A few principles of wave and ray optics are reviewed here for the benefit of those who need them. They provide both a short review and a definition of the terms and conventions used in the rest of the text.
2.1 Photons, Waves, and Rays
Light, both visible and invisible, can be described in terms of photons, waves, rays, and probability amplitudes. The latter hardly seem necessary for the purposes of this text, but the previous three certainly are required for a full understanding of prisms, interferometers, and the detection process.
Light is electromagnetic radiation that can be described mathematically by any function Î¨ that has the form Î¨(tâzâv) where t is time, z is the Cartesian coordinate of the direction of the flow of the wave, and v is the velocity of the wave. This can be seen by showing Î¨ as a solution for the one-dimensional wave equation, The solution may be written as Î¨=Î¨ 0 e jÏ(tâz v ) =Î¨ 0 e j(Ïtâkz) =Î¨ 0 e j(2Ïc Î» tâkz) =Î¨ 0 e j(2ÏÏtâkz) , where Î¨ is the Fourier transform of Î¨ and Î¨ 0 is the amplitude of the field. The details and derivation are shown in the appendix.
2.2 The Detection of Radiation
It is well known that detectors of visible and infrared radiation sense the average value of the square of the amplitude of the electric field.
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