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ABSTRACT: The effect of Doppler broadening on the gain spectrum is theoretically investigated in a hot N-type active Raman gain atomic system. It is found that the gain peak in the spectrum can be extremely narrowed and amplified by two orders at room temperature as compared with that in the cold atomic system. This remarkable result originates from the shift of the dressed levels and the modification to the transition probability between dressed states when the Doppler effect is considered in the hot atomic system. The enhanced subluminal and superluminal pulse propagation for the probe field in the hot atomic system has also been obtained by numerical simulation; the probe pulse undergoes no absorption and little pulse distortion.
Journal of Physics B Atomic Molecular and Optical Physics 06/2011; 44(13):135505. · 1.88 Impact Factor
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ABSTRACT: In an Fe = 0↔Fg = 1 transition interacting with a weak π-polarized probe and a strong σ-polarized standing-wave coupling, we obtain single or double photonic band gaps depending on the applied magnetic field. Moreover, the coherently induced two-photonic-band gap structure can be tuned by the magnitude of the magnetic field. Such a magnetic-field-dependent feature is exploited to devise magneto-optical switching and routing of two light pulses. The efficient magneto-optical control of light propagation may have applications in an optical network and optical information processing.
Journal of Physics B Atomic Molecular and Optical Physics 02/2011; 44(6):065502. · 1.88 Impact Factor
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Ying-Fei Zhang,
Rong Wang,
Zhi-Hui Kang,
Li-Li Qu, Yun Jiang,
Jin-Yue Gao,
Yury M Andreev,
Grigory V Lanskii,
Konstantin A Kokh,
Alexander N Morozov,
Anna V Shaiduko,
Vladimir V Zuev
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ABSTRACT: We report a systematic study of AgGaS2- and Al-doped GaSe crystals in comparison with pure GaSe and S-doped GaSe crystals. AgGaS2-doped GaSe (GaSe:AgGaS2) crystal was grown by Bridgman technique from the melt of GaSe:AgGaS2 (10.6 wt.%). Its real composition was identified as GaSe:S (2 wt.%). Al-doped GaSe-(GaSe: Al) crystals were grown from the melt of GaSe and 0.01, 0.05, 0.1, 0.5, 1, 2 mass% of aluminium. Al content in the grown crystals is too small to be measured. The hardness of GaSe:S (2 wt.%) crystal grown from the melt of GaSe:AgGaS2 is 25% higher than that of GaSe:S (2 wt.%) crystal grown by a conventional S-doping technique and 1.5- to 1.9-times higher than that of pure GaSe. GaSe:Al crystals are characterized by 2.5- to 3-times higher hardness than that of pure GaSe and by extremely low conductivity of <= 10(-7) Om(-1) cm(-1). A comparative experiment on SHG in AgGaS2-, Al-, S-doped GaSe and pure GaSe is carried out under the pumps of 2.12-2.9 mu m fs OPA and 9.2-10.8 mu m ns CO2 laser. It was found that GaSe:S crystals possess the best physical properties for mid-IR applications among these doped GaSe crystals. GaSe:Al crystals have relatively low conductivity which have strong potential for THz application. (C) 2010 Elsevier B.V. All rights reserved.
Optics Communications 01/2011; 284(6):1677-1681. · 1.49 Impact Factor
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ABSTRACT: We demonstrate in experiment an efficient cw four-wave mixing scheme with maximal intensity conversion efficiency up to 73% in a double-Λ system of hot rubidium atoms. Relevant theoretical analysis shows that this high conversion efficiency benefits greatly from the constructive interference between two four-wave mixing channels, characterized by two different space-dependent phases.
Optics Letters 11/2010; 35(22):3778-80. · 3.40 Impact Factor
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ABSTRACT: We report an experimental demonstration of dual-channel all-optical wavelength conversion switching in hot Rb vapor. In a four-level atomic system, a coupling field and a pump field interact with both (87)Rb and (85)Rb isotopes simultaneously and facilitate the generation of two nonlinear signals when the probe field is applied to the corresponding transition. Each nonlinear signal is switched on and off separately by the pump field at different frequencies based on four-wave mixing and isotope shifts.
