Monolithically integrated mid-infrared sensor with a millimeter-scale sensing range

Abstract

On-chip sensors based on quantum cascade laser technology are attracting broad attention because of their extreme compactness and abundant absorption fingerprints in the mid-infrared wavelength range. Recent continuous wave operation microcavity quantum cascade lasers are well suited for high-density optoelectronic integration because their volumes are small and thresholds are low. In this experimental work, we demonstrate a monolithically integrated sensor comprising a notched elliptical resonator as transmitter, a quantum cascade detector as receiver, and a surface plasmon structure as light-sensing waveguide. The sensor structure is designed to exploit the highly unidirectional lasing properties of the notched elliptical resonator to increase the optical absorption path length. Combined with the evanescent nature of the dielectric loaded surface plasmon polariton waveguides, the structure also ensures a strong light–matter interactions. The sensing transmission distance obtained is approximately 1.16 mm, which is about one order of magnitude improvement over the traditional Fabry–Perot waveguide. This sensor opens new opportunities for long-range and high-sensitivity on-chip gas sensing and spectroscopy.

Environmental Monitoring: A Comprehensive Review on Optical Waveguide and Fiber-Based Sensors

“…Additionally, there is a connection between the optical attenuation at a certain wavelength and the gas content. Numerous gas sensors based on optical waveguides [ 14 , 17 , 79 , 80 ] and optical fiber [ 81 , 82 ] have been developed to operate on this phenomenon.…”

Room-temperature continuous-wave InP-based 2.01 µm microcavity lasers in whispering-gallery modes with InGaAsSb quantum well

“…The term "eye-safe" is used to describe this place of wavelengths, wherein laser systems provide an outstanding upper hand concerning free-zone implementations when compared with standard systems operating at narrower wavelengths. Recently developed on-chip sensing by integrating lasers, sensing waveguides, and detectors on a single chip is preferred for portable sensing applications [5][6][7][8][9][10] . Microresonator-based lasers are well suited for high-density optoelectronic integration because of their small volumes and low thresholds [11,12] .…”