Author Affiliations
Abstract
College of Optoelectric Science and Engineering, National University of Defence Technology, Changsha 410073, China
A Closed Cavity measuring platform is built on the basis of a 1000 W-class direct current (DC)-discharge drived continuous-wave (CW) HF/DF chemical laser. On this platform, the absorption coefficients of optical thin films coated on the surfaces of monocrystalline silicon substrates, at the wavelength of 3.6–4.1 μm, is measured, when the power density on the surfaces of optical thin films reaches about 3.16 kW/cm2. The measuring principle and structure of the Closed Cavity is introduced. The temperature curves and balanced temperature rises of the film-substrate systems under test measured through the experiment is presented in this Letter. The experiments show high reliability, good repeatability and strong practicality. The Closed Cavity measuring platform is applicable for not only absorption measurement but other performance measurement of optical thin films under high power density.
310.6860 Thin films, optical properties 140.3070 Infrared and far-infrared lasers 140.3330 Laser damage 140.3460 Lasers Chinese Optics Letters
2015, 13(3): 033101
国防科学技术大学 光电科学与工程学院, 长沙 410073
对一台小型电激励连续波DF化学激光器进行了实验研究，在光轴位于喷管阵列出口平面下游10 mm处和15 mm处分别进行了出光实验，得到188.4 W和205.8 W的DF激光输出，输出激光波长为3.6~4.1 μm，激光器的电效率分别为2.3%和2.5%。该小型电激励连续波DF化学激光器长时间(100 s)运行的功率稳定性峰谷值和均方根值分别为±1.04%和0.49%，工作状态较为稳定，实验可重复性好，操作方便，是强光条件下镜片膜层吸收系数测量的适用红外激光光源。
激光器 电激励DF化学激光器 红外激光光源 laser DC-discharge excited DF chemical laser infrared laser source 强激光与粒子束
2015, 27(11): 111005
国防科技大学光电科学与工程学院, 湖南 长沙 410073
开展了HF/DF激光器谐振腔内基态分子光吸收对其输出性能影响的实验研究，测量并分析了从不同位置注入H2/D2时激光器的输出功率和光谱变化。结果表明：振动基态HF(ν=0)/DF(ν=0)分子通过单光子共振机制吸收1P支谱线，通过双光子共振机制吸收2P支谱线；振动转动激射带间存在一定程度的级联跃迁效应；在基态分子与激发态分子数量相当(11)的情况下，HF激光器输出功率降低了50%左右，DF激光器输出功率降低了90%左右；利用传统的燃料组合研制燃烧驱动HF-DF双波段化学激光器是不可行的。
激光器 氟化氢激光器 氟化氘激光器 光吸收 双波段激光
Author Affiliations
Abstract
We propose a continuous-wave (CW) middle infrared (MIR) and long infrared (LIR) dual-band laser for the calibration and effect research of infrared detecting and imaging systems. A total output power of 18 W is achieved by the proposed dual-band laser through one DF gain medium module and one parallel placed CO2 gain medium module using a common stable resonator and output mirror with nominal transmissivities of ~5% in the MIR band and ~10% in the LIR band. Spectra of dual-band laser are acquired. The power extracting efficiency of this dual-band laser can be significantly improved, as validated by a single-band test of optimized parameters.
140.3070 Infrared and far-infrared lasers 110.3080 Infrared imaging 140.1550 Chemical lasers 140.3470 Lasers, carbon dioxide Chinese Optics Letters
2012, 10(3): 031404
Author Affiliations
Abstract
College of Opto-electric Science and Engineer, National University of Defense Technology, Changsha 410073, China
The chemiluminescence spectrum in the optical cavity of discharge-driven hydrogen fluoride (HF) chemical laser is measured. The result reveals that the spectra of the helium and fluorine (F) atoms are the major components. Moreover, the green chemiluminescence in the downstream of the optical axis is mostly composed of the 60P20 spectral line of the HF molecule. The analysis shows that, except for the cold pumping reaction, the recombination of the F atoms and the hot pumping reaction also occur in the optical cavity. Due to the hot pumping reaction and the optical cavity temperature in a specific range, the 60P20 line becomes the strongest HF molecule in the downstream region of the optical axis. After the hot pumping reaction, the green chemiluminescence always appears in the downstream region of the optical axis when the optical cavity temperature varies in a greater range.