Optics Express 12/2009; 17(25):23332-7. · 3.59 Impact Factor
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ABSTRACT: We theoretically investigate the influence of a coherent pump field on the propagation of a weak light pulse of a probe field in a four-level atomic system. Due to the modulation of the pump field, the light pulse can be manipulated from subluminal to superluminal with negligible distortion. This scheme can be realized in both the ultracold and Doppler-broadened atomic systems. We also demonstrate that the spectral linewidth with an anomalous dispersion is reduced by thermal averaging; therefore, one can obtain a larger negative group refractive index in room-temperature vapor than the largest value achieved in ultracold atomic gas.
Journal of the Optical Society of America B 11/2009; 26(12):2256-2260. · 2.18 Impact Factor
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ABSTRACT: We experimentally demonstrate the slowing and storage of double light pulses in a Pr(3+):Y(2)SiO(5) crystal using a multilevel-tripod scheme. Owing to double dark-state polaritons of the tripod-type system, two signal pulses can be simultaneously slowed. Also, we realize the simultaneous storage (and retrieval) of double light pulses by switching off (and back on) the control field. Slowing and storage of double light pulses in solids may have practical applications in quantum information and quantum networks.
Optics Letters 10/2009; 34(17):2596-8. · 3.40 Impact Factor
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ABSTRACT: We experimentally demonstrate a three-channel all-optical routing based on light storage in a Pr(3+):Y(2)SiO(5) crystal. By switching off the control field under the condition of electromagnetically induced transparency, the optical information of the probe light pulse can be stored in the crystal. When three retrieve control fields are switched on in the release process, the stored optical information from one light channel can be transferred (or distributed) into three different light channels. Also we show that this all-optical routing can be time-delayed. Such a multichannel all-optical routing in solids may have practical applications in quantum information and all-optical network.
Optics Express 08/2009; 17(14):12197-202. · 3.59 Impact Factor
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ABSTRACT: We experimentally and theoretically demonstrate that multioptical signals can be effectively stored and retrieved by fractional stimulated Raman adiabatic passage technique in a tripod-type four-level 87Rb atomic system. The optical pulses stored can be controllably released into two of the three different channels. The restored pulses have the same frequency, polarization, and propagation direction as the writing pulses. The experimental results fit very well with the numerical simulations.
Phys. Rev. A. 05/2009; 79(5).
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ABSTRACT: We experimentally demonstrate an enhanced four-wave mixing (FWM) based on atomic coherence in a Pr3+:Y2SiO5 crystal. By employing coherent population return and fractional stimulated Raman adiabatic passage to prepare maximum atomic coherence in the crystal, an efficient FWM signal can be generated. By measuring the generated FWM signal, the time-dependent atomic coherence is monitored. Such an enhanced FWM in solids may have practical applications in nonlinear optics and laser spectroscopy.
Applied Physics Letters 12/2008; 93(23):231107-231107-3. · 3.84 Impact Factor
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ABSTRACT: We experimentally demonstrate an all-optical routing based on light storage in a Pr3+:Y2SiO5 crystal. Under electromagnetically induced transparency, the optical information of the probe light pulse can be stored in the crystal. By simultaneously switching on two retrieve control fields in the release process, the stored optical information from one light channel can be distributed into two light channels. Such an all-optical routing in solids may have practical applications in quantum information and all-optical network.
Applied Physics Letters 12/2008; 93(22):221112-221112-3. · 3.84 Impact Factor
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ABSTRACT: We experimentally and theoretically demonstrate that the atomic coherence can be completely transferred or arbitrarily contributed among the different levels in a four-level atomic (tripod) scheme by a group of coupled pulse sequences. This technique can be applied to the information conversion in slow-light storage, quantum logical gates, and so on, which is based on the atomic coherence effect.
Optics Letters 11/2008; 33(20):2380-2. · 3.40 Impact Factor
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ABSTRACT: We theoretically study the transmission and reflection of the probe travelling wave in an electromagnetically induced absorption grating (EIG), which is created in a three-level Lambda-type atomic system when the coupling field is a standing wave. Using the system, we show that a photonic stop band can exist on one side away from the resonance point in ultracold atomic gas, while there is an enhanced absorption at resonance and small reflection around it in the thermal atomic gas. Because our method can deal with such two cases, it is helpful to further understand the effects of the Doppler effect on atomic coherence and interference.
Optics Express 10/2008; 16(20):15455-62. · 3.59 Impact Factor
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ABSTRACT: We show theoretically that the propagation of light can be slowed down considerably using the method of coherent hole-burning in a Doppler broadened three-level lambda-type atomic medium without the Doppler-free configurations. The reduction of group velocity of light pulse is achieved by the application of a saturating beam and a strong coupling beam which produce a narrow spectral hole-burning at resonance. We can obtain a larger group index than that using the method of saturation absorption spectroscopy in Doppler-broadened two-level atomic systems.
