Multicolor time-resolved upconversion imaging by Adiabatic Sum Frequency Conversion

TL;DR

This paper introduces a novel adiabatic frequency conversion method for multicolor mid IR upconversion imaging, enabling simultaneous spectral and spatial imaging with high resolution and ultrafast capabilities.

Contribution

The work presents a new adiabatic upconversion scheme that allows broadband, multicolor, and spectrally resolved mid IR imaging on a CMOS camera.

Findings

Simultaneous imaging of 2-4 μm spectrum on CMOS camera.

Demonstration of spectrally resolved spatio-temporal imaging.

Broadband mid IR imaging with ultrafast, coherent conversion.

Abstract

Upconversion imaging, where mid infrared (IR) photons are converted to visible and near IR photons via a nonlinear crystal and detected on cheap and high-performance Silicon detectors, is an appealing method to address the limitations of thermal sensors which are expensive, often require cooling and suffer from both limited spectral response and limited spatial resolution as well as poor sensitivity. However, phase matching severely limits the spectral bandwidth of this technique therefore requiring serial acquisitions in order to cover a large spectrum. Here, we introduce a novel upconversion imaging scheme covering the mid IR based on adiabatic frequency conversion. We present a mid IR multicolor imaging and demonstrate simultaneous imaging on a CMOS camera of radiation spanning a spectrum from 2 to 4 \mu m. Our approach being coherent and ultrafast in essence, we further demonstrate spectrally resolved spatio-temporal imaging which allows spatially distinguishing the temporal evolution of spectral components.