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1.
Opt Express ; 27(5): 6370-6376, 2019 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-30876223

RESUMO

The research of Airy beams has attained much attention due to their unique characteristics. Coherent control of Airy beams is important for further light beam manipulation and information processing. In this paper, we experimentally investigate the storage and retrieval of 2D Airy wavepackets in a solid-state medium driven by electromagnetically induced transparency (EIT). The transverse profile of the weak probe pulse is modulated by Airy wavepackets. Under EIT condition, the probe Airy wavepackets are stored into the experimental medium by manipulating the intensity of the control field, and later retrieved by the opposite process. The retrieved Airy wavepackets keep a high similarity compared with those before the storage. Furthermore, the self-healing property of the retrieved Airy wavepackets is investigated. This storage of Airy wavepackets develops the control method of Airy beams, which will be useful in further applications.

2.
Sci Rep ; 5: 18179, 2015 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-26658846

RESUMO

Coherent storage of optical image in a coherently-driven medium is a promising method with possible applications in many fields. In this work, we experimentally report a controllable spatial-frequency routing of image via atomic spin coherence in a solid-state medium driven by electromagnetically induced transparency (EIT). Under the EIT-based light-storage regime, a transverse spatial image carried by the probe field is stored into atomic spin coherence. By manipulating the frequency and spatial propagation direction of the read control field, the stored image is transferred into a new spatial-frequency channel. When two read control fields are used to retrieve the stored information, the image information is converted into a superposition of two spatial-frequency modes. Through this technique, the image is manipulated coherently and all-optically in a controlled fashion.

3.
Photochem Photobiol ; 90(1): 29-34, 2014 01.
Artigo em Inglês | MEDLINE | ID: mdl-23931414

RESUMO

The effects of π-spacer and electron donor groups on the photophysical behaviors of fluorenone-based linear conjugated oligomers have been systemically investigated. Solvent-dependent steady-state measurements exhibit that the fluorene vinylene (FV) spacer and the electron-donating ability of donor group are able to modulate the spectral features of oligomers and the fluorescence quantum yield could decrease with the increasing of the solvent polarity. Meanwhile, quantum chemical calculation simulates their absorption spectra, and analyzes their electron transition components simultaneously. The transient absorption measurements focus on the photoexcitation dynamics of these oligomers in the toluene solution, which show that an intramolecular charge transfer state exists in the relaxation process of excited states, and its generation process could accelerate with the introduction of FV spacer and the enhancement of donor strength.

4.
Photochem Photobiol ; 90(1): 45-50, 2014 01.
Artigo em Inglês | MEDLINE | ID: mdl-23962208

RESUMO

We study the photophysical characters of two oligofluorenes-functionalized anthracenes molecules with different fluorine-vinylene (FV) units, which exhibits that "excimer" state appears in the solution after photoexcitation. The dynamic data shows that two mechanisms are responsible for the generation of "excimer". The fast one is controlled by the arene-arene interaction between molecules and the slow one is influenced by the diffusion motion of molecules. Increasing the number of FV units may suppress the DM-dependent "excimer" and enhance the yield of intrinsic fluorescence, which finally improves the fluorescence property of molecules in solution.

5.
Opt Express ; 20(21): 23559-69, 2012 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-23188319

RESUMO

We experimentally study the resonance fluorescence from an excited two-level atom when the atomic upper level is coupled by a nonresonant field to a higher-lying state in a rubidium atomic beam. The heights, widths and positions of the fluorescence peaks can be controlled by modifying the detuning of the auxiliary field. We explain the observed spectrum with the transition properties of the dressed states generated by the coupling of the two laser fields. We also attribute the line narrowing to the effects of Spontaneously Generated Coherence between the close-lying levels in the dressed state picture generated by the auxiliary field. And the corresponding spectrum can be viewed as the evidence of Spontaneously Generated Coherence. The experimental results agree well with calculations based on the density-matrix equations.


Assuntos
Fluorescência , Luz , Modelos Teóricos , Teoria Quântica , Espalhamento de Radiação , Simulação por Computador
6.
Opt Express ; 20(4): 3509-18, 2012 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-22418110

RESUMO

We demonstrate coherent control of spontaneous emission from an indirectly coupled transition in a microwave driven four-level atomic system. The transition of concern is not directly coupled by any laser fields, while the ground state is coupled to another ground state by a microwave field. We show that the coupling of the microwave field produces interesting features such as double narrow lines in the emission spectrum. The heights, widths and positions of the emission peaks can be controlled by modifying the Rabi frequency and detuning of the microwave field. We discuss the spectra in the dressed states basis.

7.
Opt Lett ; 35(22): 3778-80, 2010 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-21081994

RESUMO

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.

8.
Opt Lett ; 34(17): 2596-8, 2009 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-19724501

RESUMO

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.

9.
Opt Express ; 17(14): 12197-202, 2009 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-19582135

RESUMO

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.

10.
Opt Express ; 17(25): 23332-7, 2009 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-20052260

RESUMO

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.