Optics Express 07/2008; 16(15):11604-10. · 3.59 Impact Factor
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Hong-Zhi Zhang,
Zhi-Hui Kang, Yun Jiang,
Jin-Yue Gao,
Feng-Guang Wu,
Zhi-Shu Feng,
Yury M Andreev,
Grigory V Lanskii,
Aleksander N Morozov,
Elena I Sachkova,
Sergei Y Sarkisov
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ABSTRACT: The optical properties of p-type GaSe and mixed GaSe(1-x)S(x), x=0.04, 0.023, 0.090, 0.133, 0.175, 0.216, 0.256, 0.362, 0.369, and 0.412, crystals were studied to reveal the potentials for phase matching and frequency conversion. Comparative experiment on Er3+:YSGG and CO2 laser SHG at identical experimental conditions is carried out at room temperature. Any change in polytype structure of GaSe1(1-x)S(x) was not found.
Optics Express 07/2008; 16(13):9951-7. · 3.59 Impact Factor
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ABSTRACT: Optical transmission range and phase matching (PM) conditions for second harmonic generation (SHG) of Er3+:YSGG and CO2 laser in indium doped GaSe:In(0.1, 1.23, 2.32 mass%) are studied in comparison with these in pure and sulfur doped GaSe:S(0.09, 0.5, 2.2, 3 mass%) crystals. No changes in transparency curve are found in GaSe crystals up to 2.32 mass% indium content, but as small change as 0.18 degrees in PM angle for 2.79 microm Er3+:YSGG laser SHG and approximately 0.06 degrees for 9.58 microm CO2 laser emission line SHG are detected. PM properties of the crystals are evaluated as a function of temperature over the range from -165 to 230 degrees C. The value of dtheta/dT, the change in PM angle with variation of temperature, is found to be very small for GaSe:In crystals. While for SHG of Er3+:YSGG laser, dtheta/dT =22"/1 degrees C only, it is as small as -4.9"/1 degrees C for that of CO2 laser radiation. Linear variation of PM angle with temperature increasing is an indicator of absence of crystals structure transformation within temperature range from -165 to 230 degrees C. Thus, application of GaSe:In solid solutions in high average power nonlinear optical systems seems to be prospective.
Optics Express 07/2008; 16(13):9978-85. · 3.59 Impact Factor
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ABSTRACT: The refractive-index profile of ion-exchange channel waveguide is reconstructed by near-field measurement combined with two-dimensional inverse matrix method, which can avoid the problems brought by multimeasurements and iteration smoothing in the process. The method used here has the advantages of convenient operation and accurate results for the characteristics of the asymmetric channel waveguide. It can be also applied to the refractive-index profile measurements of graded index fibers, polarization maintaining fibers, and single-mode planar waveguides.
Review of Scientific Instruments 03/2008; 79(2 Pt 1):025104. · 1.37 Impact Factor
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ABSTRACT: We experimentally demonstrate an erasure of stored optical information in a Pr <sup>3+</sup>: Y <sub>2</sub> Si O <sub>5</sub> crystal by applying an erasing pulse to destroy atomic spin coherence. We observed an erasing efficiency of about 85%. Such an erasing operation of stored optical information may have practical applications in the field of information processing and all-optical network.
Applied Physics Letters 02/2008; · 3.84 Impact Factor
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ABSTRACT: We demonstrate storage and selective release of a light pulse in a Pr:YSO crystal, which is based on atomic spin coherence created by fractional stimulated Raman adiabatic passage (STIRAP). The fractional STIRAP gives better storage fidelity compared to STIRAP. Selective release of stored optical information and better storage fidelity have practical applications in information processing and all-optical communication.
Applied Physics Letters 02/2008; · 3.84 Impact Factor
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ABSTRACT: We experimentally demonstrate light storage and release in a four-level double-lambda atomic system of a Pr (3+):Y(2)SiO(5) crystal. Based on the technique of light storage, we realize optical information transfer between two light channels. The coherent optical information of a probe pulse stored in the crystal can be selectively released into two different light channels by varying the frequency and propagation direction of the switch-on control field.
Optics Express 12/2007; 15(24):16044-50. · 3.59 Impact Factor
