Temporal Diffraction of Chirped Pulses Revealed by Dispersive Fourier Transform Optical Heterodyne Detection

When monochromatic spatial light encounters an aperture, diffraction occurs in the wavefront. According to the theory of spatiotemporal duality, diffraction should also occur in the time domain.

The time lens technique investigates the propagation of pulsed light in dispersive fibers, which is mathematically equivalent to paraxial diffraction in space. However, when the spectrum of pulsed light encounters the GHz "barrier", the time-domain pulse envelope also produces diffraction, with diffraction fringes on the order of~ps. Theoretical analysis and experimental observation of ultrafast diffraction phenomena caused by spectral "aperture" will provide new means for ultrafast pulse shaping, ultrafast time-domain spectroscopy technology, basic physics research, and other fields.