Temporal and spatial resolutions of optical time stretch imaging with dispersive grating pair

Optical time stretch imaging (OTSI), providing the capability of capturing the dynamics of fast single-shot or random events, overcomes the fundamental trade-off between imaging speed and sensitivity in ultrafast imaging regions. Lying at the heart of the OTSI is dispersive Fourier transformation, being capable of using large chromatic dispersion to map the spectrum of a broadband ultrashort optical pulse into a stretched time-domain waveform. Dispersive grating pair (DGP) is a unique solution to generate large chromatic dispersion for dispersive Fourier transformation at the wavebands, in which dispersion compensation fibers commonly suffer from high dispersion-to-loss ratio. Here we characterize the performances of DGP-based OTSI modality and analyze the crucial parameters that strongly impact on the temporal as well as spatial resolutions, and further discuss its merits and challenges. Our results demonstrate DGP-based OTSI, allowing creation of high resolution images, is an effective modality compared to fiber-based OTSI