💿🐜 Antkeeper source code
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117 lines
3.1 KiB
117 lines
3.1 KiB
/*
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* Copyright (C) 2021 Christopher J. Howard
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*
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* This file is part of Antkeeper source code.
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*
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* Antkeeper source code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Antkeeper source code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef ANTKEEPER_PHYSICS_LIGHT_REFRACTION_HPP
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#define ANTKEEPER_PHYSICS_LIGHT_REFRACTION_HPP
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namespace physics {
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namespace light {
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/// Index of refraction formulas.
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namespace ior {
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/**
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* Two-term form of Cauchy's transmission equation.
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*
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* @param lambda Wavelength of light, in micrometers.
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* @param a First coefficient of the medium.
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* @param b Second coefficient of the medium.
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* @return Refractive index.
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*
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* @see https://en.wikipedia.org/wiki/Cauchy%27s_equation
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*/
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template <class T>
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T cauchy(T lambda, T a, T b)
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{
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return a + b / (lambda * lambda);
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}
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/**
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* Three-term form of Cauchy's transmission equation.
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*
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* @param lambda Wavelength of light, in micrometers.
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* @param a First coefficient.
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* @param b Second coefficient.
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* @param c Third coefficient.
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* @return Refractive index.
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*
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* @see https://en.wikipedia.org/wiki/Cauchy%27s_equation
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*/
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template <class T>
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T cauchy(T lambda, T a, T b, T c)
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{
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const T lambda2 = lambda * lambda;
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return a + b / lambda2 + c / (lambda2 * lambda2);
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}
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/**
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* Two-term form of the Sellmeier equation.
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*
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* @param lambda Wavelength of light, in micrometers.
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* @param b1 B1 coefficient.
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* @param c1 C1 coefficient.
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* @param b2 B2 coefficient.
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* @param c2 C2 coefficient.
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* @return Refractive index.
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*
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* @see https://en.wikipedia.org/wiki/Sellmeier_equation
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*/
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template <class T>
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T sellmeier(T lambda, T b1, T c1, T b2, T c2)
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{
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const T lambda2 = lambda * lambda;
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const T t1 = (b1 * lambda2) / (lambda2 - c1);
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const T t2 = (b2 * lambda2) / (lambda2 - c2);
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return std::sqrt(T(1) + t1 + t2);
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}
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/**
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* Three-term form of the Sellmeier equation.
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*
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* @param lambda Wavelength of light, in micrometers.
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* @param b1 B1 coefficient.
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* @param c1 C1 coefficient.
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* @param b2 B2 coefficient.
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* @param c2 C2 coefficient.
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* @param b3 B3 coefficient.
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* @param c3 C3 coefficient.
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* @return Refractive index.
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*
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* @see https://en.wikipedia.org/wiki/Sellmeier_equation
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*/
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template <class T>
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T sellmeier(T lambda, T b1, T c1, T b2, T c2, T b3, T c3)
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{
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const T lambda2 = lambda * lambda;
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const T t1 = (b1 * lambda2) / (lambda2 - c1);
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const T t2 = (b2 * lambda2) / (lambda2 - c2);
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const T t3 = (b3 * lambda2) / (lambda2 - c3);
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return std::sqrt(T(1) + t1 + t2 + t3);
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}
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} // namespace ior
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} // namespace light
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} // namespace physics
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#endif // ANTKEEPER_PHYSICS_LIGHT_REFRACTION_HPP
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