Intracavity image upconversion system with fast and flexible electro-optic image gating based on...

Area of Science:

• Nonlinear Optics
• Quantum Optics
• Photonics

Background:

• Intracavity nonlinear image upconversion systems are crucial for extending imaging capabilities into spectral regions with low-sensitivity detectors.
• Existing methods for temporal gating in such systems often lack speed, flexibility, or introduce significant complexity.
• Achieving high-speed, precise temporal control of upconverted images is essential for advanced imaging applications.

Purpose of the Study:

• To introduce and demonstrate a new image gating mechanism for intracavity nonlinear image upconversion.
• To enable fast and flexible temporal gating of upconverted images using electro-optic control.
• To facilitate the use of low shutter-speed detectors in range-gated imaging systems.

Main Methods:

• Development of an image gating mechanism utilizing sum-frequency mixing of an external infrared image and a pump laser beam.
• Implementation of transient electro-optic frustration of the phase-matching condition within a nonlinear crystal inside the pump beam's cavity.
• Control of phase-matching via alteration of laser cavity beam polarization using a Pockels cell without interrupting laser oscillation.

Main Results:

• Achieved fast and flexible time duration gating of upconverted images.
• Successfully integrated an external image shutter mechanism into the upconverter system.
• Demonstrated the capability to use low shutter-speed Electron Multiplying CCD (EMCCD) cameras.

Conclusions:

• The proposed image gating mechanism provides effective temporal control for intracavity upconversion systems.
• This technique enhances range-gated imaging capabilities, particularly for the infrared and potentially terahertz spectrum.
• The method allows for the use of readily available, lower-speed detectors, broadening the applicability of upconversion imaging.