Lightweight high-frequency whisk-broom hyperspectral imager using optical switch.

The whisk-broom hyperspectral imaging system has the advantages of cost-effectiveness, wide field of view and simplicity, therefore it is suitable for civilian airborne remote sensing applications. The cost advantage is particularly evident in the spectral range of shortwave infrared (SWIR), as it is quite important for agricultural and forestry remote sensing and the SWIR area detectors are much more expensive. However, the whisk-broom hyperspectral imaging method encounters challenges in limited point-by-point integration time and low efficiency, thereby constraining its practical applicability. To address this issue, a lightweight high-frequency whisk-broom hyperspectral imager operating in the 900-2500 nm spectral range is proposed in this study. The system utilizes a lightweight parabolic mirror as a telescope and integrates an optical fiber spectrometer to achieve whisk-broom hyperspectral imaging, thereby simplifying the system. Moreover, an optical switch device is incorporated to enable rapid switching of whisk-broom field of view, thereby enabling time-division multiplexing of the same spectrometer acquisition process and improving the acquisition frequency. The proof-of-principle prototype was constructed, and subsequently, the scanning spectral imaging experiment was conducted on the target within a laboratory setting, thereby confirming the efficacy of the high-frequency whisk-broom spectral imaging system.