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Chinese Physics B 2016年第6期25卷 259-263页

作者：王河林吴彬王肖隆 center for optics and optoelectronics research Zhejiang University of Technology

Based on the designed As2Se3 and As2S3 chalcogenide glass photonic crystal fiber（PCF） and the scalar nonlinear Schrdinger equation,the effects of pump power and wavelength on modulation instability（MI） gain are comprehensively studied in the abnormal dispersion regime of chalcogenide glass PCF.Owing to high Raman effect and high nonlinearity,ultra-broadband MI gain is obtained in chalcogenide glass PCF.By choosing the appropriate pump parameter,the MI gain bandwidth reaches 2738 nm for the As2Se3 glass PCF in the abnormal-dispersion region,while it is 1961 nm for the As2S3 glass PCF.

关键词： ultra-broadband modulation instability Raman effect high nonlinearity chalcogenide glass photonic crystal fiber

A new ellipse fitting method of the minimum differential-mode noise in the atom interference gravimeter

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Chinese Physics B 2018年第7期27卷 190-195页

作者：许翱鹏王兆英孔德龙付志杰林强 Institute of optics Department of Physics Zhejiang University center for optics and optoelectronics research College of Science Zhejiang University of Technology

Ellipse fitting is a useful tool to obtain the differential signal of two atom interference gravimeters. The quality standard of ellipse fitting should be the deviation between the true phase and the fitting phase of the interference fringe. In this paper, we present a new algorithm to fit the ellipse. The algorithm is to minimize the differential noise of two interference gravimeters and obtain a more accurate value of the gravity gradient. We have theoretically derived the expression of the differential-mode noise and implemented the ellipse fitting in the program. This new algorithm is also compared with the classical methods.

关键词： ellipse fitting atom interference gravity measurement

Simultaneous electromagnetically induced transparency and absorption in thermal atomic medium

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Chinese optics Letters 2017年第9期15卷 41-45页

作者：梁尚清徐云飞林强 Institute of optics Department of Physics Zhejiang University Center for Optics & Optoelectronics Research College of Science Zhejiang University of Technology

A three-level lambda system driven by multicolor control, pump, and probe fields is investigated. The pump and probe fields are derived from the same laser with opposite propagating directions. Due to the Doppler effect, the zero group-velocity atoms face bichromatic fields, while other atoms face trichromatic fields. The atomic medium shows distinct characteristics and exhibits simultaneous electromagnetically induced transparency（EIT） and electromagnetically induced absorption（EIA） at two frequencies. EIT and EIA peaks have a fixed relationship with frequency, which is determined by the Doppler shifts.

关键词： EIT EIA Simultaneous electromagnetically induced transparency and absorption in thermal atomic medium

Investigation of the thermal adaptability for a mobile cold atom gravimeter

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Chinese Physics B 2016年第12期25卷 241-246页

作者：王启宇王兆英付志杰林强 Institute of optics Department of PhysicsZhejiang University center for optics and optoelectronics research College of ScienceZhejiang University of Technology

The cold atom gravimeter offers the prospect of a new generation of inertial sensors for field applications. We ac- complish a mobile atom gravimeter. With the compact and stable system, a sensitivity of 1.4× 10-7 g.Hz-1/2 is achieved. Moreover, a continuous gravity monitoring of 80 h is carried out. However, the harsh outdoor environment is a big challenge for the atom gravimeter when it is for field applications. In this paper, we present the preliminary investigation of the thermal adaptability for our mobile cold atom gravimeter. Here, we focus on the influence of the air temperature on the performance of the atom gravimeter. The responses to different factors （such as laser power, fiber coupling efficiency, etc.） are evaluated when there is a great temperature shift of 10 ℃. The result is that the performances of all the factors deteriorate to different extent, nevertheless, they can easily recover as the temperature comes back. Finally, we conclude that the variation of air temperature induces the increase of noise and the system error of the atom gravimeter as well, while the process is reversible with the recovery of the temperature.

关键词： atom gravimeter the environmental adaptability atom intefferometer

Pressure dependent modulation instability in photonic crystal fiber filled with argon gas

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Chinese Physics B 2018年第9期27卷 338-341页

作者：王河林杨爱军王肖隆吴彬阮乂 Center for Optics & Optoelectronics Research Zhejiang University of Technology College of Science Zhejiang University of Technology

By using the designed photonic crystal fiber filled with argon gas, the effect of gas pressure on modulation instability（MI） gain is analyzed in detail. The MI gain bandwidth increases gradually as the argon gas pressure rises from 1 P0 to 400 P0（P0 is one standard atmosphere）, while its gain amplitude slightly decreases. Moreover, the increase of the incident light power also results in the increase of MI gain bandwidth in the Stokes or anti-Stokes region when the incident power increases from 1 W to 200 W. Making use of the optimal parameters including the higher argon gas pressure（400 P0） and the incident light power（200 W）, we finally obtain a 100 nm broadband MI gain. These results indicate that controlling the MI gain characteristic by changing the argon gas pressure in PCF is an effective way when the incident light source is not easy to satisfy the requirement of practical application. This method of controlling MI gain can be used in optical communication and laser shaping.

关键词： modulation instability gas pressure light power.broadband gain

Rapid extraction of the phase shift of the cold-atom interferometer via phase demodulation

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Chinese Physics B 2015年第11期24卷 250-254页

作者：程冰王兆英许翱鹏王启宇林强 Institute of optics Department of Physics Zhejiang University center for optics and optoelectronics research College of Science Zhejiang University of Technology

Generally, the phase of the cold-atom interferometer is extracted from the atomic interference fringe, which can be obtained by scanning the chirp rate of the Raman lasers at a given interrogation time T. If mapping the phase shift for each T with a series of measurements, the extraction time is limited by the protocol of each T measurement, and therefore increases dramatically when doing fine mapping with a small step of T. Here we present a new method for rapid extraction of the phase shift via phase demodulation. By using this method, the systematic shifts can be mapped though the whole interference area. This method enables quick diagnostics of the potential cause of the phase shift in specific time. We demonstrate experimentally that this method is effective for the evaluation of the systematic errors of the cold atomic gravimeter. The systematic phase error induced by the quadratic Zeeman effect in the free-falling region is extracted by this method. The measured results correspond well with the theoretic prediction and also agree with the results obtained by the fringe fitting method for each T.

