Torregrosa, Adrián José, Karamehmedović, Emir, Maestre, Haroldo, Rico Soliveres, María Luisa, Capmany, Juan
Up-Conversion Sensing of 2D Spatially-Modulated Infrared Information-Carrying Beams with Si-Based Cameras
Torregrosa AJ, Karamehmedović E, Maestre H, Rico ML, Capmany J. Up-Conversion Sensing of 2D Spatially-Modulated Infrared Information-Carrying Beams with Si-Based Cameras. Sensors. 2020; 20(12):3610. doi:10.3390/s20123610
URI: http://hdl.handle.net/10045/107853
DOI: 10.3390/s20123610
ISSN: 1424-8220
Abstract: 
Up-conversion sensing based on optical heterodyning of an IR (infrared) image with a local oscillator laser wave in a nonlinear optical sum-frequency mixing (SFM) process is a practical solution to circumvent some limitations of IR image sensors in terms of signal-to-noise ratio, speed, resolution, or cooling needs in some demanding applications. In this way, the spectral content of an IR image can become spectrally shifted to the visible/near infrared (VIS/NWIR) and then detected with silicon focal plane arrayed sensors (Si-FPA), such as CCD/CMOS (charge-coupled and complementary metal-oxide-semiconductor devices). This work is an extension of a previous study where we recently introduced this technique in the context of optical communications, in particular in FSOC (free-space optical communications). Herein, we present an image up-conversion system based on a 1064 nm Nd3+: YVO4 solid-state laser with a KTP (potassium titanyl phosphate) nonlinear crystal located intra-cavity where a laser beam at 1550 nm 2D spatially-modulated with a binary Quick Response (QR) code is mixed, giving an up-converted code image at 631 nm that is detected with an Si-based camera. The underlying technology allows for the extension of other IR spectral allocations, construction of compact receivers at low cost, and provides a natural way for increased protection against eavesdropping.
Keywords:Image up-conversion, Infrared imaging, Free-space laser communications, Intra-cavity wavelength conversion, Infrared sensing
MDPI
info:eu-repo/semantics/article