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1.
熊志成  朱丽霖  刘诚  高淑梅  朱健强 《物理学报》2015,64(24):247301-247301
设计了一种带有纳米天线的金属微腔结构, 以实现高强度表面等离子的定向激发. 在利用双狭缝结构实现表面等离子体波定向激发的基础上, 分别结合共振增强和干涉相长原理, 在传统结构的入射端面上添加纳米天线结构, 并增加狭缝通道数, 实现了定向激发的表面等离子体波的能量增强. 基于纳米天线的多通道高强度定向表面等离子体波激发装置结构简单, 系统紧凑, 并能够有效提高定向传播的表面等离子体波的能量密度和传播距离, 其对微纳光学传输和高密度光学集成领域等方面的研究具有重要意义.  相似文献   

2.
采用氙灯抽运自倍频晶体Nd^3 :Ga4GdO(BO3)3(简称Nd:GdCOB),Cr^4 :YAG被动调Q,实现了Nd:GdCOB晶体被动调Q激光运转,测量了饱和吸收体Cr^4 :YAG不同小信号透过率小绿激光单脉冲的输出能量、脉冲宽度、重复率,给出了描述Nd:GdCOB晶体调Q工作原理的耦合波方程组,数值求解了该方程组,所得的理论结果与实验值相符合。  相似文献   

3.
给出了Nd∶YVO4/KTP内腔倍频声光调Q工作原理的耦合波速率方程组实现了半导体激光器(LD)抽运折叠腔倍频声光调Q绿激光的运转,在抽运光功率3.8W、重复频率10kHz时,获得绿光脉冲宽度为33.2ns,单脉冲能量为59.6μJ,峰值功率达到1.8kW数值求解耦合波方程组理论值与实验结果相符  相似文献   

4.
顾本源 《物理》2007,36(4):280-287
表面等离子体是沿着导体表面传播的波,当改变金属表面结构时,表面等离子体激元(surface plasmon polaritons,SPPs)的性质、色散关系、激发模式、耦合效应等都将产生重大的变化.通过SPPs与光场之间相互作用,能够实现对光传播的主动操控.表面等离子体光子学(plasmonics)已成为一门新兴的学科,它的原理、新颖效应以及机制的探究,都极大地吸引研究者们的兴趣.SPPs具有广阔的应用前景,例如,应用于制作各种SPPs元器件和回路,制作纳米波导、表面等离子体光子芯片、耦合器、调制器和开关,应用于亚波长光学数据存储、新型光源、突破衍射极限的超分辨成像、SPPs纳米光刻蚀术、以及生物光学(作为传感器和探测器).文章介绍了表面等离子体光子学原理、新颖效应和物理机制,并简述若干应用。  相似文献   

5.
LD泵浦Nd∶YVO4/KTP内腔倍频声光调Q理论和实验研究   总被引:7,自引:0,他引:7  
赵宏明  赵圣之  杨克建  李桂秋 《光子学报》2004,33(11):1294-1297
给出了Nd∶YVO4/KTP内腔倍频声光调Q工作原理的耦合波速率方程组.实现了半导体激光器(LD)抽运折叠腔倍频声光调Q绿激光的运转,在抽运光功率3.8 W、重复频率10 kHz时,获得绿光脉冲宽度为33.2 ns,单脉冲能量为59.6 μJ, 峰值功率达到1.8 kW.数值求解耦合波方程组理论值与实验结果相符.  相似文献   

6.
利用表面等离子体共振效应,研究了金属镀层厚度对光纤表面等离子体波传感器的影响。在其它参量一定的情况下,不同金属膜层厚度的传感器对应着不同的共振波长,根据这一特性设计了分布式光纤表达等离子体波传感器。突出优点是能进行多点测量。  相似文献   

7.
采用氙灯抽运自倍频晶体Nd3 +∶Ca4GdO(BO3 ) 3 (简称Nd∶GdCOB) ,Cr4+∶YAG被动调Q ,实现了Nd∶GdCOB晶体被动调Q激光运转 ,测量了饱和吸收体Cr4+∶YAG不同小信号透过率下绿激光单脉冲的输出能量、脉冲宽度、重复率 ,给出了描述Nd∶GdCOB晶体调Q工作原理的耦合波方程组 ,数值求解了该方程组 ,所得的理论结果与实验值相符合  相似文献   

