation of a ring cavity to enhance the efficiency of parametric four-wave mixing in rubidium. Using an input coupler with 95% reflectance, a finesse of 19.6$\\pm$0.5 is achieved with a rubidium cell inside. This increases the circulating intensity by a factor of 5.6$\\pm$0.5, and through two-photon excitation on the $5s_{1/2}\\rightarrow5d_{5/2}$ transition with a single excitation laser, up to 1.9$\\pm$0.3 mW of power at 420 nm is generated, 50 times what was previously generated with this scheme. The dependence of the output on Rb density and input power has been explored, suggesting the process may be approaching saturation. The blue output of the cavity also shows greatly improved spatial quality, combining to make this a promising source of 420 nm light for future experiments.

  11. Degenerate four-wave mixing in semiconductor-doped glasses below the absorption edge

    Science.gov (United States)

    Bindra, K. S.; Oak, S. M.; Rustagi, K. C.

    1999-01-01

    We report measurements of degenerate four-wave-mixing reflectivity at a frequency below the band gap of semiconductor-doped glasses in the intensity range 0.5-10 GW/cm2. Up to intensities ~2.5 GW/cm2, the conjugate reflectivity varies like the fourth power of intensity signifying a fifth-order nonlinearity due to band filling by two-photon absorption. Surprisingly, at a higher intensity range the conjugate signal showed a cubic dependence on the pump intensity, which is typical of the χ(3) process. We show that this cubic dependence does not necessarily indicate a third-order process as usually assumed. Instead, it is shown to arise due to a reduction of the effective intensity by nonlinear absorption of the interacting beams.

  12. Analytical study of four-wave mixing with large atomic coherence

    CERN Document Server

    Korsunsky, E A; Marangos, J P; Bergmann, K

    2002-01-01

    Four-wave mixing in resonant atomic vapors based on maximum coherence induced by Stark-chirped rapid adiabatic passage (SCRAP) is investigated theoretically. We show the advantages of a coupling scheme involving maximum coherence and demonstrate how a large atomic coherence between a ground and an highly excited state can be prepared by SCRAP. Full analytic solutions of the field propagation problem taking into account pump field depletion are derived. The solutions are obtained with the help of an Hamiltonian approach which in the adiabatic limit permits to reduce the full set of Maxwell-Bloch equations to simple canonical equations of Hamiltonian mechanics for the field variables. It is found that the conversion efficiency reached is largely enhanced if the phase mismatch induced by linear refraction is compensated. A detailed analysis of the phase matching conditions shows, however, that the phase mismatch contribution from the Kerr effect cannot be compensated simultaneously with linear refraction contrib...

  13. Low-light-level four-wave mixing by quantum interference

    CERN Document Server

    Chiu, Chang-Kai; Chen, Yen-Chun; Yu, Ite A; Chen, Ying-Cheng; Chen, Yong-Fan

    2013-01-01

    We observed electromagnetically-induced-transparency-based four-wave mixing (FWM) in the pulsed regime at low light levels. The FWM conversion efficiency of 3.8(9)% was observed in a four-level system of cold 87Rb atoms using a driving laser pulse with a peak intensity of approximately 80 {\\mu}W/cm^2, corresponding to an energy of approximately 60 photons per atomic cross section. Comparison between the experimental data and the theoretical predictions proposed by Harris and Hau [Phys. Rev. Lett. 82, 4611 (1999)] showed strong agreement. Additionally, a high conversion efficiency of 46(2)% was demonstrated when applying this scheme using a driving laser intensity of approximately 1.8 mW/cm^2. According to our theoretical predictions, this FWM scheme can achieve a conversion efficiency of nearly 100% when using a dense medium with an optical depth of 500.

  14. Threshold based Bit Error Rate Optimization in Four Wave Mixing Optical WDM Systems

    Directory of Open Access Journals (Sweden)

    Er. Karamjeet Kaur

    2016-07-01

    Full Text Available Optical communication is communication at a distance using light to carry information which can be performed visually or by using electronic devices. The trend toward higher bit rates in light-wave communication has interest in dispersion-shifted fibre to reduce dispersion penalties. At an equivalent time optical amplifiers have exaggerated interest in wavelength multiplexing. This paper describes optical communication systems where we discuss different optical multiplexing schemes. The effect of channel power depletion due to generation of Four Wave Mixing waves and the effect of FWM cross talk on the performance of a WDM receiver has been studied in this paper. The main focus is to minimize Bit Error Rate to increase the QoS of the optical WDM system.

  15. Quantitative degenerate four-wave mixing spectroscopy: Probes for molecular species

    Energy Technology Data Exchange (ETDEWEB)

    Farrow, R.; Rakestraw, D.; Paul, P.; Lucht, R.; Danehy, P.; Friedman-Hill, E.; Germann, G. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    Resonant degenerate four-wave mixing (DFWM) is currently the subject of intensive investigation as a sensitive diagnostic tool for molecular species. DFWM has the advantage of generating a coherent (beam-like) signal which results in null-background detection and provides excellent immunity to background-light interference. Since multiple one-photon resonances are involved in the signal generation process, the DFWM technique can allow sensitive detection of molecules via electronic, vibrational or rotational transitions. These properties combine to make DFWM a widely applicable diagnostic technique for the probing of molecular species. The authors are conducting fundamental and applied investigations of DFWM for quantitative measurements of trace species in reacting gases. During the past year, efforts have been focussed in two areas: (1) understanding the effects of collisional processes on the DFWM signal generation process, and (2) exploring the applicability of infrared DFWM to detect polyatomic molecules via rovibrational transitions.

  16. Four-wave-mixing in the loss low submicrometer Ta₂O₅ channel waveguide.

    Science.gov (United States)

    Wu, Chung-Lun; Chiu, Yi-Jen; Chen, Cong-Long; Lin, Yuan-Yao; Chu, Ann-Kuo; Lee, Chao-Kuei

    2015-10-01

    A degenerate four-wave-mixing (FWM) operation in the Ta2O5 submicrometer channel waveguide has been successfully demonstrated. The propagation loss of 1.5  dB/cm and total insertion loss of 5.1 dB are realized in a 12.6 mm long waveguide with inverse taper structure. The wavelength and quadratic pumping power-dependent measurements on optical transmission confirm FWM performance and characterize the nonlinearity of waveguide. The conversion efficiency of -50  dB at coupled pump power of 40 mW is observed, suggesting that the nonlinear refractive index of Ta2O5 waveguide at 1550 nm is estimated to be 1×10(-14)  cm2/W. Our primary results indicate that the Ta2O5 submicrometer channel waveguide has great potential in developing nonlinear waveguide applications.

  17. Degenerate four wave mixing in large mode area hybrid photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Lægsgaard, Jesper

    2013-01-01

    Spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers, in which photonic bandgap guidance and index guidance is combined. Calculations show the parametric gain is maximum on the edge of a photonic bandgap, for a large range of pump...... wavelengths. The FWM products are observed on the edges of a transmission band experimentally, in good agreement with the numerical results. Thereby the bandedges can be used to control the spectral positions of FWM products through a proper fiber design. The parametric gain control combined with a large mode...... area fiber design potentially allows for power scaling of light at wavelengths not easily accessible with e.g. rare earth ions....

  18. Scanning nonreciprocity spatial four-wave mixing process in moving photonic band gap

    Science.gov (United States)

    Wang, Hang; Zhang, Yunzhe; Li, Mingyue; Ma, Danmeng; Guo, Ji; Zhang, Dan; Zhang, Yanpeng

    2017-03-01

    We experimentally investigate the scanning nonreciprocity of four-wave mixing process induced by optical parametric amplification in moving photonic band gap, which is different from the propagation nonreciprocity in the optical diode. Meanwhile the frequency offset and the intensity difference are observed when we scan the frequency of the beams on two arm ramps of one round trip. Such scanning nonreciprocities can be controlled by changing the frequency detuning of the dressing beams. For the first time, we find that the intensity difference can cause the nonreciprocity in spatial image. In the nonreciprocity process, the focusing or defocusing is resulted from the feedback dressing self-phase modulation while shift and split is attributed to feedback dressing cross-phase modulation. Our study could have a potential application in the controllable optical diode.

  19. Spectral properties of photon pairs generated by spontaneous four wave mixing in inhomogeneous photonic crystal fibers

    CERN Document Server

    Cui, Liang; Zhao, Ningbo

    2012-01-01

    The photonic crystal fiber (PCF) is one of the excellent media for generating photon pairs via spontaneous four wave mixing. Here we study how the inhomogeneity of PCFs affect the spectral properties of photon pairs from both the theoretical and experimental aspects. The theoretical model shows that the photon pairs born in different place of the inhomogeneous PCF are coherently superposed, and a modulation in the broadened spectrum of phase matching function will appear, which prevents the realization of spectral factorable photon pairs. In particular, the inhomogeneity induced modulation can be examined by measuring the spectrum of individual signal or idler field when the asymmetric group velocity matching is approximately fulfilled. Our experiments are performed by tailoring the spectrum of pulsed pump to satisfy the specified phase matching condition. The observed spectra of individual signal photons, which are produced from different segments of the 1.9 m inhomogeneous PCF, agree with the theoretical pr...

  20. Two-Photon Correlation of Spontaneously Generated Broadband Four Wave Mixing

    CERN Document Server

    Vered, Rafi; Pe'er, Avi

    2011-01-01

    We precisely measure the time-energy correlation of broadband, spontaneously generated four waves mixing (FWM), and demonstrate novel time-frequency coupling effects. By pumping a photonic crystal fiber with narrowband picosecond pulses we generate FWM in a unique regime, where extremely broadband (>100nm), sidebands are generated that are incoherent, yet time-energy correlated. Although conceptually similar to parametric down conversion (PDC), the time-energy correlation in FWM is unique in its dependence on pump intensity due to self and cross phase modulation effects, yielding surprising spectral and temporal structure in the correlations. Specifically, a power dependent splitting of the correlation in both energy and time is observed at high power. While these effects are minute compared to the time duration and bandwidth of the FWM sidebands, they are well observed using sum frequency generation as a precise, ultrafast correlation detector. A theoretical model accounts for the results and highlights the ...

  1. Enhanced four-wave mixing in a hollow-core photonic-crystal fiber.

    Science.gov (United States)

    Konorov, S O; Fedotov, A B; Zheltikov, A M

    2003-08-15

    Hollow-core photonic-crystal fibers are shown to substantially enhance four-wave mixing (FWM) of laser pulses in a gas filling the fiber core. Picosecond pulses of Nd:YAG fundamental radiation and its second harmonic are used to generate a signal at the frequency of the third harmonic by the FWM process 3omega = 2omega + 2omega - omega. The efficiency achieved for this process in a 9-cm-long, 13-microm-hollow-core-diameter photonic-crystal fiber, designed to simultaneously transmit a two-color pump and the FWM signal, is shown to be approximately 800 times higher than the maximum FWM efficiency attainable with the same laser pulses in the tight-focusing regime.

  2. Four-wave mixing in slow light photonic crystal waveguides with very high group index.

    Science.gov (United States)

    Li, Juntao; O'Faolain, Liam; Krauss, Thomas F

    2012-07-30

    We report efficient four-wave mixing in dispersion engineered slow light silicon photonic crystal waveguides with a flat band group index of n(g) = 60. Using only 15 mW continuous wave coupled input power, we observe a conversion efficiency of -28 dB. This efficiency represents a 30 dB enhancement compared to a silicon nanowire of the same length. At higher powers, thermal redshifting due to linear absorption was found to detune the slow light regime preventing the expected improvement in efficiency. We then overcome this thermal limitation by using oxide-clad waveguides, which we demonstrate for group indices of ng = 30. Higher group indices may be achieved with oxide clad-waveguides, and we predict conversion efficiencies approaching -10 dB, which is equivalent to that already achieved in silicon nanowires but for a 50x shorter length.

  3. Four-wave mixing in slow light engineered silicon photonic crystal waveguides.

    Science.gov (United States)

    Monat, C; Ebnali-Heidari, M; Grillet, C; Corcoran, B; Eggleton, B J; White, T P; O'Faolain, L; Li, J; Krauss, T F

    2010-10-25

    We experimentally investigate four-wave mixing (FWM) in short (80 μm) dispersion-engineered slow light silicon photonic crystal waveguides. The pump, probe and idler signals all lie in a 14 nm wide low dispersion region with a near-constant group velocity of c/30. We measure an instantaneous conversion efficiency of up to -9dB between the idler and the continuous-wave probe, with 1W peak pump power and 6 nm pump-probe detuning. This conversion efficiency is found to be considerably higher (>10 × ) than that of a Si nanowire with a group velocity ten times larger. In addition, we estimate the FWM bandwidth to be at least that of the flat band slow light window. These results, supported by numerical simulations, emphasize the importance of engineering the dispersion of PhC waveguides to exploit the slow light enhancement of FWM efficiency, even for short device lengths.

  4. Broadband wavelength converter based on four-wave mixing in a highly nonlinear photonic crystal fiber.

    Science.gov (United States)

    Zhang, Ailing; Demokan, M S

    2005-09-15

    We demonstrate a 10 Gbit/s nonreturn-to-zero wavelength converter based on four-wave mixing in a 20 m highly nonlinear photonic crystal fiber. The tunable wavelength conversion bandwidth (3 dB) is about 100 nm. The conversion efficiency is -16 dB when the pump power is 22.5 dBm. Phase modulation was not used to suppress the stimulated Brillouin scattering; thus the linewidth of the converted wavelength remained very narrow. The eye diagrams show that there is no additional noise during wavelength conversion. The measured power penalty at a 10(-9) bit-error-rate level is about 0.7 dB.

  5. Four-wave mixing in photonic crystal waveguides: slow light enhancement and limitations.

    Science.gov (United States)

    Li, Juntao; O'Faolain, Liam; Rey, Isabella H; Krauss, Thomas F

    2011-02-28

    We demonstrate continuous wave four-wave mixing in silicon photonic crystal waveguides of 396 μm length with a group index of ng=30. The highest observed conversion efficiency is -24 dB for 90 mW coupled input pump power. The key question we address is whether the predicted fourth power dependence of the conversion efficiency on the slowdown factor (η≈S4) can indeed be observed in this system, and how the conversion efficiency depends on device length in the presence of propagation losses. We find that the expected dependencies hold as long as both realistic losses and the variation of mode shape with slowdown factor are taken into account. Having achieved a good agreement between a simple analytical model and the experiment, we also predict structures that can achieve the same conversion efficiency as already observed in nanowires for the same input power, yet for a device length that is 50 times shorter.

  6. Degenerate four wave mixing in large mode area hybrid photonic crystal fibers.

    Science.gov (United States)

    Petersen, Sidsel R; Alkeskjold, Thomas T; Lægsgaard, Jesper

    2013-07-29

    Spontaneous degenerate four wave mixing (FWM) is investigated in large mode area hybrid photonic crystal fibers, in which photonic bandgap guidance and index guidance is combined. Calculations show the parametric gain is maximum on the edge of a photonic bandgap, for a large range of pump wavelengths. The FWM products are observed on the edges of a transmission band experimentally, in good agreement with the numerical results. Thereby the bandedges can be used to control the spectral positions of FWM products through a proper fiber design. The parametric gain control combined with a large mode area fiber design potentially allows for power scaling of light at wavelengths not easily accessible with e.g. rare earth ions.

  7. Rational design of metallic nanocavities for resonantly enhanced four-wave mixing

    CERN Document Server

    Almeida, Euclides

    2015-01-01

    Optimizing the shape of nanostructures and nano antennas for specific optical properties has evolved to be a very fruitful activity. With modern fabrication tools a large variety of possibilities is available for shaping both nanoparticles and nanocavities; in particular nanocavities in thin metal films have emerged as attractive candidates for new metamaterials and strong linear and nonlinear optical systems. Here we rationally design metallic nanocavities to boost their Four Wave Mixing response by resonating the optical plasmonic resonances with the incoming and generated beams. The linear and nonlinear optical responses as well as the propagation of the electric fields inside the cavities are derived from the solution of Maxwell equations by using the 3D finite-differences time domain method. The observed conversion-efficiency of near infra-red to visible light equals or surpasses that of BBO of equivalent thickness. Implications to further optimization for efficient and broadband ultrathin nonlinear opti...

  8. Rational design of metallic nanocavities for resonantly enhanced four-wave mixing

    Science.gov (United States)

    Almeida, Euclides; Prior, Yehiam

    2015-01-01

    Optimizing the shape of nanostructures and nano-antennas for specific optical properties has evolved to be a very fruitful activity. With modern fabrication tools a large variety of possibilities is available for shaping both nanoparticles and nanocavities; in particular nanocavities in thin metal films have emerged as attractive candidates for new metamaterials and strong linear and nonlinear optical systems. Here we rationally design metallic nanocavities to boost their Four-Wave Mixing response by resonating the optical plasmonic resonances with the incoming and generated beams. The linear and nonlinear optical responses as well as the propagation of the electric fields inside the cavities are derived from the solution of Maxwell’s equations by using the 3D finite-differences time domain method. The observed conversion-efficiency of near-infrared to visible light equals or surpasses that of BBO of equivalent thickness. Implications to further optimization for efficient and broadband ultrathin nonlinear optical materials are discussed. PMID:25974175

  9. Broadband photon pair generation in green fluorescent proteins through spontaneous four-wave mixing.

    Science.gov (United States)

    Shi, Siyuan; Thomas, Abu; Corzo, Neil V; Kumar, Prem; Huang, Yuping; Lee, Kim Fook

    2016-04-14

    Recent studies in quantum biology suggest that quantum mechanics help us to explore quantum processes in biological system. Here, we demonstrate generation of photon pairs through spontaneous four-wave mixing process in naturally occurring fluorescent proteins. We develop a general empirical method for analyzing the relative strength of nonlinear optical interaction processes in five different organic fluorophores. Our results indicate that the generation of photon pairs in green fluorescent proteins is subject to less background noises than in other fluorophores, leading to a coincidence-to-accidental ratio ~145. As such proteins can be genetically engineered and fused to many biological cells, our experiment enables a new platform for quantum information processing in a biological environment such as biomimetic quantum networks and quantum sensors.

  10. Nonlinear Optical Imaging of Individual Carbon Nanotubes with Four-Wave-Mixing Microscopy

    Science.gov (United States)

    Kim, Hyunmin; Sheps, Tatyana; Collins, Philip G.; Potma, Eric O.

    2014-01-01

    Dual color four-wave-mixing (FWM) microscopy is used to spatially resolve the third-order optical response from individual carbon nanotubes. Good signal-to-noise is obtained from single-walled carbon nanotubes (SWNT) sitting on substrates, when the excitation beams are resonant with electronic transitions of the nanotube, by detecting the FWM response at the anti-Stokes frequency. Whereas the coherent anti-Stokes (CAS) signal is sensitive to both electronic and vibrational resonances of the material, it is shown that the signal from individual SWNTs is dominated by the electronic response. The CAS signal is strongly polarization dependent, with the highest signals found parallel with the enhanced electronic polarizibility along the long axis of the SWNT. PMID:19637886

  11. Observation of Optical Undular Bores in Multiple Four-Wave Mixing

    Directory of Open Access Journals (Sweden)

    J. Fatome

    2014-05-01

    Full Text Available We demonstrate that wave-breaking dramatically affects the dynamics of nonlinear frequency conversion processes that operate in the regime of high efficiency (strong multiple four-wave mixing. In particular, by exploiting an all-optical-fiber platform, we show that input modulations propagating in standard telecom fibers in the regime of weak normal dispersion lead to the formation of undular bores (dispersive shock waves that mimic the typical behavior of dispersive hydrodynamics exhibited, e.g., by gravity waves and tidal bores. Thanks to the nonpulsed nature of the beat signal employed in our experiment, we are able to clearly observe how the periodic nature of the input modulation forces adjacent undular bores to collide elastically.

  12. Experimental observation of quantum correlations in four-wave mixing with a conical pump.

    Science.gov (United States)

    Cao, Leiming; Du, Jinjian; Feng, Jingliang; Qin, Zhongzhong; Marino, Alberto M; Kolobov, Mikhail I; Jing, Jietai

    2017-04-01

    Generation of multimode quantum states has drawn much attention recently due to its importance for both fundamental science and the future development of quantum technologies. Here, by using a four-wave mixing process with a conical pump beam, we have experimentally observed about -3.8  dB of intensity-difference squeezing between a single-axial probe beam and a conical conjugate beam. The multi-spatial-mode nature of the generated quantum-correlated beams has been shown by comparing the variation tendencies of the intensity-difference noise of the probe and conjugate beams under global attenuation and local cutting attenuation. Due to its compactness, phase-insensitive nature, and easy scalability, our scheme may find potential applications in quantum imaging, quantum information processing, and quantum metrology.

  13. Correlated photon pair generation in AlGaAs nanowaveguides via spontaneous four-wave mixing

    CERN Document Server

    Kultavewuti, Pisek; Qian, Li; Pusino, Vincenzo; Sorel, Marc; Aitchison, J Stewart

    2016-01-01

    We demonstrate a source of correlated photon pairs which will have applications in future integrated quantum photonic circuits. The source utilizes spontaneous four-wave mixing (SFWM) in a dispersion-engineered nanowaveguide made of AlGaAs, which has merits of negligible two-photon absorption and low spontaneous Raman scattering (SpRS). We observe a coincidence-to-accidental (CAR) ratio up to 177, mainly limited by propagation losses. Experimental results agree well with theoretical predictions of the SFWM photon pair generation and the SpRS noise photon generation. We also study the effects from the SpRS, propagation losses, and waveguide lengths on the quality of our source.

  14. Wavelength conversion by use of four-wave mixing in a novel optical loop configuration

    DEFF Research Database (Denmark)

    Yu, Jianjun; Jeppesen, Palle

    2000-01-01

    A novel loop configuration for generation of four-wave mixing (FWM) and suppression of input pump wave, signal wave, and amplified spontaneous emission is proposed and experimentally demonstrated. The novel loop configuration is very simple and functions independently of the wavelengths of the pump...... and the signal waves. By use of the novel loop configuration, nonreturn-to-zero wavelength conversion at 10 Gbits/s is achieved. The FWM-to-pump ratio, the FWM-to-signal ratio, and the signal-to-noise ratio are improved by 17.9, 18.8, and 8.2 dB, respectively. A principle experiment of wavelength conversion...... of four simultaneous channels is demonstrated....

  15. Degenerate four-wave mixing in a silica hollow bottle-like microresonator.

    Science.gov (United States)

    Yang, Yong; Ooka, Yuta; Thompson, Ruth M; Ward, Jonathan M; Chormaic, Síle Nic

    2016-02-01

    A hollow, bottle-like microresonator (BLMR) was fabricated from a microcapillary with a nearly parabolic profile. From simulations at 1.55 μm the fundamental bottle mode is shown to be in the anomalous dispersion regime, while the conventional whispering gallery mode, confined to the center of the BLMR, is in the normal dispersion regime. Therefore, we have experimentally shown that, for a BLMR with a diameter of 102 um, degenerate four-wave mixing can only be observed by judicious selection of the tapered fiber coupling position. Dispersion tuning in such a system is also briefly discussed theoretically. BLMRs are promising devices for the implementation of sparsely distributed, widely spanned frequency combs at the telecommunications C-band.

  16. Inter-modal four-wave mixing study in a two-mode fiber.

    Science.gov (United States)

    Friis, S M M; Begleris, I; Jung, Y; Rottwitt, K; Petropoulos, P; Richardson, D J; Horak, P; Parmigiani, F

    2016-12-26

    We demonstrate efficient four-wave mixing among different spatial modes in a 1-km long two-mode fiber at telecommunication wavelengths. Two pumps excite the LP01 and LP11 modes, respectively, while the probe signal excites the LP01 mode, and the phase conjugation (PC) and Bragg scattering (BS) idlers are generated in the LP11 mode. For these processes we experimentally characterize their phase matching efficiency and bandwidth and find that they depend critically on the wavelength separation of the two pumps, in good agreement with the numerical study we carried out. We also confirm experimentally that BS has a larger bandwidth than PC for the optimum choice of the pump wavelength separation.

  17. Probing the acoustic vibrations of complex-shaped metal nanoparticles with four-wave mixing.

    Science.gov (United States)

    Wu, Jian; Xiang, Dao; Hajisalem, Ghazal; Lin, Fan-Cheng; Huang, Jer-Shing; Kuo, Chun-Hong; Gordon, Reuven

    2016-10-17

    We probe the acoustic vibrations of silver nanoprisms and gold nano-octahedrons in aqueous solution with four-wave mixing. The nonlinear optical response shows two acoustic vibrational modes: an in-plane mode of nanoprisms with vertexial expansion and contraction; an extensional mode of nano-octahedrons with longitudinal expansion and transverse contraction. The particles were also analyzed with electron microscopy and the acoustic resonance frequencies were then calculated by the finite element analysis, showing good agreement with experimental observations. The experimental mode frequencies also fit with theoretical approximations, which show an inverse dependence of the mode frequency on the edge length, for both nanoprisms and nano-octahedrons. This technique is promising for in situ monitoring of colloidal growth.

  18. Freely designable optical frequency conversion in Raman-resonant four-wave-mixing process

    Science.gov (United States)

    Zheng, Jian; Katsuragawa, Masayuki

    2015-01-01

    Nonlinear optical processes are governed by the relative-phase relationships among the relevant electromagnetic fields in these processes. In this Report, we describe the physics of arbitrary manipulation of Raman-resonant four-wave-mixing process by artificial control of relative phases. As a typical example, we show freely designable optical-frequency conversions to extreme spectral regions, mid-infrared and vacuum-ultraviolet, with near-unity quantum efficiencies. Furthermore, we show that such optical-frequency conversions can be realized by using a surprisingly simple technology where transparent plates are placed in a nonlinear optical medium and their positions and thicknesses are adjusted precisely. In a numerical simulation assuming practically applicable parameters in detail, we demonstrate a single-frequency tunable laser that covers the whole vacuum-ultraviolet spectral range of 120 to 200 nm. PMID:25748023

  19. Detailed characterization of CW- and pulsed-pump four-wave mixing in highly nonlinear fibers.

    Science.gov (United States)

    Lillieholm, M; Galili, M; Grüner-Nielsen, L; Oxenløwe, L K

    2016-11-01

    We present a quantitative comparison of continuous-wave- (CW) and pulsed-pump four-wave mixing (FWM) in commercially available highly nonlinear fibers (HNLFs), and suggest properties for which the CW- and pulsed-pump FWM bandwidths are limited in practice. The CW- and pulsed-pump parametric gain is characterized experimentally for several HNLFs with various dispersion properties, including zero-dispersion wavelength fluctuations, and the results are interpreted in conjunction with detailed numerical simulations. It is found that a low third-order dispersion (TOD) is essential for the pulsed-pump FWM bandwidth. However, an inverse scaling of the TOD with the dispersion fluctuations leads to different CW-optimized fibers, which depend only on the even dispersion orders.

  20. Optical Stark effect in the four-wave mixing and stimulated Raman spectra of N2

    Science.gov (United States)

    Moosmuller, H.; She, C. Y.; Huo, Winifred M.

    1989-01-01

    The influence of the optical Stark effect on spectral line shapes in four-wave-mixing Raman spectroscopy (FWMRS) and stimulated Raman spectroscopy (SRS) is investigated experimentally and theoretically. Using an experimental setup capable of rapid alternation between the simultaneous measurement of coherent Stokes Raman spectroscopy and inverse Raman spectroscopy at low and high intensities, together with a sophisticated frequency reference scheme, it was possible to perform a rather direct comparison between Stark-broadened and non-Stark-broadened spectra of both classes of Raman spectroscopies. The results demonstrate that SRS spectra show more Stark shift and broadening than their FWMRS counterparts. A discrepancy with theoretical results is pointed out, and an attempt is made to explain it.

  1. Analytical investigation of surface plasmon excitation on a graphene sheet using four-wave mixing.

    Science.gov (United States)

    Jamalpoor, Kamal; Zarifkar, Abbas

    2017-01-20

    In the present paper, the general conditions for exciting graphene surface plasmon polaritons (GSPPs) on a suspended graphene using nonlinear optics are investigated. The approach uses the Green's function analysis to derive GSPP fields generated under the basis of momentum conservation using four-wave mixing (FWM). Since the incident beam polarization is challenging in the nonlinear excitation of GSPPs, the significant target of this paper has been set to achieve the conditions for the third-order susceptibility tensor and the wave vectors so that the incident beams with varied polarizations are able to excite GSPPs. Nonlinear optics, in particular FWM, is utilized to compensate the mismatch between the free-space and GSPPs wave vectors. In addition, it avoids the need for applying any patterning or lithography on graphene or its substrate.

  2. Correlated photon pair generation in AlGaAs nanowaveguides via spontaneous four-wave mixing.

    Science.gov (United States)

    Kultavewuti, Pisek; Zhu, Eric Y; Qian, Li; Pusino, Vincenzo; Sorel, Marc; Stewart Aitchison, J

    2016-02-22

    We demonstrate a source of correlated photon pairs which will have applications in future integrated quantum photonic circuits. The source utilizes spontaneous four-wave mixing (SFWM) in a dispersion-engineered nanowaveguide made of AlGaAs, which has merits of negligible two-photon absorption and low spontaneous Raman scattering (SpRS). We observe a coincidence-to-accidental (CAR) ratio up to 177, mainly limited by propagation losses. Experimental results agree well with theoretical predictions of the SFWM photon pair generation and the SpRS noise photon generation. We also study the effects from the SpRS, propagation losses, and waveguide lengths on the quality of our source.

