短脉冲高斯光束的时空形式

Space Time Characteristic of Ultrashort Pulsed Gaussian Beam

考虑到腔模光腰尺寸的频率依赖性，得到了一短脉冲高斯光束在自由空间传播的时域解析形式，发现其可由一复时间变量来描述。复时间变量的实部给出了脉冲的传输时间，其与波前曲率有关，虚部给出了空间量值，两者的交叉项称为时空耦合。

Considering the frequency dependence of waist size on the cavity modes, an analytical form of the ultrashort pulsed Gaussian beam is derived by using a complex temporal varible, which contains all the information about the spatial and temporal properties of the pulsed beam. The real part of the complex time gives the pulse traveling time, which is related to the wavefront. The imaginary part gives the information of spatial distribution and the crossed part gives the coupling between space and time on propagation of the pulse. Then the space time characteristices of a transform limited Gaussian pulse and a Gaussian pulse with linear chirp are analyszed.