为了实现煤热解过程中痕量乙烯（C₂H₄）标识气体的在线识别与检测，结合波长调制与长光程技术，搭建了煤热解乙烯在线激光吸收光谱检测装置。采用中心波长为1 620 nm通信波段DFB激光器作为激光光源，有效光程为15 m的多光程吸收池为样品吸收池，利用SR830进行波长解调，通过二次谐波信号反演得到乙烯浓度。使用高精度流量控制器，利用高纯氮气稀释乙烯配比，制备得到10×10^-6到90×10^-6的标准乙烯样气，其线性拟合的相关系数R²为0.998 9；对浓度为20×10^-6的乙烯进行连续4 000 s的Allan方差分析，实验结果表明，检测极限为121×10^-9。为了研究不同气体氛围下煤热解过程中乙烯浓度的演化规律，控制气体流速为150 mL/min，分别在氮气、空气以及合成空气中对乙烯标识气体的释放过程进行热重分析实验。研究发现，当温度小于500 ℃时，3种气体环境下乙烯释放量较少且基本一致，当温度在500~700 ℃时，氮气环境中乙烯释放量要远高于其他两种气体，但空气中乙烯释放的增速最快，最大释放量约为40×10^-6，温度高于700 ℃时乙烯释放量均开始减少。这一结果为进一步探索煤热解中乙烯的生成机理提供了理论和实验基础。

基于相关一致aug-cc-pV6Z基组, 采用高精度多参考组态相互作用 (MRCI) 的方法, 计算了BX (X = H, D) 分子两个最低解离极限 B(²P_u)+X(²S_g) 和B(⁴P_g)+X(²S_g) 所对应的8个Λ-S态 (X¹Σ⁺, a³Π, A¹Π, 1³Σ⁺, b³Σ^-, 2³Π, 1⁵Σ^-和1⁵Π) 的势能曲线。求解径向薛定谔方程并利用LEVEL8.0程序拟合出分子的Λ-S束缚态光谱常数。计算了A¹Π-X¹Σ⁺ 的跃迁偶极矩、Franck-Condon因子和振动能级辐射寿命。根据计算结果, 制定了电子跃迁系统的激光冷却方案, 为进一步研究BX (X = H, D) 分子光谱特性奠定了理论基础。

A quantum sensor network with multipartite entanglement offers a sensitivity advantage in optical phase estimation over the classical scheme. To tackle richer sensing problems, we construct a distributed sensor network with four nodes via four partite entanglements, unveil the estimation of the higher order derivative of radio-frequency signal phase, and unlock the potential of quantum target ranging and space positioning. Taking phased-array radar as an example, we demonstrate the optimal quantum advantages for space positioning and target ranging missions. Without doubt, the demonstration that endows innovative physical conception opens up widespread application of quantum sensor networks.

Our previous work had proved pump field noise coupling in the seed field injected optical parametric amplifier (OPA) at a certain analysis frequency. Inspired by this noise coupling mechanism, the frequency dependent squeezing factor due to excess pump noise was experimentally demonstrated. Apart from a reduced squeezing level with an increased noise, the results also prove that a broadband squeezing noise spectrum is not frequency dependent on the amplitude modulated pump field, but limited by the bandwidth of the amplitude modulator and OPA resonator, and the effective measurement is carried out in the frequency range of 2–10 MHz. It provides a guidance to design a broader-bandwidth, higher-level bright squeezed light.

Squeezed states belong to the most prominent non-classical resources. They have compelling applications in precise measurement, quantum computation, and detection. Here, we report on the direct measurement of 13.8 dB squeezed vacuum states by improving the interference efficiency and gain of balanced homodyne detection. By employing an auxiliary laser beam, the homodyne visibility is increased to 99.8%. The equivalent loss of the electronic noise is reduced to 0.05% by integrating a junction field-effect transistor (JFET) buffering input and another JFET bootstrap structure in the balanced homodyne detector.