共查询到20条相似文献,搜索用时 13 毫秒
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在分析现有的激光远场能量密度分布测试方法的基础上提出了一种新的测试方法.采用激光束照射漫反射靶,CCD相机对靶上激光光斑成像并在靶面上布置能量计探头以获取能量抽样绝对值的方法进行激光束远场大气传输后空域分布测试.从基本组成、测试原理、试验结果等方面对新测试方法进行了分析研究,并通过采用532nm脉冲激光照射1Km外的漫反射靶的实验对新测试方法进行了可行性验证,获得了远场激光光斑的图像和能量抽样值. 相似文献
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高功率脉冲激光的远场能量密度分布测试方法研究 总被引:2,自引:0,他引:2
在分析现有的激光远场能量密度分布测试方法的基础上提出了一种新的测试方法.采用激光束照射漫反射靶,CCD相机对靶上激光光斑成像并在靶面上布置能量计探头以获取能量抽样绝对值的方法进行激光束远场大气传输后空域分布测试.从基本组成、测试原理、试验结果等方面对新测试方法进行了分析研究,并通过采用532nm脉冲激光照射1Km外的漫反射靶的实验对新测试方法进行了可行性验证,获得了远场激光光斑的图像和能量抽样值. 相似文献
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激光器是DNA测序仪中的重要部件,寻求合适波长的激光器可有效提高DNA测序仪性能。分析了DNA检测所用的四种荧光染料FAM、JOE、TAMRA和ROX的激发谱和发射谱,设计实验技术方案利用488nm、505nm和515nm三种不同波长的激光器分别对其进行激发。在相同的积分时间和相同的功率下,488nm激光器对于荧光染料ROX的激发强度太低,515nm激光器对于荧光染料FAM的激发强度太低,而505nm激光器对于四种荧光染料的激发强度均比较强。实验结果表明在三种不同波长中,505nm激光器对四种荧光染料的激发效果最佳,可以替代目前大多数DNA测序仪中的氩离子激光器。 相似文献
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Isakova A. A. Savinov K. N. Golovin N. N. Sabakar K. M. Dmitriev A. K. Rundau A. A. 《Russian Physics Journal》2020,63(1):171-175
Russian Physics Journal - The diode laser oscillating modes are identified at which a resolved HF-structure is registered at every sideband, and an equality of the intensities of the sideband... 相似文献
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R. Kuz’menko A. Ganzha J. Schreiber S. Hildebrandt 《Physics of the Solid State》1997,39(12):1900-1905
The paper considers methods used to identify the multicomponent character of photoreflectance (PR) spectra in the vicinity
of the E
0 transition measured at room temperature from moderately doped GaAs substrates. It is shown that that if an E
0 PR spectrum contains an excitonic component, its presence can be established from both a mathematical and phase analysis,
as well as from measurements performed at different laser excitation densities.
Fiz. Tverd. Tela (St. Petersburg) 39, 2123–2129 (December 1997) 相似文献
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宽频带激光自由空间传输的调制特性研究 总被引:9,自引:0,他引:9
基于惠更斯-菲涅耳衍射积分公式,研究了宽带光束在菲涅耳衍射区的自由空间传输特性,得到宽带光束传输的调制深度与光束带宽Δλ及菲涅耳数F的变化关系。结果表明:一定的带宽对光束的均匀性有适当的改善;当光束的带宽Δλ<2λ0/F时,带宽越大,光束越均匀;当带宽满足条件Δλ=2λ0/F时,菲涅耳衍射完全消失;在一定的菲涅耳数范围内,宽带光束的调制深度随菲涅耳数振荡变化,振荡曲线的主极大值和次极大值分别出现在菲涅耳数为奇数和偶数处,而极小值则出现在菲涅耳数F=2k±1/3(k=1,2,3,…)处,在极小值处光束的均匀性最好。 相似文献
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通过显微光致发光技术和显微拉曼(Raman)技术研究了半绝缘GaAs (SI-GaAs)晶体的带边附近的发光. 在光荧光谱中,观察到在高于GaAs带边0.348eV处有一个新的荧光峰. 结合Raman谱指认此发光峰来源于GaAs的E0+Δ0能级的非平衡荧光发射. 同时, 通过研究E0+Δ0能级的偏振、激发光强度依赖关系,以及温度依赖关系说明E0+Δ0能级与带边E0共享了共同的导带位置Γ6,同时这也说明在GaAs中主要是导带的性质决定了材料的光学行为.同时,通过与n-GaAs和δ掺杂GaAs相比较,半绝缘GaAs晶体的E0+Δ0能级的发光峰更能反映GaAs电子能级高临界点E0+Δ0的能量位置和物理性质. 研究结果说明显微光致发光技术是研究半导体材料带边以上能级光学性质的一种非常有力的研究工具.
