Monolithic Photonic Crystal On-Chip Spectrometer for Laser Absorption Spectroscopy

Omega Optics aims at developing a commercially viable monolithically integrated, light weight, easily portable system-on-chip (SoC) infrared spectrometer for diode laser absorption spectroscopy of chemical warfare simulants such as triethylphosphate, tributylphosphate, enabling much earlier warning of chem bio toxic gases. Chip scale miniaturization is enabled by slow light phenomenon in photonic crystal (PC) waveguides that enables 100 times reduced absorption path length; 15 times increased optical mode overlap with analyte compared to integrated ridge waveguides is enabled by the slot at the center of the PC waveguide. Both factors combine for 1500 times greater sensor sensitivity and specificity versus conventional approaches. In Phase 1, feasibility of achieving desired triethylphosphate detection sensitivity by absorption signatures at 9.48 micron was determined with an experimentally fabricated sensor with PC slot waveguides in a Ge/BaF2 platform that provides the largest photonic bandgap, low loss and compatibility on diverse substrates including silicon, GaAs and InP and paves a smooth path for phase II. Fully integrated SoC designs monolithically integrating quantum cascade lasers, PC slot waveguide absorption elements and detectors were completed. Full experimental implementation demonstrating chip integrated monolithic infrared absorption spectrometer covering 8-10 micron will be realized in phase II to meet final program goal.