  3. Phase matched parametric amplification via four-wave mixing in optical microfibers.

    Science.gov (United States)

    Abdul Khudus, Muhammad I M; De Lucia, Francesco; Corbari, Costantino; Lee, Timothy; Horak, Peter; Sazio, Pier; Brambilla, Gilberto

    2016-02-15

    Four-wave mixing (FWM) based parametric amplification in optical microfibers (OMFs) is demonstrated over a wavelength range of over 1000 nm by exploiting their tailorable dispersion characteristics to achieve phase matching. Simulations indicate that for any set of wavelengths satisfying the FWM energy conservation condition there are two diameters at which phase matching in the fundamental mode can occur. Experiments with a high-power pulsed source working in conjunction with a periodically poled silica fiber (PPSF), producing both fundamental and second harmonic signals, are undertaken to investigate the possibility of FWM parametric amplification in OMFs. Large increases of idler output power at the third harmonic wavelength were recorded for diameters close to the two phase matching diameters. A total amplification of more than 25 dB from the initial signal was observed in a 6 mm long optical microfiber, after accounting for the thermal drift of the PPSF and other losses in the system.

  4. Detailed study of four-wave mixing in Raman DFB fiber lasers.

    Science.gov (United States)

    Shi, Jindan; Horak, Peter; Alam, Shaif-Ul; Ibsen, Morten

    2014-09-22

    We both experimentally and numerically studied the ultra-compact wavelength conversion by using the four-wave mixing (FWM) process in Raman distributed-feedback (R-DFB) fiber lasers. The R-DFB fiber laser is formed in a 30 cm-long commercially available Ge/Si standard optical fiber. The internal generated R-DFB signal acts as the pump wave for the FWM process and is in the normal dispersion range of the fiber. Utilizing a tunable laser source as a probe wave, FWM frequency conversion up to ~40 THz has been demonstrated with conversion efficiency > -40 dB. The principle of such a wide bandwidth and high conversion efficiency in such a short R-DFB cavity has been theoretically analyzed. The simulation results match well with the experimental data.

  5. Atomic coherence effects in four-wave mixing process of a ladder-type atomic system.

    Science.gov (United States)

    Lee, Yoon-Seok; Moon, Han Seb

    2016-05-16

    We investigate the effects of atomic coherence on four-wave mixing (FWM), with respect to the transition routes between the hyperfine states in the 5S1/2-5P3/2-5D5/2 transition of 87Rb atoms. By comparing the FWM spectra with the electromagnetically induced transparency (EIT) spectra of the hyperfine states, we confirm that the FWM process is significantly influenced by both ladder-type and V-type two-photon coherences. From the observed FWM signal of each hyperfine structure, we clarify the role of two-photon coherence in the FWM process under EIT, double-resonance optical pumping (DROP), and two-photon absorption (TPA) conditions in a ladder-type atomic system, which is dependent on the open degree of the hyperfine states, the laser intensity, and the laser frequency detuning.

  6. Nonlinear Sagnac interferometer based on the four-wave mixing process.

    Science.gov (United States)

    Xin, Jun; Liu, Jinming; Jing, Jietai

    2017-01-23

    A new nonlinear Sagnac interferometer (NSI) is proposed by replacing the beam-splitter in the traditional Sagnac interferometer (TSI) with a four-wave mixing process. Such a NSI has better angular velocity sensitivity than the one of the TSI. The standard quantum limit can be beaten and the Heisenberg Limit can even be reached for the ideal case by the NSI. We study the effect of the losses on the angular velocity sensitivity of the NSI and find that the optimal angular velocity, where the best angular velocity sensitivity can be obtained, of the NSI may be dependent on the losses inside the interferometer. Such a NSI has its advantages compared with the TSI and may find its potential applications in quantum metrology.

  7. Degenerate four-wave-mixing in a silica hollow bottle-like microresonator

    CERN Document Server

    Yang, Yong; Thompson, Ruth; Ward, Jonathan; Chormaic, Síle Nic

    2015-01-01

    A hollow bottle-like microresonator (BLMR) with ultra-high quality factor is fabricated from a microcapillary with nearly parabolic profile. At 1.55 $\\mu m$ pumping, degenerate four-wave mixing can be observed for a BLMR of diameter 102 $\\mu$m. The parabolic profile of the BLMR guarantees a nearly zero waveguide dispersion, which is theoretically discussed in detail. From the simulation, at 1.55 $\\mu$m wavelength in such a BLMR, the fundamental bottle mode is in the anomalous dispersion regime, whilst the ordinary whispering gallery mode (WGM) confined at the center of the BLMR is in the normal dispersion regime. Experimentally, no degenerate FWM is observed for the WGM selected by positioning the coupling tapered fiber in the same BLMR. Furthermore, dispersion tuning is briefly discussed. As the work predicted, the BLMR shows promise for the implementation of sparsely distributed, widely spanned frequency combs at the telecommunication wavelength.

  8. A method for achieving larger enhancement in Four-Wave Mixing via plasmonic path interference effects

    CERN Document Server

    Singh, Shailendra Kumar; Tasgin, Mehmet Emre

    2016-01-01

    Enhancement and suppression of nonlinear processes in coupled systems of plasmonic converters and quantum emitters are well-studied theoretically, numerically and experimentally, in the past decade. Here, in difference, we explicitly demonstrate --with a single equation-- how the presence of a Fano resonance leads to cancellation of nonresonant terms in a four-wave mixing process. Cancellation in the denominator gives rise to enhancement in the nonlinearity. The explicit demonstration, we present here, guides us to the method for achieving more and more orders of magnitude enhancement factors via path interference effects. We also study the coupled system of a plasmonic converter with two quantum emitters. We show that the potential for the enhancement increases dramatically due to better cancellation of the terms in the denominator.

  9. Pseudo-Hermitian Transition in Degenerate Nonlinear Four-Wave Mixing

    CERN Document Server

    Ge, Li

    2016-01-01

    We show that degenerate four-wave mixing (FWM) in nonlinear optics can be described by an effective Hamiltonian that is pseudo-Hermitian, which enables a transition between a pseudo-Hermitian phase with real eigenvalues and a broken pseudo-Hermitian phase with complex conjugate eigenvalues. While bearing certain similarity to that in Parity-Time symmetric systems, this transition is in stark contrast because of the absence of gain and loss in the effective Hamiltonian. The latter is real after factoring out the system decay, and the onset of non-Hermiticity in degenerate FWM is due to the total phase change of the signal wave and the idler wave. This property underlines the intrinsic coherence in FWM, which opens the door to probe quantum implications of exceptional points.

  10. Linear Growth of Continuous-Wave Four-Wave Mixing with Dual Induced Transparency

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-Yi; LI Jia-Hua

    2005-01-01

    Using Schrodinger-Maxwell formalism, we propose and analyze an optical four-wave mixing (FWM) scheme for the generation of coherent light in a coherent six-level atomic medium based on dual electromagnetically induced transparency (EIT). We show that the significantly enhanced conversion efficiency enabled by ultraslow propagation of pump waves has no direct relationship with the single-photon detuning, which is different from the FWM with a single EIT. The most important feature is that our scheme is also capable of inhibiting and delaying the onset of the detrimental three-photon destructive interference that looks like a recent scheme [Phys. Rev. Lett. 91 (2003) 243902] andmay be used for generating short-wave-length coherent radiation.

  11. Squeezing of thermal fluctuations in four-wave mixing in a Λ scheme

    Science.gov (United States)

    Erukhimova, Maria; Tokman, Mikhail

    2017-01-01

    We theoretically investigated the mechanism of two-mode quadrature squeezing in a regime of four-wave mixing in a Λ scheme of three-level atoms embedded in a thermal reservoir. We demonstrated that the process of nonlinear transfer of noise from the low frequency of ground state splitting to the optical frequency is significant if the number of thermal photons at the low frequency is high. We have shown that correct calculation of the two-mode squeezing level taking into account both thermal noise and distortion of dissipative properties of the thermally excited medium resulted in a simple expression for the maximum squeezing level, which is defined by the ground-state coherence decay rate and the drive-field intensity. We found the optimal conditions for squeezing, in particular, the optimal density-length product of the active medium depending on the atomic relaxation parameters and the drive-field intensity.

  12. Exploitation of transverse spatial modes in spontaneous four wave mixing photon-pair sources

    Science.gov (United States)

    Cruz-Ramirez, Hector; Ramirez-Alarcon, Roberto; Cruz-Delgado, Daniel; Monroy-Ruz, Jorge; Ortiz-Ricardo, Erasto; Dominguez-Serna, Francisco; Garay-Palmett, Karina; U'Ren, Alfred B.

    2016-09-01

    We present a source for which multiple spontaneous four-wave mixing (SFWM) processes are supported in a few mode birefringent fiber, each process associated with a particular combination of transverse modes for the four participating waves. Within the weakly guiding regime, for which the propagation modes may be well approximated by linearly polarized (LP) modes, the departure from circular symmetry due to the fiber birefringence translates into orbital angular momentum (OAM) and parity conservation rules, i.e. reflecting elements from both azimuthal and rectangular symmetries. In our source: i) each process is group-velocity-matched so that it is, by design, nearly-factorable, and ii) the spectral separation between neighboring processes is greater than the marginal spectral width of each process. Consequently, there is a direct correspondence between the joint amplitude of each process and each of the Schmidt mode pairs of the overall two-photon state. The present paper covers work presented in Refs.1 and.2

  13. Detection of elastic photon-photon scattering through four-wave coupling

    CERN Document Server

    Lundstrom, E

    2005-01-01

    According to the theory of quantum electrodynamics, photon-photon scattering can take place via exchange of virtual electron-positron pairs. Effectively, the interaction can be formulated in terms of non-linear corrections to Maxwell's equations, and hence may be treated by classical non-linear electrodynamics. Due to the strong electromagnetic fields needed to reach any noticeable effect, photon-photon scattering has not yet been observed experimentally, but recent improvements in laser technology have increased the possibility of direct detection. A verification of the phenomena would be of great scientific value as a confirmation of quantum electrodynamics. In this thesis the possibility of direct detection of elastic photon-photon scattering through four-wave coupling is investigated, both for current and future systems. It is shown how three colliding laser pulses satisfying certain matching conditions, can generate scattered radiation in a fourth resonant direction. The interaction is modeled, and the n...

  14. Observation of Optical Undular Bores in Multiple Four-Wave Mixing

    Science.gov (United States)

    Fatome, J.; Finot, C.; Millot, G.; Armaroli, A.; Trillo, S.

    2014-04-01

    We demonstrate that wave-breaking dramatically affects the dynamics of nonlinear frequency conversion processes that operate in the regime of high efficiency (strong multiple four-wave mixing). In particular, by exploiting an all-optical-fiber platform, we show that input modulations propagating in standard telecom fibers in the regime of weak normal dispersion lead to the formation of undular bores (dispersive shock waves) that mimic the typical behavior of dispersive hydrodynamics exhibited, e.g., by gravity waves and tidal bores. Thanks to the nonpulsed nature of the beat signal employed in our experiment, we are able to clearly observe how the periodic nature of the input modulation forces adjacent undular bores to collide elastically.

  15. Broadband photon pair generation in green fluorescent proteins through spontaneous four-wave mixing

    Science.gov (United States)

    Shi, Siyuan; Thomas, Abu; Corzo, Neil V.; Kumar, Prem; Huang, Yuping; Lee, Kim Fook

    2016-04-01

    Recent studies in quantum biology suggest that quantum mechanics help us to explore quantum processes in biological system. Here, we demonstrate generation of photon pairs through spontaneous four-wave mixing process in naturally occurring fluorescent proteins. We develop a general empirical method for analyzing the relative strength of nonlinear optical interaction processes in five different organic fluorophores. Our results indicate that the generation of photon pairs in green fluorescent proteins is subject to less background noises than in other fluorophores, leading to a coincidence-to-accidental ratio ~145. As such proteins can be genetically engineered and fused to many biological cells, our experiment enables a new platform for quantum information processing in a biological environment such as biomimetic quantum networks and quantum sensors.

  16. Output Rate of Atomic Four-Wave Mixing in Two-Component Bose-Einstein Condensate

    Institute of Scientific and Technical Information of China (English)

    LI Jia-Hua; LI Wei-Bing; PENG Ju-Cun

    2004-01-01

    In this letter, following the proposal of Heurich et al. [Phys. Rev. A63 (2001) 033605], we analyze and discuss output rate of atomic four-wave mixing in the two-component Bose-Einstein condensate under the condition of the steady state. The results show that the magnitude of the signal beam increases with the increase of the intensity of the probe beam, up to a saturated value, then it decreases as the probe beam increases. The influence of the interaction range on the signal beam is also predicted. In particular, it is worth while pointing out that in contrast to the previous solutions, our obtained analytical solutions are of very simple and explicit forms, which open the door for further investigating the related physical mechanisms.

  17. Phase quadrature discrimination based on three-pump four-wave mixing in nonlinear optical fibers.

    Science.gov (United States)

    Baillot, Maxime; Gay, Mathilde; Peucheret, Christophe; Michel, Joindot; Chartier, Thierry

    2016-11-14

    We theoretically and experimentally study the principle of phase-sensitive frequency conversion in a highly-nonlinear fiber using three pump waves. This mechanism, originally demonstrated with four continuous-wave pumps and a signal wave, is based on four-wave mixing and enables to convert the two quadrature components of the signal to different frequencies. In this work, we derive a set of two simple equations to describe this mechanism and find analytic solutions. We show that only three pumps are required, instead of four as originally proposed. We give simple relations to determine the initial conditions for the power levels and the phases of the pumps. To validate this approach, we perform an experimental demonstration of the three-pump scheme and find excellent agreement with the theory.

  18. Four-wave mixing of Nd3+-doped crystals and glasses

    Science.gov (United States)

    Powell, Richard C.; Payne, Stephen A.; Chase, L. L.; Wilke, G. D.

    1990-05-01

    Degenerate four-wave-mixing measurements have been performed on a wide variety of Nd3+-doped oxide and fluoride glasses and crystals. Crossed beams from a cw argon-ion laser were used to excite the Nd3+ ions directly and establish population gratings. Absolute measurements of the signal strengths were made, and their magnitudes were found to be sensitively influenced by the composition of the host. A theoretical model was developed to interpret the results, and it was found that the dominant contribution to the signal is associated with the difference in polarizability of the Nd3+ ions in the metastable state versus the ground state. The magnitude of the observed change in the polarizability indicates that the 4f-->5d transitions are responsible for this effect, and as a result, the value of the radial integral sensitively affects the calculated polarizability change.

  19. Numerical analysis of four-wave-mixing based multichannel wavelength conversion techniques in fibers

    Institute of Scientific and Technical Information of China (English)

    Jia Liang; Zhang Fan; Li Ming; Liu Yuliang; Chen Zhangyuan

    2009-01-01

    We numerically investigate four-wave-mixing (FWM) based multichannel wavelength conversion for amplitude-modulated signals, phase-modulated signals, together with mixed amplitude and phase modulated signals. This paper also discusses the influence of stimulated Brillouin scattering (SBS) effects on high-efficiency FWM-based wavelength conversion applications. Our simulation results show that DPSK signals are more suitable for FWM-based multichannel wavelength conversion because the OOK signals will suffer from the inevitable datapattern-dependent pump depletion. In future applications, when the modulation format is partially upgraded from OOK to DPSK, the influence of OOK signals on the updated DPSK signals must be considered when using multichannel wavelength conversion. This influence becomes severe with the increase of OOK channel number. It can be concluded that DPSK signals are more appropriate for both transmission and multichannel wavelength conversion,especially in long haul and high bit-rate system.

  20. Polarization properties of optical phase conjugation by two-photon resonant degenerate four-wave mixing

    Science.gov (United States)

    Kauranen, Martti; Gauthier, Daniel J.; Malcuit, Michelle S.; Boyd, Robert W.

    1989-08-01

    We develop a semiclassical theory of the polarization properties of phase conjugation by two-photon resonant degenerate four-wave mixing. The theory includes the effects of saturation by the pump waves. We solve the density-matrix equations of motion in steady state for a nonlinear medium consisting of stationary atoms with a ground and excited state connected by two-photon transitions. As an illustration of the general results, we consider an S0-->S0 two-photon transition, which is known to lead to perfect polarization conjugation in the limit of third-order theory. We show that the fidelity of the polarization-conjugation process is degraded for excessively large pump intensities. The degradation can occur both due to transfer of population to the excited state and due to nonresonant Stark shifts. Theoretical results are compared to those of a recent experiment [Malcuit, Gauthier, and Boyd, Opt. Lett. 13, 663 (1988)].

  1. Stimulated generation of superluminal light pulses via four-wave mixing.

    Science.gov (United States)

    Glasser, Ryan T; Vogl, Ulrich; Lett, Paul D

    2012-04-27

    We report on the four-wave mixing of superluminal pulses, in which both the injected and generated pulses involved in the process propagate with negative group velocities. Generated pulses with negative group velocities of up to v(g)=-1/880c are demonstrated, corresponding to the generated pulse's peak exiting the 1.7 cm long medium ≈50 ns earlier than if it had propagated at the speed of light in vacuum, c. We also show that in some cases the seeded pulse may propagate with a group velocity larger than c, and that the generated conjugate pulse peak may exit the medium even earlier than the amplified seed pulse peak. We can control the group velocities of the two pulses by changing the seed detuning and the input seed power.

  2. Intermodal four-wave mixing in a higher-order-mode fiber.

    Science.gov (United States)

    Cheng, Ji; Pedersen, Martin E V; Charan, Kriti; Wang, Ke; Xu, Chris; Grüner-Nielsen, Lars; Jakobsen, Dan

    2012-10-15

    We demonstrate a high-efficiency intermodal four-wave-mixing process in an all-fiber system, comprising a picosecond fiber laser and a high-order-mode (HOM) fiber. Two pump photons in the LP(01) mode of the fiber can generate an anti-Stokes photon in the LP(01) mode and a Stokes photon in the LP(02) mode. The wavelength dependent mode profiles of the HOM fiber produce significant spatial overlap between the modes involved. The anti-Stokes wave at 941 nm is generated with 20% conversion efficiency with input pulse energy of 20 nJ. The guidance of the anti-Stokes and Stokes waves in the HOM fiber enhances system stability.

  3. Rational design of metallic nanocavities for resonantly enhanced four-wave mixing.

    Science.gov (United States)

    Almeida, Euclides; Prior, Yehiam

    2015-05-14

    Optimizing the shape of nanostructures and nano-antennas for specific optical properties has evolved to be a very fruitful activity. With modern fabrication tools a large variety of possibilities is available for shaping both nanoparticles and nanocavities; in particular nanocavities in thin metal films have emerged as attractive candidates for new metamaterials and strong linear and nonlinear optical systems. Here we rationally design metallic nanocavities to boost their Four-Wave Mixing response by resonating the optical plasmonic resonances with the incoming and generated beams. The linear and nonlinear optical responses as well as the propagation of the electric fields inside the cavities are derived from the solution of Maxwell's equations by using the 3D finite-differences time domain method. The observed conversion-efficiency of near-infrared to visible light equals or surpasses that of BBO of equivalent thickness. Implications to further optimization for efficient and broadband ultrathin nonlinear optical materials are discussed.

  4. Enhancement of four-wave mixing via interference of multiple plasmonic conversion paths

    Science.gov (United States)

    Singh, Shailendra K.; Abak, M. Kurtulus; Tasgin, Mehmet Emre

    2016-01-01

    Recent experiments demonstrate that plasmonic resonators can enhance the four-wave mixing (FWM) process by several orders of magnitude, due to the localization of the incident fields. We show that, when the plasmonic resonator is coupled to two quantum emitters, a three orders of magnitude enhancement can be obtained on top of the enhancement due to the localization. We explicitly demonstrate—on an expression for the steady-state FWM amplitude—how the presence of a Fano resonance leads to the cancellation of nonresonant terms in a FWM process. A cancellation in the denominator gives rise to an enhancement in the nonlinearity. The explicit demonstration we present here guides one to a method for achieving even larger enhancement factors by introducing additional coupling terms. The method is also applicable to Fano resonances induced by all-plasmonic couplings, which are easier to control in experiments.

  5. Squeezing of thermal fluctuations in four-wave mixing in a \\Lambda-scheme

    CERN Document Server

    Erukhimova, Maria

    2016-01-01

    We theoretically investigate the mechanism of two-mode quadrature squeezing in regime of four-wave mixing in a \\Lambda-scheme of three-level atoms embedded in a thermal reservoir. We demonstrate that the process of nonlinear transfer of noise from the low frequency of ground state splitting to the optical frequency drastically modifies the condition of effective two-mode squeezing. The damage factor is significant if number of thermal photons at the low frequency is high and the role of inelastic processes in ground state coherence decay is not negligible. We found the optimal conditions for squeezing, in particular optimal density-length product of active medium depending on the relaxation parameters and drive intensity.

  6. Observation of the four wave mixing photonic band gap signal in electromagnetically induced grating.

    Science.gov (United States)

    Ullah, Zakir; Wang, Zhiguo; Gao, Mengqin; Zhang, Dan; Zhang, Yiqi; Gao, Hong; Zhang, Yanpeng

    2014-12-01

    For the first time, we experimentally and theoretically research about the probe transmission signal (PTS), the reflected four wave mixing band gap signal(FWM BGS) and fluorescence signal (FLS) under the double dressing effect in an inverted Y-type four level system. FWM BGS results from photonic band gap structure. We demonstrate that the characteristics of PTS, FWM BGS and FLS can be controlled by power, phase and the frequency detuning of the dressing beams. It is observed in our experiment that FWM BGS switches from suppression to enhancement, corresponding to the switch from transmission enhancement to absorption enhancement in the PTS with changing the relative phase. We also observe the relation among the three signals, which satisfy the law of conservation of energy. Such scheme could have potential applications in optical diodes, amplifiers and quantum information processing.

  7. 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.

  8. Microwave photonic notch filter with complex coefficient based on four wave mixing

    Science.gov (United States)

    Xu, Dong; Cao, Ye; Tong, Zheng-rong; Yang, Jing-peng

    2016-11-01

    A microwave photonic notch filter with a complex coefficient is proposed and demonstrated based on four wave mixing (FWM). FWM effect of two single-frequency laser beams occurs in a highly nonlinear fiber (HNLF), and multi-wavelength optical signals are generated and used to generate the multi-tap of microwave photonic filter (MPF). The complex coefficient is generated by using a Fourier-domain optical processor (FD-OP) to control the amplitude and phase of the optical carrier and phase modulation sidebands. The results show that this filter can be changed from bandpass filter to notch filter by controlling the FD-OP. The center frequency of the notch filter can be continuously tuned from 5.853 GHz to 29.311 GHz with free spectral range ( FSR) of 11.729 GHz. The shape of the frequency response keeps unchanged when the phase is tuned.

  9. Photon statistics of pulse-pumped four-wave mixing in fiber with weak signal injection

    Science.gov (United States)

    Nan-Nan, Liu; Yu-Hong, Liu; Jia-Min, Li; Xiao-Ying, Li

    2016-07-01

    We study the photon statistics of pulse-pumped four-wave mixing in fibers with weak coherent signal injection by measuring the intensity correlation functions of individual signal and idler fields. The experimental results show that the intensity correlation function of individual signal (idler) field decreases with the intensity of signal injection. After applying narrow band filter in signal (idler) band, the value of decreases from 1.9 ± 0.02 (1.9 ± 0.02) to 1.03 ± 0.02 (1.05 ± 0.02) when the intensity of signal injection varies from 0 to 120 photons/pulse. The results indicate that the photon statistics changes from Bose-Einstein distribution to Poisson distribution. We calculate the intensity correlation functions by using the multi-mode theory of four-wave mixing in fibers. The theoretical curves well fit the experimental results. Our investigation will be useful for mitigating the crosstalk between quantum and classical channels in a dense wavelength division multiplexing network. Project supported by the National Natural Science Foundation of China (Grant No. 11527808), the State Key Development Program for Basic Research of China (Grant No. 2014CB340103), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120032110055), the Natural Science Foundation of Tianjin, China (Grant No. 14JCQNJC02300), the Program for Changjiang Scholars and Innovative Research Team in University, China, and the Program of Introducing Talents of Discipline to Universities, China (Grant No. B07014).

  10. Efficient four-wave mixing in an ultra-highly nonlinear suspended-core chalcogenide As38Se62 fiber.

    Science.gov (United States)

    Le, Sy Dat; Nguyen, Duc Minh; Thual, Monique; Bramerie, Laurent; Costa e Silva, Marcia; Lenglé, Kevin; Gay, Mathilde; Chartier, Thierry; Brilland, Laurent; Méchin, David; Toupin, Perrine; Troles, Johann

    2011-12-12

    We report a chalcogenide suspended-core fiber with ultra-high nonlinearity and low attenuation loss. The glass composition is As(38)Se(62).With a core diameter as small as 1.13 µm, a record Kerr nonlinearity of 46,000 W(-1) km(-1) is demonstrated with attenuation loss of 0.9 dB/m. Four-wave mixing is experimented by using a 1m-long chalcogenide fiber for 10 GHz and 42.7 GHz signals. Four-wave mixing efficiencies of -5.6 dB at 10 GHz and -17.5 dB at 42.7 GHz are obtained. We also observed higher orders of four-wave mixing for both repetition rates. © 2011 Optical Society of America

  11. v-representability and density functional theory. [for nonrelativistic electrons in nondegenerate ground state

    Science.gov (United States)

    Kohn, W.

    1983-01-01

    It is shown that if n(r) is the discrete density on a lattice (enclosed in a finite box) associated with a nondegenerate ground state in an external potential v(r) (i.e., is 'v-representable'), then the density n(r) + mu(r), with m(r) arbitrary (apart from trivial constraints) and mu small enough, is also associated with a nondegenerate ground state in an external potential v'(r) near v(r); i.e., n(r) + m(r) is also v-representable. Implications for the Hohenberg-Kohn variational principle and the Kohn-Sham equations are discussed.

  12. Squeezing based on nondegenerate frequency doubling internal to a realistic laser

    DEFF Research Database (Denmark)

    Andersen, Ulrik Lund; Tidemand-Lichtenberg, Peter; Buchhave, Preben

    2004-01-01

    We investigate theoretically the quantum fluctuations of the fundamental field in the output of a nondegenerate second-harmonic generation process occurring inside a laser cavity. Due to the nondegenerate character of the nonlinear medium, a field orthogonal to the laser field is for some operating...... conditions independent of the fluctuations produced by the laser medium. We show that this fact may lead to perfect squeezing for a certain polarization mode of the fundamental field. The experimental feasibility of the system is also discussed....

  13. Stimulated and spontaneous four-wave mixing in silicon-on-insulator coupled photonic wire nano-cavities

    Science.gov (United States)

    Azzini, Stefano; Grassani, Davide; Galli, Matteo; Gerace, Dario; Patrini, Maddalena; Liscidini, Marco; Velha, Philippe; Bajoni, Daniele

    2013-07-01

    We report on four-wave mixing in coupled photonic crystal nano-cavities on a silicon-on-insulator platform. Three photonic wire cavities are side-coupled to obtain three modes equally separated in energy. The structure is designed to be self-filtering, and we show that the pump is rejected by almost two orders of magnitude. We study both the stimulated and the spontaneous four-wave mixing processes: owing to the small modal volume, we find that signal and idler photons are generated with a hundred-fold increase in efficiency as compared to silicon micro-ring resonators.

  14. Characterization of Chirped Pump Four-Wave Mixing in Nonlinear Fibers using only Continuous-Wave-Lasers

    DEFF Research Database (Denmark)

    Lillieholm, Mads; Guan, Pengyu; Møller-kristensen, M. S.

    2017-01-01

    We propose a novel fiber characterization method that reveals the four-wave mixing bandwidth for chirped pump operation, using two tunable continuous-wave-lasers. The method accurately predicts the bandwidth for optical time lenses with broadband multi-carrier input......We propose a novel fiber characterization method that reveals the four-wave mixing bandwidth for chirped pump operation, using two tunable continuous-wave-lasers. The method accurately predicts the bandwidth for optical time lenses with broadband multi-carrier input...

  15. Nonlinear photonic crystal fiber with a structured multi-component glass core for four-wave mixing and supercontinuum generation.

    Science.gov (United States)

    Tombelaine, Vincent; Labruyère, Alexis; Kobelke, Jens; Schuster, Kay; Reichel, Volker; Leproux, Philippe; Couderc, Vincent; Jamier, Raphaël; Bartelt, Hartmut

    2009-08-31

    We report about a new type of nonlinear photonic crystal fibers allowing broadband four-wave mixing and supercontinuum generation. The microstructured optical fiber has a structured core consisting of a rod of highly nonlinear glass material inserted in a silica tube. This particular structure enables four wave mixing processes with very large frequency detuning (>135 THz), which permitted the generation of a wide supercontinuum spectrum extending over 1650 nm after 2.15 m of propagation length. The comparison with results obtained from germanium-doped holey fibers confirms the important role of the rod material properties regarding nonlinear process and dispersion.

