An exploration of the freeform two-mirror off-axis solution space

Abstract

Abstract We use a differential construction procedure to construct three starting solutions for a thermal infrared telescope design problem. We further refine these solutions with a simple optimization procedure. We show that this hybrid method is interesting by its flexibility that makes it suitable to find solutions to problems with tight volume constraints and its ease of use with little designer interaction required. Taking advantage of a fully automated process, we are able to investigate for each solution and its starting geometry, the impact of the Zernike order on the final performance obtained. Finally we show the systems proposed are sufficient for thermal infrared applications and while not as performant as the three mirror system used for comparison, their simplicity makes them an interesting alternative.