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51.
52.
The behaviour of passively Q-switched solid-state lasers containing intracavity optical parametric oscillators (OPOs) is described, and a model to optimize this system‘s performance is developed. Meanwhile, an Nd:YAG laserpumped KTiOPO4 (KTP) intracavity OPO for eye safe laser output is studied experimentally. A Brewster-oriented bis-(4-dimethylaminodithiobenzil)-nickel (BDN) dye film is employed in laser cavity, which plays the double role of a passive Q-switch and a Brewster plate, to Q-switch the light to increase its intensity and polarize the light so that the polarization plane of fundamental irradiation is perpendicular to the Z-axis of KTP serving as the OPO nonlinear crystal, thereby providing type Ⅱ phase matching conditions to generate 1.572μm eye-safe signal laser. Eye-safe signal radiations of 6.6mJ per pulse at 1.572μm wavelength and pulse width as narrow as 6.0ns (FWHM) were obtained. Peak power was up to 1.1MW. 相似文献
53.
Measurement of intensity difference squeezing via non-degenerate four-wave mixing process in an atomic vapor
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We report the measurement of the intensity difference squeezing via the non-degenerate four-wave mixing process in a rubidium atomic vapor medium. Two pairs of balanced detection systems are employed to measure the probe and the conjugate beams, respectively. It is convenient to get the quantum shot noise limit, the squeezed and the amplified noise power spectra. We also investigate the influence of the input extra quadrature amplitude noise of the probe beam. The influence of the extra noise can be minimized and the squeezing can be optimized under the proper parameter condition. We measure the -3.7-dB intensity difference squeezing when the probe beam has a 3-dB extra quadrature amplitude noise. This result is slightly smaller than -4.1 dB when the ideal coherent light (no extra noise) for the probe beam is used. 相似文献
54.
Coherent effect of triple-resonant optical parametric amplification inside a cavity with injection of a squeezed vacuum field
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In theory, we study the quantum tluctuatlons ot tlae suDllarmonlc renecteu nela Irom a ulplc-rc~ulltUtt IdU~ClIClatC optical parametric amplifier (OPA) inside an optical cavity. We discuss two cases, where the linewidth of the harmonic field is either much narrower or broader than the subharmonic field. Since an electromagnetically-induced-transparency (EIT)-like effect can be simulated in a triple-resonant OPA, the output spectra from a triple-resonant OPA with a squeezed vacuum input may simulate the phenomenon of the response of an EIT medium for squeezed states. This scheme can be implemented with present experimental setups. 相似文献
55.
平衡零拍探测是测量量子光场的重要方法之一. 通过对相位灵敏光学参量放大器注入的信号进行位相调制, 然后利用平衡零拍探测系统测量光学参量放大器输出的压缩光. 将相位灵敏光学参量分别运转在参量放大和参量缩小, 通过观察噪声谱中的调制信号就可确定测量的量子光场是正交振幅或位相分量. 通过解调位相调制信号可获得误差信号, 实现锁定平衡零拍探测系统本底光与待测光场相对位相为零(对应于待测光场振幅噪声分量).
关键词:
平衡零拍探测
位相锁定 相似文献
56.
Experimental investigation of evaporative cooling mixture of bosonic 87Rb and fermionic 40K atoms with microwave and radio frequency radiation
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We investigate sympathetic cooling fermions 40K by evaporatively cooling bosonic 87Rb atoms in a magnetic trap with microwave and radio frequency induced evaporations in detail. The mixture of bosonic and fermionic atoms is prepared in their polarized spin states |F=9/2, mF=9/2> for 40K and |F=2, mF=2> for 87Rb, which is trapped in Quadrupole--Ioffe--Configuration trap. Comparing microwave with radio frequency evaporatively cooling bosonic 87Rb atoms with sympathetically cooling Fermi gas 40K, we find that the presence of rubidium atoms in the |2,1> Zeeman states, which are generated in the evaporative process, gives rise to a significant loss of 40K due to inelastic collisions. Thus, the rubidium atoms populated in the |2, 1> Zeeman states should be removed in order to effectively perform sympathetically cooling 40K with the evaporatively cooled 87Rb atoms. 相似文献
57.
为提高农药利用率,减少农药流失,降低农药对环境的危害,研究一种以凹凸棒土(Attapulgite, ATP)为载体、毒死蜱(Chlorpyrifos, CPF)为目标农药分子制备能够减少农药流失的纳米控失毒死蜱(Nano Loss Control Chlorpyrifos, NLCC),并通过滤纸和甘蔗叶片研究ATP对CPF的控失效果,利用扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)和X射线衍射仪(XRD)等表征手段研究了纳米控失毒死蜱的附着机理。最后,通过大田试验探究其实际防治效果。结果表明,凹凸棒土能够通过氢键作用吸附毒死蜱,且凹凸棒土对毒死蜱的附着量在模拟降水前后分别提高5.4和5.6 μg; 凹凸棒土对毒死蜱的最大负载量为500 mg/g; 玉米螟死亡率在模拟降水前后分别提高了20%;在大田实验中施用NLCC的甘蔗虫株率降低了21%,虫节率降低了4.3%,虫眼数减少了2个/株,株高增加了23.1 cm,也表明纳米控失毒死蜱能够有效降低虫害并在一定程度上促进甘蔗生长。这种能够减少农药流失、提高农药利用率、降低环境污染的简单且具有广泛应用前景的方法,对病虫害防治和绿色农业发展有较好的实用价值。 相似文献
58.
We study a scheme for Mach-Zehnder(MZ) interferometer as a quantum linear device by injecting two-mode squeezed input states into two ports of interferometer.Two-mode squeezed states can be changed into two types of inputs for MZ interferometer:two squeezed states and Einstein-Podolsky-Rosen(EPR) entangled states.The interference patterns of the MZ interferometer vary periodically as the relative phase of the two arms of the interferometer is scanned,and are measured by the balanced homodyne detection system.Our experiments show that there are different interference patterns and periodicity of the output quantum states for two cases which depend on the relative phase of input optical fields.Since MZ interferometer can be used to realize some quantum operations,this work will have the important applications in quantum information and metrology. 相似文献
59.
60.
Influence on the Lifetime of ~(87)Rb Bose-Einstein Condensation for Far-Detuning Single-Frequency Lasers with Different Phase Noises
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We study the influence of the phase noises of far detuning single frequency lasers on the lifetime of Bose-Einstein condensation(BEC)of~(87)Rb in an optical dipole trap.As a comparison,we shine a continuous-wave singlefrequency Ti:sapphire laser,an external-cavity diode laser and a phase-locked diode laser on BEC.We measure the heating and lifetime of BEC in two different hyperfine states:|F=2,m_F=2〉and|F=1,m_F=1〉.Due to the narrow linewidth and small phase noise,the continuous-wave single-frequency Ti:sapphire laser has less influence on the lifetime of~(87)Rb BEC than the external-cavity diode laser.To reduce the phase noise of the external-cavity diode laser,we use an optical phase-locked loop for the external-cavity diode laser to be locked on a Ti:sapphire laser.The lifetime of BEC is increased when applfying the phase-Jocked diode laser in contrast with the external-cavity diode laser. 相似文献