Integrated photonics for infrared spectroscopic sensing

Abstract

Infrared (IR) spectroscopy is widely recognized as a gold standard technique for chemical analysis. Traditional IR spectroscopy relies on fragile bench-top instruments located in dedicated laboratory settings, and is thus not suitable for emerging field-deployed applications such as in-line industrial process control, environmental monitoring, and point-ofcare diagnosis. Recent strides in photonic integration technologies provide a promising route towards enabling miniaturized, rugged platforms for IR spectroscopic analysis. Chalcogenide glasses, the amorphous compounds containing S, Se or Te, have stand out as a promising material for infrared photonic integration given their broadband infrared transparency and compatibility with silicon photonic integration. In this paper, we discuss our recent work exploring integrated chalcogenide glass based photonic devices for IR spectroscopic chemical analysis, including on-chip cavityenhanced chemical sensing and monolithic integration of mid-IR waveguides with photodetectors.

Shortening Nucleation Time to Enable Ultrafast Phase Transition in Zn1Sb7Te12 Pseudo-Binary Alloy

“…Chalcogenide-based thin films are important for modern electro-optic devices such as thin-film infrared transistors, optical waveguides, or phase-recording media. , Especially, Ge–Sb–Te films with a typical composition of Ge 2 Sb 2 Te 5 (GST) located at the pseudo-binary line connecting GeTe and Sb 2 Te 3 in the phase diagram have been applied as phase-change materials. − However, its nucleation-dominated crystallization has led to slow phase-transition speed. , For example, the writing speed of commercialized optical disk and phase-change memory (PCM) products is limited by tens of nanoseconds due to the crystalline nucleation during the crystallization of amorphous GST. , On the other hand, Sb-rich thin films have been elucidated to possess a different crystallization behavior . The growth-dominated crystallization allows Sb-rich thin films to crystallize at faster speeds.…”