共查询到20条相似文献,搜索用时 123 毫秒
1.
有机染料激光器是一种重要的可调谐相干光源。它以荧光染料作为工作物质,用闪光灯、氮分子激光器、倍频的钇铝石榴石激光器、准分子激光器、铜蒸汽激光器、较高功率的氩或氪离子激光器作泵浦源。染料产生的荧光波长比泵浦波长稍长一些(称为斯托克斯位移),当满足一定的物理条件后,这种荧光就能转变为激光。其激光作用可以出现在强荧光的任何波长上。由于染料的荧光谱带很宽,因此染料激光作用的可能范围也很宽。只要我们适当地选择几种染料,并采用某些调谐元件,就可以使激光波长在宽广的光 相似文献
2.
长春光机所染料激光器组 《激光与红外》1980,(12)
本文叙述了环形连续波染料激光器的设计考虑和试验结果。采用若丹明6G染料,连续Ar~+激光作泵浦源,当Ar~+激光全线泵浦功率为4瓦时,染料激光器(空腔)输出功率800毫瓦;腔内插入法拉弟旋转器和调谐元件后,获得单向行波单频振荡,单频功 相似文献
3.
为了实现可调谐双波长激光输出,提出并设计了一种基于自反馈光注入结构的掺Er3+光纤(EDF)激光器,并对激光器的基本原理及实现方案进行了理论分析和实验验证。系统结构设计采用976nm波长的LD作为泵浦源,结合EDF,两支光纤布拉格光栅(FBG)和光纤环形镜(FLM)产生激光,并通过在FLM中熔接饱和吸收体(SA)起到稳频作用;将FLM输出激光耦合进入谐振腔形成自注入结构,与腔内振荡激光形成干涉,抑制模式跳变;通过控制两支FBG之间的可调谐衰减器调节谐振腔内的增益和损耗,实现单个波长或双波长输出。实验结果表明:SA长采用4m、EDF长采用6m时,激光输出阈值为28mW,将反馈光注入谐振腔后,系统阈值为25mW,输出激光波长随时间漂移得到明显抑制;当泵浦光功率为80mW时,通过调节位于两支FBG之间的可调谐衰减器(VA)获得稳定的双波长激光输出;随着泵浦功率增加,激光输出功率具有良好的线性度和稳定性。在1 540nm波长处激光输出最大功率为1.16mW,信噪比(SNR)大于50dB;在1 545nm波长处激光输出最大功率为1.89mW,SNR大于50dB。 相似文献
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郑玉霞 《激光与光电子学进展》1979,16(8):23
本文报导了在激光泵浦的染料激光器中再生振荡的观察。从波长为5320埃,50亳微秒脉冲泵浦的若丹明6G染料激光器中观察到1亳微秒的脉沖序列。应用最近发展起来的一种新的反转腔技术产生再生振荡。描述了这种技术的原理和在染料激光器中的实验结果。 相似文献
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双波长环形腔掺铒光纤激光器输出的稳定性 总被引:5,自引:0,他引:5
使用掺铒光纤平均反转粒子数模型推导了双波长激光器平衡振荡需满足的条件,并据此设计实验系统,对抽运功率、模式损耗以及波长间隔对输出功率的影响进行了实验研究.结果表明,可通过调节腔内损耗谱实现掺铒光纤环形腔内多波长激光输出,双模平衡振荡条件在远离阈值点情况下成立;可变衰减器的稳定性对双波长平衡的影响极大,允许的偏离值小于0.4 dB;而起振波长的偏离对双波长平衡的影响较小,大于1 nm的波长偏离才会导致平衡破坏;掺铒光纤的非均匀加宽效应允许平衡时损耗在一定范围内波动,这有助于提高激光器的输出稳定性,30 min内1546 nm和1556 nm双波长的功率波动小于0.5 dB. 相似文献
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《量子电子学报》2014,(1)
正紧凑的被动锁模全固态激光器在精密测量加工、非线性光学频率变换等方面具有重要的应用。Nd~(3+)掺杂的晶体材料是超短脉冲锁模激光器的主要增益介质,其中Nd:GdVO_4晶体具有高热导率、宽增益带宽、短上能级寿命等优势,使其在获得高功率、窄脉冲皮秒激光方面具有很大的潜力、采用主振功率放大(MOPA)方案,获得了高功率、窄脉冲皮秒1063 nm激光、对于振荡级,为了减小量子亏损热,利用879 nm半导体激光直接泵浦Nd:GdVO_4晶体;采用半导体可饱和吸收镜作为锁模元件。在热近非稳腔运转条件下获得了输出平均功率为7 W的皮秒1063 nm激光,重复频率约为250 MHz,光光转换效率和斜效率分别为55.2%和56.8%。对于放大级,为了减小晶体中的热量,同时使得振荡级和放大级的波长匹配,仍然采用879 nm半导体激光直接泵浦Nd:GdVO_4晶体。对振荡级输出的皮秒1063 nm激光,平均功率为5.8 W时进行了单程放大。在吸收泵浦光功率为64.3 W时,放大器最大输出平均功率为21.7 W的皮秒1063 nm激光,对应提取效率为33.7%、1063 nm激光输出平均功率为21.7 W时,脉冲宽度为7.1 ps,光束质量因子为1.24,这也说明放大器输出激光处于单模运转状态。 相似文献
11.
