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Production of cold CN molecules by photodissociating ICN precursors in brute-force field

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Chinese physics B 2017年第5期26卷 108-112页

作者：徐文霞杨永成邓联忠 state key laboratory of precision spectroscopy East China Normal University Shanghai 200062 China

We theoretically investigate the production of cold CN molecules by photodissociating ICN precursors in a brute-force field. The energy shifts and adiabatic orientation of the rotational ICN precursors are first investigated as a function of the external field strength. The dynamical photofragmentation of ICN precursors is numerically simulated for cases with and without orienting field. The CN products are compared in terms of their velocity distributions. A small portion of the CN fragments are recoiled to near zero speed in the lab frame by appropriately selecting the photo energy for dissociation. With a precursor ICN molecular beam of - 1.5 K in rotational temperature, the production of low speed CN fragments can be improved by more than 5 times when an orienting electrical field of 100 k V/cm is present. The corresponding production rate for decelerated fragments with speeds ≤ 50 m/s is simulated to be about ～2.1×10^-4 and CN number densities of 10^8 –10^10 cm^-3 can be reached with precursor ICN densities of ～10^12 –10^14 cm^-3 from supersonic expansion.

关键词： rotational supersonic dissociation dynamical adiabatic selecting excited dipole numerically conveniently

Parameter analysis for a nuclear magnetic resonance gyroscope based on ^(133)Cs–^(129)Xe/^(131)Xe

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Chinese physics B 2017年第2期26卷 161-165页

作者： Da-Wei Zhang Zheng-Yi Xu Min Zhou Xin-Ye Xu state key laboratory of precision spectroscopy East China Normal University Shanghai 200062 China

We theoretically investigate several parameters for the nuclear magnetic resonance gyroscope based on ^（133）C_（s–）^（129）Xe/^（131）Xe. For a cell containing a mixture of ^（133）Cs at saturated pressure, we investigate the optimal quenching gas（N_2） pressure and the corresponding pump laser intensity to achieve 30% ^（133）Cs polarization at the center of the cell when the static magnetic field B0 is 5 μT with different ^（129）Xe/^（131）Xe pressure. The effective field produced by spin-exchange polarized ^（129）Xe or ^（131）Xe sensed by ^（133）Cs can also be discussed in different^（129）Xe/^（131）Xe pressure conditions. Furthermore,the relationship between the detected signal and the probe laser frequency is researched. We obtain the optimum probe laser detuning from the D2（6~2S_（1/2）→ 6~2P_（3/2）） resonance with different ^（129）Xe/^（131）Xe pressure owing to the pressure broadening.

关键词： nuclear magnetic resonance gyroscope optical pumping spin-exchange collision optical rotation

Franck-Condon Factors and Band Origins for MgH in the A2П-X2∑＋ System

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Chinese Journal of Chemical physics 2015年第3期28卷 253-256,I0001页

作者： Xu Cheng Jiao Bai Jian-ping Yin Hai-ling Wang state key laboratory of precision spectroscopy East China Normal University ShanEhai 200052 China

We measure the dispersed spectrum of the A2H-X2E＋ system of MgH using laser abla- tion/laser induced Fluorescence method and obtain the Frank-Condon factors and related transition frequencies of the A2H（v＇=0）-X2∑＋（v＂=0,1） system by analyzing the experimental spectrum. Also, we calculate the Franck-Condon factors and transition frequencies of the A2H-X2∑＋ system of MgH. A comparison of our theoretical calculation and experimental results with other reported theoretical results was carried out as well.

关键词： Franck-Condon factors Energy curve Vibrational frequencies Dispersed fluorescence

Laser-assisted Stark deceleration of CaF in its rovibronic ground (high-field-seeking) state

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Chinese physics B 2019年第4期28卷 170-176页

作者： Yuefeng Gu Kai Chen Yunxia Huang Xiaohua Yang School of Science Nantong University state key laboratory of precision spectroscopy East China Normal University

A near-resonant, red-detuning laser-assisted Stark deceleration scheme is proposed to slow CaF in its high-fieldseeking rovibronic ground state. The assisting Gaussian laser beam can confine CaF molecules transversely owing to the optical Stark effect. Simulations suggest that the present scheme is superior to previous Stark decelerators. Under typical experimental conditions, when the assisting laser frequency is red-detuned to the molecular transition(λ～606.3 nm) by5.0 GHz and the laser power is about 5.6 W, the proposed decelerator can achieve a total number at the order of 10~4 CaF molecules with a number density at the order of 10~8 cm^(-3). The equivalent temperature of the obtained cold CaF molecules is 2.3 mK. Additionally, the desired assisting laser power can be as low as about 1.2 W if keeping the red-detuning value to be 1.0 GHz, which further suggests its experimental feasibility.

