首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   66篇
  免费   10篇
物理学   76篇
  2023年   1篇
  2022年   2篇
  2020年   2篇
  2019年   2篇
  2018年   2篇
  2015年   1篇
  2014年   3篇
  2013年   6篇
  2012年   3篇
  2011年   8篇
  2010年   4篇
  2009年   6篇
  2008年   7篇
  2007年   11篇
  2006年   6篇
  2005年   5篇
  2004年   4篇
  2003年   2篇
  1997年   1篇
排序方式: 共有76条查询结果,搜索用时 15 毫秒
1.
A 1 064-nm pulsed coherent Doppler lidar (CDL) prototype is developed to measure short range wind speed in the lower altitude troposphere layer. The CDL system adopts an injection-seeded Nd:YAG laser with the pulse duration of 80 ns, single pulse energy of 0.5 mJ, and pulse repetition rate of 200 Hz. Speed calibration experiments are implemented to obtain a speed accuracy of 0.3 m/s using a hard target. Data analysis results show that the CDL system can obtain a line-of-sight wind velocity at a range of 30 to 500 m with the range resolution of 40 m and 38 pulses accumulation.  相似文献   
2.
A frequency stabilizing system for a pulsed injection seeded 1550 nm optical parametric oscillator(OPO) at 20 Hz repetition rate is demonstrated.The optical heterodyne method is used to measure the frequency difference between the seed laser and the OPO output.Using the frequency difference as the error signal,a proportionalintegral controller in combination with a scanner is applied to stably match the OPO cavity length to the seed laser frequency.The root-mean-square(rms) error of the frequency discrimination method is 0.07 MHz according to a ‘frequency shifting-chopping-beat' evaluation.The frequency fluctuation of the frequency-stabilized OPO is0.29 MHz(rms),and the Allan deviation is less than 20 k Hz for averaging time of more than 3 s.  相似文献   
3.
We develop a compact and high-energy Nd:YAG slab laser system consisting of an oscillator and an amplifier for space applications. The oscillator is a diode-side-pumped electro-optically Q-switched slab laser with a cross-Porro resonator. The KD*P Pockels cell with a low driving voltage of 950 V is used to polarization output coupling. The amplifier is a Nd:YAG zigzag slab pumped at bounces. The maximum output pulse energy of 341 m3 with 13 ns pulse duration is obtained from the system at the repetition rate of 20 Hz and the beam quality factors are M2=3.1 and M2=3.5. The beam pointing stabilities of the laser system are 3.05μrad in the X-direction and 3.99 grad in the Y-direction, respectively.  相似文献   
4.
 研制了基于菲佐干涉仪的测风激光雷达系统,并使用高斯拟合法和最大似然法反演风速,对两种风速反演方法进行了分析,结果表明:风速较小时,两种方法具有相似的风速反演精度,但高斯拟合法收敛快、受条纹信噪比影响较小;风速较大时,高斯拟合法会由于条纹移出而产生较大误差,而最大似然法在处理风速较大情况时具有优势。实际风速测量时,应根据风速估计值的大小,采用两种方法分别处理大风速和小风速时的情况。最后,使用研制的测风激光雷达系统和风速反演算法,得到了1.5 km以内的大气风速廓线。  相似文献   
5.
A novel design for a highly efficient 1-kHz single-frequency green laser is proposed.An efficient singlefrequency laser pulse output at 532-nm wavelength may be obtained by combining the injection seeding with intracavity frequency doubling in a compact U-shaped cavity formed by two plano dichroic mirrors in an end-pumping arrangement.The laser is capable of producing green pulses with a total energy of 6.3 mJ at a pulse repetition rate of 1 kHz.The pulse width is about 10 ns and the optical-optical efficiency from the 808-nm pump source to the 532-nm green output is around 12.7%.  相似文献   
6.
A Yb:YAG disk laser with V-shaped stable resonator and active-mirror configuration,end-pumped by a 940-nm InGaAs laser diode array,is demonstrated.Performances and optimization of the disk laser at low temperature over a range of 130-200 K are investigated theoretically and experimentally.Laser output energy of 1.46 J/pulse operating at 10-Hz repetition rate is obtained with the optimum output coupler transmission of 30%,and the corresponding optical-to-optical efficiency is 48.7%.  相似文献   
7.
基于RS编码及网格编码调制的光PPM通信纠错技术   总被引:1,自引:0,他引:1  
梁波  陈卫标 《光子学报》2008,37(7):1361-1364
分析了RS(Reed-Solomon)纠错码和网格编码调制(Trellis Coded Modulation,TCM)技术在光脉冲位置调制通信中的应用.在此基础上,提出了以RS码作为外码,以网格编码调制技术作为内码,用于光脉冲位置调制通信的新编码方案,能以几乎不减少通信速率的优势,提高传统RS码系统在时变带限光信道中的通信性能.模拟研究了在不同空间光信道条件下,传统RS码的符号正确传输率和误码率,并对网格编码调制的编码增益、RS码与网格编码调制级联时的编码增益进行了仿真研究,证实了本方案的有效性.  相似文献   
8.
注入锁定激光器的边带锁频技术稳频系统优化分析   总被引:1,自引:0,他引:1  
孙旭涛  陈卫标 《光子学报》2008,37(9):1748-1752
介绍了边带锁频技术稳频方法,推导出鉴频曲线,对稳频控制过程进行了分析.建立了注入锁定激光器的边带锁频技术稳频系统理论模型,讨论了相关参量对稳频效果的影响并且进行了优化.结果表明,增加入射光强,采用窄线宽的法布里-珀罗以及对法布里-珀罗进行高准确度温控都可以增强稳频效果.提出适用于注入锁定激光器的两种稳频方案并进行比较.  相似文献   
9.
Diode pumped, injection seeded single-longitudinal-mode (SLM) Nd:YAG laser is achieved through buildup time minimizing technique in Q-switching operation. Pulses with energy of 20 mJ are obtained at a repetition rate of 100 Hz. Mx2 and My2 are 1.41 and 1.38, respectively.  相似文献   
10.
激光二极管端面抽运的棒状Yb:YAG激光器   总被引:5,自引:1,他引:4  
分析了影响激光二极管抽运Yb:YAG激光器调Q效率的参量,推导了激光二极管端面脉冲抽运Yb:YAG晶体的速率方程,解出了双程抽运情况下的净抽运量子产率。利用数值计算方法,模拟了净抽运量子产率与晶体长度,抽运光脉冲宽度等关系,得出晶体长度的优化可以提高Yb:YAG激光器输出效率。计算了词Q Yb:YAG激光器的最大增益、最大储能,分析了放大自发辐射对于Yb:YAG能量存储的影响。同时给出了激光二极管端面抽运调Q Yb:YAG优化设计方法。这些分析和计算为实际器件的研制提供参考。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号