Paper
24 May 2018 Increasing image resolution in near-infrared to visible upconversion detection for long-range active imaging
Romain Demur, Arnaud Grisard, Eric Lallier, Luc Leviandier, Loïc Morvan, Nicolas Treps, Claude Fabre
Author Affiliations +
Abstract
Near-infrared imaging InGaAs sensors show lower performances in term of noise and sensitivity compared to silicon based cameras. Image frequency conversion from near-infrared to visible wavelengths by nonlinear parametric sumfrequency mixing in a χ(2) medium should increase detection performances in active imaging applied to long range target identification. For such applications, both energy conservation and phase matching conditions are ideally suited to efficient upconversion. Nevertheless, the available resolution still hampers the development of upconversion imagers.

In this paper, we upconvert images provided by 1.5 μm collimated continuous wave lasers illuminating resolution targets and small objects. Using a 2.7 nm wide pump spectrum at 1064 nm, we resolve 56x64 spatial elements whereas we obtained only 16x19 spatial elements with a narrow spectrum pump laser at 1064 nm with the same beam diameter and 8x8 spatial elements with a 0.5 mm thick crystal. These results are compatible with long range target recognition. A laboratory scale experiment of active imaging of diffusive objects is shown as an illustration.
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Romain Demur, Arnaud Grisard, Eric Lallier, Luc Leviandier, Loïc Morvan, Nicolas Treps, and Claude Fabre "Increasing image resolution in near-infrared to visible upconversion detection for long-range active imaging", Proc. SPIE 10677, Unconventional Optical Imaging, 1067703 (24 May 2018); https://doi.org/10.1117/12.2306279
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Crystals

Upconversion

Image resolution

Phase matching

Signal detection

Imaging systems

Nonlinear crystals

Back to Top