Assuntos
Dispositivos Ópticos , Rubídio/química , Projeto Auxiliado por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Fótons , Rubídio/efeitos da radiação , Espalhamento de Radiação
11.
Opt Lett ; 33(20): 2380-2, 2008 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-18923629

RESUMO

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.

12.
Opt Express ; 16(13): 9951-7, 2008 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-18575565

RESUMO

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.


Assuntos
Gálio/química , Lasers , Modelos Teóricos , Óptica e Fotônica/instrumentação , Selênio/química , Simulação por Computador , Cristalização/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Espalhamento de Radiação , Temperatura Ambiente
13.
Opt Express ; 16(13): 9978-85, 2008 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-18575568

RESUMO

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.


Assuntos
Cristalização/métodos , Gálio/química , Lasers de Estado Sólido , Modelos Teóricos , Refratometria/instrumentação , Selênio/química , Transdutores , Simulação por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Espalhamento de Radiação
14.
Opt Lett ; 33(7): 687-9, 2008 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-18382518

RESUMO

We investigate the effects of spontaneously generated coherence (SGC) on the electromagnetically induced transparency features in a four-level Lambda-type system. We show that double-transparency windows and a controllable narrow absorption peak can be obtained with the presence of SGC. We present an equivalent system without the rigorous requirement of close-lying levels to observe the phenomena. We also experimentally demonstrate the corresponding features in a rubidium atomic beam.

15.
Rev Sci Instrum ; 79(2 Pt 1): 025104, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18315326

RESUMO

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.

16.
Guang Pu Xue Yu Guang Pu Fen Xi ; 28(12): 2812-5, 2008 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-19248489

RESUMO

Quaternized polyvinyl alcohol (QAPVA) and phosphate monoester polyvinyl alcohol (PMPVA) were self-assembled into polyion complex (PIC) membrane. The infrared spectra (IR) of PIC membrane dipped in 95% ethanol for 48 h were studied in the temperature range of 20-120 degrees C with an interval of 20 degrees C by analyzing the temperature dependent variations of OH stretch vibration base bands (upsilonOH) at >3000 cm(-1). Hydrogen-bond of water in 95% ethanol with PIC was studied. Since the upsilonOH strongly overlapped at >3000 cm(-1), combined with the static electric effect between water in 95% ethanol and ion-bond of PIC at 1300-1700 cm(-1), two-dimensional infrared (2DIR) correlation analysis was applied to describe the possible combined modes between PIC and water in water-alcohol. The result shows that the upsilonOH overlapped was distinguished at >3000 cm(-1), the change of water with varing tempertature was earlier than the intra-membrane OH self association and water was desorbed to separate from ethanol. The absorption peak of water and poly-electrolyte group intra-PIC membrane was identified. The water combined with ion-bond in PIC membrane by static electric effect was adsorbed with the temperature going up and separate from ethanol. The present study provides a simple method for investigating the separation performance of PIC membrane used in dehydration of organic compounds.

17.
Appl Opt ; 46(2): 234-8, 2007 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-17268569

RESUMO

A dynamic light scattering (DLS) experimental system has been set up to study the influence of the sampling rate on the precision of monodispersed particle sizing. Several different parameters relating to the measurement, such as the sampling rate, the number of the correlation channels, the storage depth, and the lag time, are selected to execute the DLS measurement. The experimental results obtained in different cases are reported, and the influences of the sampling rate on particle sizing are also discussed. From the results and discussion it can be seen that the sampling rate plays an important role in the measurement of the particle size. The variety of the sampling rate can lead to the presentation of different correlation functions and then different precision levels for the particle size. In conclusion, a suitable sampling rate is presented to direct the measurement of test particle size.

18.
Opt Express ; 15(12): 7499-505, 2007 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-19547073

RESUMO

We control the atomic coherence and the population transfer among Rb hyperfine atomic levels by the fractional stimulated Raman adiabatic passage (F-STIRAP) in a L-type configuration, and verify the theoretical predictions. Applying this technique, we are able to prepare the atoms with maximal coherence to enhance coherent anti-Stokes Raman scattering (CARS) signal. In our experiment by scanning the frequency of one laser from 794.9839 nm to 794.9844 nm with the 794.9698 nm laser frequency fixed to generate a maximum of the CARS signal we are able to obtain the energy level diagram of the sample.

19.
Opt Express ; 15(24): 16044-50, 2007 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-19550892

RESUMO

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.

20.
Appl Opt ; 45(33): 8537-40, 2006 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-17086266

RESUMO

A multiline absorption spectroscopy technique was investigated based on the single-line absorption spectroscopy technique. An open-path methane-detecting system was designed. An LED was used as a broadband source, and a Fabry-Perot interferometer whose transmission peaks matched the methane R-branch absorption lines was used to enhance the detectable sensitivity. We demonstrate a minimum-detectable concentration of 7600 +/- 10% ppm (parts per million) with a multiline differential absorption spectroscopy technique and a concentration of 1000 +/- 10% ppm with a multiline wavelength modulation spectroscopy technique.

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