Our paper "Mid-infrared germanium photonic crystal cavity" is published online in Optics Letters.

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-42-15-2882

The mid-infrared (MIR) spectral range holds significant potential for spectroscopic and sensing applications because it encompasses the fingerprint region that unveils the vibrational and rotational signatures of molecules. CMOS-compatible on-chip devices that can achieve strong light-matter interaction in the entire fingerprint region are considered as a promising way for such applications, but remain unprecedented. Here we present an on-chip MIR germanium photonic crystal cavity that covers the entire fingerprint region. This is made possible by harnessing a home-made air-cladding germanium platform. Our MIR device creates a new avenue toward integrated nonlinear optics and on-chip biochemical sensing in the fingerprint region.