96 dB Linear High Dynamic Range CAOS Spectrometer Demonstration

TL;DR

This paper demonstrates a novel CAOS spectrometer with programmable high dynamic range capabilities, achieving up to 96.2 dB linear dynamic range, suitable for various material inspection applications.

Contribution

First demonstration of a CAOS spectrometer with programmable HDR performance using a DMD and diffraction grating, achieving up to 96.2 dB dynamic range.

Findings

Achieved 96.2 dB linear dynamic range with FM-TDMA mode.

Demonstrated spectral measurement from 369 nm to 715 nm.

Validated spectrometer performance with various optical filters.

Abstract

For the first time, a CAOS (i.e., Coded Access Optical Sensor) spectrometer is demonstrated. The design implemented uses a reflective diffraction grating and a time-frequency CAOS mode operations Digital Micromirror Device (DMD) in combination with a large area point photo-detector to enable highly programmable linear High Dynamic Range (HDR) spectrometry. Experiments are conducted with a 2850 K color temperature light bulb source and visible band color bandpass and high-pass filters as well as neutral density (ND) attenuation filters. A ~369 nm to ~715 nm input light source spectrum is measured with a designed ~1 nm spectral resolution. Using the optical filters and different CAOS modes, namely, Code Division Multiple Access (CDMA), Frequency Modulation (FM)-CDMA and FM-Time Division Multiple Access (TDMA) modes, measured are improving spectrometer linear dynamic ranges of 28 dB, 50 dB, and 96.2 dB, respectively. Applications for the linear HDR CAOS spectrometer includes materials inspection in biomedicine, foods, forensics, and pharmaceuticals.