The technological innovation of thin-film lithium niobate (TFLN) is supplanting the traditional lithium niobate industry and generating a vast array of ultra-compact and low-loss optical waveguide devices, providing an unprecedented prospect for chip-scale integrated optics. Because of its unique strong quadratic nonlinearity, TFLN is widely used to create new coherent light, which significantly promotes all-optical signal processes, especially in terms of speed. Herein, we review recent advances in TFLN, review the thorough optimization strategies of all-optical devices with unique characteristics based on TFLN, and discuss the challenges and perspectives of the developed nonlinear devices.

针对裸光纤光栅在声波作用下的应变灵敏度过低导致难以检测到有效反射波长变化的问题，文章提出以光纤光栅纵向传感为模型，并在光栅周围涂上一层厚度远超光纤内径的低杨氏模量圆柱状涂覆层，以增加光纤光栅的应变灵敏度，并用相移光栅反射谱的线性区作为边缘滤波法边缘来提高激光检测的灵敏度，利用传输矩阵法仿真分析光栅反射谱及激光反射率曲线。仿真结果表明，声波纵向传感模型的应变灵敏度要优于横向传感模型，且低杨氏模量的涂覆层可以显著提高光栅的应变灵敏度，在频率低于1.7 kHz的声波作用下，涂有聚氨酯涂覆层的光纤光栅纵向传感灵敏度达到了6.1 nm/MPa，是裸光纤光栅的381倍，结合相移光栅反射谱线性区综合灵敏度提升2 203.6倍，有效地提升了光纤光栅在声波检测方面的灵敏度。

Remarkable progress has been made in satellite-based quantum key distribution (QKD), which can effectively provide QKD service even at the intercontinental scale and construct an ultralong-distance global quantum network. But there are still some places where terrestrial fiber and ground stations cannot be constructed, like harsh mountainous areas and air space above the sea. So the airborne platform is expected to replace the ground station and provide flexible and relay links for the large-scale integrated communication network. However, the photon transmission rate would be randomly reduced, owing to the randomly distributed boundary layer that surrounds the surface of the aircraft when the flight speed is larger than 0.3 Ma. Previous research of airborne QKD with boundary layer effects is mainly under the air-to-ground scenario in which the aircraft is a transmitter, while the satellite-to-aircraft scenario is rarely reported. In this article, we propose a performance evaluation scheme of satellite-to-aircraft QKD with boundary layer effects in which the aircraft is the receiver. With common experimental settings, the boundary layer would introduce a ∼31dB loss to the transmitted photons, decrease ∼47% of the quantum communication time, and decrease ∼51% of the secure key rate, which shows that the aero-optical effects caused by the boundary layer cannot be ignored. Our study can be performed in future airborne quantum communication designs.

Considerable progress has been made in organic light-emitting diodes (OLEDs) to achieve high external quantum efficiency, among which dipole orientation has a remarkable effect. In most cases, the radiation of the dipoles in OLEDs is theoretically predicted with only one orientation parameter to match with corresponding experiments. Here, we develop a new theory with three orientation parameters to fully describe the relationship between dipole orientation and power density. Furthermore, we design an optimal test structure for measuring all three orientation parameters. All three orientation parameters could be retrieved from non-polarized spectra. Our theory provides a universal plot of dipole orientations in OLEDs, paving the way for designing more complicated OLED devices.

从赤泥中提取稀土金属, 开发高附加值产品, 对保护环境特别是提高矿产资源的综合利用率以及实现可持续发展有着重要的意义。 赤泥中的稀土元素含量较低(0.001 0%~0.050%), 且存在大量的铝和铁等基体元素, 如何掩蔽基体元素对稀土元素的干扰是准确定量的关键。 传统酸溶法会造成部分元素消解不完全, 难以准确定量, 回收率低, 碱熔法则会由于引入大量的碱熔剂造成严重的基体干扰, 同时还会堵塞雾化器。 采用氢氧化钠熔融赤泥, 熔融物用热水浸取, 三乙醇胺溶液掩蔽铝和铁, 乙二胺四乙酸二钠溶液络合钙、 镁等干扰元素, 稀土氢氧化物留存于沉淀中, 沉淀经盐酸溶解进入待测液, 从而将稀土元素与熔剂和基体元素分离。 实验结果表明: 标准溶液无需基体匹配, 各稀土氧化物校准曲线的线性相关系数均不小于0.999 9, 检出限在0.000 2%~0.001 5%之间; 按照实验方法分析实际样品中稀土氧化物的含量, 测定结果的相对标准偏差(RSD, n=6)为2.5%~7.2%, 回收率为85.0%~105.0%; 本方法与电感耦合等离子体质谱法(ICP-MS)相比, 两种方法的测定结果无显著性差异。 ICP-OES实现了赤泥中稀土氧化物的同时测定, 为今后分析赤泥中的稀土氧化物奠定了基础。