  16. Wideband tuning of four-wave mixing in solid-core liquid-filled photonic crystal fibers.

    Science.gov (United States)

    Velázquez-Ibarra, Lorena; Díez, Antonio; Silvestre, Enrique; Andrés, Miguel V

    2016-06-01

    We present an experimental study of parametric four-wave mixing generation in photonic crystal fibers that have been infiltrated with ethanol. A silica photonic crystal fiber was designed to have the proper dispersion properties after ethanol infiltration for the generation of widely spaced four-wave mixing (FWM) bands under 1064 nm pumping. We demonstrate that the FWM bands can be tuned in a wide wavelength range through the thermo-optic effect. Band shifts of 175 and over 500 nm for the signal and idler bands, respectively, are reported. The reported results can be of interest in many applications, such as CARS microscopy.

  17. Terahertz generation based on four-wave mixing difference frequency by resonance-enhanced third-order nonlinear of media

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shao-hua; YAO Jian-quan; ZHOU Rui; WEN Wu-qi; XU De-gang; WANG Peng

    2011-01-01

    Using nanosecond pulse near-infrared and mid-infrared laser pulses as the pump source,we obtain terahertz wave sources via four-wave difference frequency mixing.From the coupled wave theory,.we analyze the four-wave mixing process of GaSe crystal and alkali metal vapor in detail,get the analytical expression of terahertz wave output power,and discuss the conditions for achieving phase matching.By adjusting the pump frequency,the third-order nonlinear polarization of alkali metal vapor is resonance-enhanced.This program offers a new type of high-power terahertz radiation source.

  18. Stimulated and spontaneous four-wave mixing in silicon-on-insulator coupled photonic wire nano-cavities

    OpenAIRE

    Azzini, Stefano; Grassani, Davide; Galli, Matteo; Gerace,Dario; Patrini, Maddalena; Liscidini, Marco; Velha, Philippe; Bajoni, Daniele

    2013-01-01

    We report on four-wave mixing in coupled photonic crystal nano-cavities on a silicon-on-insulator platform. Three photonic wire cavities are side-coupled to obtain three modes equally separated in energy. The structure is designed to be self-filtering, and we show that the pump is rejected by almost two orders of magnitudes. We study both the stimulated and the spontaneous four-wave mixing processes: owing to the small modal volume, we find that signal and idler photons are generated with a h...

  19. Stimulated and spontaneous four-wave mixing in silicon-on-insulator coupled photonic wire nano-cavities

    OpenAIRE

    Azzini, Stefano; Grassani, Davide; Galli, Matteo; Gerace, Dario; Patrini, Maddalena; Liscidini, Marco; Velha, Philippe; Bajoni, Daniele

    2013-01-01

    We report on four-wave mixing in coupled photonic crystal nano-cavities on a silicon-on-insulator platform. Three photonic wire cavities are side-coupled to obtain three modes equally separated in energy. The structure is designed to be self-filtering, and we show that the pump is rejected by almost two orders of magnitudes. We study both the stimulated and the spontaneous four-wave mixing processes: owing to the small modal volume, we find that signal and idler photons are generated with a h...

  20. Experimental setups for FEL-based four-wave mixing experiments at FERMI

    Energy Technology Data Exchange (ETDEWEB)

    Bencivenga, Filippo; Zangrando, Marco; Svetina, Cristian; Abrami, Alessandro; Battistoni, Andrea; Borghes, Roberto; Capotondi, Flavio; Cucini, Riccardo; Dallari, Francesco; Danailov, Miltcho; Demidovich, Alexander; Fava, Claudio; Gaio, Giulio; Gerusina, Simone; Gessini, Alessandro; Giacuzzo, Fabio; Gobessi, Riccardo; Godnig, Roberto; Grisonich, Riccardo; Kiskinova, Maya; Kurdi, Gabor; Loda, Giorgio; Lonza, Marco; Mahne, Nicola; Manfredda, Michele; Mincigrucci, Riccardo; Pangon, Gianpiero; Parisse, Pietro; Passuello, Roberto; Pedersoli, Emanuele; Pivetta, Lorenzo; Prica, Milan; Principi, Emiliano; Rago, Ilaria; Raimondi, Lorenzo; Sauro, Roberto; Scarcia, Martin; Sigalotti, Paolo; Zaccaria, Maurizio; Masciovecchio, Claudio

    2016-01-01

    The recent advent of free-electron laser (FEL) sources is driving the scientific community to extend table-top laser research to shorter wavelengths adding elemental selectivity and chemical state specificity. Both a compact setup (mini-TIMER) and a separate instrument (EIS-TIMER) dedicated to four-wave-mixing (FWM) experiments has been designed and constructed, to be operated as a branch of the Elastic and Inelastic Scattering beamline: EIS. The FWM experiments that are planned at EIS-TIMER are based on the transient grating approach, where two crossed FEL pulses create a controlled modulation of the sample excitations while a third time-delayed pulse is used to monitor the dynamics of the excited state. This manuscript describes such experimental facilities, showing the preliminary results of the commissioning of the EIS-TIMER beamline, and discusses original experimental strategies being developed to study the dynamics of matter at the fs–nm time–length scales. In the near future such experimental tools will allow more sophisticated FEL-based FWM applications, that also include the use of multiple and multi-color FEL pulses.

  1. All-optical wavelength conversion by four-wave mixing in a semiconductor optical amplifier

    Science.gov (United States)

    Lee, Robert Bumju

    1997-11-01

    Wavelength division multiplexed optical communication systems will soon become an integral part of commercial optical networks. A crucial new function required in WDM networks is wavelength conversion, the spectral translation of information-laden optical carriers, which enhances wavelength routing options and greatly improves network reconfigurability. One of several techniques for implementing this function is four-wave mixing utilizing ultra-fast intraband nonlinearities in semiconductor optical amplifiers. The effects of input power, noise prefiltering and semiconductor optical amplifier length on the conversion efficiency and optical signal-to-noise ratio were examined. Systems experiments have been conducted in which several important performance characteristics of the wavelength converter were studied. A bit-error-rate performance of BER performance were studied at 2.5 Gb/s for both a single-channel conversion and a simultaneous 2-channel conversion. The crosstalk penalty induced by parasitic cross-gain modulation in 2-channel conversion is quantified. The spectral inversion which results from the conversion process is studied by time-resolved spectral analysis, and its application as a technique for dispersion compensation is demonstrated. Finally, the application of selective organometallic vapor-phase epitaxy for the formation of highly-uniform and densely-packed arrays of GaAs quantum dots is demonstrated. GaAs dots of 15-20 nm in base diameter and 8-10 nm in height terminated by slow-growth crystallographic planes were grown within dielectric-mask openings and characterized by atomic force microscopy.

  2. Experimental setups for FEL-based four-wave mixing experiments at FERMI.

    Science.gov (United States)

    Bencivenga, Filippo; Zangrando, Marco; Svetina, Cristian; Abrami, Alessandro; Battistoni, Andrea; Borghes, Roberto; Capotondi, Flavio; Cucini, Riccardo; Dallari, Francesco; Danailov, Miltcho; Demidovich, Alexander; Fava, Claudio; Gaio, Giulio; Gerusina, Simone; Gessini, Alessandro; Giacuzzo, Fabio; Gobessi, Riccardo; Godnig, Roberto; Grisonich, Riccardo; Kiskinova, Maya; Kurdi, Gabor; Loda, Giorgio; Lonza, Marco; Mahne, Nicola; Manfredda, Michele; Mincigrucci, Riccardo; Pangon, Gianpiero; Parisse, Pietro; Passuello, Roberto; Pedersoli, Emanuele; Pivetta, Lorenzo; Prica, Milan; Principi, Emiliano; Rago, Ilaria; Raimondi, Lorenzo; Sauro, Roberto; Scarcia, Martin; Sigalotti, Paolo; Zaccaria, Maurizio; Masciovecchio, Claudio

    2016-01-01

    The recent advent of free-electron laser (FEL) sources is driving the scientific community to extend table-top laser research to shorter wavelengths adding elemental selectivity and chemical state specificity. Both a compact setup (mini-TIMER) and a separate instrument (EIS-TIMER) dedicated to four-wave-mixing (FWM) experiments has been designed and constructed, to be operated as a branch of the Elastic and Inelastic Scattering beamline: EIS. The FWM experiments that are planned at EIS-TIMER are based on the transient grating approach, where two crossed FEL pulses create a controlled modulation of the sample excitations while a third time-delayed pulse is used to monitor the dynamics of the excited state. This manuscript describes such experimental facilities, showing the preliminary results of the commissioning of the EIS-TIMER beamline, and discusses original experimental strategies being developed to study the dynamics of matter at the fs-nm time-length scales. In the near future such experimental tools will allow more sophisticated FEL-based FWM applications, that also include the use of multiple and multi-color FEL pulses.

  3. Electric field strength determination in filamentary DBDs by CARS-based four-wave mixing

    Science.gov (United States)

    Boehm, Patrick; Kettlitz, Manfred; Brandenburg, Ronny; Hoeft, Hans; Czarnetzki, Uwe

    2016-09-01

    The electric field strength is a basic parameter of non-thermal plasmas. Therefore, a profound knowledge of the electric field distribution is crucial. In this contribution a four wave mixing technique based on Coherent Anti-Stokes Raman spectroscopy (CARS) is used to measure electric field strengths in filamentary dielectric barrier discharges (DBDs). The discharges are operated with a pulsed voltage in nitrogen at atmospheric pressure. Small amounts hydrogen (10 vol%) are admixed as tracer gas to evaluate the electric field strength in the 1 mm discharge gap. Absolute values of the electric field strength are determined by calibration of the CARS setup with high voltage amplitudes below the ignition threshold of the arrangement. Alteration of the electric field strength has been observed during the internal polarity reversal and the breakdown process. In this case the major advantage over emission based methods is that this technique can be used independently from emission, e.g. in the pre-phase and in between two consecutive, opposite discharge pulses where no emission occurs at all. This work was supported by the Deutsche Forschungsgemeinschaft, Forschergruppe FOR 1123 and Sonderforschungsbereich TRR 24 ``Fundamentals of complex plasmas''.

  4. Efficient and broadband optical parametric four wave mixing in chalcogenide-PMMA hybrid microwires

    CERN Document Server

    Ahmad, Raja

    2012-01-01

    The recent development of devices based on novel nonlinear materials like chalcogenides (ChGs), silicon (Si) and other semi-conductors has revolutionized the field of nonlinear photonics [1,2,3]. Among the nonlinear effects observed in these materials, four-wave mixing (FWM) is the process that finds the most applications including wavelength conversion [4], optical regeneration [5,6], optical delay [7], time-domain demultiplexing[8], temporal cloaking[9] and negative refraction[10]. Although FWM has been observed in several media including chalcogenides [11,12,13,14], silicon[15, 16], bismuth [17] and silica [18,19], there is a continued quest for devices that realize efficient and broadband FWM while offering compactness, low-power consumption and compatibility with optical fibers. Here, we demonstrate the fabrication of 10 cm long polymer cladded chalcogenide (As2Se3) microwires to realize FWM-led sub watt threshold (70-370 mW) wavelength conversion with a 12 dB bandwidth as broad as 190 nm, and conversion...

  5. Experimental setups for FEL-based four-wave mixing experiments at FERMI

    Energy Technology Data Exchange (ETDEWEB)

    Bencivenga, Filippo; Zangrando, Marco; Svetina, Cristian; Abrami, Alessandro; Battistoni, Andrea; Borghes, Roberto; Capotondi, Flavio; Cucini, Riccardo; Dallari, Francesco; Danailov, Miltcho; Demidovich, Alexander; Fava, Claudio; Gaio, Giulio; Gerusina, Simone; Gessini, Alessandro; Giacuzzo, Fabio; Gobessi, Riccardo; Godnig, Roberto; Grisonich, Riccardo; Kiskinova, Maya; Kurdi, Gabor; Loda, Giorgio; Lonza, Marco; Mahne, Nicola; Manfredda, Michele; Mincigrucci, Riccardo; Pangon, Gianpiero; Parisse, Pietro; Passuello, Roberto; Pedersoli, Emanuele; Pivetta, Lorenzo; Prica, Milan; Principi, Emiliano; Rago, Ilaria; Raimondi, Lorenzo; Sauro, Roberto; Scarcia, Martin; Sigalotti, Paolo; Zaccaria, Maurizio; Masciovecchio, Claudio

    2016-01-01

    The recent advent of free-electron laser (FEL) sources is driving the scientific community to extend table-top laser research to shorter wavelengths adding elemental selectivity and chemical state specificity. Both a compact setup (mini-TIMER) and a separate instrument (EIS-TIMER) dedicated to four-wave-mixing (FWM) experiments has been designed and constructed, to be operated as a branch of the Elastic and Inelastic Scattering beamline: EIS. The FWM experiments that are planned at EIS-TIMER are based on the transient grating approach, where two crossed FEL pulses create a controlled modulation of the sample excitations while a third time-delayed pulse is used to monitor the dynamics of the excited state. This manuscript describes such experimental facilities, showing the preliminary results of the commissioning of the EIS-TIMER beamline, and discusses original experimental strategies being developed to study the dynamics of matter at the fs–nm time–length scales. In the near future such experimental tools will allow more sophisticated FEL-based FWM applications, that also include the use of multiple and multi-color FEL pulses.

  6. Fast-light Assisted Four-Wave-Mixing in Photonic Bandgap

    CERN Document Server

    Feng, Cheng; Zhang, Liang; Liu, Jinmei; Zhan, Li

    2014-01-01

    Since the forward and backward waves are coupled with each other and a standing wave with no net propagation of energy is formed in the photonic bandgap, it is a commonsense of basic physics that, any kinds of effects associated with wave propagation including four-wave-mixing (FWM) are thought to be impossible. However, we lay great emphasis here on explaining that this commonsense could be broken under specific circumstances. In this article, we report with the first experimental observation of the energy conversion in the photonic bandgap into other channel via FWM. Owing to the phase manipulation by fast light effect in the photonic bandgap, we manage to achieve the phase-match condition and thus occurred FWM transfer energy into other channels outside the photonic bandgap efficiently. As one-dimensional photonic crystal, simulations on fiber Bragg grating (FBG) with and without fast light were conducted respectively, and an enhanced FWM in photonic bandgap of FBG was observed. The experimental result sho...

  7. Time-resolved four-wave-mixing spectroscopy for inner-valence transitions.

    Science.gov (United States)

    Ding, Thomas; Ott, Christian; Kaldun, Andreas; Blättermann, Alexander; Meyer, Kristina; Stooss, Veit; Rebholz, Marc; Birk, Paul; Hartmann, Maximilian; Brown, Andrew; Van Der Hart, Hugo; Pfeifer, Thomas

    2016-02-15

    Noncollinear four-wave-mixing (FWM) techniques at near-infrared (NIR), visible, and ultraviolet frequencies have been widely used to map vibrational and electronic couplings, typically in complex molecules. However, correlations between spatially localized inner-valence transitions among different sites of a molecule in the extreme ultraviolet (XUV) spectral range have not been observed yet. As an experimental step toward this goal, we perform time-resolved FWM spectroscopy with femtosecond NIR and attosecond XUV pulses. The first two pulses (XUV-NIR) coincide in time and act as coherent excitation fields, while the third pulse (NIR) acts as a probe. As a first application, we show how coupling dynamics between odd- and even-parity, inner-valence excited states of neon can be revealed using a two-dimensional spectral representation. Experimentally obtained results are found to be in good agreement with ab initio time-dependent R-matrix calculations providing the full description of multielectron interactions, as well as few-level model simulations. Future applications of this method also include site-specific probing of electronic processes in molecules.

  8. Phase conjugation by degenerate four wave mixing in disodium fluorescein solution in methanol

    Science.gov (United States)

    Abdeldayem, Hossin; Sekhar, P. Chandra; Venkateswarlu, P.; Geroge, M. C.

    1989-01-01

    Organic dyes are known to show the resonant type of nonlinear optical properties, including phase conjugation. In the present work, disodium fluorescein in methanol is used as an organic nonlinear medium for degenerate four wave mixing at 532 nm to see the intensity dependence of the phase conjugate signal at different concentrations of the solution. It is observed that the maximum reflectivity of the signal occurs in a concentration range of 5 x 10(exp -3)/cu cm to 1.2 x 10(exp -2) g/cu cm. It is also observed that the intensity of the signal drops suddenly to less than half of its maximum outside the concentration range mentioned above. An investigation of the phase conjugate signal intensity by changing the delay time between probe signal and the forward pump is also examined. Briefly discussed is the possibility of population grating in dye liquids as a source of enhancing the third order susceptibility besides the other techniques mentioned in reference. The experiment is done by beam splitting the second harmonic (532 nm) of Nd:YAG laser, Q-switched at 20 pulses/sec (pulse width is approximately 8 and 200 mJ per pulse).

  9. Pulsed Rydberg four-wave mixing with motion-induced dephasing in a thermal vapor

    CERN Document Server

    Chen, Yi-Hsin; Löw, Robert; Pfau, Tilman

    2015-01-01

    We report on time-resolved pulsed four-wave mixing (FWM) signals in a thermal Rubidium vapor involving a Rydberg state. We observe FWM signals with dephasing times up to 7 ns, strongly dependent on the excitation bandwidth to the Rydberg state. The excitation to the Rydberg state is driven by a pulsed two-photon transition on ns time scales. Combined with a third cw de-excitation laser, a strongly directional and collective emission is generated according to a combination of the phase matching effect and averaging over Doppler classes. In contrast to a previous report [1] using off-resonant FWM, at a resonant FWM scheme we observe additional revivals of the signal shortly after the incident pulse has ended. We infer that this is a revival of motion-induced constructive interference between the coherent emissions of the thermal atoms. The resonant FWM scheme reveals a richer temporal structure of the signals, compared to similar, but off-resonant excitation schemes. A simple explanation lies in the selectivity...

  10. Pulsed Rydberg four-wave mixing with motion-induced dephasing in a thermal vapor.

    Science.gov (United States)

    Chen, Yi-Hsin; Ripka, Fabian; Löw, Robert; Pfau, Tilman

    We report on time-resolved pulsed four-wave mixing (FWM) signals in a thermal Rubidium vapor involving a Rydberg state. We observe FWM signals with dephasing times up to 7 ns, strongly dependent on the excitation bandwidth to the Rydberg state. The excitation to the Rydberg state is driven by a pulsed two-photon transition on ns timescales. Combined with a cw de-excitation laser, a strongly directional and collective emission is generated according to a combination of the phase matching effect and averaging over Doppler classes. In contrast to a previous report (Huber et al. in Phys Rev A 90: 053806, 2014) using off-resonant FWM, at a resonant FWM scheme we observe additional revivals of the signal shortly after the incident pulse has ended. We infer that this is a revival of motion-induced constructive interference between the coherent emissions of the thermal atoms. The resonant FWM scheme reveals a richer temporal structure of the signals, compared to similar, but off-resonant excitation schemes. A simple explanation lies in the selectivity of Doppler classes. Our numerical simulations based on a four-level model including a whole Doppler ensemble can qualitatively describe the data.

  11. Plasmonic nanofocused four-wave mixing for femtosecond near-field imaging.

    Science.gov (United States)

    Kravtsov, Vasily; Ulbricht, Ronald; Atkin, Joanna M; Raschke, Markus B

    2016-05-01

    Femtosecond nonlinear optical imaging with nanoscale spatial resolution would provide access to coupled degrees of freedom and ultrafast response functions on the characteristic length scales of electronic and vibrational excitations. Although near-field microscopy provides the desired spatial resolution, the design of a broadband high-contrast nanoprobe for ultrafast temporal resolution is challenging due to the inherently weak nonlinear optical signals generated in subwavelength volumes. Here, we demonstrate broadband four-wave mixing with enhanced nonlinear frequency conversion efficiency at the apex of a nanometre conical tip. Far-field light is coupled through a grating at the shaft of the tip, generating plasmons that propagate to the apex while undergoing asymptotic compression and amplification, resulting in a nonlinear conversion efficiency of up to 1 × 10(-5). We apply this nonlinear nanoprobe to image the few-femtosecond coherent dynamics of plasmonic hotspots on a nanostructured gold surface with spatial resolution of a few tens of nanometres. The approach can be generalized towards spatiotemporal imaging and control of coherent dynamics on the nanoscale, including the extension to multidimensional spectroscopy and imaging.

  12. Triply resonant coherent four-wave mixing in silicon nitride microresonators.

    Science.gov (United States)

    Fülöp, Attila; Krückel, Clemens J; Castelló-Lurbe, David; Silvestre, Enrique; Torres-Company, Victor

    2015-09-01

    Generation of multiple tones using four-wave mixing (FWM) has been exploited for many applications, ranging from wavelength conversion to frequency comb generation. FWM is a coherent process, meaning that its dynamics strongly depend on the relative phase among the waves involved. The coherent nature of FWM has been exploited for phase-sensitive processing in different waveguide structures, but it has never been studied in integrated microresonators. Waveguides arranged in a resonant way allow for an effective increase in the wavelength conversion efficiency (at the expense of a reduction in the operational bandwidth). In this Letter, we show that phase shaping of a three-wave pump provides an extra degree of freedom for controlling the FWM dynamics in microresonators. We present experimental results in single-mode, normal-dispersion high-Q silicon nitride resonators, and numerical calculations of systems operating in the anomalous dispersion regime. Our results indicate that the wavelength conversion efficiency and modulation instability gain in microcavities pumped by multiple waves can be significantly modified with the aid of simple lossless coherent control techniques.

  13. Polarization-dependent intermodal four-wave mixing in a birefringent multimode photonic crystal fiber.

    Science.gov (United States)

    Yuan, Jinhui; Kang, Zhe; Li, Feng; Zhou, Guiyao; Sang, Xinzhu; Wu, Qiang; Yan, Binbin; Zhou, Xian; Zhong, Kangping; Wang, Liang; Wang, Kuiru; Yu, Chongxiu; Lu, Chao; Tam, Hwa Yaw; Wai, P K A

    2017-05-01

    In this Letter, polarization-dependent intermodal four-wave mixing (FWM) is demonstrated experimentally in a birefringent multimode photonic crystal fiber (BM-PCF) designed and fabricated in-house. Femtosecond pump pulses at wavelengths ∼800  nm polarized along one of the principal axes of the BM-PCF are coupled into a normal dispersion region away from the zero-dispersion wavelengths of the fundamental guided mode of the BM-PCF. Anti-Stokes and Stokes waves are generated in the 2nd guided mode at visible and near-infrared wavelengths, respectively. For pump pulses at an average input power of 500 mW polarized along the slow axis, the conversion efficiencies ηas and ηs of the anti-Stokes and Stokes waves generated at wavelengths 579.7 and 1290.4 nm are 19% and 14%, respectively. For pump pulses polarized along the fast axis, the corresponding ηas and ηs at 530.4 and 1627 nm are 23% and 18%, respectively. We also observed that fiber bending and intermodal walk-off have a small effect on the polarization-dependent intermodal FWM-based frequency conversion process.

  14. Combined third-harmonic generation and four-wave mixing microscopy of tissues and embryos.

    Science.gov (United States)

    Mahou, Pierre; Olivier, Nicolas; Labroille, Guillaume; Duloquin, Louise; Sintes, Jean-Marc; Peyriéras, Nadine; Legouis, Renaud; Débarre, Delphine; Beaurepaire, Emmanuel

    2011-10-01

    Nonlinear microscopy can be used to probe the intrinsic optical properties of biological tissues. Using femtosecond pulses, third-harmonic generation (THG) and four-wave mixing (FWM) signals can be efficiently produced and detected simultaneously. Both signals probe a similar parameter, i.e. the real part of the third-order nonlinear susceptibility χ((3)). However THG and FWM images result from different phase matching conditions and provide complementary information. We analyze this complementarity using calculations, z-scan measurements on water and oils, and THG-FWM imaging of cell divisions in live zebrafish embryos. The two signals exhibit different sensitivity to sample size and clustering in the half-wavelength regime. Far from resonance, THG images reveal spatial variations |Δχ((3))(-3ω;ω,ω,ω)| with remarkable sensitivity while FWM directly reflects the distribution of χ((3))(-2ω(1) + ω(2);ω(1), -ω(2), ω(1)). We show that FWM images provide χ((3)) maps useful for proper interpretation of cellular THG signals, and that combined imaging carries additional structural information. Finally we present simultaneous imaging of intrinsic THG, FWM, second-harmonic (SHG) and two-photon-excited fluorescence (2PEF) signals in live Caenorhabditis elegans worms illustrating the information provided by multimodal nonlinear imaging of unstained tissue.

  15. Time-resolved four-wave-mixing spectroscopy for inner-valence transitions

    CERN Document Server

    Ding, Thomas; Kaldun, Andreas; Blättermann, Alexander; Meyer, Kristina; Stooß, Veit; Rebholz, Marc; Birk, Paul; Hartmann, Maximilian; Brown, Andrew; Van Der Hart, Hugo; Pfeifer, Thomas

    2015-01-01

    Non-collinear four-wave mixing (FWM) techniques at near-infrared (NIR), visible, and ultraviolet frequencies have been widely used to map vibrational and electronic couplings, typically in complex molecules. However, correlations between spatially localized inner-valence transitions among different sites of a molecule in the extreme ultraviolet (XUV) spectral range have not been observed yet. As an experimental step towards this goal we perform time-resolved FWM spectroscopy with femtosecond NIR and attosecond XUV pulses. The first two pulses (XUV-NIR) coincide in time and act as coherent excitation fields, while the third pulse (NIR) acts as a probe. As a first application we show how coupling dynamics between odd- and even-parity inner-valence excited states of neon can be revealed using a two-dimensional spectral representation. Experimentally obtained results are found to be in good agreement with ab initio time-dependent R-matrix calculations providing the full description of multi-electron interactions,...

  16. Superluminal reflection and transmission of light pulses via resonant four-wave mixing in cesium vapor.

    Science.gov (United States)

    Jiang, Qichang; Zhang, Yan; Wang, Dan; Ahrens, Sven; Zhang, Junxiang; Zhu, Shiyao

    2016-10-17

    We report the experimental manipulation of the group velocities of reflected and transmitted light pulses in a degenerate two-level atomic system driven by a standing wave, which is created by two counter-propagating light beams of equal frequencies but variable amplitudes. It is shown that the light pulse is reflected with superluminal group velocity while the transmitted pulse propagates from subluminal to superluminal velocities via changing the power of the backward coupling field. We find that the simultaneous superluminal light reflection and transmission can be reached when the power of the backward field becomes closer or equal to the forward power, in this case the periodical absorption modulation for photonic structure is established in atoms. The theoretical discussion shows that the anomalous dispersion associated with a resonant absorption dip within the gain peak due to four-wave mixing leads to the superluminal reflection, while the varying dispersion from normal to anomalous at transparency, transparency within absorption, and electromagnetically induced absorption windows leads to the subluminal to superluminal transmission.

  17. Highlighting short-lived excited electronic states with pump-degenerate-four-wave-mixing.

    Science.gov (United States)

    Marek, Marie S; Buckup, Tiago; Southall, June; Cogdell, Richard J; Motzkus, Marcus

    2013-08-21

    Detection of short-lived transient species is a major challenge in femtosecond spectroscopy, especially when third-order techniques like transient absorption are used. Higher order methods employ additional interactions between light and matter to highlight such transient species. In this work we address numerically and experimentally the detection of ultrafast species with pump-Degenerate Four Wave Mixing (pump-DFWM). In this respect, conclusive identification of ultrafast species requires the proper determination of time-zero between all four laser pulses (pump pulse and the DFWM sequence). This is addressed here under the light of experimental parameters as well as molecular properties: The role of pulse durations, amount of pulse chirp as well as excited state life time is investigated by measuring a row of natural pigments differing mainly in the number of conjugated double bonds (N = 9 to 13). A comparison of the different signals reveals a strikingly unusual behavior of spheroidene (N = 10). Complete analysis of the pump-DFWM signal illustrates the power of the method and clearly assigns the uniqueness of spheroidene to a mixing of the initially excited state with a dark excited electronic state.

  18. Measurement Induced Enhancement of Squeezing in Nondegenerate Two-Photon Jaynes-Cummings Model

    Institute of Scientific and Technical Information of China (English)

    YE Sai-Yun

    2006-01-01

    Squeezing properties in the nondegenerate two-photon Jaynes-Cummings model are investigated. The effects of direct selective atomic measurement and the application of the classical field followed by atomic measurement are analyzed. Different values of the parameters of the classical field are taken into account. It is found that the field squeezing can be enhanced by measurement.

  19. Detailed Characterization of Continuous-Wave and Pulsed-Pump Four-Wave Mixing in Nonlinear Fibers

    DEFF Research Database (Denmark)

    Lillieholm, Mads; Galili, Michael; Grüner-Nielsen, Lars;

    2016-01-01

    We explore the parametric gain differences for continuous-wave and pulse-pumped four-wave mixing, using various highly nonlinear fibers. Detailed simulations support our findings that the dispersion slope determines the experimentally observed differences, limiting the pulsed-pump performance....

