常压百级洁净度环境中SiO2薄膜稳定性

在常压百级洁净度环境下,采用三种不同折射率的SiO₂溶胶在熔石英基底上涂制四种不同薄膜,利用光学理论计算模拟了三种胶体涂制的膜层稳定性,通过实验考查了膜层光学指标随时间的变化规律。SiO₂薄膜能够显著提升光学元件透射率,但由于膜层表面的大量羟基及其多孔结构,SiO₂薄膜易吸附周围环境中的有机污染物及水分填充膜层孔隙,从而导致膜层折射率发生变化,影响膜层透射率、反射率等光学性能。实验结果发现,三种溶胶凝胶化学膜在常压百级环境中的有效期为80 d(绝对变化率小于0.1%),且三种胶体涂制的膜层稳定性由高到低依次为折射率1.19, 1.15, 1.25的膜层。     

MW级地面燃气轮机热力循环分析

本文以俄罗斯GTDl250型燃气轮机为样本对MW级地面燃气轮机进行了热力循环分析.MW级地面燃气轮机作为一类小型(轻型)、多转子(双转子)、具有简单或复杂循环的燃气轮机,在电力工业、石油工业和战车动力等方面有着广泛的用途.在热力循环分析的基础上,提出了我国在研制高性能MW级地面燃气轮机时应重点解决的问题.     

Flat Top Optical Frequency Combs Based on a Single-Core Quantum Cascade Laser at Wavelength of ～8.7 μm

We present optical frequency combs with a spectral emission of 48 cm^-1and an output power of 420 m W based on a single-core quantum cascade laser at λ ～ 8.7μm. A flat top spectrum sustains up to 130 comb modes delivering ～ 3.2 m W of optical power per mode, making it a valuable tool for dual comb spectroscopy. The homogeneous gain medium, relying on a slightly diagonal bound-to-continuum structure, promises to provide a broad and stable gain for comb operating. Remarkably, the dispers...     

Automatic measurement device of laser-induced damage threshold and its experiment北大核心

A set of 1 064 nm and 532 nm automatic measurement device of laser-induced damage threshold (LIDT) of dual-wavelength optical elements was designed and constructed for automatic detection of LIDT of optical elements film. The device was mainly composed of pulsed laser light source, beam parameter diagnosis component, damage online diagnosis component, scanning motion platform for parts to be tested and control system. The whole measuring device and measurement process were automatically controlled by the computer integrated measuring software based on Labview, which could realize the automatic measurement of damage threshold in the range of energy density from 0.1 J/cm2～100 J/cm2, and the device was also used to measure the 1 064 nm antireflection film and aluminum reflection film samples. The results show that the damage thresholds are 27.09 J/cm2 and 3.21 J/cm2, with a relative uncertainty of 3.91% and 5.61%, respectively. © 2023 Editorial office of Journal of Applied Optics. All rights reserved.     

一种小型化半导体激光器温控电路的设计

为了满足激光器小型化的需求，设计了一种小尺寸的半导体激光器温度控制电路。电路采用内置半桥的DC-DC转换芯片SY8368AQQC作为半导体制冷器的驱动，采用STM32F302K8U6作为主控芯片，内置PID算法。最终实现了电路的小型化，尺寸可以做到30 mm×30 mm,同时也能达到理想的控制效果。实验结果表明，该电路的温度控制精度可以到±0.1℃。