Design and Modelling of a Dual-Magnification Galilean IR Telescope and Associated Focusing Optics

摘要

In this paper, the complete design and modelling of a dual-magnification 8-12 μm infrared Galilean telescope along with the associated focusing optics and scanning mechanism is described. Preliminary calculations are done to determine the first-order parameters of the narrow and the wide-field modes. Initially, the telescope (narrow and wide-angel modes) and the focusing optics are designed as individual subsystems. Later, they are combined together and the complete optical system is modelled and optimized as one unit to get the required final performance. It is shown that this final optimization step is very important to access the overall performance of the complete system. We can actually reduce the total number of lenses or the number of conic surfaces used in the final system by modelling and optimizing it as one unit. This reduces the cost and the complexity of the overall system. The final optical designs along with their aberrations curves and MTF plots are presented showing excellent performance in both the high and the low magnification modes.