关键词： Stark deceleration polar molecule optical Stark effect high-field-seeking state

A Yb optical clock with a lattice power enhancement cavity

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Chinese physics B 2024年第3期33卷 70-74页

作者：王春云姚远师浩森于洪浮马龙生蒋燕义 state key laboratory of precision spectroscopy East China Normal UniversityShanghai 200062China

We construct a power enhancement cavity to form an optical lattice in an ytterbium optical *** is demonstrated that the intra-cavity lattice power can be increased by about 45 times,and the trap depth can be as large as 1400Er when laser light with a power of only 0.6 W incident to the lattice *** high trap depths are the key to accurate evaluation of the lattice-induced light shift with an uncertainty down to~1×*** probing the ytterbium atoms trapped in the power-enhanced optical lattice,we obtain a 4.3 Hz-linewidth Rabi spectrum,which is then used to feedback to the clock laser for the close loop operation of the optical lattice *** evaluate the density shift of the Yb optical lattice clock based on interleaving measurements,which is-0.46(62)*** result is smaller compared to the density shift of our first Yb optical clock without lattice power enhancement cavity mainly due to a larger lattice diameter of 344μm.

关键词： optical atomic clock optical lattice optical cavity Stark shift

Deterministic controlled bidirectional remote state preparation in dissipative environments

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Communications in Theoretical physics 2022年第7期74卷 72-83页

作者： Jun-Rong Gu Jin-Ming Liu state key laboratory of precision spectroscopy School of Physics and Electronic ScienceEast China Normal UniversityShanghai 200241China

It is a significant subject to explore effective quantum communication protocol and enhance the efficiency of the transmission process in noisy environments. In this paper, we investigate the bidirectional controlled remote preparation of an arbitrary single-qubit state in the presence of dissipative environments by using two EPR states as the entanglement source. We first construct the quantum circuit of our scheme by means of unitary matrix decomposition procedure, then the effects of the Markovian and non-Markovian environmental noises acting on the EPR states are considered through the analytical derivation and numerical calculations of the corresponding average fidelity. Moreover, we adopt two methods of weak measurement reversal(WMR) and detuning modulation to improve the average fidelity. Our results show that the average fidelity can be remarkably enhanced under appropriate conditions of the WMR strength and the detuning. Compared with the average fidelity behaviors in dissipative environments, it is also shown that the two methods for fidelity improvement are more efficient in the non-Markovian regime than in the Markovian regime.

关键词： remote state preparation non-Markovian noise fidelity weak measurement reversal

Influence of Noises on Remote state Preparation Using GHZ state

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Communications in Theoretical physics 2008年第9期50卷 643-647页

作者： LIANG Hua-Qiu LIU Jin-Ming state key laboratory of precision spectroscopy Department of Physics East China Normal University Shanghai 200062 China department of physics Taizhou University Linhai 317000 China

Using a quantum channel consisting of a GHZ state exposed to noisy environment,we investigate how toremotely prepare an entangled state and a qubit state,*** solving the master equation in the Lindbladform,the influence of the various types of noises on the GHZ state is first *** we use the fidelity to describehow close the remotely prepared state and the initial state *** results show that the fidelity is a function of thedecoherence rates and the angles of the initial *** is found that for each of the two RSP schemes,the influence ofthe noise acting simultaneously in x,y,and z directions on the average fidelity is the strongest while the influence of thenoise acting in x or z direction on the average fidelity is relatively weaker.

关键词： remote state preparation fidelity GHZ state noisy environment

Effects of Pumping Sizes on THz Radiation Based on Ultrashort Light Pulse Optical Rectification for High Spatial Resolution T-Ray Imaging

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Chinese physics Letters 2008年第12期25卷 4262-4265页

作者：徐世祥戴小明杨晓华李景镇 state key laboratory of precision spectroscopy and Department of Physics East China Normal University Shanghai 200062 Shenzhen key Lab of Micro-Nano Photonics department Shenzhen University Shenzhen 518060

We present our experimental studies on the effects of the pumping sizes on THz radiation based on ultrashort light pulse optical rectification for high spatial resolution T-Ray imaging. Our experiments show that high spatial resolution T-ray imaging requires both thin THz emitter and sample, and rigorous tolerance of the gap between the sample and the emitter, as well as small pumping size which usually much smaller compared with THz wavelength. Such a small pumping size results in dramatic decrease of the THz wave power, which originates from strong diffraction of THz wave, the depolarization of the focused tightly pumping beam, the spatial filtering of the emitter exit-surface, and the strong phase-mismatching between the pumping and the high spatial Fourier components of the THz signal, rather than two-photon absorption.

关键词： field emission molybdenum dioxide enhancement factor

Ultrafast Heavy Hole-Phonon Scattering in Highly n-Doped GaAs

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Chinese physics Letters 1999年第10期16卷 758-760页

作者： LIN Wei-zhu HUANG Chun ZHANG Hai-chao WEN Jin-hui GUO Bing LAI Tian-shu state key laboratory of Ultrafast Laser spectroscopy Department of Physics Zhongshan UniversityGuangzhou 510275

Ultrafast heavy hole-phonon interactions in highly n-doped GaAs have been selectively studied with femtosecond absorption saturation measurements by tuning the pump-probe photon energy just above the doped electron Fermi edge.A heavy hole-phonon scattering time of~300fs has been measured,which is consistent with that calculated by a numerical ***,an optical deformation potential of about 31 eV has been estimated for this highly n-doped sample.

关键词： tuning pump scattering