共查询到20条相似文献,搜索用时 78 毫秒
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利用重复频率为1kHz的钛宝石激光的倍频蓝光抽运Ⅰ类相位匹配的偏硼酸钡(BBO)晶体,获得了可见光区的非共线参量超荧光.给出了最强光强处参量超荧光的非共线角,波长随相位匹配角的变化.理论计算了在参量超荧光中三波的群速失配随非共线角和相位匹配角的变化规律.结果表明,Ⅰ类非共线相位匹配的参量超荧光关于抽运光中心对称.并且沿光强最强的参量超荧光方向三波的群速失配最小,有效互作用长度最大,即参量超荧光的强度角分布是三波的相速和群速自匹配的结果.该理论和实验研究为减小飞秒光参量放大中三波的群速失配提供了一个理想的几何模型,为获得高增益、窄脉冲宽度的参量光输出提供了理论依据和实验验证.
关键词:
群速自匹配
参量超荧光
非共线相位匹配
飞秒光参量放大 相似文献
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系统分析了基于准相位匹配晶体的光参量放大过程中极化周期和非共线结构对信号光调谐带宽的影响.提出了最大极化周期的概念,用于描述非共线相位匹配和群速度匹配同时满足时晶体的极化周期所能达到的最大值,给出了用于计算不同温度下周期极化铌酸锂晶体的最大极化周期的数学公式,并确定了宽带可调谐光参量放大过程应使用的最佳非共线结构.当采用此非共线结构时,通过将晶体的极化周期设定为最大极化周期可以在相对最大的波长范围内实现信号光的调谐放大输出.在此基础上提出了一个用于最大化光参量放大过程的信号光调谐带宽、确定工作温度等最佳工作参数以及简化实验操作方法的可行性方案.最后对最大极化周期和非共线结构对光参量放大的参量带宽的影响进行了研究.
关键词:
光参量放大
极化周期
非共线结构
带宽 相似文献
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利用BBO晶体在400nm的抽运光与信号光夹角为37°时,可同时在可见光范围内很宽的光谱范围里实现相位匹配的特点,实现了在可见光范围内具有极宽输出光谱宽度的飞秒光学参量放大器(OPA)的稳定运转,其输出脉冲能量大于15μJ,转换效率超过15%.并且在仅采用啁啾镜作为脉冲压缩器的情况下,获得了输出脉冲宽度为135fs的极窄光脉冲,其脉冲宽度压缩比高达22倍
关键词:
非共线相位匹配
光学参量放大
啁啾镜 相似文献
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基于非共线光学参量放大的飞秒时间分辨荧光光谱技术是一种新的超快光谱研究方法.文章研究了荧光放大的参量过程.超连续的种子光其瞬时光强可以被线性放大.由于系统高达107的放大能力,泵浦脉冲能量的微小不稳定性在最终放大输出信号中将产生很大起伏.提出了一种利用圆锥辐射作为参考消除此干扰的方法.研究表明,探测的荧光动力学曲线有显著改善. 相似文献
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研究了一种基于单晶体的可调谐超荧光产生机理,在一个偏硼酸钡(BBO)晶体中实现了飞秒脉冲倍频过程和光参量产生过程.实验中采用kHz高功率钛宝石激光系统输出的飞秒脉冲光倍频后的蓝光作为抽运光,获得了可调谐范围为480—530 nm参量超荧光光谱输出.理论上分析了这种超荧光产生机理,并利用放大传递函数模拟出参量超荧光环的产生过程.结果表明,在一个BBO晶体中,当抽运光源输出光入射晶体角度同时满足倍频相位匹配角和非共线光参量产生相位匹配角时可产生参量超荧光环,通过微调相位匹配角可控制参量超荧光光谱调谐输出.该理论和实验研究为控制参量超荧光和量子纠缠态的产生提供了理论依据,对于量子成像和量子通讯等领域的发展具有重要意义. 相似文献
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We setup an ultrafast noncollinear optical parametric amplification system for fluorescence spectral dynamics study. The simultaneous broadband amplifying ability makes it suitable as an ultrafast spectrometer with femtosecond time-resolution. By real-time fluctuation correction, femtosecond fluorescence spectra are obtained efficiently by a single scan. With this technique, the solvation dynamics of DCM dye in four solvents are measured to demonstrate the performance of the system. We show that this ultrafast time-resolved spectrometer is very useful and efficient in studying ultrafast spectral dynamics. 相似文献
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光学参变啁啾脉冲放大相位失配啁啾脉冲频谱整形新方法 总被引:1,自引:0,他引:1
相位匹配是实现高效光学参变啁啾脉冲放大(OPCPA)能量转换的关键之一,通过对几种常用非线性晶体的光学参变啁啾脉冲放大过程进行数值模拟研究,结果表明一定程度的相位失配不但能增加光学参变啁啾脉冲放大增益带宽,而且会使啁啾脉冲光谱强度分布中间凹陷。提出利用光学参变啁啾脉冲放大相位失配放大作为啁啾脉冲频谱整形的新方法,通过理论分析和模拟计算,找到了光学参变啁啾脉冲放大相位失配啁啾脉冲频谱整形效果的控制量;并对几种常用非线性晶体在简并、近简并、非简并等条件下的光学参变啁啾脉冲放大相位失配放大特性进行了比较。 相似文献
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饱和放大情形下光纤参量放大器的增益和带宽特性研究 总被引:2,自引:0,他引:2
利用龙格库塔法数值求解非线性耦合方程,研究了单抽运光纤参量放大器在增益饱和区的增益谱特性.通过比较考虑抽运光损耗与忽略抽运光损耗增益谱的差别,分析了抽运光损耗对增益谱的影响.此外,给出了在饱和放大区,信号光的增益谱与光纤长度、输入信号光功率、抽运光波长与零色散波长偏离之间的关系.发现在饱和放大区,增益的整体水平有所下降,增益谱的可用带宽相对于小信号放大有所减少,增益谱在可用带宽范围内出现了旁瓣.这些结果将对工作在饱和放大区的单抽运光参量放大器的设计提供有益的帮助. 相似文献
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Giuliana Borsa Stefania Castelletto Aldo Godone Carlo Novero Maria Luisa Rastello 《Optical Review》1997,4(4):484-489
