Development of a high-resolution high-sensitivity compressive Raman microscope (Conference Presentation)

The high data bandwidth of Raman imaging precludes high-speed spectroscopic imaging. Conversely, emerging compressive sensing hyperspectroscopy techniques could, in principle, address this issue by using undersampling methodologies with computational reconstructions. However, compressive spectrometer layouts have prohibitive losses for low-light levels applications, such as in the spontaneous Raman imaging of dynamic biological specimens. These losses are due to the fact that high-sensitivity light detectors (photo-counters) have too small active area (typically 100 um) compared to the size of digital micromirror devices (DMD) (~10 mm) used in most compressive layouts. Inspired by pulse shaping techniques of ultrafast spectroscopy, we present a new programmable spectrometer layout with high-throughput and large spectral coupling bandwidths. Exploiting amplitude spectral modulation with DMD allows conventional and compressive Raman imaging and spectroscopy acquisitions with shot-noise-limited sensitivity. With this spectrometer, we demonstrate compressed hyperspectroscopy at faster speeds and at lower costs than traditional cameras used in Raman imaging applications. We showcase imaging of biological specimens at high spatial resolution (250 nm).