  20. Nanoroughness localization of excitons in GaAs multiple quantum wells studied by transient four-wave mixing

    DEFF Research Database (Denmark)

    Birkedal, Dan; Vadim, Lyssenko; Pantke, Karl-Heinz

    1995-01-01

    The interface roughness on a nanometer scale plays a decisive role in dephasing of excitons in GaAs multiple quantum wells. The excitonic four-wave mixing signal shows a free polarization decay and a corresponding homogeneously broadened line from areas with interface roughness on a scale larger ...

  1. Transient and time-resolved four-wave mixing with collinear pump and probe pulses using the heterodyne technique

    DEFF Research Database (Denmark)

    Mecozzi, A.; Mørk, Jesper

    1998-01-01

    We review the recently proposed heterodyne technique for four-wave mixing experiments with collinear and co-polarized pulses. We discuss issues related to the parameters of the nonlinear dynamics of the sample that can be extracted by this technique....

  2. Efficiency of four-wave mixing between orthogonally polarized linear waves and solitons in a birefringent fiber

    Science.gov (United States)

    Mas Arabí, C.; Bessin, F.; Kudlinski, A.; Mussot, A.; Skryabin, D.; Conforti, M.

    2016-12-01

    We analyze the interaction between orthogonally polarized solitons and dispersive waves via four-wave mixing in a birefringent fiber. We calculate analytically the efficiency of the phase-sensitive scattering between orthogonally polarized solitons and dispersive waves. Experiments performed by using a photonic crystal fiber perfectly match the analytical predictions.

  3. Phase-sensitive Four-wave Mixing in AlGaAs-on-Insulator Nano-waveguides

    DEFF Research Database (Denmark)

    Da Ros, Francesco; Pu, Minhao; Ottaviano, Luisa

    2016-01-01

    Phase-sensitive four-wave mixing is experimentally demonstrated in a 5-mm long AlGaAsOI nano-waveguide. More than 7 dB of phase-sensitive extinction ratio are reported without neither using active biasing nor polarization-assisted schemes. Measurements show a good match with numerical predictions....

  4. Polarization-insensitive 640 Gb/s demultiplexing based on four wave mixing in a polarization-maintaining fibre loop

    DEFF Research Database (Denmark)

    Hu, Hao; Mulvad, Hans Christian Hansen; Galili, Michael

    2010-01-01

    Polarization-insensitive 640 Gbit/s demultiplexing for OTDM data signals is demonstrated using a 100 m polarization-maintaining highly non-linear fibre. The scheme is based on four wave mixing (FWM) in a polarization-maintaining fibre loop (PMFL) with bidirectional operation. Less than 0.2 d...

  5. Bragg-Scattering Four-Wave Mixing in Nonlinear Fibers with Intracavity Frequency-Shifted Laser Pumps

    Directory of Open Access Journals (Sweden)

    Katarzyna Krupa

    2012-01-01

    Full Text Available We experimentally study four-wave mixing in highly nonlinear fibers using two independent and partially coherent laser pumps and a third coherent signal. We focus our attention on the Bragg-scattering frequency conversion. The two pumps were obtained by amplifying two Intracavity frequency-shifted feedback lasers working in a continuous wave regime.

  6. Dynamic Interactions of CdSe/ZnS Quantum Dots with Cyclic Solvents Probed by Femtosecond Four-Wave Mixing

    Directory of Open Access Journals (Sweden)

    Biju V.

    2013-03-01

    Full Text Available We studied dynamic interactions between CdSe/ZnS quantum dots (QDs and cyclic solvents probed by femtosecond four-wave mixing. We found that the dynamic interactions of QDs strongly depend on the existence of π-bonds in solvent molecules.

  7. Longitudinal interplay between posttraumatic stress symptoms and coping self-efficacy : A four-wave prospective study

    NARCIS (Netherlands)

    Bosmans, M.W.G.; van der Velden, P.G.

    2015-01-01

    Trauma-related coping self-efficacy (CSE), the perceived capability to manage one's personal functioning and the myriad environmental demands of the aftermath of potentially traumatic events (PTE), has been shown to affect psychological outcomes after these events. Aim of the present four-wave study

  8. Study of inter-modal four wave mixing in two few-mode fibres with different phase matching properties

    DEFF Research Database (Denmark)

    Parmigiani, F.; Jung, Y.; Friis, Søren Michael Mørk

    2016-01-01

    We experimentally study inter-modal four-wave mixing (FWM) in few-mode fibres with different phase matching properties. The possibility of transmitting two spatial modes without intermodal FWM cross-talk in the C-band is presented....

  9. Novel Raman Parametric Hybrid L-Band Amplifier with Four-Wave Mixing Suppressed Pump for Terabits Dense Wavelength Division Multiplexed Systems

    Directory of Open Access Journals (Sweden)

    Gaganpreet Kaur

    2016-01-01

    Full Text Available We demonstrate improved performance of parametric amplifier cascaded with Raman amplifier for gain of 54.79 dB. We report amplification of L-band using 100 × 10 Gbps Dense Wavelength Division Multiplexed (DWDM system with 25 GHz channel spacing. The gain achieved is the highest reported so far with gain flatness of 3.38 dB without using any gain flattening technique. Hybrid modulated parametric pump is used for suppressing four-wave mixing (FWM around pump region, resulting in improvement of gain flatness by 2.42 dB. The peak to peak variation of gain is achieved less than 1.6 dB. DWDM system with 16-channel, 25 GHz spaced system has been analyzed thoroughly with hybrid modulated parametric pump amplified Raman-FOPA amplifier for gain flatness and improved performance in terms of BER and Q-factor.

  10. Diffractive optics based four-wave, six-wave, ..., nu-wave nonlinear spectroscopy.

    Science.gov (United States)

    Miller, R J Dwayne; Paarmann, Alexander; Prokhorenko, Valentyn I

    2009-09-15

    A detailed understanding of chemical processes requires information about both structure and dynamics. By definition, a reaction involves nonstationary states and is a dynamic process. Structure describes the atomic positions at global minima in the nuclear potential energy surface. Dynamics are related to the anharmonicities in this potential that couple different minima and lead to changes in atomic positions (reactions) and correlations. Studies of molecular dynamics can be configured to directly access information on the anharmonic interactions that lead to chemical reactions and are as central to chemistry as structural information. In this regard, nonlinear spectroscopies have distinct advantages over more conventional linear spectroscopies. Because of this potential, nonlinear spectroscopies could eventually attain a comparable level of importance for studying dynamics on the relevant time scales to barrier crossings and reactive processes as NMR has for determining structure. Despite this potential, nonlinear spectroscopy has not attained the same degree of utility as linear spectroscopy largely because nonlinear studies are more technically challenging. For example, unlike the linear spectrometers that exist in almost all chemistry departments, there are no "black box" four-wave mixing spectrometers. This Account describes recent advances in the application of diffractive optics (DOs) to nonlinear spectroscopy, which reduces the complexity level of this technology to be closer to that of linear spectroscopy. The combination of recent advances in femtosecond laser technology and this single optic approach could bring this form of spectroscopy out of the exclusive realm of specialists and into the general user community. However, the real driving force for this research is the pursuit of higher sensitivity limits, which would enable new forms of nonlinear spectroscopy. This Account chronicles the research that has now extended nonlinear spectroscopy to six

  11. Parastatistical Factors for Cascade Emission of a Pair of Paraparticles

    CERN Document Server

    Nelson, Charles A; Mera, Calvin S; Shapiro, Alanna M

    2013-01-01

    The empirical absence to date of particles obeying parastatistics in high energy collider experiments might be due to their large masses and lack of gauge couplings. If there is a portal to such particles, they might be cascade emitted as a pair of para-Majorana neutrinos or as a pair of scalar paraparticles. In this paper, for an assumed portal Lagrangian, the associated parastatistical factors are obtained for the case of order p=2 parastatistics and the, in general differing factors, for the cases of emission of a non-degenerate or a degenerate pair of particles which obey normal statistics.

  12. Learning Cascading

    CERN Document Server

    Covert, Michael

    2015-01-01

    This book is intended for software developers, system architects and analysts, big data project managers, and data scientists who wish to deploy big data solutions using the Cascading framework. You must have a basic understanding of the big data paradigm and should be familiar with Java development techniques.

  13. Efficient four-wave mixing by usage of resonances in mercury; Effizientes Vierwellenmischen durch Ausnutzen von Resonanzen in Quecksilber

    Energy Technology Data Exchange (ETDEWEB)

    Kolbe, Daniel

    2011-05-05

    A continuous, coherent radiation source in the vacuum ultraviolet spectral region is presented. It is based on four-wave-mixing in mercury vapor with fundamental beams at 253.7 nm, 407.9 nm und 545.5 nm wavelength. The fundamental beams are produced by frequency doubling and quadrupling of beams from solid-state laser-systems respectively. Due to the 6{sup 1}S-7{sup 1}S two-photon resonance and additionally the 6{sup 1}S-6{sup 3}P one-photon resonance the efficiency can be increased compared to former sources. A near one-photon resonance reduces the optimal phasematching temperature of the four-wave-mixing process. This leads to smaller Doppler and pressure broadening resulting in a higher four-wave-mixing efficiency. A maximum power of 0.3 nW at 121.56 nm wavelength, the 1S-2P Lyman-{alpha} transition in hydrogen, can be obtained. This Lyman-{alpha} source is needed for future laser cooling of antihydrogen. Apart from the Lyman-{alpha} generation, four-wave-mixing with a slightly different third fundamental wavelength results in radiation near a one-photon resonance in the VUV at the 6{sup 1}S-12{sup 1}P transition in mercury. Due to this additional one-photon resonance the nonlinear susceptibility, responsible for the four-wave-mixing, can be strongly increased without an influence on the phasematching. With such a mixing process the efficiency can be enlarged by three orders of magnitude and powers up to 6 {mu}W in the VUV could be realised. This is an improvement of a factor of 30 to former laser sources in this VUV regime. Furthermore the two-photon resonance of mercury could be investigated in detail. We observed a velocity-selective double resonance at small Rabi frequencies of the fundamental beams, which has the same origin as dark resonances in {lambda}-systems. At high Rabi frequencies excitation to the two-photon level can be high enough to initiate a laser process on the 7{sup 1}S-6{sup 1}P transition. This process could be observed with continuouswave

  14. Energy correlations of photon pairs generated by a silicon microring resonator probed by Stimulated Four Wave Mixing.

    Science.gov (United States)

    Grassani, Davide; Simbula, Angelica; Pirotta, Stefano; Galli, Matteo; Menotti, Matteo; Harris, Nicholas C; Baehr-Jones, Tom; Hochberg, Michael; Galland, Christophe; Liscidini, Marco; Bajoni, Daniele

    2016-04-01

    Compact silicon integrated devices, such as micro-ring resonators, have recently been demonstrated as efficient sources of quantum correlated photon pairs. The mass production of integrated devices demands the implementation of fast and reliable techniques to monitor the device performances. In the case of time-energy correlations, this is particularly challenging, as it requires high spectral resolution that is not currently achievable in coincidence measurements. Here we reconstruct the joint spectral density of photons pairs generated by spontaneous four-wave mixing in a silicon ring resonator by studying the corresponding stimulated process, namely stimulated four wave mixing. We show that this approach, featuring high spectral resolution and short measurement times, allows one to discriminate between nearly-uncorrelated and highly-correlated photon pairs.

  15. Broadband and efficient dual-pump four-wave-mixing in AlGaAs-on-insulator nano-waveguides

    DEFF Research Database (Denmark)

    Da Ros, Francesco; Pu, Minhao; Ottaviano, Luisa

    2016-01-01

    We characterize dual-pump four-wave-mixing in AlGaAs-on-insulator nano-waveguides and demonstrate an output conversion efficiency as high as −8.5 dB at 155-mW pump power. The idler optical signal-to-noise ratio is above 25 dB over a 26-nm bandwidth.......We characterize dual-pump four-wave-mixing in AlGaAs-on-insulator nano-waveguides and demonstrate an output conversion efficiency as high as −8.5 dB at 155-mW pump power. The idler optical signal-to-noise ratio is above 25 dB over a 26-nm bandwidth....

  16. Photon pair-state preparation with tailored spectral properties by spontaneous four-wave mixing in photonic-crystal fiber.

    Science.gov (United States)

    Garay-Palmett, K; McGuinness, H J; Cohen, Offir; Lundeen, J S; Rangel-Rojo, R; U'ren, A B; Raymer, M G; McKinstrie, C J; Radic, S; Walmsley, I A

    2007-10-29

    We study theoretically the generation of photon pairs by spontaneous four-wave mixing (SFWM) in photonic crystal optical fiber. We show that it is possible to engineer two-photon states with specific spectral correlation ("entanglement") properties suitable for quantum information processing applications. We focus on the case exhibiting no spectral correlations in the two-photon component of the state, which we call factorability, and which allows heralding of single-photon pure-state wave packets without the need for spectral post filtering. We show that spontaneous four wave mixing exhibits a remarkable flexibility, permitting a wider class of two-photon states, including ultra-broadband, highly-anticorrelated states.

  17. Design and optimization of highly nonlinear low-dispersion crystal fiber with high birefringence for four-wave mixing.

    Science.gov (United States)

    Zhang, Ya-Ni; Ren, Li-Yong; Gong, Yong-Kang; Li, Xiao-Hui; Wang, Lei-Ran; Sun, Chuan-Dong

    2010-06-01

    We have proposed a novel type of photonic crystal fiber (PCF) with low dispersion and high nonlinearity for four-wave mixing. This type of fiber is composed of a solid silica core and a cladding with a squeezed hexagonal lattice elliptical airhole along the fiber length. Its dispersion and nonlinearity coefficient are investigated simultaneously by using the full vectorial finite element method. Numerical results show that the proposed highly nonlinear low-dispersion fiber has a total dispersion as low as +/-2.5 ps nm(-1) km(-1) over an ultrabroad wavelength range from 1.43 to 1.8 microm, and the corresponding nonlinearity coefficient and birefringence are about 150 W(-1) km(-1) and 2.5x10(-3) at 1.55 microm, respectively. The proposed PCF with low ultraflattened dispersion, high nonlinearity, and high birefringence can have important application in four-wave mixing.

  18. Heterodyne pump-probe and four-wave mixing in semiconductor optical amplifiers using balanced lock-in detection

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang; Mørk, Jesper;

    1999-01-01

    We demonstrate a new detection scheme for pump-probe and four-wave mixing heterodyne experiments, using balanced detection and a dual-phase lock-in for spectral filtering. The technique allows the use of low repetition-rate laser systems, as is demonstrated on an InGaAsP/InP bulk optical amplifier...... at 1.53 mym. Ultrafast pump-induced changes in the amplitude and phase of the transmitted probe signal are simultaneously measured, going from small to large signal changes and with no need of an absolute phase calibration, showing the versatility and the sensitivity of this detection scheme....... The results for small perturbations are consistent with previous pump-probe experiments reported in literature. Time-resolved four-wave mixing in the absorption regime of the device is measured, and compared with numerical simulations, indicating a 100 fs dephasing time....

  19. Uni-directional wavelength conversion in silicon using four-wave mixing driven by cross-polarized pumps.

    Science.gov (United States)

    Bell, Bryn A; Xiong, Chunle; Marpaung, David; McKinstrie, Colin J; Eggleton, Benjamin J

    2017-05-01

    We demonstrate optical frequency conversion between telecom wavelengths using four-wave mixing Bragg scattering powered by two pump pulses polarized on orthogonal axes of a silicon waveguide. This allows conversion in a single frequency direction while, with co-polarized pumps, the signal is redshifted or blueshifted with similar efficiency. Our approach exploits the birefringence of the waveguide and its effect on the phase matching of the four-wave mixing process. The blue or red direction can be selected by the input polarization of the signal, and 20 dB extinction ratios are observed with the unintended direction. This technique will allow efficient and controlled conversion between specified wavelength channels in integrated photonic devices.

  20. Energy correlations of photon pairs generated by a silicon microring resonator probed by Stimulated Four Wave Mixing

    CERN Document Server

    Grassani, Davide; Pirotta, Stefano; Galli, Matteo; Menotti, Matteo; Harris, Nicholas C; Baehr-Jones, Tom; Hochberg, Michael; Galland, Christophe; Liscidini, Marco; Bajoni, Daniele

    2016-01-01

    Compact silicon integrated devices, such as micro-ring resonators, have recently been demonstrated as efficient sources of quantum correlated photon pairs. The mass production of integrated devices demands the implementation of fast and reliable techniques to monitor the device performances. In the case of time-energy correlations, this is particularly challenging, as it requires high spectral resolution that is not currently achievable in coincidence measurements. Here we reconstruct the joint spectral density of photons pairs generated by spontaneous four-wave mixing in a silicon ring resonator by studying the corresponding stimulated process, namely stimulated four wave mixing. We show that this approach, featuring high spectral resolution and short measurement times, allows one to discriminate between nearly-uncorrelated and highly-correlated photon pairs.

  1. Four-wave mixing parametric oscillation and frequency comb generation at visible wavelengths in a silica microbubble resonator.

    Science.gov (United States)

    Yang, Yong; Jiang, Xuefeng; Kasumie, Sho; Zhao, Guangming; Xu, Linhua; Ward, Jonathan M; Yang, Lan; Chormaic, Síle Nic

    2016-11-15

    Frequency comb generation in microresonators at visible wavelengths has found applications in a variety of areas such as metrology, sensing, and imaging. To achieve Kerr combs based on four-wave mixing in a microresonator, dispersion must be in the anomalous regime. In this Letter, we demonstrate dispersion engineering in a microbubble resonator (MBR) fabricated by a two-CO2 laser beam technique. By decreasing the wall thickness of the MBR to 1.4 μm, the zero dispersion wavelength shifts to values shorter than 764 nm, making phase matching possible around 765 nm. With the optical Q-factor of the MBR modes being greater than 107, four-wave mixing is observed at 765 nm for a pump power of 3 mW. By increasing the pump power, parametric oscillation is achieved, and a frequency comb with 14 comb lines is generated at visible wavelengths.

  2. Broadband and Efficient Dual-Pump Four-Wave Mixing in AlGaAs-On-Insulator Nano-Waveguide

    DEFF Research Database (Denmark)

    Da Ros, Francesco; Pu, Minhao; Ottaviano, Luisa

    2016-01-01

    We characterize dual-pump four-wave-mixing in AlGaAs-on-insulator nano-waveguides and demonstrate an output conversion efficiency as high as -8.5 dB at 155-mW pump power. The idler optical signal-to-noise ratio is above 25 dB over a 26-nm bandwidth.......We characterize dual-pump four-wave-mixing in AlGaAs-on-insulator nano-waveguides and demonstrate an output conversion efficiency as high as -8.5 dB at 155-mW pump power. The idler optical signal-to-noise ratio is above 25 dB over a 26-nm bandwidth....

  3. Broadband and efficient dual-pump four-wave-mixing in AlGaAs-on-insulator nano-waveguides

    DEFF Research Database (Denmark)

    Da Ros, Francesco; Pu, Minhao; Ottaviano, Luisa

    2016-01-01

    We characterize dual-pump four-wave-mixing in AlGaAs-on-insulator nano-waveguides and demonstrate an output conversion efficiency as high as −8.5 dB at 155-mW pump power. The idler optical signal-to-noise ratio is above 25 dB over a 26-nm bandwidth.......We characterize dual-pump four-wave-mixing in AlGaAs-on-insulator nano-waveguides and demonstrate an output conversion efficiency as high as −8.5 dB at 155-mW pump power. The idler optical signal-to-noise ratio is above 25 dB over a 26-nm bandwidth....

  4. Four-wave mixing parametric oscillation and frequency comb generation at visible wavelengths in a silica microbubble resonator

    CERN Document Server

    Yang, Yong; Kasumie, Sho; Zhao, Guangming; Xu, Linhua; Ward, Jonathan; Yang, Lan; Chormaic, Síle Nic

    2016-01-01

    Frequency comb generation in microresonators at visible wavelengths has found applications in a variety of areas such as metrology, sensing, and imaging. To achieve Kerr combs based on four-wave mixing in a microresonator, dispersion must be in the anomalous regime. In this work, we demonstrate dispersion engineering in a microbubble resonator (MBR) fabricated by a two-CO$_2$ laser beam technique. By decreasing the wall thickness of the MBR down to 1.4 $\\mu$m, the zero dispersion wavelength shifts to values shorter than 764 nm, making phase matching possible around 765 nm. With the optical \\textit{Q}-factor of the MBR modes being greater than $10^7$, four-wave mixing is observed at 765 nm for a pump power of 3 mW. By increasing the pump power, parametric oscillation is achieved, and a frequency comb with 14 comb lines is generated at visible wavelengths.

  5. Light non-degenerate composite partners at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Delaunay, Cédric [LAPTH, Université de Savoie, CNRS,B.P.110, F-74941 Annecy-le-Vieux (France); CERN Physics Department, Theory Division,CH-1211 Geneva 23 (Switzerland); Flacke, Thomas [Department of Physics, Korea Advanced Institute of Science and Technology,335 Gwahak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Gonzalez-Fraile, J. [Departament d’Estructura i Constituents de la Matèria and ICC-UB,Universitat de Barcelona, 647 Diagonal, E-08028 Barcelona (Spain); Lee, Seung J. [Department of Physics, Korea Advanced Institute of Science and Technology,335 Gwahak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); School of Physics, Korea Institute for Advanced Study,Seoul 130-722 (Korea, Republic of); Panico, Giuliano [CERN Physics Department, Theory Division,CH-1211 Geneva 23 (Switzerland); Perez, Gilad [CERN Physics Department, Theory Division,CH-1211 Geneva 23 (Switzerland); Department of Particle Physics and Astrophysics, Weizmann Institute of Science,Rehovot 76100 (Israel)

    2014-02-13

    new channels including cascade processes.

  6. Dual-dressed four-wave mixing and dressed six-wave mixing in a five-level atomic system

    Institute of Scientific and Technical Information of China (English)

    Cuicui Zuo; Yigang Du; Tong Jiang; Zhiqiang Nie; Yanpeng Zhang; Huaibin Zheng; Chenli Gan; Weifeng Zhang; Keqing Lu

    2008-01-01

    We study the co-existing four-wave mixing (FWM) process with two dressing fields and the six-wave mixing (SWM) process with one dressing field in a five-level system with carefully arranged laser beams. We also show two kinds of doubly dressing mechanisms in the FWM process. FWM and SWM signals propagatingalong the same direction compete with each other. With the properly controlled dressing fields, the FWM signals can be suppressed, while the SWM signals have been enhanced.

  7. Extinction ratio improvement by pump-modulated four-wave mixing in a dispersion-flattened nonlinear photonic crystal fiber.

    Science.gov (United States)

    Chow, K K; Shu, C; Lin, Chinlon; Bjarklev, A

    2005-10-31

    We demonstrate extinction ratio improvement by using pump-modulated four-wave mixing in a dispersion-flattened nonlinear photonic crystal fiber. A 6-dB improvement in the extinction ratio of a degraded return-to-zero signal has been achieved. A power penalty improvement of 3 dB at 10(-9) bit-error-rate level is obtained in the 10 Gb/s bit-error-rate measurements.

  8. Observation of parametric gain due to four-wave mixing in dispersion engineered GaInP photonic crystal waveguides.

    Science.gov (United States)

    Colman, Pierre; Cestier, Isabelle; Willinger, Amnon; Combrié, Sylvain; Lehoucq, Gaëlle; Eisenstein, Gadi; De Rossi, Alfredo

    2011-07-15

    We investigate four-wave mixing (FWM) in GaInP 1.5 mm long dispersion engineered photonic crystal waveguides. We demonstrate an 11 nm FWM bandwidth in the CW mode and a conversion efficiency of -24 dB in the quasi-CW mode. For picosecond pump and probe pulses, we report a 3 dB parametric gain and nearly a -5 dB conversion efficiency at watt-level peak pump powers.

  9. Non-perturbative four-wave mixing in InSb with intense off-resonant multi-THz pulses

    Directory of Open Access Journals (Sweden)

    Huber R.

    2013-03-01

    Full Text Available High-field multi-THz pulses are employed to analyze the coherent nonlinear response of the narrow-gap semiconductor InSb which is driven off-resonantly. Field-resolved four-wave mixing signals manifest the onset of a non-perturbative regime of Rabi flopping at external amplitudes above 5 MV/cm per pulse. Simulations based on a two-level quantum system confirm these experimental results.

  10. Phase conjugation of vector fields by degenerate four-wave mixing in a Fe-doped LiNbO₃.

    Science.gov (United States)

    Qian, Sheng-Xia; Li, Yongnan; Kong, Ling-Jun; Tu, Chenghou; Wang, Hui-Tian

    2014-08-15

    We propose a method to generate the phase-conjugate wave of the vector field by degenerate four-wave mixing in a c-cut Fe-doped LiNbO3 crystal. We demonstrate experimentally that the phase-conjugate wave of the vector field can be generated. In particular, the phase-conjugate vector field has also the peculiar function of compensating the polarization distortion, as the traditional phase-conjugate scaler field can compensate the phase distortion.

  11. High-Energy Four-Wave Mixing, with Large-Mode-Area Higher-Order Modes in Optical Fibres

    DEFF Research Database (Denmark)

    Rishøj, Lars Søgaard; Steinvurzel, P. E.; Chen, Y.;

    2012-01-01

    We demonstrate, for the first time, four-wave mixing, in the 1-μm spectral regime, in an LMA silica fiber. Pumping a 618-μm2 LP07 mode (λo = 1038.4 nm) with a 1064.6-nm Nd:YAG laser results in the generation of modulation instability, and multiple Stokes/anti-Stokes lines, opening up the prospect...

  12. Buffer gas-assisted four-wave mixing resonances in alkali vapor excited by a single cw laser

    Science.gov (United States)

    Shmavonyan, Svetlana; Khanbekyan, Aleksandr; Khanbekyan, Alen; Mariotti, Emilio; Papoyan, Aram V.

    2016-12-01

    We report the observation of a fluorescence peak appearing in dilute alkali (Rb, Cs) vapor in the presence of a buffer gas when the cw laser radiation frequency is tuned between the Doppler-broadened hyperfine transition groups of an atomic D2 line. Based on steep laser radiation intensity dependence above the threshold and spectral composition of the observed features corresponding to atomic resonance transitions, we have attributed these features to the buffer gas-assisted four-wave mixing process.

  13. Results of the four-wave kinetic integral computation for spectra of special forms. The case of Zakharov spectra

    CERN Document Server

    Polnikov, Vlad

    2014-01-01

    With the aim to show explicitly the non stationarity of the Zakharov spectra, obtained analytically as the stationary solution of the four-wave kinetic equation for stochastic nonlinear surface gravity waves[1,2], we have calculated directly the proper kinetic integral by means of two independent algorithms[3,4] both for an isotropic and anisotropic angular distribution of spectra given on the restricted frequency band.

  14. Lamb shift of non-degenerate energy level systems placed between two infinite parallel conducting plates

    CERN Document Server

    Billaud, B

    2012-01-01

    The issue of the observability of the Lamb shift in systems with non-degenerate energy levels is put to question. To this end, we compute the Lamb shift of such systems in the electromagnetic environment provided by two infinite parallel conducting plates, which is instrumental in demonstrating the existence of the so-called Casimir effect. A formula giving the relative change in the Lamb shift (as compared to the standard one in vacuum) is explicitly obtained for spherical semiconductor Quantum Dots (QD). It suggests a possibility of QD non-degenerate energy spectrum fine-tuning for experimental purposes as well as a {\\it Gedankenexperiment} to observe the Lamb shift in spherical semiconductor quantum dots.

  15. Convergence of formal invertible CR mappings between minimal holomorphically nondegenerate real analytic hypersurfaces

    Directory of Open Access Journals (Sweden)

    Joël Merker

    2001-01-01

    Full Text Available Recent advances in CR (Cauchy-Riemann geometry have raised interesting fine questions about the regularity of CR mappings between real analytic hypersurfaces. In analogy with the known optimal results about the algebraicity of holomorphic mappings between real algebraic sets, some statements about the optimal regularity of formal CR mappings between real analytic CR manifolds can be naturally conjectured. Concentrating on the hypersurface case, we show in this paper that a formal invertible CR mapping between two minimal holomorphically nondegenerate real analytic hypersurfaces in ℂn is convergent. The necessity of holomorphic nondegeneracy was known previously. Our technique is an adaptation of the inductional study of the jets of formal CR maps which was discovered by Baouendi-Ebenfelt-Rothschild. However, as the manifolds we consider are far from being finitely nondegenerate, we must consider some new conjugate reflection identities which appear to be crucial in the proof. The higher codimensional case will be studied in a forthcoming paper.

