Design and demonstration of ultrafast holographic microscopic system based on time stretching

Abstract

Evolving from time stretching technique based on ultrashort optical pulse, wavelength-to-space-mapping imaging has become a common strategy for single-shot ultrafast imaging. In the technique, chirped broadband child pulses are generated and used to probe the transient scene typically, and the frames with temporal resolution up to picosecond scale can be achieved. Here we propose a single-shot ultrafast holographic microscopic system through a wide-spectrum pulse. A digital micromirror device (DMD)-based quasi-4f system and a dispersive medium are involved to generate chirped multi-wavelengths child pulses in sequence. A series of off-axis holograms are spatially dispersed and separated by a grating and captured simultaneously. The time-resolved three-dimensional (3D) profiles are retrieved using the reconstruction algorithm. In the paper, the temporal evolution of optical pulse and the mechanism of holographic imaging are detailed and numerically analyzed. A 10-frames holographic microscopic system with field of view (FOV) of 0.2 mm × 0.2 mm, frame rate of 6.8 × 1010 fps and exposure time of 5.4 ps is realized, where the interval and linewidth of the multi-wavelengths are 10 nm and 0.25 nm, respectively.