Snapshot imaging Fraunhofer line discriminator

Reflectance measurements have been a long standing means of quantifying chlorophyll, and other chemical contents, within vegetation. Conventional metrics that are common include normalized difference vegetative index (NDVI) and photochemical reflectance index (PRI). However, to gain more information about the plant canopy and go beyond reflectance measurements, fluorescence measurements are also being pursued. While active laser- or illuminator-based methods exist, passive methods are often preferred due to their lower power requirements and their reduced system complexity and eye safety concerns. To this end, preliminary results for the development of a high throughput imaging Fraunhofer line discriminator (FLD) are presented. This system, which is based on a multiple-image Fourier transform spectrometer and a spatial heterodyne interferometer can, for the first time, leverage the snapshot advantage for high throughput FLD. In this paper, the concept of the system is presented and preliminary experimental calibration results are summarized.