  16. Nondegenerate piecewise linear systems: a finite Newton algorithm and applications in machine learning.

    Science.gov (United States)

    Yuan, Xiao-Tong; Yan, Shuicheng

    2012-04-01

    We investigate Newton-type optimization methods for solving piecewise linear systems (PLSs) with nondegenerate coefficient matrix. Such systems arise, for example, from the numerical solution of linear complementarity problem, which is useful to model several learning and optimization problems. In this letter, we propose an effective damped Newton method, PLS-DN, to find the exact (up to machine precision) solution of nondegenerate PLSs. PLS-DN exhibits provable semiiterative property, that is, the algorithm converges globally to the exact solution in a finite number of iterations. The rate of convergence is shown to be at least linear before termination. We emphasize the applications of our method in modeling, from a novel perspective of PLSs, some statistical learning problems such as box-constrained least squares, elitist Lasso (Kowalski & Torreesani, 2008), and support vector machines (Cortes & Vapnik, 1995). Numerical results on synthetic and benchmark data sets are presented to demonstrate the effectiveness and efficiency of PLS-DN on these problems.

  17. Non-degenerate 2-photon excitation in scattering medium for fluorescence microscopy

    CERN Document Server

    Yang, Mu-Han; Saisan, Payam A; Tian, Peifang; Ferri, Christopher G L; AnnaDevor,; Fainman, Yeshaiahu

    2016-01-01

    Non-degenerate 2-photon excitation (ND-2PE) of a fluorophore with two laser beams of different photon energies offers an independent degree of freedom in tuning of the photon flux for each beam. This feature takes advantage of the infrared wavelengths used in 3-photon microscopy to achieve an increased penetration depth, while preserving a relatively high degenerate 2-photon excitation (D-2PE) cross section, exceeding that achievable with 3-photon excitation. Here, using spatially and temporally aligned Ti:Sapphire laser and optical parametric oscillator beams operating at near infrared (NIR) and short-wavelength infrared (SWIR) optical frequencies, respectively, we provide a practical demonstration that the emission intensity of a fluorophore excited in the non-degenerate regime in a scattering medium is more efficient than the commonly used D-2PE.

  18. Raman-noise induced quantum limits for $\\chi^{(3)}$ nondegenerate phase-sensitive amplification and quadrature squeezing

    CERN Document Server

    Voss, P L; Kumar, P; Voss, Paul L.; K\\"{o}pr\\"{u}l\\"{u}, Kahraman G.; Kumar, Prem

    2004-01-01

    We present a quantum theory of nondegenerate phase-sensitive parametric amplification in a $\\chi^{(3)}$ nonlinear medium. The non-zero response time of the Kerr $(\\chi^{(3)})$ nonlinearity determines the quantum-limited noise figure of $\\chi^{(3)}$ parametric amplification, as well as the limit on quadrature squeezing. This non-zero response time of the nonlinearity requires coupling of the parametric process to a molecular-vibration phonon bath, causing the addition of excess noise through spontaneous Raman scattering. We present analytical expressions for the quantum-limited noise figure of frequency non-degenerate and frequency degenerate $\\chi^{(3)}$ parametric amplifiers operated as phase-sensitive amplifiers. We also present results for frequency non-degenerate quadrature squeezing. We show that our non-degenerate squeezing theory agrees with the degenerate squeezing theory of Boivin and Shapiro as degeneracy is approached. We have also included the effect of linear loss on the phase-sensitive process.

  19. Experimental investigation of combined four-wave mixing and Raman effect in the normal dispersion regime of a photonic crystal fiber.

    Science.gov (United States)

    Kudlinski, A; Pureur, V; Bouwmans, G; Mussot, A

    2008-11-01

    We study the effect of stimulated Raman scattering on four-wave mixing sidebands generated by pumping in the normal dispersion regime of a photonic crystal fiber. Q-switch nanosecond pulses at 1064 nm are used to generate signal and idler wavelengths by degenerate four-wave mixing. These three waves generate their own Raman Stokes orders, leading to a broadband supercontinuum.

  20. The Husain-Kuchar Model Time Variables and Non-degenerate Metrics

    CERN Document Server

    Barbero, J F G; Tresguerres, R; Tiemblo, Alfredo; Treseguerres, Romualdo

    1998-01-01

    We study the Husain-Kuchar model by introducing a new action principle similar to the self-dual action used in the Ashtekar variables approach to Quantum Gravity. This new action has several interesting features; among them, the presence of a scalar time variable that allows the definition of geometric observables without adding new degrees of freedom, the appearance of a natural non-degenerate four-metric and the possibility of coupling ordinary matter.

  1. Analytical Study of Nonclassical Behaviour for a Disturbed Non-Degenerated Parameter Amplifier

    Institute of Scientific and Technical Information of China (English)

    PANG Qian-Jun

    2007-01-01

    We analytically discuss the nonclassical behaviour for a disturbed non-degenerated parameter amplifier.The thermal Glauber-Sudarshan diagonal presentation (GSP)function for the system is derived.The detailed analysis on the threshold temperatures of both the individual photon subsystem and the complete photon-photon complex is presented.The offect of the photon-photon interaction on the threshold temperature is observed.

  2. The SU(1, 1) Perelomov number coherent states and the non-degenerate parametric amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda-Guillén, D., E-mail: dojedag@ipn.mx; Granados, V. D. [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Ed. 9, Unidad Profesional Adolfo López Mateos, C.P. 07738 México D. F. (Mexico); Mota, R. D. [Escuela Superior de Ingeniería Mecánica y Eléctrica, Unidad Culhuacán, Instituto Politécnico Nacional, Av. Santa Ana No. 1000, Col. San Francisco Culhuacán, Delegación Coyoacán, C.P. 04430, México D. F. (Mexico)

    2014-04-15

    We construct the Perelomov number coherent states for an arbitrary su(1, 1) group operation and study some of their properties. We introduce three operators which act on Perelomov number coherent states and close the su(1, 1) Lie algebra. By using the tilting transformation we apply our results to obtain the energy spectrum and eigenfunctions of the non-degenerate parametric amplifier. We show that these eigenfunctions are the Perelomov number coherent states of the two-dimensional harmonic oscillator.

  3. From non-degenerate conducting polymers to dense matter in the massive Gross-Neveu model

    CERN Document Server

    Thies, M; Thies, Michael; Urlichs, Konrad

    2005-01-01

    Using results from the theory of non-degenerate conducting polymers like cis-polyacetylene, we generalize our previous work on baryonic matter in the massless Gross-Neveu model to finite bare fermion mass. In the large N limit, the exact ground state is constructed analytically, in close analogy to the bipolaron lattice in polymers. These findings are contrasted to the standard scenario with a first order phase transition as a function of density.

  4. Enhancement of Two-photon Absorption in Quantum Wells for Extremely Nondegenerate Photon Pairs

    CERN Document Server

    Pattanaik, Himansu S; Khurgin, Jacob B; Hagan, David J; Van Stryland, Eric W

    2015-01-01

    We recently demonstrated orders of magnitude enhancement of two-photon absorption (2PA) in direct gap semiconductors due to intermediate state resonance enhancement for photons of very different energies. It can be expected that further enhancement of nondegenerate 2PA will be observed in quantum wells (QWs) since the intraband matrix elements do not vanish near the band center as they do in the bulk, and the density of states in QWs is larger near the band edge. Here we present a perturbation-theory based theoretical description of nondegenerate 2PA in semiconductor QWs, where both frequency and polarization of two incident waves can vary independently. Analytical expressions for all possible permutations of frequencies and polarizations have been obtained, and the results are compared with degenerate 2PA in quantum wells along with degenerate and nondegenerate 2PA in bulk semiconductors. We show that using QWs in place of bulk semiconductors with both beams in the TM-polarized mode leads to an additional or...

  5. Non-degenerate 2-photon excitation for fluorescence microscopy in scattering medium (Conference Presentation)

    Science.gov (United States)

    Fainman, Yeshaiahu; Yang, Mu-Han; Abashin, Maxim; Saisan, Payam; Tian, Peifang; Ferri, Christopher; Devor, Anna

    2016-10-01

    Non-degenerate 2-photon excitation of a fluorophore with two laser beams of different photon energies may offer independent degree of freedom in tuning of the photon flux (i.e., the power) for each beam. Wereport a practical demonstration that the emission intensity of a fluorophore excited in the non-degenerate regime in scattering medium is more efficient than the commonly used degenerate 2-photon excitation. In our experiments we use spatially and temporally aligned Ti:Sapphiremode-locked laser and optical parametric oscillator beams operating at near infrared (NIR) and short-wavelength infrared (SWIR) optical frequencies, respectively. The non-degenerate 2-photon excitation mechanism takes advantage of the infrared wavelengths used in 3-photon microscopy to achieve increased penetration depth, while preserving relatively high 2-photon excitation cross section, exceeding that achievable with the 3-photon excitation. Importantly, independent control of power for each beam implies that the flux requirement for the higher photon energy NIR beam, which experiences higher scattering in biological tissue, can be relaxed at the expense of increasing the flux of the lower photon energy SWIR beam which experiences lower scattering, thus promising deeper penetration with higher efficiency of excitation.Applications for in vivo brain imaging will be also discussed.

  6. Cascading Cosmology

    CERN Document Server

    Agarwal, Nishant; Khoury, Justin; Trodden, Mark

    2009-01-01

    We develop a fully covariant, well-posed 5D effective action for the 6D cascading gravity brane-world model, and use this to study cosmological solutions. We obtain this effective action through the 6D decoupling limit, in which an additional scalar degree mode, \\pi, called the brane-bending mode, determines the bulk-brane gravitational interaction. The 5D action obtained this way inherits from the sixth dimension an extra \\pi self-interaction kinetic term. We compute appropriate boundary terms, to supplement the 5D action, and hence derive fully covariant junction conditions and the 5D Einstein field equations. Using these, we derive the cosmological evolution induced on a 3-brane moving in a static bulk. We study the strong- and weak-coupling regimes analytically in this static ansatz, and perform a complete numerical analysis of our solution. Although the cascading model can generate an accelerating solution in which the \\pi field comes to dominate at late times, the presence of a critical singularity prev...

  7. Upconversion enhanced degenerate four-wave mixing in the mid-infrared for sensitive detection of acetylene in gas flows

    DEFF Research Database (Denmark)

    Høgstedt, Lasse; Dam, Jeppe Seidelin; Sahlberg, Anna-Lena;

    2014-01-01

    We present a new background free method for in situ gas detection that combines degenerate four-wave mixing with an infra-red light detector based on parametric frequency upconversion of infra-red light. The system is demonstrated at mid infrared wavelengths for low concentration measurements...... of acetylene diluted in a N2 gas flow at ambient conditions. It is demonstrated that the system is able to cover more than 100 nm in scanning range and detect concentrations as low as 3 ppm based on the R9e line. A major issue in small signal measurements is scattered light and it is showed how a spatial...

  8. Highly sensitive and simple method for refractive index sensing of liquids in microstructured optical fibers using four-wave mixing

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch; Stefani, Alessio; Bang, Ole

    2011-01-01

    We present both experimental measurements and simulations for a simple fiber-optical liquid refractive index sensor, made using only commercially available components and without advanced postprocessing of the fiber. Despite the simplicity, we obtain the highest sensitivity experimentally...... demonstrated to date for aqueous solutions (refractive index around 1.33), which is relevant for extensions to biosensing. The sensor is based on measuring the spectral shift of peaks arising from four-wave mixing (FWM), when filling the holes of a microstructured fiber with different liquid samples...

  9. Stimulated emission pumping of NH in flames by using two-color resonant four-wave mixing

    Energy Technology Data Exchange (ETDEWEB)

    Radi, P.P.; Frey, H.M.; Mischler, B.; Tzannis, A.P.; Beaud, P.; Gerber, T. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    In this work we examine the analytical potential of two-color resonant four-wave mixing for the determination and characterization of trace elements in a combustion environment. Experimental results for NH in flames at atmospheric pressure are presented. The selectivity of the technique is used to simplify the Q-branch region of the (0-0)A{sup 3}{Pi}-X{sup 3}{Sigma} vibronic transition of NH. In addition, we demonstrate that the technique is sensitive to state changing collisions. (author) 2 figs., 5 refs.

  10. Time domain switching/demultiplexing using four wave mixing in GaInP photonic crystal waveguides.

    Science.gov (United States)

    Cestier, I; Willinger, A; Eckhouse, V; Eisenstein, G; Combrié, S; Colman, P; Lehoucq, G; De Rossi, A

    2011-03-28

    We describe dynamical four wave mixing (FWM) functionalities of an GaInP photonic crystal waveguide. A W1 waveguide was used to wavelength convert 100 ps pulses and for sampling a 10.56 Gbit/s data stream so as to time demultiplex it into 16 or 32 channels. In all cases, the extracted pulses at the idler wavelength are undistorted and have a high signal to noise ratio proving the high efficiency and the versatility of the FWM process in the GaInP PhC waveguides we used.

  11. Depolarization technique for wavelength conversion using four-wave mixing in a dispersion-flattened photonic crystal fiber.

    Science.gov (United States)

    Yang, Taotao; Shu, Chester; Lin, Chinlon

    2005-07-11

    We have developed a depolarization technique to achieve polarization-insensitive wavelength conversion using four-wave mixing in an optical fiber. A maximum conversion efficiency of -11.79 dB was achieved over a 3 dB bandwidth of 26 nm in a 100-m-long dispersion-flattened photonic crystal fiber. The polarization-dependent conversion efficiency was less than 0.38 dB and the measured power penalty for a 10 Gbit/s NRZ signal was 1.9 dB. The relation between the conversion efficiency and the degree of polarization of the pump was also formulated.

  12. Aberration-free ultra-fast optical oscilloscope using a four-wave mixing based time-lens

    Science.gov (United States)

    Schröder, Jochen; Wang, Fan; Clarke, Aisling; Ryckeboer, Eva; Pelusi, Mark; Roelens, Michaël A. F.; Eggleton, Benjamin J.

    2010-06-01

    We demonstrate an aberration-free, all-optical, ultra-fast oscilloscope based on the concept of Fourier-transformation with an optical time-lens. By combining the four-wave mixing time-lens with a Fourier-domain optical processor as the dispersive element we avoid aberrations associated with the traditional method of using lengths of fibre for the dispersive elements. We investigate the impact of aberrations due to third-order dispersion and inaccuracies in matching the Fourier-transform condition and demonstrate how these are overcome using the optical processor. The resolution of the oscilloscope is 750 fs.

  13. Four-Wave Mixing of a Laser and Its Frequency-Doubled Version in a Multimode Optical Fiber

    Directory of Open Access Journals (Sweden)

    Hamed Pourbeyram

    2015-08-01

    Full Text Available It is shown that it is possible to couple a laser beam and its frequency-doubled daughter into a multimode optical fiber through the four-wave mixing nonlinear process and generate a new wavelength. The frequency-doubled daughter can be generated in an external crystal with a large second order nonlinearity. It is argued that while this possibility is within the design parameter range of conventional multimode optical fibers, it necessitates a lower-bound for the core-cladding refractive index contrast of the multimode optical fiber.

  14. Optimisation of amplitude limiters for phase preservation based on the exact solution to degenerate four-wave mixing.

    Science.gov (United States)

    Bottrill, K R H; Hesketh, G; Parmigiani, F; Richardson, D J; Petropoulos, P

    2016-02-08

    Adopting an exact solution to four-wave mixing (FWM), wherein harmonic evolution is described by the sum of two Bessel functions, we identify two causes of amplitude to phase noise conversion which impair FWM saturation based amplitude regenerators: self-phase modulation (SPM) and Bessel-order mixing (BOM). By increasing the pump to signal power ratio, we may arbitrarily reduce their impact, realising a phase preserving amplitude regenerator. We demonstrate the technique by applying it to the regeneration of a 10 GBaud QPSK signal, achieving a high level of amplitude squeezing with minimal amplitude to phase noise conversion.

  15. Low-power continuous-wave four-wave mixing wavelength conversion in AlGaAs-nanowaveguide microresonators.

    Science.gov (United States)

    Kultavewuti, Pisek; Pusino, Vincenzo; Sorel, Marc; Stewart Aitchison, J

    2015-07-01

    We experimentally demonstrate enhanced wavelength conversion in a Q∼7500 deeply etched AlGaAs-nanowaveguide microresonator via degenerate continuous-wave four-wave mixing with a pump power of 24 mW. The maximum conversion efficiency is -43  dB and accounts for 12 dB enhancement compared to that of a straight nanowaveguide. The experimental results and theoretical predictions agree very well and show optimized conversion efficiency of -15  dB. This work represents a step toward realizing a fully integrated optical devices for generating new optical frequencies.

  16. Efficient continuous-wave four-wave mixing in bandgap-engineered AlGaAs waveguides.

    Science.gov (United States)

    Wathen, Jeremiah J; Apiratikul, Paveen; Richardson, Christopher J K; Porkolab, Gyorgy A; Carter, Gary M; Murphy, Thomas E

    2014-06-01

    We present a side-by-side comparison of the nonlinear behavior of four passive AlGaAs ridge waveguides where the bandgap energy of the core layers ranges from 1.60 to 1.79 eV. By engineering the bandgap to suppress two-photon absorption, minimizing the linear loss, and minimizing the mode area, we achieve efficient wavelength conversion in the C-band via partially degenerate four-wave mixing with a continuous-wave pump. The observed conversion efficiency [Idler(OUT)/Signal(IN)=-6.8  dB] is among the highest reported in passive semiconductor or glass waveguides.

  17. High-speed all-optical NAND/AND logic gates using four-wave mixing Bragg scattering.

    Science.gov (United States)

    Li, Kangmei; Ting, Hong-Fu; Foster, Mark A; Foster, Amy C

    2016-07-15

    A high-speed all-optical NAND logic gate is proposed and experimentally demonstrated using four-wave mixing Bragg scattering in highly nonlinear fiber. NAND/AND logic functions are implemented at two wavelengths by encoding logic inputs on two pumps via on-off keying. A 15.2-dB depletion of the signal is obtained for NAND operation, and time domain measurements show 10-Gb/s NAND/AND logic operations with open eye diagrams. The approach can be readily extended to higher data rates and transferred to on-chip waveguide platforms.

  18. Low-power continuous-wave four-wave mixing wavelength conversion in AlGaAs-nanowaveguide microresonators

    CERN Document Server

    Kultavewuti, Pisek; Sorel, Marc; Aitchison, J Stewart

    2016-01-01

    We experimentally demonstrate enhanced wavelength conversion in a Q=7500 deeply etched AlGaAs-nanowaveguide microresonator via degenerate continuous-wave four-wave mixing with a pump power of 24 mW. The maximum conversion efficiency is -43 dB and accounts for 12 dB enhancement compared to that of a straight nanowaveguide. The experimental results and theoretical predictions agree very well and show optimized conversion efficiency of -15 dB. This work represents a step toward realizing a fully integrated optical devices for generating new optical frequencies.

  19. Toward the Extreme Ultra Violet Four Wave Mixing Experiments: From Table Top Lasers to Fourth Generation Light Sources

    Directory of Open Access Journals (Sweden)

    Riccardo Cucini

    2015-01-01

    Full Text Available Three different Transient Grating setups are presented, with pulsed and continuous wave probe at different wavelengths, ranging from infrared to the extreme ultra violet region. Both heterodyne and homodyne detections are considered. Each scheme introduces variations with respect to the previous one, allowing moving from classical table top laser experiments towards a new four wave mixing scheme based on free electron laser radiation. A comparison between the various setups and the first results from extreme ultra violet transient grating experiments is also discussed.

  20. High-Frequency Einstein-Podolsky-Rosen Entanglement via Atomic Memory Effects in Four-Wave Mixing

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xue-Hua; HU Xiang-Ming; KONG Ling-Feng; ZHANG Xiu

    2010-01-01

    @@ Atomic memory effects occur when the atomic relaxation times are comparable to or much longer than the cavity relaxation times.We show that by using the memory effects,it is possible to obtain high-frequency Einstein-Podolsky-Rosen entanglement between a pair of Stokes and anti-Stokes fields in a four-wave mixing system.The physical origin is traced to the dynamical Stark splittings of dressed states due to the parametrically amplified fields.This mechanism provides an alternative and efficient way for sideband entanglement.

  1. Bit rate and pulse width dependence of four-wave mixing of short optical pulses in semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Diez, S.; Mecozzi, A.; Mørk, Jesper

    1999-01-01

    We investigate the saturation properties of four-wave mixing of short optical pulses in a semiconductor optical amplifier. By varying the gain of the optical amplifier, we find a strong dependence of both conversion efficiency and signal-to-background ratio on pulse width and bit rate....... In particular, the signal-to-background ratio can be optimized for a specific amplifier gain. This behavior, which is coherently described in experiment and theory, is attributed to the dynamics of the amplified spontaneous emission, which is the main source of noise in a semiconductor optical amplifier....

  2. Four-Wave Mixing Scheme in a Four-Level Ladder-Type Atomic System Based on Electromagnetically Induced Transparency

    Institute of Scientific and Technical Information of China (English)

    LI Jia-Hua; CHEN Ai-Xi; PENG Ju-Cun

    2004-01-01

    @@ A nonlinear optical four-wave mixing scheme is presented and analysed for the generation of coherent light in a nearly four-level ladder-type atomic system in the context of electromagnetically induced transparency (EIT).We find that EIT can suppress nonlinear photon absorption and the peak of the generated mixing field is located at the centre of the transparency window where the loss is minimal, though there is a dip in the centre. Such a nonlinear optical process can also be used for generating coherent short-wavelength radiation.

  3. Polarization properties of coherent VUV light at 125 nm generated by sum-frequency four-wave mixing in mercury

    Science.gov (United States)

    Museur, L.; Olivero, C.; Riedel, D.; Castex, M. C.

    The polarization of the VUV light generated by four-wave sum-frequency mixing process ω4=2ω1+ω2 in mercury vapor at room temperature is analyzed in detail. Due to the specific two-photon transition used to enhance the nonlinear process, the polarization of the VUV wave is shown to be identical to the polarization of the wave at the frequency ω2. In particular, circularly polarized VUV is observed with degree of circular polarization exceeding 0.99.

  4. Narrowband Biphoton Generation with Four-Wave Mixing in a Far-Detuning Three-Level System

    Institute of Scientific and Technical Information of China (English)

    CHEN Peng; ZHOU Shu-Yu; XU Zhen; DUAN Ya-Fan; CUI Guo-Dong; HONG Tao; WANG Yu-Zhu

    2011-01-01

    Non-classical paired photons are generated by a four-wave mixing process in a far-detuning three-level system with cold atoms.A violation of the Cauchy-Schwartz inequality of a factor of 310 is observed.This phenomenon shows that paired photons have a non-classical correlation. The experimental results are compared with theoretical results obtained using perturbation theory.The oscillation frequencies of the two-photon intensity correlation functions are in reasonable agreement with the effective Rabi frequencies of the coupling laser.However,we find that the dephasing rates (or decay rates) observed are far larger than the theoretical values.

  5. Sensitivity to Dark Energy candidates by searching for four-wave mixing of high-intensity lasers in the vacuum

    CERN Document Server

    Homma, Kensuke

    2012-01-01

    Theoretical challenges to understand Dark Matter and Dark Energy suggest the existence of low-mass and weakly coupling fields in the universe. The quasi-parallel photon-photon collision system (QPS) can provide chances to probe the resonant production of these light dark fields and the induced decay by the coherent nature of laser fields simultaneously. By focusing high-intensity lasers with different colors in the vacuum, new colors emerge as the signature of the interaction. Because four photons in the initial and final states interplay via the dark field exchange, this process is analogous to four-wave mixing in quantum optics, where the frequency sum and difference among the incident three waves generate the fourth wave with a new frequency via the nonlinear property of crystals. The interaction rate of the four-wave mixing process has the cubic dependence on the intensity of each wave. Therefore, if high-intensity laser fields are given, the sensitivity to the weakly coupling of dark fields to photons ra...

  6. Kinetic Temperature and Electron Density Measurement in an Inductively Coupled Plasma Torch using Degenerate Four-Wave Mixing

    Science.gov (United States)

    Schafer, Julia; Lyons, Wendy; Tong, WIlliam G.; Danehy, Paul M.

    2008-01-01

    Laser wave mixing is presented as an effective technique for spatially resolved kinetic temperature measurements in an atmospheric-pressure radio-frequency inductively-coupled plasma. Measurements are performed in a 1 kW, 27 MHz RF plasma using a continuous-wave, tunable 811.5-nm diode laser to excite the 4s(sup 3)P2 approaches 4p(sup 3)D3 argon transition. Kinetic temperature measurements are made at five radial steps from the center of the torch and at four different torch heights. The kinetic temperature is determined by measuring simultaneously the line shape of the sub-Doppler backward phase-conjugate degenerate four-wave mixing and the Doppler-broadened forward-scattering degenerate four-wave mixing. The temperature measurements result in a range of 3,500 to 14,000 K+/-150 K. Electron densities measured range from 6.1 (+/-0.3) x 10(exp 15)/cu cm to 10.1 (+/-0.3) x 10(exp 15)/cu cm. The experimental spectra are analyzed using a perturbative treatment of the backward phase-conjugate and forward-geometry wave-mixing theory. Stark width is determined from the collisional broadening measured in the phase-conjugate geometry. Electron density measurements are made based on the Stark width. The kinetic temperature of the plasma was found to be more than halved by adding deionized water through the nebulizer.

  7. Optical micro-spectroscopy of single metallic nanoparticles: quantitative extinction and transient resonant four-wave mixing.

    Science.gov (United States)

    Payne, Lukas; Zoriniants, George; Masia, Francesco; Arkill, Kenton P; Verkade, Paul; Rowles, Darren; Langbein, Wolfgang; Borri, Paola

    2015-01-01

    We report a wide-field imaging method to rapidly and quantitatively measure the optical extinction cross-section σ(ext) (also polarisation resolved) of a large number of individual gold nanoparticles, for statistically-relevant single particle analysis. We demonstrate a sensitivity of 5 nm(2) in σ(ext), enabling detection of single 5 nm gold nanoparticles with total acquisition times in the 1 min range. Moreover, we have developed an analytical model of the polarisation resolved σ(ext), which enabled us to extract geometrical particle aspect ratios from the measured σ(ext). Using this method, we have characterized a large number of nominally-spherical gold nanoparticles in the 10-100 nm size range. Furthermore, the method provided measurements of in-house fabricated nanoparticle conjugates, allowing distinction of individual dimers from single particles and larger aggregates. The same particle conjugates were investigated correlatively by phase-resolved transient resonant four-wave mixing micro-spectroscopy. A direct comparison of the phase-resolved response between single gold nanoparticles and dimers highlighted the promise of the four-wave mixing technique for sensing applications with dimers as plasmon rulers.

  8. Tunable, multiwavelength Tm-doped fiber laser based on polarization rotation and four-wave-mixing effect.

    Science.gov (United States)

    Wang, Xiong; Zhu, Yadong; Zhou, Pu; Wang, Xiaolin; Xiao, Hu; Si, Lei

    2013-11-04

    We propose and demonstrate a tunable multiwavelength fiber laser employing polarization-maintaining Tm-doped fiber based on polarization rotation and four-wave-mixing effect. Polarization-maintaining Tm-doped fiber and polarization controllers were employed to manipulate the polarization modes in the laser, and 400 m long single-mode passive fiber was used to enhance the four-wave-mixing effect and suppress the polarization mode competition. Stable fiber laser operation of 1-6 wavelengths around 1.9 μm was achieved at room temperatures. The wavelengths can be tuned through adjusting the polarization controllers. The optical signal-to-noise ratio of the laser is more than 31 dB. The wavelength shift is less than 0.05 nm and the peak fluctuation of each wavelength is analyzed. For most of the wavelengths the peak fluctuations are less than 3 dB and the peak fluctuations of wavelengths with more stability are below 1.5 dB.

  9. Photon-pair generation by intermodal spontaneous four-wave mixing in birefringent, weakly guiding optical fibers

    Science.gov (United States)

    Garay-Palmett, K.; Cruz-Delgado, D.; Dominguez-Serna, F.; Ortiz-Ricardo, E.; Monroy-Ruz, J.; Cruz-Ramirez, H.; Ramirez-Alarcon, R.; U'Ren, A. B.

    2016-03-01

    We present a theoretical and experimental study of the generation of photon pairs through the process of spontaneous four-wave mixing (SFWM) in a few-mode, birefringent fiber. Under these conditions, multiple SFWM processes are in fact possible, each associated with a different combination of transverse modes for the four waves involved. We show that in the weakly guiding regime, for which the propagation modes may be well approximated by linearly polarized modes, the departure from circular symmetry due to the fiber birefringence translates into conservation rules, which retain elements from azimuthal and rectangular symmetries: both OAM and parity must be conserved for a process to be viable. We have implemented a SFWM source based on a bowtie birefringent fiber, and have measured for a collection of pump wavelengths the SFWM spectra of each of the signal and idler photons in coincidence with its partner photon. We have used this information, together with knowledge of the transverse modes into which the signal and idler photons are emitted, as input for a genetic algorithm, which accomplishes two tasks: (i) the identification of the particular SFWM processes that are present in the source, and (ii) the characterization of the fiber used.

