Compact liquid crystal waveguide based Fourier transform spectrometer for in-situ and remote gas and chemical sensing

Abstract

Vescent Photonics Inc. and Jet Propulsion Lab are jointly developing an innovative ultra-compact (volume < 10 cm³), ultra-low power (<10^-3 Watt-hours per measurement and zero power consumption when not measuring), completely non-mechanical electro-optic Fourier transform spectrometers (EO-FTS) that will be suitable for a variety of remoteplatform, in-situ measurements. These devices are made possible by a novel electro-evanescent waveguide architecture, enabling "chip-scale" EO-FTS sensors. The potential performance of these EO-FTS sensors include: i) a spectral range throughout 0.4-5 &mu;m (25000 - 2000 cm^-1), ii) high-resolution (&utri;&lambda;&le; 0.1 nm), iii) high-speed (< 1 ms) measurements, and iv) rugged integrated optical construction. This performance potential enables the detection and quantification of a large number of different atmospheric gases simultaneously in the same air mass and the rugged construction will enable deployment on previously inaccessible platforms. The sensor construction is also amenable for analyzing aqueous samples on remote floating or submerged platforms. To date a proof-of-principle prototype EO-FTS sensor has been demonstrated in the near-IR (range of 1450-1700 nm) with a 5 nm resolution. This performance is in good agreement with theoretical models, which are being used to design and build the next generation of EO-FTS devices.