Measurement of Gouy Phase Shift by Supercontinuum Spectral Interference

利用两束超连续光干涉得到的信号,测量了透镜焦点附近飞秒激光脉冲的古依(Gouy)相移。根据得到的光谱干涉信号,利用傅里叶变换得到相对相位值。激光光束在聚焦透镜后的束腰半径可以由成像方法测得。根据测量得到的激光光束束腰半径,用非线性拟合的方法得到了古依相移曲线,拟合曲线与实验结果符合得非常好。给出了古依相位在焦点前后1 mm区域内的移动量。The spectral interference between two white-light continuum beams is adopted to measure the Gouy phase shift of focused femtosecond laser pulses near the lens focus. From the spectral interference signal, the relative phase is extracted by the Fourier transform method. The beam waist of the laser pulses after the focusing lens is measured by imaging method. According to the beam radius, the curves of nonlinear fitting are drawn, and fit the data of experiments very well. The Gouy phase shift at the positions of 1 mm before and after the focal spot is presented