8.
 为了研究激光推进技术中激光与材料相互作用的机制,获取等离子体状态参数及力学参数,采用Nd:YAG被动调Q固体激光器烧蚀硬铝,通过激光诱导等离子体光谱技术测得等离子体光谱和温度,由冲量摆测得力学参数。实验结果显示:在激光功率密度0.534×108 W/cm2时,靶材表面的等离子体温度在等离子体辐射过程中呈二次曲线衰减;改变靶材等离子体点燃阈值附近的激光功率密度时,随着功率密度的增加,等离子体温度、冲量耦合系数也随着增大,当功率密度达到靶材的等离子体点燃阈值时,各参数达到最大,此后随着功率密度增加,由于等离子体对能量的屏蔽作用,导致靶材表面的等离子体温度降低,等离子体获得的动能减少,靶材耦合的冲量降低。  相似文献   

9.
表面等离子体波检测的新技术研究   总被引:8,自引:2,他引:6  
郭继华  刘通 《光学学报》1996,16(9):322-1325
报道表面等离子体波的一种新的检测技术,可以同时获得表面等离子体波激发过程中反射光的相位和光强变化。理论计算表明,表面等离子体激发过程中,P偏振反射波相位的变化可达300°。在此基础上建立了光学外差测量装置,可同时获得相位和强度变化的信息,实验数据和理论计算吻合非常好。此方法比仅能给出强度变化的角度扫描衰减全反射(ATR)方法,提供了更多的信息,而且相位检测比强度检测灵敏度高,为表面光学性质的研究、LB膜特征研究以及表面等离子体波传感器的研究提供了更有力的工具。  相似文献   

10.
简介了近年来发展起来的若干种新型固体激光器被动调Q用吸收体:掺Cr4+系列,Cr,Nd∶YAG自调Q激光晶体,人眼安全激光器被动调Q用吸收体,GaAs吸收体,半导体可饱和吸收镜。着重介绍了固体激光器和光纤激光器调Q用半导体可饱和吸收镜的原理、研制方法及应用状况。  相似文献   

11.
激光调Q CAI   总被引:4,自引:3,他引:1  
从激光调Q速率方程出发,分析推导了激光调Q过程中,腔内光子数与工作物质内反转粒子数间的关系.再根据激光调Q的过程中,对腔Q值控制方式不同,将激光调Q技术分为:转镜调Q、声光调Q、电光调Q、饱和吸收调Q和脉冲透射式调Q.用C语言进行了激光调Q CAI软件的开发研制,获得了将文学、图形、动画和计算融为一体的,直观而生动地将调Q的理论和过程再现于屏幕的CAI课件.介绍了课件的内容、结构及其特点.  相似文献   

12.
A microwave propagating along vacuum—dielectric—plasma interface excites surface plasma wave (SPW). A periodic slow-wave structure placed over dielectric slows down the SPW. The phase velocity of slow SPW is sensitive to height, periodicity, number of periods, thickness and the separation between dielectric and slow-wave structure. These slow SPW can couple the microwave energy to the plasma and can sustain the discharge. The efficiency of the power coupling is few per cent and is sensitive to separation between dielectric and slow-wave structure.  相似文献   

13.
Compared to steadily propagating waves (SPW), damped waves (DW), another solution to the nonlinear wave equation, are seldom studied. In cardiac tissue after electrical stimulation in an SPW wake, we observe DW with diminished amplitude and velocity that either gradually decrease as the DW dies, or exhibit a sharp amplitude increase after a delay to become an SPW. The cardiac DW-SPW transition is a key link in understanding defibrillation and stimulation close to the refractory period, and is ideal for a general study of DW dynamics.  相似文献   

14.
The excitation of terahertz surface plasma wave (SPW) over bismuth thin film-glass structure by a parallel propagating electron beam is studied. The SPW phase velocity is sensitive to the thickness of bismuth film and it is driven via the Cerenkov resonance. The growth rate for terahertz radiation generation by an electron beam is obtained under small signal approximation.  相似文献   

