Fundamentals of Nonlinear Optics, 2nd Edition

Appendix C: Programming Techniques

C.1Programming Δk

As an example, consider Δk for a Type I difference-frequency interaction (o → e + e) in a positive uniaxial crystal

Δk(λ1,λ2,T,θ)=2π(no(λ1)λ1−ne(λ2,θ)λ2−ne(λ3,θ)λ3),(C.1)

where λ3 is determined from energy conservation. The pseudocode for Δk appears as follows:

 Function Deltak(lambda1,lambda2,temp,theta)
   lambda3=1/(1/lambda1-1/lambda2)
   Deltak=2*pi*(no(lambda1)/lambda1-ne(lambda2,theta)/lambda2-ne(lambda3,theta)/lambda3)
   return Deltak
 EndFunction

Note that the program makes two calls to subfunctions no(lambda) and ne(lambda,theta). no(lambda) is a function that returns the index of refraction based on the Sellmeier equation for the ordinary index. ne(lambda,theta) returns the extraordinary ...