掺Yb光纤激光器中温度对可饱和吸收效应的影响

针对运行于准四能级的掺Yb光纤激光器,研究了未泵浦光纤吸收区掺Yb光纤温度对可饱和吸收效应,以及对F-P腔先纤激光嚣运行激光的影响.可饱和吸收效应随温度升高而增强.     

自由谐振腔激光器的激光谐振过程研究

探索一种新型光电干扰技术自由谐振腔激光器,它利用光学系统的"猫眼"效应,将其作为激光谐振腔的一面腔镜,和本地后向反射镜组成一个大腔长的激光谐振腔实现激光谐振。从激光谐振腔的基本原理出发,建立了自由谐振腔激光器的理论模型,用Fox-Li迭代算法模拟了该谐振腔内的激光谐振过程;计算了后向反射镜误差,"猫眼"系统离焦,对准误差,激光增益介质热效应等因素对谐振腔模式的影响。     

调Q锁模激光器创新实验设计

结合目前热门的二维材料性能研究,设计了基于二硫化钼可饱和吸收体的被动调Q锁模激光器输出性能优化综合实验。实验采用液相剥离方法,制备性能稳定的二硫化钼可饱和吸收体,利用制成的可饱和吸收体实现被动调Q锁模激光器的稳定输出。实验设计可以应用于光电专业实验以及大学生创新实验,有助于学生熟悉激光材料、加深对激光原理的理解,提升学生的创新实践能力。     

数值模拟在激光原理教学中的应用

为了增强激光原理教学中激光器光场分布的直观性,采用快速傅立叶变换法求解傍轴近似波动方程,计算模拟了激光器光场分布,直观地给出了三维稳态分布图,并探讨了腔镜倾斜对激光光场分布的影响。     

飞秒钛宝石激光器的工作原理研究

飞秒激光是一种持续时间极短(10-15s),峰值功率高的以脉冲形式运转的激光.它不仅能使人们获得超短时间的分辨能力,同时,由于它的高峰值功率,使它在各个领域都得到了广泛的应用.飞秒钛宝石激光器包括飞秒激光振荡器和飞秒激光放大器两部分,是目前能产生飞秒量级脉冲的应用最广泛的激光器.它通过钛宝石的自锁模原理.并采用世界上先进的啁啾脉冲放大(CPA)技术,已能直接产生零点几个飞秒、峰值功率达太瓦量级的激光脉冲.文章从钛宝石晶体的增益特性、自锁模原理、色散及色散补偿、脉冲的展宽与压缩、再生放大器等方面,对飞秒钛宝石激光振荡器和放大器的工作原理做详细的阐述.     

基于改进的单次自相关测量飞秒激光脉冲的时空特性(英文)

针对单次自相关方法只能测量一个脉宽的缺点,提出一种改进的单次相关方法测量超短激光脉冲全空域中不同空间位置的时空特性.通过实验测量了钛宝石激光器输出飞秒激光脉冲的时空特性,结果表明飞秒激光脉冲全空域中不同位置的复杂空间特性得以精密测量;不同空间位置的时间脉宽不同,它们服从高斯分布;当飞秒激光脉冲经过二硫化碳非线性介质传输后,随着输入平均功率的增加,同一空间位置的时间脉宽呈现慢慢变窄的趋势.实验结果验证了所提方法可以有效地测量超短激光脉冲全空域中不同空间位置的时空特性.     

大功率横流CO_2激光器折叠腔的研究

报道大功率流CO2激光器折叠腔技术的研究结果。用普通的镀金反射镜和GaAs输出耦合镜构成五折光学谐振腔,实验低阶模输出。腔内不加光栏输出横模为TEM∞＋TEM10模,功率1550瓦,发散用1．6毫弧度,腔内加35mm光栏情况下横模基本为TEM∞模,输出1300瓦,发散角1～3毫弧度。     

掺铒光纤激光器混沌同步实验研究

激光混沌信号的宽带、随机和不可预测性,使其具有天然的屏蔽性和保密能力,成为保密通信的优选光源。混沌同步作为混沌通信的基础,是混沌通信的研究热点。基于长腔的混沌光纤激光器,实验研究掺铒光纤放大器输出的混沌激光与光纤激光器的同步特性。结果表明：通过改变偏振控制器和泵浦电流,混沌光纤激光器与掺铒放大器在很大的范围内具有同步特性。     

折叠腔折叠角度对倍频光输出功率的影响

利用Jones矩阵法研究折叠腔腔内倍频偏振状态的改变,获得折叠角度对倍频光输出功率的影响.采用不需要进行严格温度控制的KTP晶体倍频Nd:YVO4折叠腔激光器产生671 nm激光,比较折叠腔不同折叠角度的红光输出功率,获得最佳折叠角度25(°),其有效倍频效率为10.8%.实验结果与理论一致.     

声光调Q激光关断与调制实验研究

设计了端面抽运Nd:YVO4晶体声光调Q激光实验,开展声光调Q激光关断与调制特性研究．将Q开关分别工作于自由运转、高衍射和调Q三种状态,对比采用15%、30%和45%三个透过率耦合腔镜的输出功率．结果表明,在自由运转连续波状态下工作时,三个耦合腔镜对应的激光输出功率差别较小;处于高衍射状态下,耦合腔镜透过率越大,越有利于抑制激光振荡,减少激光处于关断状态对上能级粒子数的消耗;处于调Q状态下,抽运功率达到一定值后,总会出现输出功率饱和现象,调Q激光腔内的功率密度非常高,过小的透过率不利于激光的有效输出,因此透过率越低的越早出现饱和现象．     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.