《The Journal of communication》1967,17(2):176-182
Book reviewed in this articles:
P ress P hotography . By Robert B. Rhode and Floyd H. McCall.
I ntroduction to P hotography . By Robert B. Rhode and Floyd H. McCall.
T he A ct of W riting and R eading : A C ombined T ext . By Alan Casty, of Santa Monica City College.
W riting by P atterns . By Helen E. Lefevre, of Chicago City Junior College, and Carl A. Lefevre, of Chicago Teachers College.
A natomy of W riting . By Peter Swiggart, of Brandeis University.
A n I ndex or I deas for W riters and S peakers . By Zebulon Vance Hooker II, of Roanoke College.
M r . J ustice M urphy and the B ill of R ights . By Harold Norris, of the Detroit College of Law.
M ental H ealth B ook R eview I ndex , Volume 10, 1965. Compiled by the Editorial Committee and Contributing Librarians.
L anguages of the M ass M edia : R eadings in A nalysis . Edited by Irving and Harriet Deer, Dickinson State College.
H ow to C ommunicate O rally . By Glenn R. Capp, of Baylor University.
D ocumentary in A merican T elevision . By A. William Bluem.
T he T echnique of the T elevision C ameraman . By Peter Jones.
W ho's W ho in the H istory of P hilosophy . By Thomas Kiernan.
E ssays for C ollege W riting . By A.J.M. Smith.
E ssentials of G rammar and S tyle . By John I. McCollum, Jr.
M ental H ealth B ook R eview , I ndex , Vol. 11, 1966.
D ynamics of R esponse . By Joseph M. Nottennan and Donald E. Mintz.
I mprovement of T eaching by T elevision . Edited by Barton L. Griffith and Donald W. MacLennan.
N eurolocical O rganization and R eading . By Carl H. Delacato.
A R eader for W riters . By Jerome W. Archer, of Arizona State University, and Joseph Schwartz, of Marquette University.
A G lossary for C ollege E nglish . By Martin Stevens, of Ohio State University, and Charles H. Kegel, of Idaho State University. 相似文献
P ress P hotography . By Robert B. Rhode and Floyd H. McCall.
I ntroduction to P hotography . By Robert B. Rhode and Floyd H. McCall.
T he A ct of W riting and R eading : A C ombined T ext . By Alan Casty, of Santa Monica City College.
W riting by P atterns . By Helen E. Lefevre, of Chicago City Junior College, and Carl A. Lefevre, of Chicago Teachers College.
A natomy of W riting . By Peter Swiggart, of Brandeis University.
A n I ndex or I deas for W riters and S peakers . By Zebulon Vance Hooker II, of Roanoke College.
M r . J ustice M urphy and the B ill of R ights . By Harold Norris, of the Detroit College of Law.
M ental H ealth B ook R eview I ndex , Volume 10, 1965. Compiled by the Editorial Committee and Contributing Librarians.
L anguages of the M ass M edia : R eadings in A nalysis . Edited by Irving and Harriet Deer, Dickinson State College.
H ow to C ommunicate O rally . By Glenn R. Capp, of Baylor University.
D ocumentary in A merican T elevision . By A. William Bluem.
T he T echnique of the T elevision C ameraman . By Peter Jones.
W ho's W ho in the H istory of P hilosophy . By Thomas Kiernan.
E ssays for C ollege W riting . By A.J.M. Smith.
E ssentials of G rammar and S tyle . By John I. McCollum, Jr.
M ental H ealth B ook R eview , I ndex , Vol. 11, 1966.
D ynamics of R esponse . By Joseph M. Nottennan and Donald E. Mintz.
I mprovement of T eaching by T elevision . Edited by Barton L. Griffith and Donald W. MacLennan.
N eurolocical O rganization and R eading . By Carl H. Delacato.
A R eader for W riters . By Jerome W. Archer, of Arizona State University, and Joseph Schwartz, of Marquette University.
A G lossary for C ollege E nglish . By Martin Stevens, of Ohio State University, and Charles H. Kegel, of Idaho State University. 相似文献
12.
S. V. Koshevaya V. V. Grimalsky Yu. N. Kotsarenko M. Tecpoyotl-T. 《Radioelectronics and Communications Systems》2016,59(11):489-495
Inthe framework of developed approximate phenomenological model we have performed the investigation of modulation instability of transversely limited electromagnetic waves of terahertz range in paraelectric crystals SrTiO3 at the temperatures of about 77 K. Cubic nonlinearity and frequency dispersion correspond to the existence of modulation instability of long input pulses. The results of numerical investigations of the modulation instability are presented. Transversal boundedness of the input pulses can stabilize the modulation instability. Modulation instability threshold is reduced in the presence of reflections from the crystal boundaries. In the case of development of the modulation instability it is possible to generate a sequence of short terahertz pulses at the output of the crystal. The focusing of input pulses reduces the threshold of modulation instability. 相似文献
13.
