Chirped Spectral Mapping Photography Using a Hyperspectral Camera

Spectral imaging captures spatial and spectral data simultaneously with each pixel of an image of a scene or object representing a radiance or reflectance spectrum. Among the various spectral imaging techniques, the spectral filtering-based method has shown superior performance and robustness. With the development of ultrashort laser technologies, temporal–spectral encoding techniques establishing the one-to-one correspondence between time instants and wavelength components make it possible to empower spectral imaging with the time-resolving ability. In this chapter, the principles and approaches of spectral filtering-based imaging and temporal stretching of laser pulses are presented, and a novel temporal imaging method, chirped spectral mapping ultrafast photography (CSMUP), is further introduced, which enables real-time recording of ultrafast dynamic scenes at an imaging rate of hundreds of billion frames per second and a sequence depth of a few tens of frames by incorporating the temporal–spectral encoding based on the time-stretching of laser pulses and the snapshot spectral imaging. Moreover, CSMUP manifests itself by exploring the femtosecond laser ablation dynamics in real time and extends a new paradigm to laser–matter interaction study.