Up-Conversion Sensing of 2D Spatially-Modulated Infrared Information-Carrying Beams with Si-Based Cameras

Area of Science:

• Nonlinear Optics
• Infrared Sensing
• Optical Communications

Background:

• Infrared (IR) sensors face limitations in signal-to-noise ratio, speed, resolution, and cooling requirements.
• Up-conversion sensing offers a method to overcome these limitations by shifting IR spectral content.
• Previous work introduced this technique for free-space optical communications (FSOC).

Purpose of the Study:

• To present an image up-conversion system for detecting IR images.
• To demonstrate the application of this technology for secure data transmission.
• To extend the utility of IR sensing to visible/near-infrared detection.

Main Methods:

• Utilized optical heterodyning with a local oscillator laser wave.
• Employed nonlinear optical sum-frequency mixing (SFM) for spectral shifting.
• Integrated a 1064 nm Nd3+:YVO4 laser with an intra-cavity KTP nonlinear crystal.

Main Results:

• Successfully up-converted a 1550 nm IR QR code image to 631 nm.
• Detected the up-converted image using a silicon-based camera (Si-FPA).
• Achieved a practical solution for IR image sensing and data transmission.

Conclusions:

• The developed up-conversion system enhances IR image detection capabilities.
• This technology facilitates the use of silicon focal plane array sensors for IR imaging.
• The method offers potential for compact, low-cost receivers and enhanced eavesdropping protection.