为了解决传统铝合金焊接接头气孔数量多、晶粒粗大及力学性能差的问题,以5083-O铝合金为研究对象,进行了超声振动辅助激光-电弧复合焊接试验。研究了超声振动对铝合金焊缝气孔数量、微观组织及抗拉强度的影响,并探讨了超声波在焊接熔池中对气孔排出和组织细化的作用机理。结果表明,超声辅助焊接的焊缝气孔数量显著降低,主要归功于超声空化效应降低了铝合金熔体中的氢浓度,并促进气泡的快速逸出;超声波的空化效应和声流效应改变了熔体的压力、温度以及流动状态,使熔池的结晶条件发生改变,从而通过提高形核率和破碎枝晶细化了焊缝晶粒组织;施加超声振动后的焊缝平均拉伸强度由242.9MPa提高到270MPa,且断裂位置发生在热影响区,主要是因为焊缝区气孔减少和组织细化。此研究对深入理解铝合金焊接过程中缺陷形成机理及提高接头强度是有帮助的。 相似文献
14.
金属颗粒掺杂型复合涂层是重要的航天器热控材料,除了粒子材料、尺寸、体积分数、几何形貌、涂层厚度等常规调控手段,颗粒的取向也是影响涂层辐射特性的重要因素。颗粒取向可以通过改变工艺参数或使用定向剂控制,然而目前关于颗粒整体取向对涂层吸收发射比的影响规律尚不清晰,而且现有的采用二流法的研究中大多都将散射假定为各向同性。以热控涂层中常用的大尺寸铝片粒子掺杂型复合涂层为计算模型,采用考虑衍射的几何光学方法和考虑各向异性散射的二流法研究了铝片取向角对热控涂层吸收发射比的调控规律,同时考虑了铝片体积分数和涂层厚度等因素。结果表明:通过调节粒子取向可实现涂层吸收发射比在0.48~1.69范围内的调控。涂层平均吸收率和平均发射率在铝片取向角超过45°时明显增大。涂层吸收发射比在铝片取向角45°附近最小,并且随铝片体积分数的增大而减小。研究表明:通过控制粒子的整体取向可有效实现吸收发射比的调控,为热控涂层的设计和调控提供了新的思路。 相似文献
15.
基于两棱镜组合的光学特点提出了一种改进的光振荡装置。该装置由四个直角棱镜组成,通过调节棱镜间的相对距离和位置,可以改变基线长度和振荡次数,使光线在光振荡装置中实现立体分布,达到增加光程的目的。通过测量输出光强度,得到大气消光系数和能见度;对实际应用中激光器发散角所引起的光传输过程中光斑直径随光程增加而增大的情况进行了数值模拟,并分析了不同能见度对应消光系数及不同光程的光强衰减比,为探测器的选取提供参考。 相似文献
16.
J.L. Roca 《Microelectronics Reliability》1987,27(1)
In this paper an approach in the L.C.C. of I.L.S. is presented. Beginning with the three state Markov model of each equipment of the system and by considering the problem of the scheduling of preventive maintenance, the optimum interval between inspections of equipment-system is determined. Then the total cost of the I.L.S. is calculated for both the contractor and the customer. 相似文献
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利用中波红外和长波红外热像仪对某型
喷气飞机发动机尾焰的红外辐射特性进行了测量,得到了3~5 μm
和8~12 μm波段的尾焰辐射亮度分布。结果表明,从飞机
尾向上观测到的中波红外和长波红外尾焰均成对称分布,前者的最高辐射亮
度和尾焰面积分别是后者的4.6倍和2.1倍;从飞机侧向上观测到的
中波红外尾焰的最高辐射亮度、尾焰长度和面积分别是长波红外尾焰
的2.2倍、3.8倍和5.7倍,前者的优势非常明显。另外,受高温尾焰加热的影响,尾
焰周围空气的温度明显上升,使其辐
射亮度高于其他背景的辐射亮度。本文获得的测量结果对尾焰红外辐射特性仿
真和计算研究具有一定的参考价值。 相似文献
19.
《IEEE transactions on information theory / Professional Technical Group on Information Theory》1972,18(3):402-409
This paper presents a number of interesting results relating to the determination of actual minimum distance of cyclic codes. Codes with multiple sets of consecutive roots are constructed. A bound on the minimum weight of odd-weight codewords is determined. Relations on the distribution of roots of the generator polynomial are investigated. Location polynomials of reversible codes are examined. These results are used to obtain better estimates of the minimum distance of many new cyclic codes. 相似文献
20.
The negativity of Wigner function (WF) is one of the important symbols of non-classical properties of light field. Therefore, it is of great significance to study the evolution of WF in dissipative process. The evolution formula of WF in laser process under the action of linear resonance force is given by virtue of thermo entangled state representation and the technique of integration within an ordered product of operator. As its application, the evolution of WF of thermal field and that of single-photon-added coherent state are discussed. The results show that the WF of thermal field maintains its original character. On the other hand, the negative region size and the depth of negativity of WF of single- photon-added coherent state decrease until it vanishes with dissipation. This shows that the non-classical property of single-photon-added coherent state is weakened, until it disappears with dissipation time increasing. 相似文献