He Huanrong, Liu Shengshuai, Lou Yanbo, Jing Jietai
Opt Express. 2020 Nov 23;28(24):36487-36496. doi: 10.1364/OE.400870.
We give the general expressions of intensity-difference squeezing (IDS) generated from two types of optical parametric amplifiers [i.e. phase-sensitive amplifier (PSA) and phase-insensitive amplifier (PIA)] based on the four-wave mixing process, which clearly shows the IDS transition between the ultra-low average input photon number regime and the ultra-high average input photon number regime. We find that both the IDS of the PSA and the IDS of the PIA get enhanced with the decrease of the average input photon number especially in the ultra-low average input photon number regime. This result is substantially different from the result in the ultra-high average input photon number regime where the IDS does not vary with the average input photon number. Moreover, under the same intensity gain, we find that the optimal IDS of the PSA is better than the IDS of the PIA in the ultra-low average input photon number regime. Our theoretical work predicts the presence of strong quantum correlation in the ultra-low average input photon number regime, which may have potential applications for probing photon-sensitive biological samples.
我们给出了基于四波混频过程的两种光学参量放大器（即相敏放大器（PSA）和相敏放大器（PIA））产生的强度差压缩（IDS）的一般表达式，这清楚地显示了超低平均输入光子数 regime 和超高平均输入光子数 regime 之间的 IDS 转变。我们发现，PSA 的 IDS 和 PIA 的 IDS 都随着平均输入光子数的减少而增强，特别是在超低平均输入光子数 regime 中。该结果与超高平均输入光子数 regime 中的结果有很大不同，在超高平均输入光子数 regime 中，IDS 不随平均输入光子数变化。此外，在相同强度增益下，我们发现在超低平均输入光子数 regime 中，PSA 的最佳 IDS 优于 PIA 的 IDS。我们的理论工作预测了在超低平均输入光子数 regime 中存在强量子相关性，这可能对探测光子敏感的生物样品有潜在应用。
