Passive Incoherent Ultrafast Mid-Infrared Upconversion Imaging and Its Calibration

TL;DR

This paper introduces a passive, ultrafast mid-infrared imaging system that uses sum-frequency upconversion to achieve high frame rates and includes a calibration workflow for real-time thermal and plasma transient monitoring.

Contribution

The work presents a novel passive MIR imaging platform with ultrafast frame rates and a drift-aware calibration method, enabling real-time monitoring of rapid thermal and plasma phenomena.

Findings

Achieved 100kHz frame rate in MIR imaging

Successfully captured electric arc dynamics in real-time

Developed a calibration workflow for noise and drift management

Abstract

Ultrafast mid-infrared (MIR) imaging is a key enabling capability for monitoring transient thermal and plasma phenomena in scientific diagnostics and industrial safety. However, conventional cryogenic MIR cameras face a fundamental trade-off between frame rate, noise, and pixel format. Here we report a passive, incoherent MIR imaging platform that leverages sum-frequency upconversion in chirped periodically poled lithium niobate (CPLN) to translate broadband 3--5um scenes to the near-infrared, enabling ultrafast acquisition on a silicon-based intensified CCD (iCCD). In fast-kinetics mode we achieve a physical frame rate of 100kHz with microsecond-scale gate control, and we directly capture the full evolution of an air-breakdown electric arc, resolving its rapid ignition, expansion, and decay dynamics. Beyond demonstrating ultrafast passive imaging, we introduce a drift-aware calibration workflow based on Allan deviation analysis to quantitatively select the gate width and averaging strategy under realistic slow-drift and multiplicative noise. This combined capability -- ultrafast passive MIR imaging plus operationally meaningful calibration -- provides a practical route toward real-time thermal surveillance and early-warning systems for hazardous fast transients.