  10. Multi-wavelength erbium-doped fiber laser using four-wave mixing effect in doped fiber

    Institute of Scientific and Technical Information of China (English)

    N.S.Shahabuddin; Z.Yusoff; H.Ahmad; S.W.Harun

    2011-01-01

    @@ We demonstrate a multi-wavelength erbium-doped fiber laser (EDFL) using erbium gain and four-wave mixing (FWM) effect in a piece of erbium-doped fiber (EDF) with high erbium ion concentration.The EDF has a pump absorption rate of 24.6 dB/m at 979 nm and is bi-directionally pumped by 980-nm laser diodes.FWM effect redistributes the energy of different oscillating lines and causes multi-wavelength operation.The laser generates more than 22 lines of optical comb with a line spacing of approximately 0.10 nm at the 1569-nm region using only 1.5-m-long EDF.%We demonstrate a multi wavelength erbium-doped fiber laser (EDFL) using erbium gain and four-wave mixing (FWM) effect in a piece of erbium-doped fiber (EDF) with high erbium ion concentration The EDF has a pump absorption rate of 24 6 dB/m at 979 nm and is bi-directionally pnmped by 980-nm laser diodes FWM effect redistributes the energy of different oscillating lines and causes multi-wavelength operation The laser generates more than 22 lines of optical comb with a line spacing of approximately 0.10 nm at the 1569-nm region using only 1.5-m-long EDF.

  11. Tunable coupled-mode dispersion compensation and its application to on-chip resonant four-wave mixing

    CERN Document Server

    Gentry, Cale M; Popovic, Milos A

    2014-01-01

    We propose and demonstrate localized mode coupling as a viable dispersion engineering technique for phase-matched resonant four-wave mixing (FWM). We demonstrate a dual-cavity resonant structure that employs coupling-induced frequency splitting at one of three resonances to compensate for cavity dispersion, enabling phase-matching. Coupling strength is controlled by thermal tuning of one cavity enabling active control of the resonant frequency-matching. In a fabricated silicon microresonator, we show an 8 dB enhancement of seeded FWM efficiency over the non-compensated state. The measured four-wave mixing has a peak wavelength conversion efficiency of -37.9 dB across a free spectral range (FSR) of 3.334 THz ($\\sim$27 nm). Enabled by strong counteraction of dispersion, this FSR is, to our knowledge, the largest in silicon to demonstrate FWM to date. This form of mode-coupling-based, active dispersion compensation can be beneficial for many FWM-based devices including wavelength converters, parametric amplifier...

  12. Phase Coupling in Langmuir Wave Packets: Evidence for Four Wave Interactions in Solar Type III Radio Bursts

    Science.gov (United States)

    Thejappa, G.; MacDowall, R. J.; Bergamo, M.

    2012-01-01

    The four wave interaction process, known as the oscillating two stream instability (OTSI) is considered as one of the mechanisms responsible for stabilizing the electron beams associated with solar type III radio bursts. It has been reported that (1) an intense localized Langmuir wave packet associated with a type III burst contains the spectral characteristics of the OTSI: (a) a resonant peak at the local electron plasma frequency, f(sub pe), (b) a Stokes peak at a frequency slightly lower than f(sub pe), (c) anti-Stokes peak at a frequency slightly higher than f(sub pe), and (d) a low frequency enhancement below a few hundred Hz, (2) the frequencies and wave numbers of these spectral components satisfy the resonance conditions of the OTSI, and (3) the peak intensity of the wave packet is well above the thresholds for the OTSI as well as spatial collapse of envelope solitons. Here, for the first time, applying the trispectral analysis on this wave packet, we show that the tricoherence, which measures the degree of coherent four-wave coupling amongst the observed spectral components exhibits a peak. This provides an additional evidence for the OTSI and related spatial collapse of Langmuir envelope solitons in type III burst sources.

  13. Electromagnetically induced absorption in a non-degenerate three-level ladder system

    CERN Document Server

    Whiting, Daniel J; Keaveney, James; Zentile, Mark A; Adams, Charles S; Hughes, Ifan G

    2015-01-01

    We investigate, theoretically and experimentally, the transmission of light through a thermal vapour of three-level ladder-type atoms, in the presence of 2 counter-propagating control fields. A simple theoretical model predicts the presence of electromagnetically induced absorption (EIA) in this pure three-level system when the control field is resonant. Experimentally, we use $^{87}$Rb in a large magnetic field of 0.62~T to reach the hyperfine Paschen-Back regime and realise a non-degenerate three-level system. Experimental observations verify the predictions over a wide range of detunings.

  14. Dicke-Narrowing Spectroscopy of Doubly Dressed Electromagnetically Induced Transparency and Singly Dressed Four-Wave-Mixing in a Confined Atomic System

    Institute of Scientific and Technical Information of China (English)

    LI Yuan-Yuan; BAI Jin-Wao; LI-Li; ZHANG Wei-Feng; LI Chang-Biao; NIE Zhi-Qiang; GAN Chen-Li; ZHANG Yan-Peng

    2008-01-01

    Dicke-narrowing effect appears both in doubly dressed electromagnetically induced transparency and singly dressed four-wave-mixing lines due to the contribution of slow atoms resulting from de-excited effects of atom-wall collision and transient behaviour of atoms in a confined system. A robust recipe for high resolution spectroscopy of electromagnetically induced transparency dressed by two fields and four-wave-mixing lines comparable with the cold atoms is achievable in a thin vapour cell in experiments.

  15. Quantum Cascade Laser Frequency Combs

    CERN Document Server

    Faist, Jérôme; Scalari, Giacomo; Rösch, Markus; Bonzon, Christopher; Hugi, Andreas; Beck, Mattias

    2015-01-01

    It was recently demonstrated that broadband quantum cascade lasers can operate as frequency combs. As such, they operate under direct electrical pumping at both mid-infrared and THz frequencies, making them very attractive for dual-comb spectroscopy. Performance levels are continuously improving, with average powers over 100 mW and frequency coverage of 100 cm$^{-1}$ in the mid-infrared. In the THz range, 10 mW of average power and 600 GHz of frequency coverage are reported. As a result of the very short upper state lifetime of the gain medium, the mode proliferation in these sources arises from four wave mixing rather than saturable absorption. As a result, their optical output is characterized by the tendency of small intensity modulation of the output power, and the relative phases of the modes to be similar to the ones of a frequency modulated laser. Recent results include the proof of comb operation down to a metrological level, the observation of a Schawlow-Townes broadened linewidth, as well as the fir...

  16. Quantum Cascade Laser Frequency Combs

    Directory of Open Access Journals (Sweden)

    Faist Jérôme

    2016-06-01

    Full Text Available It was recently demonstrated that broadband quantum cascade lasers can operate as frequency combs. As such, they operate under direct electrical pumping at both mid-infrared and THz frequencies, making them very attractive for dual-comb spectroscopy. Performance levels are continuously improving, with average powers over 100mW and frequency coverage of 100 cm-1 in the mid-infrared region. In the THz range, 10mW of average power and 600 GHz of frequency coverage are reported. As a result of the very short upper state lifetime of the gain medium, the mode proliferation in these sources arises from four-wave mixing rather than saturable absorption. As a result, their optical output is characterized by the tendency of small intensity modulation of the output power, and the relative phases of the modes to be similar to the ones of a frequency modulated laser. Recent results include the proof of comb operation down to a metrological level, the observation of a Schawlow-Townes broadened linewidth, as well as the first dual-comb spectroscopy measurements. The capability of the structure to integrate monothically nonlinear optical elements as well as to operate as a detector shows great promise for future chip integration of dual-comb systems.

  17. Tight omega(loglogn)-bound on the time for parallel RAMs to compute nondegenerated Boolean functions

    Energy Technology Data Exchange (ETDEWEB)

    Simon, H.U.

    1982-10-01

    A function f:(0,1)/sup n/=(0,1) is said to depend on dimension i iff there exists an input vector x such that f(x) differs from f(x/sup i/), where x/sup i/ agrees with x in every dimension except i. In this case x is said to be critical for f with respect to i. Function f is called nondegenerated iff it depends on all n dimensions. The main result of this paper is that for each nondegenerated function f:(0,1)/sup n/=(0,1) there exists an input vector x which is critical with respect to at least omega(log n) dimensions. A function achieving this bound is presented. Together with earlier results from Cook and Dwork (Proceedings, 14th ACM Symp. On Theory of Computing, 1982) and Reischuk (IBM Research Report, no.Rj 3431, 1982) it can be concluded that a parallel RAM requires at least omega(loglog n) steps to compute f. 3 references.

  18. Lorentz-violating modification of Dirac theory based on spin-nondegenerate operators

    Science.gov (United States)

    Reis, J. A. A. S.; Schreck, M.

    2017-04-01

    The Standard Model extension (SME) parametrizes all possible Lorentz-violating contributions to the Standard Model and general relativity. It can be considered as an effective framework to describe possible quantum-gravity effects for energies much below the Planck energy. In the current paper, the spin-nondegenerate operators of the SME fermion sector are the focus. The propagators, energies, and solutions to the modified Dirac equation are obtained for several families of coefficients including nonminimal ones. The particle energies and spinors are computed at first order in Lorentz violation and, with the optical theorem, they are shown to be consistent with the propagators. The optical theorem is then also used to derive the matrices formed from a spinor and its Dirac conjugate at all orders in Lorentz violation. The results are the first explicit ones derived for the spin-nondegenerate operators. They will prove helpful for future phenomenological calculations in the SME that rely on the footing of quantum field theory.

  19. Storage and Retrieval of Image using a Four-Wave Mixing System in a Cold Atomic Ensemble

    CERN Document Server

    Wu, Jinghui; Liu, Yang; Zhou, Zhiyuan; Shi, Baosen; Zou, Xubo; Guo, Guangcan

    2012-01-01

    We realized storage and retrieval of image of light in a two-dimensional magneto-optical trap of Rubidium 85 using a four-wave mixing system. When we imprint an image on a signal laser beam, the generated idler field also carries this image information. The retrieved signal and idler fields are observed this image information. That means the spatial patterns of the signal and idler are simultaneously mapped into the long-lived ground state coherence of the atoms. It is worth noticing that the retrieval efficiency is oscillating due to the time evolution of the ground state coherence in a uniform magnetic field. This image storage result holds promise for application in image processing, remote sensing and quantum communication.

  20. Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

    Institute of Scientific and Technical Information of China (English)

    Aiying Yang; Yunan Sun

    2008-01-01

    @@ 40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.

  1. Time-Resolved Femtosecond Degenerate Four-Wave Mixing in LiNbO3:Fe,Mg Crystal

    Institute of Scientific and Technical Information of China (English)

    WANG Zhen-Hua; HUANG Zi-Heng; LI Bing; LIU Shi-Guo; ZHANG Ling; ZHANG Xin-Zheng; XU Jing-Jun; WU Qiang; QIAO Hai-Jun; TANG Bai-Quan; RUPP Romano; KONG Yong-Fa; CHEN Shao-Lin

    2005-01-01

    @@ Forward degenerate four-wave mixing (DFWM) processes are investigated with a femtosecond pulsed laser inlithium niobate crystal doubly-doped with magnesium and iron (LiNbO3:Fe, Mg). The pulse energy dependencereveals a pure third-order nonlinear response, and the third-order nonlinear susceptibility x(3) in the materialis evaluated to be 4.96 × 10-13 esu. The time-resolved DFWM process shows a response time of x(3) shorterthan l00 fs, which is due to the nonresonant electronic nonlinearities. Our results indicate that LiNbO3 crystalshave potentials for ultrafast real-time optical processing systems, which require a large and fast x(3) opticalnonlinearity.

  2. Analysis of third harmonic generation and four wave mixing in gold nanostructures by nonlinear finite difference time domain.

    Science.gov (United States)

    Sasanpour, Pezhman; Shahmansouri, Afsaneh; Rashidian, Bizhan

    2010-11-01

    Third order nonlinear effects and its enhancement in gold nanostructures has been numerically studied. Analysis method is based on computationally solving nonlinear Maxwell's equations, considering dispersion behavior of permittivity described by Drude model and third order nonlinear susceptibility. Simulation is done by method of nonlinear finite difference time domain method, in which nonlinear equations of electric field are solved by Newton-Raphshon method. As the main outcomes of third order nonlinear susceptibility, four wave mixing and third harmonic generation terms are produced around gold nanostructures. Results of analysis on different geometries and structures show that third order nonlinearity products are more enhanced in places where electric field enhancement is occurred due to surface plasmons. Results indicates that enhancement of nonlinearities is strongly occurred in structures whose interface is dielectric. According to analysis results, nonlinear effects are highly concentrated in the vicinity of nanostructures. Hence this approach can be used in applications where localized ultraviolet light is required.

  3. Analytical analysis of adaptive defect detection in amplitude and phase structures using photorefractive four-wave mixing

    Science.gov (United States)

    Nehmetallah, George; Donoghue, John; Banerjee, Partha; Khoury, Jed; Yamamoto, Michiharu; Peyghambarian, Nasser

    2016-04-01

    In this work, brief theoretical modeling, analysis, and novel numerical verification of a photorefractive polymer based four wave mixing (FWM) setup for defect detection has been developed. The numerical simulation helps to validate our earlier experimental results to perform defect detection in periodic amplitude and phase objects using FWM. Specifically, we develop the theory behind the detection of isolated defects, and random defects in amplitude, and phase periodic patterns. In accordance with the developed theory, the results show that this technique successfully detects the slightest defects through band-pass intensity filtering and requires minimal additional post image processing contrast enhancement. This optical defect detection technique can be applied to the detection of production line defects, e.g., scratch enhancement, defect cluster enhancement, and periodic pattern dislocation enhancement. This technique is very useful in quality control systems, production line defect inspection, and computer vision.

  4. High-power picosecond terahertz-wave generation in photonic crystal fiber via four-wave mixing.

    Science.gov (United States)

    Wu, Huihui; Liu, Hongjun; Huang, Nan; Sun, Qibing; Wen, Jin

    2011-09-20

    We demonstrate picosecond terahertz (THz)-wave generation via four-wave mixing in an octagonal photonic crystal fiber (O-PCF). Perfect phase-matching is obtained at the pump wavelength of 1.55 μm and a generation scheme is proposed. Using this method, THz waves can be generated in the frequency range of 7.07-7.74 THz. Moreover, peak power of 2.55 W, average power of 1.53 mW, and peak conversion efficiency of more than -66.65 dB at 7.42 THz in a 6.25 cm long fiber are realized with a pump peak power of 2 kW.

  5. Enhanced four-wave-mixing effects by large group indices of one-dimensional silicon photonic crystal waveguides.

    Science.gov (United States)

    Kim, Dong Wook; Kim, Seung Hwan; Lee, Seoung Hun; Jong, Heung Sun; Lee, Jong-Moo; Lee, El-Hang; Kim, Kyong Hon

    2013-12-02

    Enhanced four-wave-mixing (FWM) effects have been observed with the help of large group-indices near the band edges in one-dimensional (1-D) silicon photonic crystal waveguides (Si PhCWs). A significant increase of the FWM conversion efficiency of about 17 dB was measured near the transmission band edge of the 1-D PhCW through an approximate 3.2 times increase of the group index from 8 to 24 with respect to the central transmission band region despite a large group-velocity dispersion. Numerical analyses based on the coupled-mode equations for the degenerated FWM process describe the experimentally measured results well. Our results indicate that the 1-D PhCWs are good candidates for large group-index enhanced nonlinearity devices even without having any special dispersion engineering.

  6. Performance analysis of semiconductor optical amplifier using four wave mixing based wavelength Converter for all Optical networks.

    Directory of Open Access Journals (Sweden)

    Anupjeet Kaur

    2013-07-01

    Full Text Available In this paper, investigations are made on performance analysis of the semiconductor optical amplifier (SOA using four wave mixing (FWM based wavelength converter. This analysis is done at 10Gb/s in terms of shifted wavelength conversion efficiency, quality factor (Qparameter and bit error rate (BER for up and down conversions. The investigations are carried out by varying the probe signal wavelength and bias current of SOA. From the numerical simulations it has been observed that downconversion efficiency is more than Up-conversion efficiency and it starts decreases at larger wavelengths. It is found that maximum FWM conversion efficiency is around 27.3417 dB at current 160 mA and 28.5669 dB at current 160 mA for up and down conversion respectively for 10Gb/s.

  7. FOUR WAVE MIXING SPECTROSCOPY OF THE NO_3 tilde{B} ^2E' - tilde{X} ^2A_2' transition

    Science.gov (United States)

    Fukushima, Masaru; Ishiwata, Takashi

    2014-06-01

    The tilde{B} ^2E' - tilde{X} ^2A_2' electronic transition of NO_3 generated in a supersonic free jet expansion was investigated by four wave mixing ( 4WM ) spectroscopy. The degenerated 4WM and laser induced fluorescence ( LIF ) spectra around the 0_0^0 band region were measured simultaneously. The D4WM spectrum shows broad band features for the 0_0^0 band similar to that of the LIF spectrum. The broad 0_0^0 band does not consist of one sub-band, but of several bands. The intensity distribution of the sub-bands of the D4WM spectrum is similar, but not identical to that of the LIF spectrum.

  8. Coexistence of three-wave, four-wave, and five-wave mixing processes in a superconducting artificial atom.

    Science.gov (United States)

    Li, Hai-Chao; Ge, Guo-Qin; Zhang, Hai-Yang

    2015-03-15

    We present a theoretical study of multiwave mixing in a driven superconducting quantum qubit (artificial atom) with a cyclic Ξ-type three-level structure. We first show that three-wave mixing (3WM), four-wave mixing (4WM), and five-wave mixing (5WM) processes can coexist in the microwave regime in such an artificial system due to the absence of selection rules. Because of electromagnetically induced transparency suppression of linear absorption in a standard Ξ-type configuration, the generated 4WM is enhanced greatly and its efficiency can be as high as 0.1% for only a single artificial atom. We also show that Autler-Townes splitting occurs in the 3WM and 5WM spectra and quantum interference has a significant impact on the total signal intensity being a coherent superposition of these two signals.

  9. Enhanced intermodal four-wave mixing for visible and near-infrared wavelength generation in a photonic crystal fiber.

    Science.gov (United States)

    Yuan, Jinhui; Sang, Xinzhu; Wu, Qiang; Zhou, Guiyao; Li, Feng; Zhou, Xian; Yu, Chongxiu; Wang, Kuiru; Yan, Binbin; Han, Ying; Tam, Hwa Yaw; Wai, P K A

    2015-04-01

    We demonstrate experimentally an enhanced intermodal four-wave mixing (FWM) process through coupling positively chirped femtosecond pulses into the deeply normal dispersion region of the fundamental mode of an in-house fabricated photonic crystal fiber (PCF). In the intermodal phase-matching scheme, the energy of the pump waves at 800 nm in the fundamental mode is efficiently converted into the anti-Stokes waves around 553 nm and the Stokes waves within the wavelength range of 1445-1586 nm in the second-order mode. The maximum conversion efficiency of η(as) and η(s) of anti-Stokes and Stokes waves can be up to 21% and 16%, respectively. The Stokes frequency shift Ω is 5580  cm(-1). The fiber bending and intermodal walk-off effect of pulses do not have significant influence on the nonlinear optical process.

  10. Coherent control of optical four-wave mixing by two-color $\\omega$-$3\\omega$ ultrashort laser pulses

    CERN Document Server

    Serrat, C

    2004-01-01

    A theoretical investigation on the phase control of optical transient four-wave mixing interactions in two-level systems driven by two intense temporal coherent femtosecond laser pulses of central angular frequencies $\\omega$ and $3\\omega$ is reported. By solving the full Maxwell-Bloch equations beyond the slowly-varying envelope and rotating-wave approximations in the time domain, the parametric nonlinear coupling to the optical field at frequency $5\\omega$ is found to depend critically on the initial relative phase $\\phi$ of the two propagating pulses; the coupling is enhanced when the pulses interfere constructively in the center ($\\phi=0$), while it is nearly suppressed when they are out of phase ($\\phi=\\pi$).

  11. A novel approach to photonic generate microwave signals based on optical injection locking and four-wave mixing

    Science.gov (United States)

    Zhu, Huatao; Wang, Rong; Xiang, Peng; Pu, Tao; Fang, Tao; Zheng, Jilin; Li, Yuandong

    2017-10-01

    In this paper, a novel approach for photonic generation of microwave signals based on frequency multiplication using an injected distributed-feedback (DFB) semiconductor laser is proposed and demonstrated by a proof-of-concept experiment. The proposed system is mainly made up of a dual-parallel Mach-Zehnder modulator (DPMZM) and an injected DFB laser. By properly setting the bias voltage of the DPMZM, ±2-order sidebands with carrier suppression are generated, which are then injected into the slave laser. Due to the optical sideband locking and four-wave mixing (FWM) nonlinearity in the slave laser, new sidebands are generated. Then these sidebands are sent to an optical notch filter where all the undesired sidebands are removed. Finally, after photodetector detection, frequency multiplied microwave signals can be generated. Thanks to the flexibility of the optical sideband locking and FWM, frequency octupling, 12-tupling, 14-tupling and 16-tupling can be obtained.

  12. Degenerate four-wave mixing in room-temperature GaAs/GaAlAs multiple quantum well structures

    Science.gov (United States)

    Miller, D. A. B.; Chemla, D. S.; Eilenberger, D. J.; Smith, P. W.; Gossard, A. C.; Wiegman, W.

    1983-06-01

    Degenerate four-wave mixing (DFWM) is of current interest both for practical applications (e.g., phase conjugation) and as a physical probe. DFWM makes it possible to detect very small nonlinear changes in refraction. In connection with the present investigation, the first observations of DFWM in GaAs/GaAlAs multiple quantum well structures (MQW's) at room temperature are reported. By combining DFWM and nonlinear absorption results, a direct measurement of the nonlinear refraction near the band gap of the MQW is conducted. The obtained value is compared with previous estimates. The measurements are of practical importance for possible low-power optical devices compatible with laser diodes based either on DFWM, nonlinear refraction (such as optical bistability) of nonlinear absorption. The MQW samples were grown by molecular beam epitaxy (MBE) on GaAs substrates, with the MQW layers sandwiched between GaAlAs cap layers which are transparent at the considered wavelengths.

  13. Broad and tunable multiwavelength fiber laser at the assistance of modulation-instability-assisted four-wave mixing

    Science.gov (United States)

    Liu, X. M.

    2010-04-01

    Based on a piece of highly-nonlinear near-zero-dispersion-flattened photonic crystal fiber (PCF), a broadly tunable multiwavelength erbium-doped fiber laser is proposed by using a bi-directionally pumping scheme. This kind of PCF induces the modulation-instability-assisted four-wave mixing to generate new wavelengths. The proposed laser with excellent stability is tunable and switchable by adjusting the fiber Bragg gratings and the variable optical attenuators. The outstanding merits of the proposed multiwavelength laser are the flexible tuning and the ultrabroad spectral range over 150 nm. Especially, the proposed laser source can work at the wavelength of less than 1460 nm, overcoming the limit of gain bandwidth of erbium-doped fiber.

  14. Numerical analysis for four-wave mixing based wavelength conversion of differential phase-shift keying signals

    Institute of Scientific and Technical Information of China (English)

    Liang Jia; Fan Zhang; Ming Li; Yuliang Liu; Zhangyuan Chen

    2009-01-01

    We numerically investigate the main constrains for high efficiency wavelength conversion of differential phase-shift keying (DPSK) signals based on four-wave mixing (FWM) in highly nonlinear fiber (HNLF). Using multi-tone pump phase modulation techniques, high efficiency wavelength conversion of DPSK signals is achieved with the stimulated Brillouin scattering (SBS) effects effectively suppressed. Our analysis shows that there is a compromise between conversion efficiency and converted idler degradation. By optimizing the pump phase modulation configuration, the converted DPSK idler's degradation can be dramatically decreased through balancing SBS suppression and pump phase modulation degradation. Our simulation results also show that these multi-tone pump phase modulation techniques are more appropriate for the future high bit rate systems.

  15. Enhanced generation of vacuum-ultraviolet radiation by four-wave mixing in mercury using pulsed laser vaporization

    Science.gov (United States)

    Chénais, S.; Forget, S.; Philippet, L.; Castex, M.-C.

    2007-11-01

    The efficiency of a coherent vacuum ultraviolet (VUV) source at 125 nm, based on two-photon resonant four-wave mixing in mercury vapor, has been enhanced by up to two orders of magnitude. This enhancement was obtained by locally heating a liquid mercury surface with a pulsed excimer laser, resulting in a high-density vapor plume in which the nonlinear interaction occurred. Energies up to 5 μJ (1 kW peak power) have been achieved while keeping the overall mercury cell at room temperature, avoiding the use of a complex heat pipe. We have observed a strong saturation of the VUV yield when peak power densities of the fundamental beams exceeded the GW/cm2 range, as well as a large intensity-dependent broadening (up to ˜ 30 cm-1) of the two-photon resonance. The source has potential applications for high-resolution interference lithography and photochemistry.

  16. Interference and non-linear properties of four-wave mixing resonances in thermal vapor: analytical results and experimental verification

    CERN Document Server

    Parniak, Michał

    2014-01-01

    We develop a model to calculate non-linear polarization in a non-degenerrate four-wave mixing in diamond configuration which includes the effects of hyperfine structure and Doppler broadening. We verify it against the experiment with $5^{2}S_{1/2}$, $5^{2}P_{3/2}$, $5^{2}D_{3/2}$ and $5^{2}P_{1/2}$ levels of rubidium 85. Uncomplicated algebra enables us to express the non-linear susceptibility of a thermal ensemble in low intensity regime in terms of Voight-like profiles and conforms precisely with the experiment. The agreement is also satisfactory at high intensity and the analytical model correctly predicts the position and shape of resonances. Our intelligible results elucidate the physics of coherent interaction of light with atoms involving higher excited levels in vapors at room temperature, which is used in an increasing range of applications.

  17. Intrinsic linewidth of quantum cascade laser frequency combs

    CERN Document Server

    Cappelli, Francesco; Riedi, Sabine; Faist, Jerome

    2015-01-01

    The frequency noise power spectral density of a free-running quantum cascade laser frequency comb is investigated. A plateau is observed at high frequencies, attributed to the quantum noise limit set by the Schawlow-Townes formula for the total laser power on all comb lines. In our experiment, a linewidth of 292 Hz is measured for a total power of 25 mW. This result proves that the four-wave mixing process, responsible for the comb operation, effectively correlates the quantum noise of the individual comb lines.

  18. Spatio-temporal study of non-degenerate two-wave mixing in bacteriorhodopsin films.

    Science.gov (United States)

    Blaya, Salvador; González, Alejandro; Acebal, Pablo; Carretero, Luis

    2016-10-31

    A spatio-temporal analysis of non-degenerate two-wave mixing in a saturable absorber, such as bacteriorhodopsin (bR) film, is performed. To do this, a theoretical model describing the temporal variation of the intensities is developed by taking into account the dielectric constant as a function of bR population. A good agreement between theory and experimental measurements is obtained. Thus, the dependence of the optical gain and the main dielectric constant parameters are studied at different intensities and frequencies. As a result, the best intensity-frequency zones where higher coupling is reached are proposed, and it is also demonstrated that non-uniform patterns, which evolve over time as a function of frequency difference, can be observed.

  19. Bifurcations and stability of nondegenerated homoclinic loops for higher dimensional systems.

    Science.gov (United States)

    Jin, Yinlai; Li, Feng; Xu, Han; Li, Jing; Zhang, Liqun; Ding, Benyan

    2013-01-01

    By using the foundational solutions of the linear variational equation of the unperturbed system along the homoclinic orbit as the local current coordinates system of the system in the small neighborhood of the homoclinic orbit, we discuss the bifurcation problems of nondegenerated homoclinic loops. Under the nonresonant condition, existence, uniqueness, and incoexistence of 1-homoclinic loop and 1-periodic orbit, the inexistence of k-homoclinic loop and k-periodic orbit is obtained. Under the resonant condition, we study the existence of 1-homoclinic loop, 1-periodic orbit, 2-fold 1-periodic orbit, and two 1-periodic orbits; the coexistence of 1-homoclinic loop and 1-periodic orbit. Moreover, we give the corresponding existence fields and bifurcation surfaces. At last, we study the stability of the homoclinic loop for the two cases of non-resonant and resonant, and we obtain the corresponding criterions.

  20. Non-degenerate light quark masses from 2+1f lattice QCD+QED

    Energy Technology Data Exchange (ETDEWEB)

    Drury, Shane [Southampton U.; Blum, Thomas [RIKEN BNL; Hayakawa, Masashi [Nagoya U.; Izubuchi, Taku [RIKEN BNL; Sachrajda, Chris [Southampton U.; Zhou, Ran [Indiana U.

    2014-01-01

    We report on a calculation of the effects of isospin breaking in Lattice QCD+QED. This involves using Chiral Perturbation Theory with Electromagnetic corrections to find the renormalized, non-degenerate, light quark masses. The calculations are carried out on QCD ensembles generated by the RBC and UKQCD collaborations using Domain Wall Fermions and the Iwasaki and Iwasaki+DSDR Gauge Actions with unitary pion masses down to 170 MeV. Non-compact QED is treated in the quenched approximation. The simulations use a $32^3$ lattice size with $a^{-1}=2.28(3)$ GeV (Iwasaki) and 1.37(1) (Iwasaki+DSDR). This builds on previous work from the RBC/UKQCD collaboration with lattice spacing $a^{-1}=1.78(4)$ GeV.

