iPhasematch vs Filter Calculator

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.

Design RC, RL, and RLC filters (2nd–7th order) with Butterworth & Chebyshev alignments, passive crossovers, RLC band-pass/reject, and Twin-T notch—enter specs to instantly get component values and quick Bode insights in a clean, offline-friendly, dark-mode UI for lab, classroom, and audio/embedded work. What you can design: -RC & RL filters: low-pass / high-pass, 2nd–7th order -RLC filters: band-pass & band-reject (notch) -Butterworth: maximally flat magnitude -Chebyshev: ripple-tuned sharpness -Twin-T notch: precise mains or tone suppression -Passive crossovers: 2-way/3-way starter calculations Built for engineers, hobbyist and students, it turns specs into trustworthy parts fast—so you can prototype smarter, learn by tweaking, and move from idea to BOM with confidence.