Method of direct ray tracing used for investigation and optimization of diaphragm optical system

Summary form only given. A sufficiently narrow directivity pattern of IR radiometers can be obtained with the help of an optical system (made of lenses or a parabolic/hyperbolic mirror) located at the input. However, in a number of applications it seems reasonable to use diaphragm optics. The advantages of diaphragm optics are attributed to its dust immunity, mechanical stability and simplicity of manufacturing. The fact that it can be placed after a modulator is also considered as a benefit-in this case thermal radiation of the optical system is not modulated and the error arising from reradiation of the optical system is fully eliminated.