  1. A nondegenerate code of deleterious variants in Mendelian loci contributes to complex disease risk.

    Science.gov (United States)

    Blair, David R; Lyttle, Christopher S; Mortensen, Jonathan M; Bearden, Charles F; Jensen, Anders Boeck; Khiabanian, Hossein; Melamed, Rachel; Rabadan, Raul; Bernstam, Elmer V; Brunak, Søren; Jensen, Lars Juhl; Nicolae, Dan; Shah, Nigam H; Grossman, Robert L; Cox, Nancy J; White, Kevin P; Rzhetsky, Andrey

    2013-09-26

    Although countless highly penetrant variants have been associated with Mendelian disorders, the genetic etiologies underlying complex diseases remain largely unresolved. By mining the medical records of over 110 million patients, we examine the extent to which Mendelian variation contributes to complex disease risk. We detect thousands of associations between Mendelian and complex diseases, revealing a nondegenerate, phenotypic code that links each complex disorder to a unique collection of Mendelian loci. Using genome-wide association results, we demonstrate that common variants associated with complex diseases are enriched in the genes indicated by this "Mendelian code." Finally, we detect hundreds of comorbidity associations among Mendelian disorders, and we use probabilistic genetic modeling to demonstrate that Mendelian variants likely contribute nonadditively to the risk for a subset of complex diseases. Overall, this study illustrates a complementary approach for mapping complex disease loci and provides unique predictions concerning the etiologies of specific diseases. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. A Non-Degenerate Code of Deleterious Variants in Mendelian Loci Contributes to Complex Disease Risk

    Science.gov (United States)

    Blair, David R.; Lyttle, Christopher S.; Mortensen, Jonathan M.; Bearden, Charles F.; Jensen, Anders Boeck; Khiabanian, Hossein; Melamed, Rachel; Rabadan, Raul; Bernstam, Elmer V.; Brunak, Søren; Jensen, Lars Juhl; Nicolae, Dan; Shah, Nigam H.; Grossman, Robert L.; Cox, Nancy J.; White, Kevin P.; Rzhetsky, Andrey

    2013-01-01

    Summary Whereas countless highly penetrant variants have been associated with Mendelian disorders, the genetic etiologies underlying complex diseases remain largely unresolved. Here, we examine the extent to which Mendelian variation contributes to complex disease risk by mining the medical records of over 110 million patients. We detect thousands of associations between Mendelian and complex diseases, revealing a non-degenerate, phenotypic code that links each complex disorder to a unique collection of Mendelian loci. Using genome-wide association results, we demonstrate that common variants associated with complex diseases are enriched in the genes indicated by this “Mendelian code.” Finally, we detect hundreds of comorbidity associations among Mendelian disorders, and we use probabilistic genetic modeling to demonstrate that Mendelian variants likely contribute non-additively to the risk for a subset of complex diseases. Overall, this study illustrates a complementary approach for mapping complex disease loci and provides unique predictions concerning the etiologies of specific diseases. PMID:24074861

  3. Post-selection free, integrated optical source of non-degenerate, polarization entangled photon pairs

    CERN Document Server

    Herrmann, Harald; Thomas, Abu; Poppe, Andreas; Sohler, Wolfgang; Silberhorn, Christine

    2013-01-01

    We present an integrated source of polarization entangled photon pairs in the telecom regime, which is based on type II-phasematched parametric down-conversion (PDC) in a Ti-indiffused waveguide in periodically poled lithium niobate. The domain grating -- consisting of an interlaced bi-periodic structure -- is engineered to provide simultaneous phase-matching of two PDC processes, and enables the direct generation of non-degenerate, polarization entangled photon pairs with a brightness of $B=7\\times10^3$ pairs/(s mW GHz). The spatial separation of the photon pairs is accomplished by a fiber-optical multiplexer facilitating a high compactness of the overall source. Visibilities exceeding 95% and a violation of the Bell inequality with $S=2.57\\pm0.06$ could be demonstrated.

  4. A Nondegenerate Code of Deleterious Variants in Mendelian Loci Contributes to Complex Disease Risk

    DEFF Research Database (Denmark)

    Blair, David R.; Lyttle, Christopher S.; Mortensen, Jonathan M.

    2013-01-01

    with complex diseases are enriched in the genes indicated by this ‘‘Mendelian code.’’ Finally, we detect hundreds of comorbidity associations among Mendelian disorders, and we use probabilistic genetic modeling to demonstrate that Mendelian variants likely contribute nonadditively to the risk for a subset......Although countless highly penetrant variants have been associated with Mendelian disorders, the genetic etiologies underlying complex diseases remain largely unresolved. By mining the medical records of over 110 million patients, we examine the extent to which Mendelian variation contributes...... to complex disease risk. We detect thousands of associations between Mendelian and complex diseases, revealing a nondegenerate, phenotypic code that links each complex disorder to a unique collection of Mendelian loci. Using genome-wide association results, we demonstrate that common variants associated...

  5. Actively switchable nondegenerate polarization-entangled photon-pair distribution in dense wave-division multiplexing

    Science.gov (United States)

    Zhou, Zhi-Yuan; Jiang, Yun-Kun; Ding, Dong-Sheng; Shi, Bao-Sen; Guo, Guang-Can

    2013-04-01

    We have demonstrated experimentally a nondegenerate polarization-entangled photon-pair distribution in a commercial telecom dense wave-division multiplexing device (DWDM) with eight channels. A promising point of this experiment is that an entangled photon pair is obtained via spontaneous parametric down conversion in a single type-II periodically poled KTiOPO4 crystal without postselection. Another promising advantage is that we can actively switch the distribution of the photon pair between different channel pairs in DWDM at will. There is no crosstalk between different channel pairs because of a limited emission bandwidth of the source. Maximum raw visibility of 97.88%±0.86% obtained in a Bell-type interference experiment and a Clauser-Horne-Shimony-Holt (CHSH) inequality S parameter of 2.63±0.08 calculated prove high entanglement of our source. Our work is helpful for building quantum communication networks.

  6. Observation of Nondegenerate Two-Photon Gain in GaAs

    CERN Document Server

    Reichert, Matthew; Salamo, Greg; Hagan, David J; Van Stryland, Eric W

    2016-01-01

    Two-photon lasers require materials with large two-photon gain (2PG) coefficients and low linear and nonlinear losses. Our previous demonstration of large enhancement of two-photon absorption in semiconductors for very different photon energies translates directly into enhancement of 2PG. We experimentally demonstrate nondegenerate 2PG in optically excited bulk GaAs via femtosecond pump-probe measurements. 2PG is isolated from other pump induced effects through the difference between measurements performed with parallel and perpendicular polarizations of pump and probe. An enhancement in the 2PG coefficient of nearly two orders-of-magnitude is reported. The results point a possible way toward two-photon semiconductor lasers.

  7. Effects of refractive index changes on four-wave mixing bands in Er-doped photonic crystal fibers pumped at 976 nm.

    Science.gov (United States)

    Velázquez-Ibarra, L; Díez, A; Andrés, M V; Lucio, J L

    2012-04-01

    An experimental study of the effects of an auxiliary 976 nm pump signal on the four-wave mixing parametric bands generated with a 1064 nm pump in a normal dispersion Er-doped photonic crystal fiber is presented. The four-wave mixing signal and idler bands shift to shorter and longer wavelengths, respectively, with increasing 976 nm pump power. It is shown that the wavelength-dependent resonant refractive index change in the erbium-doped core under 976 nm pumping is at the origin of the effect.

  8. Highly Efficient Four-Wave Mixing in an AlGaAs-On-Insulator (AlGaAsOI) Nano-Waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Ottaviano, Luisa; Semenova, Elizaveta

    2015-01-01

    We propose an AlGaAs-on-insulator platform for nonlinear integrated photonics. We demonstrate highly efficient four-wave mixing in a 3-mm long AlGaAs-on-insulator nanowaveguide. A conversion efficiency of -21.1 dB is obtained with only a 45-mW pump......We propose an AlGaAs-on-insulator platform for nonlinear integrated photonics. We demonstrate highly efficient four-wave mixing in a 3-mm long AlGaAs-on-insulator nanowaveguide. A conversion efficiency of -21.1 dB is obtained with only a 45-mW pump...

  9. Continuous Wave Phase-Sensitive Four-Wave Mixing in Silicon Waveguides With Reverse-Biased p-i-n Junctions

    DEFF Research Database (Denmark)

    Da Ros, Francesco; Vukovic, Dragana; Gajda, A.

    2013-01-01

    Phase-sensitive four-wave mixing is experimentally demonstrated using continuous wave pumps in silicon waveguides with p-i-n junctions. The reverse biasing allows decreasing the free carrier lifetime, enabling a phase-sensitive extinction ratio in excess of 15 dB.......Phase-sensitive four-wave mixing is experimentally demonstrated using continuous wave pumps in silicon waveguides with p-i-n junctions. The reverse biasing allows decreasing the free carrier lifetime, enabling a phase-sensitive extinction ratio in excess of 15 dB....

  10. Optoelectronic down-conversion by four-wave mixing in a highly nonlinear fiber for millimeter-wave and THz phase-locking

    CERN Document Server

    Rolland, Antoine; Brunel, Marc; Alouini, Mehdi

    2014-01-01

    Optoelectronic down-conversion of a THz optical beatnote to a RF intermediate frequency is performed with a standard Mach-Zehnder modulator followed by a zero dispersion-slope fiber. The two interleaved optical spectra obtained by four-wave mixing are shown to contain more than 75 harmonics enabling to conveniently recover the phase noise of a beatnote at 770 GHz at around 500 MHz. This four-wave mixing down-conversion technique is implemented in a two-frequency solid-state laser in order to directly phase-lock its 168 GHz beatnote to a 10 MHz local oscillator.

  11. [Study of the effect of light source stability on the signal to noise ratio in degenerate four wave mixing experiment].

    Science.gov (United States)

    Wang, Wei-Bo; Chen, De-Ying; Fan, Rong-Wei; Xia, Yuan-Qin

    2010-02-01

    The effects of the stability of dye laser on the signal to noise ratio in degenerate four-wave mixing (DFWM) were first investigated in iodine vapor using forward geometries. Frequency-doubled outputs from a multi-mode Nd : YAG laser pumped dye laser with laser dye PM580 dissolved in ethanol was used. With the help of forward compensated beam-split technique and imaging detecting system, the saturation intensity of DFWM spectrum in the iodine vapor at 5 554.013 nm was first measured to be 290 microJ under the condition of atmospheric pressure and room temperature. The features of the dye laser such as wavelength ranges, beam quality and energy conversion efficiency decreased gradually with increasing pumping service use, pulse number and intensity. Additionally, with the comparison of the stable and unstable dye laser output, it was found that the instability of dye laser output had greatly influenced the DFWM signal and decreased the signal to background noise ratio. Shot to shot jitter and the broadening in the output frequency leads to an effective broadening of the recorded spectrum and loss of the DFWM signal to noise ratio under the same pumping intensity at different time. The study is of importance to the detection of trace atom, molecule and radical in combustion diagnosis.

  12. Imaging the uptake of gold nanoshells in live cells using plasmon resonance enhanced four wave mixing microscopy.

    Science.gov (United States)

    Garrett, Natalie; Whiteman, Matt; Moger, Julian

    2011-08-29

    Gold nanoshells (GNS) are novel metal nanoparticles exhibiting attractive optical properties which make them highly suitable for biophotonics applications. We present a novel investigation using plasmon-enhanced four wave mixing microscopy combined with coherent anti-Stokes Raman scattering (CARS) microscopy to visualize the distribution of 75 nm radius GNS within live cells. During a laser tolerance study we found that cells containing nanoshells could be exposed to nanoshell uptake using two donor molecules, NaHS and GYY4137. As GYY4137 concentration was increased from 10 µM to 1 mM, the nanoshell pixel percentage as a function of cell volume (PPCV) increased from 2.15% to 3.77%. As NaHS concentration was increased over the same range, the nanoshell PPCV decreased from 12.67% to 11.47%. The most important factor affecting uptake in this study was found to be the rate of H2S release, with rapid-release from NaHS resulting in significantly greater uptake.

  13. Determination of the electric field strength of filamentary DBDs by CARS-based four-wave mixing

    Science.gov (United States)

    Böhm, P.; Kettlitz, M.; Brandenburg, R.; Höft, H.; Czarnetzki, U.

    2016-10-01

    It is demonstrated that a four-wave mixing technique based on coherent anti-Stokes Raman spectroscopy (CARS) can determine the electric field strength of a pulsed-driven filamentary dielectric barrier discharge (DBD) of 1 mm gap, using hydrogen as a tracer medium in nitrogen at atmospheric pressure. The measurements are presented for a hydrogen admixture of 10%, but even 5% H2 admixture delivers sufficient infrared signals. The lasers do not affect the discharge by photoionization or by other radiation-induced processes. The absolute values of the electric field strength can be determined by the calibration of the CARS setup with high voltage amplitudes below the ignition threshold of the arrangement. This procedure also enables the determination of the applied breakdown voltage. The alteration of the electric field is observed during the internal polarity reversal and the breakdown process. One advantage of the CARS technique over emission-based methods is that it can be used independently of emission, e.g. in the pre-phase and in between two consecutive discharges, where no emission occurs at all.

  14. Wavelength-agile high-power sources via four-wave mixing in higher-order fiber modes.

    Science.gov (United States)

    Demas, J; Prabhakar, G; He, T; Ramachandran, S

    2017-04-03

    Frequency doubling of conventional fiber lasers in the near-infrared remains the most promising method for generating integrated high-peak-power lasers in the visible, while maintaining the benefits of a fiber geometry; but since the shortest wavelength power-scalable fiber laser sources are currently restricted to either the 10XX nm or 15XX nm wavelength ranges, accessing colors other than green or red remains a challenge with this schematic. Four-wave mixing using higher-order fiber modes allows for control of dispersion while maintaining large effective areas, thus enabling a power-scalable method to extend the bandwidth of near-infrared fiber lasers, and in turn, the bandwidth of potential high-power sources in the visible. Here, two parametric sources using the LP0,7 and LP0,6 modes of two step-index multi-mode fibers are presented. The output wavelengths for the sources are 880, 974, 1173, and 1347 nm with peak powers of 10.0, 16.2, 14.7, and 6.4 kW respectively, and ~300-ps pulse durations. The efficiencies of the sources are analyzed, along with a discussion of wavelength tuning and further power scaling, representing an advance in increasing the bandwidth of near-infrared lasers as a step towards high-peak-power sources at wavelengths across the visible spectrum.

  15. Four-wave mixing based light sources for real-world biomedical applications of coherent Raman microscopy

    Science.gov (United States)

    Gottschall, Thomas; Meyer, Tobias; Jauregui, Cesar; Schmitt, Michael; Popp, Jürgen; Limpert, Jens; Tünnermann, Andreas

    2016-03-01

    Stimulated Raman Scattering requires an extremely quiet, widely wavelength tunable laser, which, up to now, is unheard of in fiber lasers. We present a compact and maintenance-free optical parametric oscillator based on degenerate four-wave mixing in a photonic crystal fiber. By employing an all-fiber frequency and repetition rate tunable laser as a seed source, we are able to generate tunable light between 1015 and 1065 nm. After amplification and subsequent conversion in the fiber OPO, signal and idler radiation between 785 and 960 nm and 1177 and 1500 nm may be generated with a repetition rate of 9 MHz. Therefore, we are able to address Raman shifts between 910 and 3030 cm-1. An additional output provides the Stokes radiation at 18 MHz required for the SRS process, which is passively synchronized to the tunable radiation. We measure the relative intensity noise of the Stokes beam at 9 MHz to be -150 dBc enabling high speed SRS imaging with a good signal-to-noise ratio. The combination of FWM based conversion, coupled with all-fiber Yb-based fiber lasers allows for the first turn-key, widely tunable and extremely compact laser systems developed for applications of CRS microscopy in clinics. This source could very well be the missing key instrument that CRS imaging requires for its real world transition.

  16. Synthesis, z-scan and degenerate four wave mixing characterization of certain functionalized photosensitive polyesters containing ortho-hydroxyazo chromophores

    Science.gov (United States)

    Jayakrishnan, K.; Siji Narendran, N. K.; Sreejith, P.; Joseph, Antony; Chandrasekharan, K.; Purushothaman, E.

    2015-07-01

    The preparation and NLO characterization of photosensitive polyesters containing azoaromatic residues in the molecular backbone, functionalized with orthohydroxy chromophores is presented. Samples were studied for its UV-vis absorption, FT-IR and intensity dependent nonlinear absorption properties. Nonlinear characterization was carried out with z-scan using frequency doubled, Q-switched Nd:YAG laser operating at 532 nm. The closed aperture z-scan spectra reveal the self defocusing effects of the samples with negative nonlinearity coefficient (n2) showing values as high as -1.28 × 10-10 (esu) for certain samples and the corresponding third order susceptibility coefficient of the order of 29.9 × 10-12 (esu). Degenerate four wave mixing technique was employed to substantiate the findings. The numerical fits show that the molecules exhibit reverse saturable absorption. A study of beam fluence dependence of nonlinear absorption coefficient (βeff) has been presented. All phenomena indicate that molecules are reverse saturable absorbers whose optical limiting property gets enhanced with increasing conjugation length.

  17. Travelling-wave resonant four-wave mixing breaks the limits of cavity-enhanced all-optical wavelength conversion

    Science.gov (United States)

    Morichetti, Francesco; Canciamilla, Antonio; Ferrari, Carlo; Samarelli, Antonio; Sorel, Marc; Melloni, Andrea

    2011-01-01

    Wave mixing inside optical resonators, while experiencing a large enhancement of the nonlinear interaction efficiency, suffers from strong bandwidth constraints, preventing its practical exploitation for processing broad-band signals. Here we show that such limits are overcome by the new concept of travelling-wave resonant four-wave mixing (FWM). This approach combines the efficiency enhancement provided by resonant propagation with a wide-band conversion process. Compared with conventional FWM in bare waveguides, it exhibits higher robustness against chromatic dispersion and propagation loss, while preserving transparency to modulation formats. Travelling-wave resonant FWM has been demonstrated in silicon-coupled ring resonators and was exploited to realize a 630-μm-long wavelength converter operating over a wavelength range wider than 60 nm and with 28-dB gain with respect to a bare waveguide of the same physical length. Full compatibility of the travelling-wave resonant FWM with optical signal processing applications has been demonstrated through signal retiming and reshaping at 10 Gb s−1 PMID:21540838

  18. Four-Wave Mixing Crosstalk Suppression Based on the Pairing Combinations of Differently Linear-Polarized Optical Signals

    Directory of Open Access Journals (Sweden)

    Haider Abd

    2014-01-01

    Full Text Available A new approach to suppressing the four-wave mixing (FWM crosstalk by using the pairing combinations of differently linear-polarized optical signals was investigated. The simulation was conducted using a four-channel system, and the total data rate was 40 Gb/s. A comparative study on the suppression of FWM for existing and suggested techniques was conducted by varying the input power from 2 dBm to 14 dBm. The robustness of the proposed technique was examined with two types of optical fiber, namely, single-mode fiber (SMF and dispersion-shifted fiber (DSF. The FWM power drastically reduced to less than −68 and −25 dBm at an input power of 14 dBm, when the polarization technique was conducted for SMF and DSF, respectively. With the conventional method, the FWM powers were, respectively, −56 and −20 dBm. The system performance greatly improved with the proposed polarization approach, where the bit error rates (BERs at the first channel were 2.57×10-40 and 3.47×10-29 at received powers of −4.90 and −13.84 dBm for SMF and DSF, respectively.

  19. Radiatively Limited Dephasing and Exciton Dynamics in MoSe2 Monolayers Revealed with Four-Wave Mixing Microscopy.

    Science.gov (United States)

    Jakubczyk, Tomasz; Delmonte, Valentin; Koperski, Maciej; Nogajewski, Karol; Faugeras, Clément; Langbein, Wolfgang; Potemski, Marek; Kasprzak, Jacek

    2016-09-14

    By implementing four-wave mixing (FWM) microspectroscopy, we measure coherence and population dynamics of the exciton transitions in monolayers of MoSe2. We reveal their dephasing times T2 and radiative lifetime T1 in a subpicosecond (ps) range, approaching T2 = 2T1 and thus indicating radiatively limited dephasing at a temperature of 6 K. We elucidate the dephasing mechanisms by varying the temperature and by probing various locations on the flake exhibiting a different local disorder. At the nanosecond range, we observe the residual FWM produced by the incoherent excitons, which initially disperse toward the dark states but then relax back to the optically active states within the light cone. By introducing polarization-resolved excitation, we infer intervalley exciton dynamics, revealing an initial polarization degree of around 30%, constant during the initial subpicosecond decay, followed by the depolarization on a picosecond time scale. The FWM hyperspectral imaging reveals the doped and undoped areas of the sample, allowing us to investigate the neutral exciton, the charged one, or both transitions at the same time. In the latter, we observe the exciton-trion beating in the coherence evolution indicating their coherent coupling.

  20. Phase correlation between four-wave mixing and optical fields in double Λ-type atomic system.

    Science.gov (United States)

    Jeong, Taek; Moon, Han Seb

    2016-12-12

    We study the spectral features and phase of four-wave mixing (FWM) light according to the relative phase-noise of the optical fields coupled to a double Λ-type atomic system of the 5S1/2-5P1/2 transition of 87Rb atoms. We observe that the spectral shape of the FWM spectrum is identical to that of the two-photon absorption (TPA) spectrum due to two-photon coherence and that it is independent of the relative phase-noise of the pump light. From these results, we clarify that the two-photon coherence plays a very important role in the FWM process. Furthermore, we measure the relative linewidth of the FWM signal to the probe and pump lasers by means of a beat interferometer. We confirmed that the phase of the FWM signal is strongly correlated with that of the pump laser under the condition of phase-locked probe and coupling lasers for two-photon coherence.

  1. Single-step fabrication of scalable multimode quantum resources using four-wave mixing with a spatially structured pump

    Science.gov (United States)

    Wang, Hailong; Fabre, Claude; Jing, Jietai

    2017-05-01

    Multimode quantum resources or states, in which quantum correlations are shared and distributed among multiple parties, are important not only for fundamental tests of quantum effects but also for their numerous possible applications in quantum technologies, such as quantum imaging and quantum metrology. Here we demonstrate the single-step fabrication of a multimode quantum resource from four-wave mixing (FWM) process in hot Rb vapor using a spatially structured pump, which consists of a coherent combination of two tilted pump beams. During this FWM process, one probe beam is amplified, three conjugate and two new probe beams are generated. The measured degrees of the intensity squeezing for the four-beam case and six-beam case are around -4.1 ±0.1 dB and -4.7 ±0.1 dB, respectively. The generated multiple quantum correlated beams are naturally separated with distinct directions, which is crucial for sending them out to quantum nodes at different locations in quantum communication. Our scheme is compact, simple, phase insensitive, and easily scalable to larger number of quantum-correlated modes.

  2. Stimulated Emission Pumping by Two-Color Resonant Four-Wave Mixing: Rotational Characterization of Vibrationally Excited HCO

    Energy Technology Data Exchange (ETDEWEB)

    Radi, P.P.; Tulej, M.; Knopp, G.; Beaud, P.; Gerber, T.

    2004-03-01

    Stimulated emission pumping by applying two-color resonant four-wave mixing is used to measure rotationally resolved spectra of the HCO (0,0,0) B {sup 2}A' - (0,3,1) X {sup 2}A' transition. The formyl radical is produced by photodissociation of formaldehyde at 31710.8 cm{sup -1} under thermalized conditions in a low pressure cell. In contrast to the highly congested one-color spectrum of HCO at room temperature, the doubleresonance method yields well isolated transitions which are assigned unambiguously due to intermediate level labeling. 89 rotational transitions have been assigned and yield accurate rotational constants for the vibrationally excited (0,3,1) band of the electronic ground state X {sup 2}A' of HCO. The determined rotational constant A = 25.84{+-}0.01 cm-1 is considerably higher than that for the vibrationless ground state and reflects the structural change due to excitation of the bending mode of the formyl radical. (author)

  3. Direct generation of graphene plasmonic polaritons at THz frequencies via four wave mixing in the hybrid graphene sheets waveguides.

    Science.gov (United States)

    Sun, Yu; Qiao, Guofu; Sun, Guodong

    2014-11-17

    A compact waveguide incorporating a high-index nano-ridge sandwiched between graphene sheets is proposed for the direct generation of graphene plasmonic polaritons (GSPs) via four wave mixing (FWM). The proposed waveguide supports GSP modes at the THz frequencies and photonic modes at the infrared wavelengths. Due to the strong confinement of coupled graphene sheets, the GSP modes concentrate in the high-index nano-ridge far below the diffraction limit, which improves integral overlap with the photonic modes and greatly facilitates the FWM process. To cope with the ultra-high effective refractive of the GSP modes, an alternative energy conservation diagram is selected for the degenerated FWM, which corresponds to one pump photon transfers its energy to two signal photons and one GSP photon. The single mode condition of the generated symmetric GSP modes is analyzed by the effective index method to suppress the undesired conversion. Due to the unique tunability of GSPs, the phase matching condition can be satisfied by tuning the chemical potential of the graphene sheets employing external gates. The FWM pumped at 1,550 nm with a peak power of 1 kW is theoretically investigated by solving the modified coupled mode equations. The generated GSP power reaches its maximum up to 67 W at a propagation distance of only 43.7 μm. The proposed waveguide have a great potential for integrated chip-scale GSP source.

  4. Polarization rotation of light propagating through a medium with efficient four-wave mixing and cross-phase modulation

    Science.gov (United States)

    Sahoo, Sushree S.; Bhowmick, Arup; Mohapatra, Ashok K.

    2017-03-01

    We have studied the rotation of an elliptically polarized light propagating through thermal rubidium vapor with efficient four-wave mixing (FWM) and cross-phase modulation (XPM). These nonlinear processes are enhanced by Zeeman coherence within the degenerate sub-levels of the two-level atomic system. The elliptically polarized light with small ellipticity is considered as the superposition of a strong-linearly-polarized pump beam and a weak-orthogonal-polarized probe beam. The interference of the probe and the newly generated light field due to degenerate FWM and their gain in the medium due to a large XPM induced by the pump beam leads to the rotation of the elliptical polarized light. A theoretical analysis of the probe propagation through the nonlinear medium was used to explain the experimental observation and the fitting of the experimental data gives the estimates of the third-order non-linear susceptibilities associated with FWM and XPM. Our study can provide useful parameters for the generation of efficient squeezed vacuum states and squeezed polarization states of light. Furthermore our study finds application in controlling the diffraction of a linearly-polarized light beam traversing the medium.

  5. Suppression of WDM four-wave mixing crosstalk in fibre optic parametric amplifier using Raman-assisted pumping.

    Science.gov (United States)

    Redyuk, A; Stephens, M F C; Doran, N J

    2015-10-19

    We perform an extensive numerical analysis of Raman-Assisted Fibre Optical Parametric Amplifiers (RA-FOPA) in the context of WDM QPSK signal amplification. A detailed comparison of the conventional FOPA and RA-FOPA is reported and the important advantages offered by the Raman pumping are clarified. We assess the impact of pump power ratios, channel count, and highly nonlinear fibre (HNLF) length on crosstalk levels at different amplifier gains. We show that for a fixed 200 m HNLF length, maximum crosstalk can be reduced by up to 7 dB when amplifying 10x58Gb/s QPSK signals at 20 dB net-gain using a Raman pump of 37 dBm and parametric pump of 28.5 dBm in comparison to a standard single-pump FOPA using 33.4 dBm pump power. It is shown that a significant reduction in four-wave mixing crosstalk is also obtained by reducing the highly nonlinear fibre interaction length. The trend is shown to be generally valid for different net-gain conditions and channel grid size. Crosstalk levels are additionally shown to strongly depend on the Raman/parametric pump power ratio, with a reduction in crosstalk seen for increased Raman pump power contribution.

  6. High efficiency quantum cascade laser frequency comb

    Science.gov (United States)

    Lu, Quanyong; Wu, Donghai; Slivken, Steven; Razeghi, Manijeh

    2017-03-01

    An efficient mid-infrared frequency comb source is of great interest to high speed, high resolution spectroscopy and metrology. Here we demonstrate a mid-IR quantum cascade laser frequency comb with a high power output and narrow beatnote linewidth at room temperature. The active region was designed with a strong-coupling between the injector and the upper lasing level for high internal quantum efficiency and a broadband gain. The group velocity dispersion was engineered for efficient, broadband mode-locking via four wave mixing. The comb device exhibits a narrow intermode beatnote linewidth of 50.5 Hz and a maximum wall-plug efficiency of 6.5% covering a spectral coverage of 110 cm‑1 at λ ~ 8 μm. The efficiency is improved by a factor of 6 compared with previous demonstrations. The high power efficiency and narrow beatnote linewidth will greatly expand the applications of quantum cascade laser frequency combs including high-precision remote sensing and spectroscopy.

