共查询到20条相似文献,搜索用时 109 毫秒
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低频压缩态光场可用于提高引力波探测器灵敏度, 近年来受到人们的广泛关注. 相对于高频段而言, 低频压缩态的产生更容易受到外界环境噪声的干扰而不易被观察到. 本文采用全固化单频倍频Nd: YVO4/KTP激光器作为光源, 利用双波长共振的光学参量振荡器实现参量过程, 以1064 nm波长的红外作为基频光, 激光器腔内倍频产生的532 nm绿光作为抽运光, 通过调节周期性极化磷酸氧钛钾晶体温度使光学参量振荡器达到双波长同时共振, 采用真空注入的方式, 利用Pound-Drever-Hall锁腔技术锁定抽运场. 输出压缩光通过平衡零拍探测, 最终在实验上获得了频率低至3 kHz的真空压缩, 所直接观察到的压缩度为2 dB. 相似文献
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《Physics letters. A》2020,384(29):126755
We propose a theoretical scheme of an enhanced phase sensitivity by introducing a nonlinear phase shifter to the nonconventional interferometer consisting of a balanced beam splitter (BBS) and an optical parameter amplifier (OPA), a modified nonlinear interferometer (MNI). Then we use coherent state and even coherent state as inputs and homodyne detection at one output port of the MNI for phase sensitivity, both without and with photon losses. We find that the nonlinear phase shifter can not only improve phase sensitivity, but also significantly resist the decoherence from photon losses. In comparison to both the BBS+OPA scheme with linear phase shifter and the traditional Mach–Zehnder interferometer with nonlinear one, the phase sensitivity of the MNI scheme shows the best performance. It is interesting that the nonlinear phase shifter can stimulate potential of the OPA, although there is no improvement in signal-to-noise ratio beyond standard quantum limit for the BBS+OPA scheme with a linear phase shifter. 相似文献
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Stable, low noise, infrared squeezed state tight at 1064 nm is generated by utilizing optical parametric down-conversion (OPDC)
technique based on periodically poled KTiOPO4 in a optical parametric amplifier (OPA) resonator. A non-classical noise reduction of 2.58 dB below the shot noise is observed
through balanced homodyne detection. The squeezed state light is used to set up an imaging system for high-resolution imaging,
and it is found that the resolution of image based on the amplitude-squeezed light is 1.26 times larger than that of infrared
coherent light under the same intensity. The experimental results indicate that squeezed light is an important non-classical
light, which can overcome the coherent laser shot-noise, the classical diffraction limit and limit of quantum noise. 相似文献
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平衡零拍探测器的改进 总被引:1,自引:0,他引:1
平衡零拍探测技术是连续变量量子信息科学研究中测量量子态量子噪声的最佳方法之一。在平衡零拍探测系统中,需要一对性能和结构尽量相同的光电探测器,以便很好地减去经典噪声,有效探测散粒噪声基准及光场噪声。根据基尔霍夫电流定律及光电二极管串联的办法,设计并制作出一种性能优良的低噪声平衡零拍探测器。该探测器从光电二极管串联节点处取出光电流相减信号,然后对信号进行放大,在对两探测器全同性要求降低的同时提高了平衡零拍探测的性能。实验结果表明,该探测器在2MHz处共模抑制比达39dB,能很好地满足量子信息对低噪声、线性增益及高共模抑制比的要求。 相似文献
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基于飞秒脉冲的同步泵浦参量过程产生的多模时域飞秒压缩光场,由于其独特的优势,特别是可以享有单模光纤网络兼容,是实现可扩展量子计算及大容量量子通讯的良好光源。由于无法实现多模时域飞秒压缩光场的空间分离,目前对于多模时域飞秒压缩光场的测量,采用最为有效的平衡零拍探测。因此如何构造与时域飞秒压缩光场时域函数分布相同的本地光,是其中的关键内容,并直接影响测量效果。本文主要理论研究了本地脉冲光的时域整形方案,分析了系统参数对整形后的多模本地光的保真度以及系统调制效率的影响,并结合实验参数提出可能的解决办法。 相似文献
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1.5 μm光通信波段非经典光场在光纤中有着极低的传输损耗, 因而是基于光纤的实用化连续变量量子信息研究的重要资源. 本文利用周期极化磷酸氧钛晶体构成的半整块结构简并光学参量放大器, 实验获得了连续变量1.5 μm光通信波段的明亮压缩态光场. 光学参量放大器的阈值功率为230 mW. 当780 nm抽运光场功率为110 mW, 1.5 μm注入信号光场功率为3 mW时, 连续变量1.5 μm明亮正交位相压缩态光场的压缩度达4.7 dB. 进而利用时域零拍探测系统测量压缩态, 采用量子层析技术重构了该明亮正交位相压缩态光场的Wigner准概率分布函数. 相似文献
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基于交叉相位调制制备四光子偏振纠缠态及其在隐形传态上的运用 总被引:1,自引:1,他引:0
利用克尔介质、偏振分束器、半波片和对强相干探测场的零拍探测,呈现了一个关于制备四光子偏振Diche态、GHZ态和W态的方案,当前量子光学实验技术条件均能有效满足该方案的要求.强的探测模相继和多个信号模光子相互作用,每次对于探测模而言,都会产生一个相位旋转.接下来,对探测模利用零拍探测,信号模可以投影得到想要的光子偏振纠缠态.此外,为了展现所制备的纠缠态作为重要的量子信息资源的价值,基于交叉相位调制进一步提出了一个隐形传送三光子偏振纠缠态的实验方案. 相似文献
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A two-mode entangled state was generated experimentally through mixing two squeezed lights from two optical parametric amplifiers on a 50/50 beam splitter.The entangled beams were measured by means of two pairs of balanced homodyne detection systems respectively.The relative phases between the local beams and the detected beams can be locked by using the optical phase modulation technique.The covariance matrix of the two-mode entangled state was obtained when the relative phase of the local beam and the detected beam in one homodyne detection system is locked and the other is scanned.This method provides a way by which one can extract the covariance matrix of any selected quadrature components of two-mode Gaussian state. 相似文献