Femtosecond pulsed lasers are widely used in applied technologies, such as laser processing, nonlinear optical microscopy, and time-of-flight measurement, wherein narrowing the pulse duration is particularly important for improving the processing efficiency and signal-to-noise ratio of measurement systems. This paper proposes a method for shortening temporal pulse waveforms using spectral intensity filtering. Symmetrical spectral filtering was specifically applied at the central wavelength of the femtosecond pulsed laser spectrum. To investigate the pulse-narrowing effect, we numerically simulated the pulse duration as a function of the filtering width and cut-off wavelength position. The results of these simulations showed that the pulse duration decreased as the filter wavelength approached the central wavelength of the light. Furthermore, increasing the filter width reduced the pulse duration. Additionally, we implemented a spatial light modulator-based pulse-shaping system to realize a spectral intensity filter. We experimentally demonstrated that the duration of a telecom-band pulse was reduced by 9.8% when using a spectral intensity filter with a width of 1 nm.

飞秒脉冲激光器广泛应用于激光加工、非线性光学显微镜、飞行时间测量等应用技术中，其中缩短脉冲持续时间对于提高测量系统的处理效率和信噪比尤为重要。本文提出了一种使用光谱强度滤波来缩短时间脉冲波形的方法。对称光谱滤波专门应用于飞秒脉冲激光光谱的中心波长。为了研究脉冲窄化效应，我们对脉冲持续时间作为滤波宽度和截止波长位置的函数进行了数值模拟。这些模拟的结果表明，随着滤光片波长接近光的中心波长，脉冲持续时间减少。此外，增加滤波器宽度会缩短脉冲持续时间。此外，我们还实现了基于空间光调制器的脉冲整形系统来实现光谱强度滤波器。我们通过实验证明，当使用宽度为 1 nm 的光谱强度滤光片时，电信频段脉冲的持续时间减少了 9.8%。