化学激光 荧光 光谱分析 动力学 HF 140.1550 Chemical lasers 260.1560 Chemiluminescence 300.6280 Spectroscopy, fluorescence and luminescence Chinese Optics Letters
2011, 9(8): 081403
国防科学技术大学 光电科学与工程学院, 长沙 410073
为了给燃烧驱动连续波DF/HF化学激光器中喷注器的设计提供参考, 采用原级标准(质量-时间法), 对5种不同结构的喷注器进行了流量标定实验, 研究了喷注器的流量特性。采用边界层的相关理论, 对实验结果进行了科学解释。实验结果显示：随着入口压力的升高, 流量系数增大, 流量系数的范围是0.677~0.772；在入口压力相同的条件下, 流量系数随着通径的增大而增大, 随着长度的增大而减小；斜孔的流量系数比尺寸相同的垂直孔略小。
化学激光器 喷注器 流量标定 流量系数 chemical laser injector flow rate calibration flow coefficient
国防科学技术大学 光电科学与工程学院, 长沙 410073
观察并记录了增大D2流量时DF激光光腔流场可见光荧光的变化现象, 对光轴处的可见光荧光进行了光谱测量, 使用波长为632.8 nm和543.5 nm的He-Ne激光器对光谱仪进行标定。对激光器光腔内介质成分进行了理论分析, 并理论计算了DF高次泛频谱线及D原子谱线, 通过比对荧光的实验测量光谱与光腔内介质成分谱线, 发现荧光是由F,He,D,N,DF及其它激发态介质共同形成的, 对光轴处荧光的颜色构成作出了解释。
化学激光器 荧光 光谱分析 DF激光 chemical laser chemiluminescence spectral analysis DF laser
国防科学技术大学 光电科学与工程学院定向能技术研究所,湖南 长沙 410073
研究了将分别应用在连续波DF/HF化学激光器增益发生器上的气膜冷却方式和在燃烧室中的两步燃烧方式相结合的方式,这可通过转移部分主稀释剂至主喷管收缩段注入来实现。通过数值模拟方法对该应用下光腔内流场进行分析,结果显示谱线小信号增益系数有小幅增大,但两步燃烧方式较高的燃烧效率没有显著体现,且高温气流对燃烧室提出更高要求。通过增加氧化剂过量系数可降低燃烧室总温,且增益系数有所增大。
激光器 化学激光器 增益发生器 两步燃烧 气膜冷却
国防科学技术大学 光电科学与工程学院,长沙 410073
为了研究直排型连续波DF/HF化学激光器的启动特性,建立了一套化学激光器气流通道双喷管小型实验模型。以氮和氦作为引射介质,采用两种面积比的引射喷管,进行了启动实验。实验表明,当以氮作为引射介质,采用大面积比的引射喷管进行实验时,实验数据与1维理论计算结果相差很大。分析认为,该次实验中,在引射喷管内剧烈地膨胀后,部分N2已经发生相变,理论计算采用的1维定常流处理法已经不再适用。计算表明,连续波DF/HF化学激光器中的光腔燃料和副稀释剂He不会发生相变,但当以N2作副稀释剂时,副稀释剂喷管面积比不能过大。
化学激光器 超声速引射器 相变 喷管 chemical laser supersonic ejector phase change nozzle
国防科学技术大学 光电科学与工程学院,长沙 410073
建立了一套文氏咀临界背压比的测量系统,分别以氮气、氩气和氧气为工作介质,对两种加工工艺、不同规格文氏咀的临界背压比进行了测量,得到了各文氏咀对应不同工作介质的临界背压比,讨论了实验系统中第一个文氏咀的作用和温度对测量结果的影响。实验结果表明:设计合理、工艺合适的Laval喷管,临界背压比明显高于临界压力比,而且,比热容比越小,表面粗糙度等级越高,喉道直径越大,对应的临界背压比越大。
化学激光器 文氏咀 临界背压比 流量控制 chemical laser Venturi critical background-pressure ratio mass flow control 强激光与粒子束
2009, 21(11): 1619
