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We present a simple theoretical model for 2 dimensional (2-D) image up-conversion of incoherent light. While image upconversion has been known for more than 40 years, the technology has been hindered by very low conversion quantum efficiency (~10-7). We show that our implementation compared to previous work can result in a feasible system: Using intracavity upconversion and Quasi Phase Matching (QPM) nonlinear materials provide increased conversion efficiency. Using a QPM crystal and choosing the wavelengths so the first order term in the phasematch wavelength acceptance vanishes, results in very large wavelength acceptance. This work describes how the bandwidth acceptance can be predicted and designed. This gives promise of a new way to make infrared imaging devices with tunable spectral sensitivity.

A simple model for 2D image upconversion of incoherent light