Gaussian Optics

Analysis of Terahertz waves comes in three main forms, physical optics, geometrical optics, and Gaussian optics. Physical optics has the highest accuracy but it is time consuming when it is applied in the design of large radio telescopes. Also, it is only capable of computing radiation characteristics. Geometrical optics, on the other hand, reduces computational time significantly. But it does not give accurate results when designing telescopes which are to operate at Terahertz frequencies. Gaussian optics is a good trade-off between these two methods and it is a popular approach used in the design of large radio telescopes — particularly those which operate near/in the Terahertz band. Since it accounts for the effects of diffraction, this method produces reasonably accurate results. This chapter describes Gaussian optics, with emphasis given on its application in the design of radio telescopes.