15.
本文从粒子振动的角度讨论了光纤表面等离子体波传感器对于温度的敏感特性。对于金属 /介质的表面等离子体波传感器 ,在界面处产生的等离子体振动实质是大量电子的集体振荡。在某一特定的波长的P光激励下 ,电子吸收了光子的能量而改变了原来的运动方式 ,当激励的光信号与电子群的固有振荡频率一致时 ,大量的电子振动变为一种谐振。由于界面处的电子密度与温度是密切相关的 ,不同的温度时密度不同———温度越高 ,电子的密度越大 ,而电子群的集体振荡又与电子的密度密切相关。所以温度的变化将对等离子体的共振频率产生非常重要的影响。利用了这一效应来补偿环境介质的温度变化 ,可以克服环境温度对测试所带来的影响。此外 ,本文也讨论了采用光纤SPW传感器可以进行多参数的测量。  相似文献   

16.
A method to obtain large transmission of light through a nano-metallic slit bordered by nano trenches is demonstrated theoretically. The model is based on the composite diffraction of evanescent waves (CDEW) theory and utilizes a single trench design to effectively convert free-space light into surface plasma waves (SPW). The effectiveness is confirmed by the finite difference time domain (FDTD) method. The SPW loss due to scattering by the trench is also analyzed. It is found that when the width of the trench is slightly larger than λspp/2, the SPW becomes localized and resonates at the bottom edges performing as a dipole-like radiation source. At this time, the propagating SPW suffers from high scattering loss. Trenches can be used to enhance the transmission of a nano-scaled slit while simultaneously preserving high conversion efficiency and low scattering loss. A nano-scaled slit bordered by 10 pairs of trenches can be enhanced by a factor as high as 16. It is determined that a device designed to have a large clear aperture of 15 μm would have an advantage in terms of alignment.  相似文献   

17.
A new method of exciting nonradiative surface plasma waves (SPW) on smooth surfaces, causing also a new phenomena in total reflexion, is described. Since the phase velocity of the SPW at a metal-vacuum surface is smaller than the velocity of light in vacuum, these waves cannot be excited by light striking the surface, provided that this is perfectly smooth. However, if a prism is brought near to the metal vacuum-interface, the SPW can be excited optically by the evanescent wave present in total reflection. The excitation is seen as a strong decrease in reflection for the transverse magnetic light and for a special angle of incidence. The method allows of an accurate evaluation of the dispersion of these waves. The experimental results on a silver-vacuum surface are compared with the theory of metal optics and are found to agree within the errors of the optical constants.  相似文献   

18.
A surface plasma wave (SPW) over bismuth-vacuum interface has a signature of mass anisotropy of free electrons. For SPW propagation along the trigonal axis there is no birefringence. The frequency cutoff of SPW lies in the far infrared region and can be accessed using free electron laser. The damping rate of waves at low temperatures is low. The surface plasma wave may be excited by an electron beam of current ∼100 mA propagating parallel to the interface in its close proximity.  相似文献   

19.
A laser incident on a metal film (deposited on a glass substrate) from the glass side at a specific angle of incidence, excites a surface plasma wave (SPW) at the metal-free space interface. The ratio of the SPW field to the laser field increases with the laser spot size b attaining a value much greater than one at b>exp(2wα/c) where a is the film thickness and ω is the laser frequency. The SPW (ω, kz,) can also he excited by a relativistic electron beam, propagating parallel to the interface in the free space region, via Cerenkov interaction when beam energy ϵb=(|ϵ|-1)mc2 where ϵ is the effective metal permittivity, and mc2 is the electron rest mass energy. When the surface has a ripple of wave number k0, the SPW (ω, kzz) can be excited at lower beam energy via sideband coupling, ω=(kzz +k0)vb where vbzˆ is the beam velocity. In both cases, however, the positioning of the beam in the close proximity of the interface is required. The scheme is useful for the generation of wavelengths longer than 1 μm  相似文献   

20.
用表面等离子波相位检测法测量液体折射率   总被引:6,自引:0,他引:6  
蒋弘 《光学技术》2000,26(1):41-42,45
表面等离子体波(SPW) 检测技术近年来已被应用在生物传感领域。它通过探测介质的折射率变化来探测生物反应。理论分析表明,利用SPW 相位检测的方法可以实现高分辨率的液体折射率测量。在优化测量参数的基础上,使用低频差横向塞曼激光器为光源,进行了验证实验,实验结果与理论相符合。  相似文献   

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