This work presents a new technique for the measurement of second-order optical nonlinear coefficients from the absolute radiant power of the parametric fluorescence emission. It is based on calibrated detectors regarded as secondary radiometric standards. This technique makes it possible to skip a number of problems usually encountered with standard techniques based on calibrated neutral density filters and reference sources of light at much higher power levels. We infer a value for the d31 nonlinear coefficient of LiIO3 from spectral measurements of the fluorescence power integrated over all solid angles, by denning the wavelength bandwidths with interference filters. Moreover, by performing the measurements on the ultraviolet and visible emission lines of an argon ion laser in the range from 351 to 488 nm, the wavelength dependence of d31 is compared with the expected one obtained by Miller’s dispersion law. 相似文献
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Time-resolved fluorescence spectroscopy of the solvent-sensitive molecule 1,8-anilinonaphthalene sulfonate (ANS) is used to probe the structure and dynamics of an aqueous methanol solution (mole fraction = 0.5). The intensity decay of ANS in the mixed solvent displays single exponential kinetics under ambient conditions. At low temperature, a simple two-state solvent relaxation model describes the fluorescence decay for ANS in both methanol and the mixed solvent. The temperature dependence of ANS fluorescence in the mixed solvent is attributed to the onset of glassy dynamics in the aqueous component at higher temperature, implying a partial demixing of the water and methanol due to self-association. We discuss the absence of more complicated fluorescence decays in such a heterogeneous solvent system. 相似文献
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非共线相位匹配LBO晶体飞秒光参变放大器的研究 总被引:4,自引:3,他引:4
对非共线相位匹配LBO晶体飞秒光参变放大器进行了系统地分析和理论研究,用数值方法得出了非共线角、相位匹配角、增益和增益带宽之间的关系,给出了放大器设计的各种最优化参量。研究结果表明,这种参变放大器不仅可以实现较高的参变增益和获得极宽的增益带宽,还具有较大的参变允许角、较小的走离角和小的群速色散。因此这种参变放大器对于以纳秒级高功率激光作为抽运光,利用光参变啁啾脉冲放大(OPCPA)技术高效率参变放大飞秒脉冲产生10^12W甚至10^15W级的超强超短激光脉冲具有重要的意义。建立的理论模型具有普遍意义,也为其他类似的参变过程提供了重要的理论依据。 相似文献
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Absolute Measurement of Second-Order Nonlinear Optical Coefficient of LiNbO3 by Parametric Processes
We have redetermined the absolute values of the nonlinear optical coefficient, d31, of LiNbO3 by parametric fluorescence and, for the first time, by difference frequency generation measurements to resolve the considerable discrepancy that existed between the values determined by second-harmonic generation (SHG) and parametric fluorescence. We obtain d31 = 4.8±0.5 and 4.3±0.5 pm/V at the pump wavelengths of 488 and 532 nm, respectively, in reasonable agreement with the SHG data. It appears that the previous parametric fluorescence value, d31=5.8 pm/V, was overestimated.Author to whom correspondence should be addressed. 相似文献
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非线性简并光学参量放大系统的量子起伏 总被引:1,自引:1,他引:0
解析求解了P表象中考虑抽运吃空后的非线性含时简并光学参量放大系统获得压缩光所满足的福克尔-普朗克(Fokker-Planck)方程,并且计算了它在阈值附近及远离阈值的量子起伏。研究表明:若略去与η成正比的项,则通解很自然地过渡到线性近似解。计及与η成正比的项后,该解与Drummond等在阈值附近的微扰展开理论相比,基本相符。但在远离阈值处,微扰展开理论不适用,而该结果在阈值附近以及远离阈值的整个区域均是适用的。当μ→0压缩很小时,起伏趋近于真空起伏;而μ〉〉1,压缩增大时,趋近1/1+μ线性理论。 相似文献
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It was found that ethanol and water molecules mixed together can form new clusters. Based on the steady state spectral characteristic
and the mole ratio method, three possible bonding constants of ethanol-water clusters were deduced. To confirm the structure
of these clusters, the fluorescence lifetimes of different emission bands were investigated, and the average lifetime of the
entire decay process was found to vary as the volume percent of ethanol changed. Furthermore, the possible bonding constant
n of molecular clusters was determined to be 2 based on the time-resolved spectra, and the cluster was concluded to be a chain
structure formed by one ethanol molecule and two water molecules with hydrogen bonds. 相似文献