Low-Threshold Mid-Infrared Optical Parametric Oscillator Using Periodically Poled LiNbO33

We report the generation of tunable mid-infrared optical pulses using all-solid-state pumped optical parametri coscillator in a periodically poled lithium niobate. Several ways were used to lower the threshold, resulting in a mean threshold as low as 6.5mW and an achievement of wavelength conversion in the 2.77-4.04μm spectral range. Continuous tuning range from 2.97 to 3.25μm was achieved. The maximum idler output power of 466mW at the wavelength of 3.41μm was obtained, which represents an optical-to-optical conversion efficiency of 19% from incident pump power to the idler output.     

利用啁啾光纤光栅色散特性实现波长可调谐的主动锁模掺铒光纤环行腔激光器

在环形腔主动锁模光纤激光器中引入啁啾光纤光栅，利用啁啾光纤光栅的大色散特性，通过调节调制频率，实现波长调谐，调谐范围2nm。所得脉冲为重复频率2．5GHz，脉宽约60ps的正啁啾脉冲，。     

Recording Fractional Fourier Transform Hologram Using Holographic Zone Plate

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　ＦＲＴ(ＦｒａｃｔｉｏｎａｌＦｏｕｒｉｅｒＴｒａｎｓｆｏｒｍ )ｗａｓｆｉｒｓｔｌｙｉｎｔｒｏｄｕｃｅｄｂｙＮａｍｉａｓｉｎ 1 980ａｓａｍａｔｈｅｍａｔｉｃｔｏｏｌｉｎｑｕａｎｔｕｍｍｅｃｈａｎｉｃｓ[1] .Ｉｎ1 993,ＭｅｎｄｌｏｖｉｃａｎｄＯｚａｋｔａｓｉｍｐｌｅｍｅｎｔｅｄｔｈｅＦＲＴａｔｏｐｔｉｃａｌｆｉｅｌｄｗｈｅｎｔｈｅｙｓｔｕｄｉｅｄｇｒａｄｉｅｎｔｉｎｄｅｘ (ＧＲＩＮ )ｆｉｂｅｒ[2 ] ａｎｄａｐｐｌｉｅｄｔｈｅｐｕｒｅｍａｔｈｅｍａｔｉｃｆｏｒｍｕｌａｔｉｏ…     

基于光纤光栅的可调谐半导体激光器

本文利用光纤光栅(FBG)形成外腔反馈及F-P半导体激光器的多模特性,得到波长稳定、可调谐的半导体激光光源,系统研究了不同反馈比率对激光器光谱特性的影响.通过向FBG施加轴向拉力和压力可实现10nm的波长调谐,得到一系列波长间隔0.94nm的激光输出,边模抑制比达35dB,光谱线宽小于0.2nm.     

Three New Diterpenoids from Euphorbia wallichii

Three new abietane diterpene lactones, 3α-hydroxyjolkinolide A (1), ent-8α, 14β-dihydroxy-13(15)-ene-16(12α)-abietanolide (2) and ent-8α,14α-dihydroxy-13(15)-ene-16(12α)-abietanolide (3) as well as a known abietane diterpene jolkinolide A (4) were isolated from the roots of Euphorbia wallichii. Their structures were elucidated on the basis of spectroscopic analysis.     

海量数据导入与导出MATLAB的有效方法

本文结合实例介绍了几种将海量统计数据快速、准确地导入与导出MATLAB系统的方法。克服了以往在编程窗口直接键入原始数据进行处理的诸多问题,因此对保证统计分析结果的准确性与加速MATLAB在统计分析领域的应用有着很重要的意义。     

A Novel Method for Measuring the Photo－Induced Birefringence of Photosensitive Fibres Based on a Fibre Loop ＊

We report a novel method for measuring photo-induced birefringence of photosensitive fibres based on a fibre loop.The method is simple and is only slightly affected by the surroundings. The experimental results show that thephoto-inducing normalized birefringence of the photosensitive fibre is multi-decaying-exponentially proportionalto the exposure and it can attain 10^-5.     

A Dual-Wavelength Cladding-Pumped Er^3＋/Yb^3＋ Codoped Fibre Laser System with More Than 2 W Output and Tunable Wavelength Spacing

A dual-wavelength laser system with wideband tunable wavelength spacing and more than 2 W output power is proposed and demonstrated. The operation principle of the laser system is based on the saturation gain characteristic of a cladding-pumped Era＋ /yba＋ co-doped fibre amplifier combining with a wideband tunable fibre laser with fiat power spectrum. The tuning range of the wavelength spacing is continuous within a 35 nm spectral range, and the power difference between both lasing wavelengths can be easily adjusted and controlled by a variable optical attenuator. The total output power can approximately keep unchangeable when the wavelength spacing and the power difference between both lasing wavelengths are continuously tuned and changed. The maximum total output power of the laser system is about 2.22 W.     

用MATLAB求解二元理想体系的泡露点问题

通过MATLAB工程计算软件，采用步长法、二分法、迭代法和黄金分割法等多种方法．求解了二元理想体系的泡露点问题．结果表明，几种计算值都能与手算值吻合地很好．相对误差远远小于1％，完全满足工程要求；用MATLAB内部函数Solve计算最为便捷．     

波长间隔可调的可开关双波长掺铒光纤激光器

对两种波长间隔可调的可开关双波长掺铒光纤激光器结构进行了实验研究。一种结构应用保偏光纤中布拉格光栅作为波长选择器件，另一种结构则利用侧向压力下的常规单模光纤光栅作为波长选择器件。两种结构均利用了光纤光栅的双折射特性。在室温下，通过调整偏振控制器的状态可使两激光器工作在稳定的双波长状态或在两单波长之间转换。通过改变加在光纤光栅上侧向应力的大小和方向，可有效控制双波长激射的波长间隔。