  7. High efficiency quantum cascade laser frequency comb

    Science.gov (United States)

    Lu, Quanyong; Wu, Donghai; Slivken, Steven; Razeghi, Manijeh

    2017-01-01

    An efficient mid-infrared frequency comb source is of great interest to high speed, high resolution spectroscopy and metrology. Here we demonstrate a mid-IR quantum cascade laser frequency comb with a high power output and narrow beatnote linewidth at room temperature. The active region was designed with a strong-coupling between the injector and the upper lasing level for high internal quantum efficiency and a broadband gain. The group velocity dispersion was engineered for efficient, broadband mode-locking via four wave mixing. The comb device exhibits a narrow intermode beatnote linewidth of 50.5 Hz and a maximum wall-plug efficiency of 6.5% covering a spectral coverage of 110 cm−1 at λ ~ 8 μm. The efficiency is improved by a factor of 6 compared with previous demonstrations. The high power efficiency and narrow beatnote linewidth will greatly expand the applications of quantum cascade laser frequency combs including high-precision remote sensing and spectroscopy. PMID:28262834

  8. All-optical wavelength multicasting with extinction ratio enhancement using pump-modulated four-wave mixing in a dispersion-flattened nonlinear photonic crystal fiber

    DEFF Research Database (Denmark)

    Chow, K.K.; Shu, Chester; Lin, Chinlon;

    2006-01-01

    All optical wavelength multicasting at 4 x 10 Gb/s with extinction ratio enhancement has been demonstrated based on pump-modulated four-wave mixing in a nonlinear photonic crystal fiber. We show that the input signal wavelength can simultaneously convert to four different wavelengths, with a power...

  9. One-to-six WDM multicasting of DPSK signals based on dual-pump four-wave mixing in a silicon waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Hu, Hao; Ji, Hua

    2011-01-01

    We present WDM multicasting based on dual-pump four-wave mixing in a 3-mm long dispersion engineered silicon waveguide. One-to-six phase-preserving WDM multicasting of 10-Gb/s differential phase-shiftkeying (DPSK) data is experimentally demonstrated with bit-error rate measurements. All the six...

  10. Study on optical nonlinearities of ZnO-Nb2O5-TeO2 glass with time-resolved four-wave mixing technique

    Institute of Scientific and Technical Information of China (English)

    Li Jiang(江丽); Shi'an Zhang(张诗按); Yufei Wang(王宇飞); Zhenrong Sun(孙真荣); Zugeng Wang(王祖赓); Jian Lin(林健); Wenhai Huang(黄文旵); Zhizhan Xu(徐至展); Ruxin Li(李儒新)

    2004-01-01

    We investigated nonlinear optical properties of ZnO-Nb2O5-TeO2 glass excited by a femtosecond laser with time-resolved four-wave mixing (FWM) technique. The unusual FWM signals were observed in samples with ZnO dopant. The mechanism for the optical nonlinearities was discussed.

  11. Re-Visiting the Electronic Energy Map of the Copper Dimer by Double-Resonant Four-Wave Mixing

    Science.gov (United States)

    Visser, Bradley; Bornhauser, Peter; Beck, Martin; Knopp, Gregor; Marquardt, Roberto; Gourlaouen, Christophe; van Bokhoven, Jeroen A.; Radi, Peter

    2017-06-01

    The copper dimer is one of the most studied transition metal (TM) diatomics due to its alkali-metal like electronic shell structure, strongly bound ground state and chemical reactivity. The high electronic promotion energy in the copper atom yields numerous low-lying electronic states compared to TM dimers with d)-hole electronic configurations. Thus, through extensive study the excited electronic structure of Cu_2 is relatively well known, however in practice few excited states have been investigated with rotational resolution or even assigned term symbols or dissociation limits. The spectroscopic methods that have been used to investigate the copper dimer until now have not possessed sufficient spectral selectivity, which has complicated the analysis of the often overlapping transitions. Resonant four-wave mixing is a non-linear absorption based spectroscopic method. In favorable cases, the two-color version (TC-RFWM) enables purely optical mass selective spectral measurements in a mixed molecular beam. Additionally, by labelling individual rotational levels in the common intermediate state the spectra are dramatically simplified. In this work, we report on the rotationally resolved characterization of low-lying electronic states of dicopper. Several term symbols have been assigned unambiguously. De-perturbation studies performed shed light on the complex electronic structure of the molecule. Furthermore, a new low-lying electronic state of Cu_2 is discovered and has important implications for the high-level theoretical structure calculations performed in parallel. In fact, the ab initio methods applied yield relative energies among the electronic levels that are almost quantitative and allow assignment of the newly observed state that is governed by spin-orbit interacting levels.

  12. Slow and stored light under conditions of electromagnetically induced transparency and four wave mixing in an atomic vapor

    Science.gov (United States)

    Phillips, Nathaniel Blair

    The recent prospect of efficient, reliable, and secure quantum communication relies on the ability to coherently and reversibly map nonclassical states of light onto long-lived atomic states. A promising technique that accomplishes this employs Electromagnetically Induced Transparency (EIT), in which a strong classical control field modifies the optical properties of a weak signal field in such a way that a previously opaque medium becomes transparent to the signal field. The accompanying steep dispersion in the index of refraction allows for pulses of light to be decelerated, then stored as an atomic excitation, and later retrieved as a photonic mode. This dissertation presents the results of investigations into methods for optimizing the memory efficiency of this process in an ensemble of hot Rb atoms. We have experimentally demonstrated the effectiveness of two protocols for yielding the best memory efficiency possible at a given atomic density. Improving memory efficiency requires operation at higher optical depths, where undesired effects such as four-wave mixing (FWM) become enhanced and can spontaneously produce a new optical mode (Stokes field). We present the results of experimental and theoretical investigations of the FWM-EIT interaction under continuous-wave (cw), slow light, and stored light conditions. In particular, we provide evidence that indicates that while a Stokes field is generated upon retrieval of the signal field, any information originally encoded in a seeded Stokes field is not independently preserved during the storage process. We present a simple model that describes the propagation dynamics and provides an intuitive description of the EIT-FWM process.

  13. Longitudinal interplay between posttraumatic stress symptoms and coping self-efficacy: A four-wave prospective study.

    Science.gov (United States)

    Bosmans, Mark W G; van der Velden, Peter G

    2015-06-01

    Trauma-related coping self-efficacy (CSE), the perceived capability to manage one's personal functioning and the myriad environmental demands of the aftermath of potentially traumatic events (PTE), has been shown to affect psychological outcomes after these events. Aim of the present four-wave study was to examine the cross-lagged relationships between CSE and posttraumatic stress disorder (PTSD) symptoms following PTEs in order to examine direction of influence. Levels of CSE and PTSD symptoms were measured with 4-month intervals. In addition, prospectively assessed personality traits and general self-efficacy perceptions as well as peritraumatic distress were entered in the analyses. The study sample consists of adult respondents of a representative internet panel who experienced PTE in the six months before T1, and did not experience any new PTE or life event between T1 and T3 (N = 400). Respondents were administered the coping self-efficacy scale (CSE-7), impact of event scale (IES) and arousal items of IES-R at each wave (T1 through T3), as well as questions on peritraumatic stress and prospectively measured personality traits (T0). Results of structural equation modeling showed that the effect of CSE on subsequent PTSD symptom levels was dominant. CSE significantly predicted subsequent symptoms, over and above earlier symptom levels, with higher CSE associated with lower PTSD. Symptoms in turn, did not predict subsequent levels of CSE. Higher peritraumatic distress was associated with both higher initial PTSD symptoms and lower initial CSE levels. Higher levels of the personality traits of emotional stability and agreeableness were associated with higher initial CSE levels. This supports a model in which CSE perceptions play an important role in recovery from trauma.

  14. Experimental and Theoretical Analysis of Nondegenerate Ultrabroadband Chirped Pulse Optical Parametric Amplification

    Institute of Scientific and Technical Information of China (English)

    刘红军; 赵卫; 陈国夫; 王屹山; 于连君; 阮驰; 卢克清

    2004-01-01

    Experimental investigations of nondegenerate ultrabroadband chirped pulse optical parametric amplification have been carried out. The general mathematical expressions for evaluating parametric bandwidth, gain and gain bandwidth for arbitrary three-wave mixing parametric amplifiers are presented. In our experiments, a type-I noncollinear phase-matched optical parametric amplifier based on lithium triborate, which was pumped by a 5-ns second harmonic pulses from a Q-switched Nd:YAG operating at 10 Hz, seeded by a 14-rs Ti:sapphire laser at 800nm, was presented. The 0.85nJ energy of input chirped signal pulse with 57-FWHM has been amplified to 3.1 μJ at pump intensity 3 G W/cm2, the corresponding parametric gain reached 3.6 × 103, the 53 nm-FWHM gain spectrum bandwidth of output signal has been obtained. The large gain and broad gain bandwidth, which have been confirmed experimentally, provide great potentials to amplify efficiently the broad bandwidth femtosecond light pulses to generate new extremes in power, intensity, and pulse duration using optical parametric chirped pulse amplifiers pumped by powerful nanosecond systems.

  15. Formation of Black Hole X-Ray Binaries with Non-degenerate Donors in Globular Clusters

    Science.gov (United States)

    Ivanova, Natalia; da Rocha, Cassio A.; Van, Kenny X.; Nandez, Jose L. A.

    2017-07-01

    In this Letter, we propose a formation channel for low-mass X-ray binaries with black hole accretors and non-degenerate donors via grazing tidal encounters with subgiants. We estimate that in a typically dense globular cluster with a core density of 105 stars pc-3, the formation rates are about one binary per Gyr per 50-100 retained black holes. The donors—stripped subgiants—will be strongly underluminous when compared to subgiant or giant branch stars of the same colors. The products of tidal stripping are underluminous by at least one magnitude for several hundred million years when compared to normal stars of the same color, and differ from underluminous red stars that could be produced by non-catastrophic mass transfer in an ordinary binary. The dynamically formed binaries become quiescent LMXBs, with lifetimes of about a Gyr. The expected number of X-ray binaries is one per 50-200 retained black holes, while the expected number of strongly underluminous subsubgiant is about half this. The presence of strongly underluminous stars in a GC may be indicative of the presence of black holes.

  16. Is A Quantum Stabilizer Code Degenerate or Nondegenerate for Pauli Channel?

    CERN Document Server

    Xiao, Fangying

    2010-01-01

    Mapping an error syndrome to the error operator is the core of quantum decoding network and is also the key step of recovery. The definitions of the bit-flip error syndrome matrix and the phase-flip error syndrome matrix were presented, and then the error syndromes of quantum errors were expressed in terms of the columns of the bit-flip error syndrome matrix and the phase-flip error syndrome matrix. It also showed that the error syndrome matrices of a stabilizer code are determined by its check matrix, which is similar to the classical case. So, the error-detection and recovery techniques of classical linear codes can be applied to quantum stabilizer codes after some modifications. Some necessary and/or sufficient conditions for the stabilizer code over GF(2) is degenerate or nondegenerate for Pauli channel based on the relationship between the error syndrome matrices and the check matrix was presented. A new way to find the minimum distance of the quantum stabilizer codes based on their check matrices was pr...

  17. Quantum correlations by four-wave mixing in an atomic vapor in a non-amplifying regime: a quantum beam splitter for photons

    CERN Document Server

    Glorieux, Quentin; Guibal, Samuel; Likforman, Jean-Pierre; Coudreau, Thomas; 10.1103/PhysRevA.84.053826

    2011-01-01

    We study the generation of intensity quantum correlations using four-wave mixing in a rubidium vapor. The absence of cavity in these experiments allows to deal with several spatial modes simultaneously. In the standard, amplifying, configuration, we measure relative intensity squeezing up to 9.2 dB below the standard quantum limit. We also theoretically identify and experimentally demonstrate an original regime where, despite no overall amplification, quantum correlations are generated. In this regime a four-wave mixing set-up can therefore play the role of a photonic beam splitter with non--classical properties, i.e. a device that splits a coherent state input into two quantum correlated beams.

  18. Generation of femtosecond anti-stokes pulses through phase-matched parametric four-wave mixing in a photonic crystal fiber.

    Science.gov (United States)

    Konorov, S O; Serebryannikov, E E; Zheltikov, A M; Zhou, Ping; Tarasevitch, A P; von der Linde, D

    2004-07-01

    Phase-matched parametric four-wave mixing in higher-order guided modes of a photonic crystal fiber is shown to result in an efficient decay of 40-fs 800-nm Ti:sapphire laser pump pulses into an anti-Stokes signal with a central wavelength around 590-600 nm and a Stokes signal centered at 1.25 microm. The photonic crystal fiber is designed in such a way as to minimize the group-velocity dispersion at the pump wavelength, phase match the parametric four-wave-mixing process, and reduce the group delay between the pump and the anti-Stokes pulses. The duration of the anti-Stokes pulse under these conditions, as shown by cross-correlation frequency-resolved optical gating measurements, is less than 200 fs.

  19. Self-pumped phase conjugation and four-wave mixing in 0- and 45-deg-cut n-type BaTiO3:Co

    Science.gov (United States)

    Garrett, M. H.; Chang, J. Y.; Jenssen, H. P.; Warde, C.

    1993-01-01

    Relatively fast self-pumped phase-conjugate and four-wave-mixing rise times are reported in n-type cobalt-doped barium titanate. With the crystal oriented in a 45-deg cut as compared with the same crystal in a 0-deg cut we find a factor of 3 decrease in the 0-90-percent rise time to 800 ms with 25-mW input power at 514.5 nm. Also, the self-pumped phase-conjugate reflectivity increases from 20 to 40 percent. We deduce that the phase conjugation is from internally seeded stimulated photorefractive backscattering. The four-wave-mixing rise time of the 45-deg-cut crystal is 4 ms with a reflectivity of 48 percent when the pumping beams are derived from self-pumped phase conjugation that has an input power of 25 mW.

  20. Multi-wavelength Erbium-doped fiber laser based on four-wave-mixing effect in single mode fiber and high nonlinear fiber.

    Science.gov (United States)

    Wang, Pinghe; Weng, Danmei; Li, Kun; Liu, Yong; Yu, Xuecai; Zhou, Xiaojun

    2013-05-20

    A multi-wavelength Erbium-doped fiber (EDF) laser based on four-wave-mixing is proposed and experimentally demonstrated. The 5 km single mode fiber in the cavity enhances the four-wave-mixing to suppress the homogenous broadening of the erbium-doped fiber and get the stable multi-wavelength comb. The lasing stability is investigated. When the pump power is 300 mW, the fiber laser has 5-lasing lines and the maximum fluctuation of the output power is about 3.18 dB. At the same time, a laser with 110 m high nonlinear fiber (HNFL) is demonstrated. When the pump power is 300 mW, it has 7-lasing lines (above -30 dBm) and the maximum fluctuation is 0.18dB.

  1. All-optical OTDM-to-WDM signal-format translation and OTDM add-drop functionality using bidirectional four wave mixing in semiconductor optical amplifier

    DEFF Research Database (Denmark)

    Buxens Azcoaga, Alvaro Juan; Poulsen, Henrik Nørskov; Clausen, Anders;

    2000-01-01

    The authors report simultaneous demultiplexing and wavelength conversion of two 10Gbit/s channels from a 40Gbit/s OTDM signal using bidirectional four wave mixing in a single semiconductor optical amplifier. Simultaneous demultiplexing and clearing of a 10Gbit/s channel from the 40Gbit/s OTDM dat...... stream is also reported. The BER penalty induced by bi-FWM is...

  2. Bandwidth scaling of a phase-modulated continuous-wave comb through four-wave mixing in a silicon nano-waveguide.

    Science.gov (United States)

    Liu, Yang; Metcalf, Andrew J; Company, Victor Torres; Wu, Rui; Fan, Li; Varghese, Leo T; Qi, Minghao; Weiner, Andrew M

    2014-11-15

    We demonstrate an on-chip four-wave mixing (FWM) scheme in a silicon nanowaveguide to scale the bandwidth of a frequency comb generated by phase modulation of continuous-wave (CW) lasers. The FWM process doubles the bandwidth of the initial comb generated by the modulation of a CW laser. For example, a wavelength-tunable frequency comb with >100 comb lines spaced by 10 GHz within a bandwidth of 5 dB is generated.

  3. Time-resolved four-wave mixing in InAs/InGaAs quantum-dot amplifiers under electrical injection

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang Werner; Hvam, Jørn Märcher;

    2000-01-01

    Time-resolved four-wave mixing in an InAs/InGaAs/GaAs electrically pumped quantum-dot amplifier is measured at room temperature for different applied bias currents going from optical absorption to gain of the device. The four-wave mixing signal from 140 fs pulses shows a transition from a delayed...... photon-echo response in the absorption regime to a prompt free polarization decay in the gain regime. This corresponds to a pronounced reduction of the dephasing time from 250 fs at zero bias to less than 50 fs at the maximum applied current. The four-wave mixing response at transparency of the device...... shows a composite structure with both photon echo and free-polarization decay. This is a signature of the digital occupation number in quantum dots, resulting at transparency in a signal from dots occupied with either zero or two excitons corresponding to absorption or gain of the dot ground state. (C...

  4. 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.

  5. Cascade quantum teleportation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Nan-run; GONG Li-hua; LIU Ye

    2006-01-01

    In this letter a cascade quantum teleportation scheme is proposed. The proposed scheme needs less local quantum operations than those of quantum multi-teleportation. A quantum teleportation scheme based on entanglement swapping is presented and compared with the cascade quantum teleportation scheme. Those two schemes can effectively teleport quantum information and extend the distance of quantum communication.

  6. The blue light indicator in rubidium 5S-5P-5D cascade excitation

    Science.gov (United States)

    Raja, Waseem; Ali, Md. Sabir; Chakrabarti, Alok; Ray, Ayan

    2017-07-01

    The cascade system has played an important role in contemporary research areas related to fields like Rydberg excitation, four wave mixing and non-classical light generation, etc. Depending on the specific objective, co or counter propagating pump-probe laser experimental geometry is followed. However, the stepwise excitation of atoms to states higher than the first excited state deals with increasingly much fewer number of atoms even compared to the population at first excited level. Hence, one needs a practical indicator to study the complex photon-atom interaction of the cascade system. Here, we experimentally analyze the case of rubidium 5S → 5P → 5D as a specimen of two-step excitation and highlight the efficacy of monitoring one branch, which emits 420 nm, of associated cascade decay route 5D → 6P → 5S, as an effective monitor of the coherence in the system.

  7. Effect of the coherent cancellation of the two-photon resonance on the generation of vacuum ultraviolet light by two-photon reasonantly enhanced four-wave mixing

    Energy Technology Data Exchange (ETDEWEB)

    Payne, M.G.; Garrett, W.R.; Judish, J.P.; Wunderlich, R.

    1988-11-01

    Many of the most impressive demonstrations of the efficient generation of vacuum ultraviolet (VUV) light have made use of two- photon resonantly enhanced four-wave mixing to generate light at ..omega../sub VUV/ = 2..omega../sub L1/ +- ..omega../sub L2/. The two-photon resonance state is coupled to the ground state both by two photons from the first laser, or by a photon from the second laser and one from the generated VUV beam. We show here that these two coherent pathways destructively interfere once the second laser is made sufficiently intense, thereby leading to an important limiting effect on the achievable conversion efficiency. 4 refs.

  8. Spectral phase transfer from near IR to deep UV by broadband phase-matched four-wave mixing in an argon-filled hollow core waveguide

    Science.gov (United States)

    Siqueira, J. P.; Mendonça, C. R.; Zilio, S. C.; Misoguti, L.

    2016-10-01

    We report on the implementation of a spectral phase transfer scheme from near IR to deep UV, in which the frequency conversion step is based on the broadband phase-matched four-wave mixing in a gas-filled hollow core waveguide. Micro joule level femtosecond pulses at 260 nm were generated by nonlinear mixing of a Ti:sapphire laser and its second-harmonic. The transfer of a π-step phase in a controllable manner was proposed and confirmed by a modulation observed in the generated deep UV femtosecond pulse spectrum due to an interference process. Numerical simulations confirmed our results.

  9. Ultrafast optical transistor and router of multi-order fluorescence and spontaneous parametric four-wave mixing in Pr³⁺:YSO.

    Science.gov (United States)

    Wen, Feng; Ali, Imran; Hasan, Abdulkhaleq; Li, Changbiao; Tang, Haijun; Zhang, Yufei; Zhang, Yanpeng

    2015-10-15

    We study the realization of an optical transistor (switch and amplifier) and router in multi-order fluorescence (FL) and spontaneous parametric four-wave mixing (SP-FWM). We estimate that the switching speed is about 15 ns. The router action results from the Autler-Townes splitting in spectral or time domain. The switch and amplifier are realized by dressing suppression and enhancement in FL and SP-FWM. The optical transistor and router can be controlled by multi-parameters (i.e., power, detuning, or polarization).

  10. Photoionization pathways and thresholds in generation of Lyman-α radiation by resonant four-wave mixing in Kr-Ar mixture

    OpenAIRE

    Oleg A. Louchev; Norihito Saito; Yu Oishi; Koji Miyazaki; Kotaro Okamura; Jumpei Nakamura; Masahiko Iwasaki; Satoshi Wada

    2016-01-01

    We develop a set of analytical approximations for the estimation of the combined effect of various photoionization processes involved in the resonant four-wave mixing generation of ns pulsed Lyman-α (L-α) radiation by using 212.556 nm and 820-845 nm laser radiation pulses in Kr-Ar mixture: (i) multi-photon ionization, (ii) step-wise (2+1)-photon ionization via the resonant 2-photon excitation of Kr followed by 1-photon ionization and (iii) laser-induced avalanche ionization produced by genera...

  11. Phase-matched waveguide four-wave mixing scaled to higher peak powers with large-core-area hollow photonic-crystal fibers.

    Science.gov (United States)

    Konorov, S O; Serebryannikov, E E; Fedotov, A B; Miles, R B; Zheltikov, A M

    2005-05-01

    Hollow photonic-crystal fibers with large core diameters are shown to allow waveguide nonlinear-optical interactions to be scaled to higher pulse peak powers. Phase-matched four-wave mixing is predicted theoretically and demonstrated experimentally for millijoule nanosecond pulses propagating in a hollow photonic-crystal fiber with a core diameter of about 50 microm , suggesting the way to substantially enhance the efficiency of nonlinear-optical spectral transformations and wave mixing of high-power laser pulses in the gas phase.

  12. Four-wave mixing based widely tunable wavelength conversion using 1-m dispersion-shifted bismuth-oxide photonic crystal fiber.

    Science.gov (United States)

    Chow, K K; Kikuchi, K; Nagashima, T; Hasegawa, T; Ohara, S; Sugimoto, N

    2007-11-12

    We demonstrate widely tunable wavelength conversion based on four-wave mixing using a dispersion-shifted bismuth-oxide photonic crystal fiber (Bi-PCF). A 1-meter-long Bi-PCF is used as the nonlinear medium for wavelength conversion of a 10 Gb/s non-return-to-zero (NRZ) signal. A 3- dB working range of the converted signal over 35 nm is obtained with around 1-dB power penalty in the bit-error-rate measurements.

  13. Measurements of the nonlinear refractive index of air, N2, and O2 at 10 μm using four-wave mixing.

    Science.gov (United States)

    Pigeon, J J; Tochitsky, S Ya; Welch, E C; Joshi, C

    2016-09-01

    We report on measurements of the nonlinear index of refraction of air, N2, and O2 at a wavelength close to 10 μm by collinear four-wave mixing of a 200 MW CO2 laser beat-wave. The use of a 200 ps long beat-wave comprising radiation amplified on the 10P20 and 10R16 lines of the CO2 laser provides a sensitive method to measure the small nonlinearities characteristic of the gas phase in a spectral region where no such data exists.

  14. SOLUTION METHOD OF DYNAMIC ROUTING AND WAVE LENGTH ASSIGNMENT PROBLEM FOR WDM NETWORKS WITH TAKING INTO ACCOUNT FOUR-WAVE MIXING EFFECT

    Directory of Open Access Journals (Sweden)

    D. V. Ageyev

    2016-05-01

    Full Text Available The problem of dynamic route selection and wavelengths assignment in WDM networks is solved. This problem is important in WDM network management when requests are serviced for short-term connection installation and excess traffic is transferred. The proposed solution method is heuristic and is an improvement of the previously known method by taking into account the influence of four-wave mixing and using the new metric for finding the routes prospective for application. This makes it possible to reduce the probability of blocking calls during the connections at the average of 13% and the value of Q factor at 0.812.

  15. QPSK-to-2×BPSK wavelength and modulation format conversion through phase-sensitive four-wave mixing in a highly nonlinear optical fiber

    DEFF Research Database (Denmark)

    Da Ros, Francesco; Dalgaard, Kjeld; Lei, Lei

    2013-01-01

    A phase-sensitive four-wave mixing (FWM) scheme enabling the simultaneous conversion of the two orthogonal quadratures of an optical signal to different wavelengths is demonstrated for the first time under dynamic operation using a highly nonlinear optical fiber (HNLF) as the nonlinear medium....... The scheme is first optimized with respect to the power levels and phases of the four phase-coherent pumps. The successful modulation and wavelength conversion of the two complex quadratures of a quadrature phase-shift keying (QPSK) signal to two binary phase-shift keying (BPSK) signals is then demonstrated...

  16. Comparative analysis of four-wave mixing of optical pulses in slow- and fast-light regimes of a silicon photonic crystal waveguide.

    Science.gov (United States)

    Lavdas, Spyros; Panoiu, Nicolae C

    2015-09-15

    We present an in-depth study of four-wave mixing (FWM) of optical pulses in silicon photonic crystal waveguides. Our analysis is based on a rigorous model that includes all relevant linear and nonlinear optical effects and their dependence on the group velocity, as well as the influence of free carriers on pulse dynamics. In particular, we reveal key differences between FWM in the slow- and fast-light regimes and how they are related to the physical parameters of the pulses and waveguide. Finally, we illustrate how these results can be used to design waveguides with optimized FWM conversion efficiency.

  17. Bandwidth and repetition rate programmable Nyquist sinc-shaped pulse train source based on intensity modulators and four-wave mixing.

    Science.gov (United States)

    Cordette, S; Vedadi, A; Shoaie, M A; Brès, C-S

    2014-12-01

    We propose and experimentally demonstrate an all-optical Nyquist sinc-shaped pulse train source based on intensity modulation and four-wave mixing. The proposed scheme allows for the tunability of the bandwidth and the full flexibility of the repetition rate in the limit of the electronic bandwidth of the modulators used through the flexible synthesis of rectangular frequency combs. Bandwidth up to 360 GHz at 40 GHz rate and up to 45 frequency lines at 5 GHz rate are demonstrated with 40 GHz modulators.

  18. A New Approach to Cascaded Stimulated Brillouin Scattering

    CERN Document Server

    Dong, Mark

    2015-01-01

    We present a novel approach to cascaded stimulated Brillouin scattering and frequency comb generation in which the multitude of interacting pump, Stokes, and anti-Stokes optical fields are described by a single forward wave and a single backward wave at a single carrier frequency. The envelopes of these two waves are modulated through coupling to a single acoustic oscillation and through four-wave mixing. Starting from a single pump field, we observe the emergence of a comb of frequencies as the intensity is increased. The set of three differential equations derived here are sufficient to describe the generation of any number of Brillouin sidebands in oscillator systems that would have required hundreds of coupled equations in the standard approach. We test the new approach on some published experiments and find excellent agreement with the results.

  19. Phase-locking in cascaded stimulated Brillouin scattering

    CERN Document Server

    Büttner, Thomas F S; Steel, M J; Hudson, Darren D; Eggleton, Benjamin J

    2015-01-01

    Cascaded stimulated Brillouin scattering (SBS) is a complex nonlinear optical process that results in the generation of several optical waves that are frequency shifted by an acoustic resonance frequency. Four-wave mixing (FWM) between these Brillouin shifted optical waves can create an equally spaced optical frequency comb with a stable spectral phase, i.e. a Brillouin frequency comb (BFC). Here, we investigate phase-locking of the spectral components of BFCs, considering FWM interactions arising from the Kerr-nonlinearity as well as from coupling by the acoustic field. Deriving for the first time the coupled-mode equations that include all relevant nonlinear interactions, we examine the contribution of the various nonlinear processes to phase-locking, and show that different regimes can be obtained that depend on the length scale on which the field amplitudes vary.

  20. Phase-locking in cascaded stimulated Brillouin scattering

    Science.gov (United States)

    Büttner, Thomas F. S.; Poulton, Christopher G.; Steel, M. J.; Hudson, Darren D.; Eggleton, Benjamin J.

    2016-02-01

    Cascaded stimulated Brillouin scattering is a complex nonlinear optical process that results in the generation of several optical waves that are frequency shifted by an acoustic resonance frequency. Four-wave mixing (FWM) between these Brillouin shifted optical waves can create an equally spaced optical frequency comb with a stable spectral phase, i.e. a Brillouin frequency comb (BFC). Here, we investigate phase-locking of the spectral components of BFCs, considering FWM interactions arising from the Kerr-nonlinearity as well as from coupling by the acoustic field. Deriving for the first time the coupled-mode equations that include all relevant nonlinear interactions, we examine the contribution of the various nonlinear processes to phase-locking, and show that different regimes can be obtained that depend on the length scale on which the field amplitudes vary.