QBG光束的传输特性

对变量为径项平方的贝塞耳函数调制的高斯光束(QBG光束)通过一阶ABCD光学系统的传输变换进行了研究,由广义菲涅耳衍射积分出发推导出了普适的传输变换公式,以QBG光束通过薄透镜系统的情况进行了分析与讨论,对详细的数值计算结果进行了分析与讨论.     

厄米-双曲余弦-高斯光束通过对称化光学系统的变换

研究了用于厄米高斯光束对称化的光学系统对像散厄米双曲余弦高斯光束的变换。分析了偏心参数和模阶数对变换后的厄米双曲余弦高斯光束对称性的影响,通过大量数值计算说明复杂像散厄米双曲余弦高斯光束对称化的物理意义。     

关于失调矩阵的讨论

本文讨论了光学元件失调矩阵的计算方法以及有关的性质。     

The influence of nonparaxiality on the spectral behavior in Young's experiment illuminated by partially coherent light

Starting from the Rayleigh--Sommerfeld diffraction integral, this paper studies the spectral behavior in Young's experiment illuminated by nonparaxial partially coherent light and compares with the paraxial case, where the influence of nonparaxiality of partially coherent light on the spectral shifts and spectral switches is stressed. It is shown that there is a spectral shift in the nonparaxial case relative to the paraxial one and the critical position changes, at which the spectral switch occurs. The ratio of the waist width to the central wavelength w₀/λ₀ and relative spatial correlation length \De affect the spectral difference. The smaller w₀/λ₀ is, the larger the difference between the nonparaxial and paraxial results appears. The effect of relative spatial correlation length Δ is relatively small.     

Can two partially coherent cosh-Gaussian beams generate far fields with the same spectral degree of coherence？

Taking partially coherent cosh--Gaussian (ChG) beams as an example of more general partially coherent beams, we have studied the spectral degree of coherence of partially coherent ChG beams in the far field. It is shown that, unlike Gaussian Schell-model (GSM) beams, in the strict sense there do not exist two partially coherent ChG beams which can generate far fields with the same spectral degree of coherence. However, under certain conditions it is possible to find two partially coherent ChG beams with the same spectral degree of coherence in the far field.     

Propagation of ultrashort pulsed beams in dispersive media

Starting from the Rayleigh diffraction integral, the propagation equation of ultrashort pulsed beams in dispersive media is derived without making the paraxial approximation and slowly varying envelope approximation (SVEA). The spatiotemporal properties of ultrashort pulsed beams in dispersive media, such as spectrum redshifting, narrowing and pulse distortion are illustrated with pulsed Gaussian beams. It is stressed that the “antibeam“ behaviour of ultrashort pulsed beams can be avoided, if a suitable truncation function is chosen.     

LD侧泵浦Nd：YAG板条双程功率放大器初步研究

 对二极管激光侧泵浦Nd：YAG板条双程功率放大器进行了初步的研究,给出了激光器的数值模拟结果,建立了二极管侧面泵浦Nd:YAG板条激光主振荡-多程放大(MOPA)系统;在100Hz重复频率时,实验获得单脉冲能量为51.9mJ的输出,光束质量M ²小于2,脉冲能量起伏小于2%, 实验结果与数值计算结果相符合。     

用K参数描述光强陡峭度的有效性研究

光束光强分布的陡峭度或平整度通常可用陡峭度参数(K参数)来描述。以双曲余弦-高斯光束、贝塞尔函数调制的高斯光束和平顶高斯光束3种光束为例,给出了详细的数值计算和物理解释。研究表明,K参数只适用于描述呈钟形光束剖面的陡峭度,但不适用于有强衍射旁瓣、强调制或有中心凹陷的光束。     

部分相干厄米-高斯光束杨氏实验中的光强分布

将杨氏干涉实验作为双缝衍射现象处理,以部分相干厄米-高斯(H-G)光束为例,研究分析了多模部分相干光的杨氏双缝干涉光强和干涉条纹可见度的空间分布。数值计算说明,多模部分相干光束的空间相干参数、模阶数和缝遮拦比对衍射场中光强的空间分布(干涉花样)都有影响。当多模部分相干光的阶数为奇数时,轴上光强与光束的相干性会出现相消干涉;当多模部分相干光的阶数为偶数时,轴上光强与光束的相干性会出现相长干涉等。