Physics professors’ study in Nature Photonics

David Hagan and Eric Van Stryland, Physics professors, recently had their study published in Nature Photonics.

The paper is titled “Sensitive mid-infrared detection in wide-bandgap semiconductors using extreme non-degenerate two-photon absorption” and can be found here.

The abstract is below: Identifying strong and fast nonlinearities for today’s photonic applications is an ongoing effort¹. Materials^{2, 3, 4, 5} and devices^{6, 7, 8, 9} are typically sought to achieve increasing nonlinear interactions. We report large enhancement of two-photon absorption through intrinsic resonances using extremely non-degenerate photon pairs. We experimentally demonstrate two-photon absorption enhancements by factors of 100–1,000 over degenerate two-photon absorption in direct-bandgap semiconductors. This enables gated detection of sub-bandgap and sub-100 pJ mid-infrared radiation using large-bandgap detectors at room temperature. Detection characteristics are comparable in performance to liquid-nitrogen-cooled HgCdTe (MCT) detectors. The temporal resolution of this gated detection by two-photon absorption is determined by the gating pulse duration.