关键词:
半绝缘GaAs
显微光致发光
自旋轨道分裂 相似文献
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The influence of various lasing-radiation polarization states and types of optical dipole transitions on the nonlinear amplitude-detuning characteristics of quantum-well semiconductor lasers with pump current modulation has been theoretically investigated. It has been established that the narrowest spectral interval, where the response is nonzero, is realized in the case of TM-mode radiation and transitions to the heavy-hole states as well as in the case of TE-mode radiation and transitions to the light-hole states. 相似文献
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H. Delibašić K. Isaković V. Petrović T. Miladinović 《International Journal of Theoretical Physics》2018,57(2):406-413
We theoretically improved the relativistic ADK formula for a linearly polarized laser field. We have taken into account the influence of the magnetic component of laser field on the transition rate, in near relativistic field intensity. It was shown that the magnetic component results in a decrease of the transition rate in comparison to the results obtained by the original relativistic expression. We gave considered noble and alkali atoms. The obtained results show that this influence is larger (more significant) for alkali atoms. 相似文献
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1.IntroductionSequentia1multisteplaserexcitationhasbeenextensivelyusedtostudydoublyexcit-edstatesofa1ka1ine-earthatoms.Mostoftheinvestig8tionsconcernedthedoublyexcitedstatesinwhichoneofthetwovalenceelectronsishighlyexcitedandtheotherisweaklyexcited[1].Inthecasewhenbothvalenceelectronarehighlyexcited(doubleRydbergstates),onlyafewresultswereobtainedduetothelimitutioninexPerimentaltech-nique['j.ThelimitationarosefromvariousaSpectS.First,duringthesequentiallaserex-citationofdoubleRydbergstatesw… 相似文献
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介绍了1.3 μm/1.5 μm光纤激光功率溯源至低温辐射计的测量方法,与传统溯源至绝对辐射计的方法相比较,最终利用低温辐射计法通过633 nm波长稳定光源标定陷阱式探测器,然后用陷阱式探测器将量值传递到陷阱式量传探测器,最后通过1310 nm/1550 nm通信用光功率稳定光源通过热释电光功率计标定InGaAs光电探测器并用于测量光纤功率。实验结果表明,溯源至低温辐射计的光纤功率测量方法在1310 nm及1550 nm波长点处对一标准光功率计修正系数测量的相对标准差分别为0.0011及0.0007,其测量不确定度可优于0.6%(k=2),在保证量值一致性的同时有效降低了测量不确定度,提高量值传递精度。 相似文献
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Influence of GaAsP Insertion Layers on Performance of InGaAsP/InGaP/A1GaAs Quantum-Well Laser 下载免费PDF全文
We report on the use of very thin GaAsP insertion layers to improve the performance of an In GaAsP/InGaP/AIGaAs single quantum-well laser structure grown by metal organic chemical vapour deposition. Compared to the noninsertion structure, the full width at half maximum of photoluminescence spectrum of the insertion structure measured at room temperature is decreased from 47 to 38 nm indicating sharper interfaces. X-ray diffraction shows that the GaAsP insertion layers between AIGaAs and InGaP compensates for the compressive strain to improve the total interface. The laser performance of the insertion structure is significantly improved as compared with the counterpart without the insertion layers. The threshold current is decreased from 560 to 450 mA while the slope efficiency is increased from 0.61 to 0.7W/A and the output power is increased from 370 to 940mW. The slope efficiency improved is very high for the devices without coated facets. The improved laser performance is attributed to the suppression of indium carry-over due to the use of the GaAsP insertion layers. 相似文献
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温度对高功率半导体激光器阵列“smile”的影响 总被引:3,自引:0,他引:3
用数值模拟与实验测试相结合的方法,研究了温度对"smile"的影响.利用有限元方法分别模拟计算了半导体激光器芯片键合及工作过程中激光器芯片中的热应力,模拟中假设激光器芯片的弯曲仅由热应力引起;计算结果表明,激光器芯片有源区的热应力随工作温度的升高而减小,由热应力导致的芯片的弯曲随温度升高而减小.实验结果表明,对于具有相同芯片、同一封装形式、同批次的器件,"smile"随温度的升高有增大或减小的趋势,这与封装前裸芯片的弯曲形态及封装热应力的综合作用有关;若封装前裸芯片为相对平直的或凸的,则封装后激光器的"smile"将随温度升高而减小;若封装前裸芯片为凹的,封装后的激光器芯片仍为凹的,则"smile"随温度升高而增大. 相似文献
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Double correlation deep level transient spectroscopy (DDLTS) has been used to determine the profile of the electron trap E3 (EC?0.33 eV) introduced in n-type GaAs after proton irradiation at 300 K and annealing at 190°C. We show that E3 anneals without long range migration by close pair recombination mechanism. 相似文献
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