关键词： atom interferometer phase extraction phase demodulation

Nonlinear optical trapping effect with reverse saturable absorption

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Advanced Photonics 2023年第4期5卷 66-73页

作者： Zheng Zhu Yuquan Zhang Shuoshuo Zhang Aurele J.L.Adam Changjun Min Hendrik Paul Urbach Xiaocong Yuan Shenzhen University Institute of Microscale Optoelectronics and State Key Laboratory of Radio Frequency Heterogeneous IntegrationNanophotonics Research CenterShenzhenChina research Institute of Intelligent Sensing Research Center for Humanoid SensingZhejiang LabHangzhouChina Delft University of Technology Optics Research GroupDelftThe Netherlands

Nonlinear responses of nanoparticles induce enlightening phenomena in optical tweezers. With thegradual increase in optical intensity, effects from saturable absorption (SA) and reverse SA (RSA) arise insequence and thereby modulate the nonlinear properties of materials. In current nonlinear optical traps,however, the underlying physical mechanism is mainly confined within the SA regime because thresholdvalues required to excite the RSA regime are extremely high. Herein, we demonstrate, both in theory andexperiment, nonlinear optical tweezing within the RSA regime, proving that a fascinating composite trappingstate is achievable at ultrahigh intensities through an optical force reversal induced through nonlinearabsorption. Integrated results help in perfecting the nonlinear optical trapping system, thereby providingbeneficial guidance for wider applications of nonlinear optics.

关键词： nonlinear optical tweezers optical force reverse saturable absorption

Participation in the absolute gravity comparison with a compact cold atom gravimeter

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Chinese optics Letters 2019年第1期17卷 52-57页

作者：付志杰王启宇王兆英吴彬程冰林强 Institute of optics Department of Physics Zhejiang University center for optics and optoelectronics research College of Science Zhejiang University of Technology

The first Asia-Pacific Comparison of Absolute Gravimeters(APMP.M.G-K1) was organized by the National Institute of Metrology(NIM) of China from December 21, 2015 to March 25, 2016 in Changping, Beijing. Our compact cold atom gravimeter(CCAG) was transported from Hangzhou to Beijing with a long distance of about1200 km to participate in this comparison. The CCAG is the only one, to the best of our knowledge, that is based on the principle of atom interferometry among all the instruments. Absolute gravity in the indicated three test sites has been measured as requested by the organizer. The sensitivity of our CCAG is estimated to be90 μGal∕Hz p, even when the measurements are carried out without any vibration isolation. Besides, the accuracy of this gravimeter has been evaluated to be about 19 μGal by considering the significant system errors.Our results show a good agreement with the given reference value.

关键词： Participation absolute gravity comparison compact cold atom gravimeter

Gain-switched watt-level thulium-doped fiber laser and amplifier operating at 1.7μm

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High Power Laser Science and Engineering 2022年第6期10卷 49-59页

作者： Yang Xiao Xusheng Xiao Lutao Liu Haitao Guo State Key Laboratory of Transient optics and Photonics Xi’an Institute of Optics and Precision MechanicsChinese Academy of SciencesXi’anChina center for Materials Science and optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina

A 1.7μm gain-switched thulium-doped all-fiber laser with a master oscillator power amplifier(MOPA)configuration,utilizing a bandpass fiber filter and a 1550 nm erbium/ytterbium-codoped fiber MOPA,is demonstrated.The influences of pump pulse parameters(repetition rate and pulse duration)and laser cavity structures(ring and linear)on the laser performances were experimentally investigated.To the best of our knowledge,the power quenching and drop were observed in the 1.7μm gain-switched thulium-doped fiber lasers for the first time,resulting from the mode-locked-resembling operation and nonlinear effects.Moreover,the fiber ring-cavity laser was more stable than the linear-cavity laser in the time domain and power.Finally,a laser with a maximum average power of 1.687 W,a slope efficiency of 19.7%,a single-pulse energy of 16.87μJ,a pulse width of 425 ns,a repetition rate of 100 kHz and a peak power of 39.69 W was obtained.

关键词： 1.7μm gain-switching fiber laser power roll-off thulium doping

Atomic motion in the magneto–optical trap consisting of partially spatially coherent laser

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Chinese Physics B 2015年第8期24卷 307-310页

作者：张宝武王兆英孔德龙林强 Institute of optics Department of Physics Zhejiang University College of Metrology & Measurement Engineering China Jiliang University center for optics and optoelectronics research College of Science Zhejiang University of Technology

Rb atom motion in a magneto–optical trap(MOT) consisting of a partially spatially coherent laser(PSCL) is investigated theoretically. The spatial coherence of the laser is controlled by the electro–optic crystal. The instantaneous spatial distribution of the dissipative force induced by the PSCL on an Rb atom is varying with time stochastically. The simulated results indicate that compared with a fully coherent laser, the spatial coherent laser has effects on the atomic trajectories;however, the capture velocity and the escape velocity are kept the same. The main reason is that the spatial coherence of the laser fluctuates temporally and spatially, but the average photon scattering rate varies little, which makes the total number of atoms and the atomic density distribution unchanged.

关键词： MOT,the partially spatially coherent laser,Rb