iPhasematch vs Polynomial Regression

iPhasematch allows you to calculate the phasematching condition of nonlinear wavelength conversion such as SHG or SFM based on published Sellmeier equiations. Downconversion (OPO) can be figured out by the reverse of SFM. It is a subset of the 'Qmix' function of a famous Windows software SNLO by Dr. Arlee Smith. This App does some of what SNLO does on your iOS device. It takes the crystal, two input wavelengths, and temperature and gives the phasematching orientations, effective nonlinear optical coefficients, walk-off angles, angular tolerance and temperature tolerance. In case of SHG, it also gives spectral tolerance. In biaxial crystals, it gives only the phasematching orientations in the principal planes, i.e., either theta=90 deg. or phi=0 or 90deg. Currently supported crystals: BBO, BiBO, CBO, CLBO, LB4, LBO, KBBF, KDP, KD*P, KN, KTP, Mg:LN, Mg:sLN, RBBF, RTP, YAB. NOTE: dn/dT data for LB4 was picked up from discrete data points in the reference and linearly extrapolated. Interface should be intuitive, giving phasematching with a tap of "PM" button,refractive index with "index" button and group index with "Gp.Idx" button, for the given condition (crystal, wavelengths, and temperature). DISCLAIMER: I cannot be held responsible for the result of the calculation it gives. I make every effort to make it accurate, and bug-free, but there could be errors in code. Please just use this on your own discretion.

Polynomial Regression is your calculator and, more importantly, learning tool. You will be able to: * Construct polynomials of up to 20 degrees from either real or complex roots. * Interpolate polynomials from points by Lagrange, Newton or Vandermonde methods and Quadratic or Cubic splines. * Perform Least Squares approximation by orthogonal projection, with or without QR factorization, or partial derivatives. * Learn about each of the algorithms with derivations, proofs, step by step demonstrations, and visual tools. * Have an option to enter data by either typing or tapping on XY plane, and save data sets between program runs.