Photizon Academy
Interactive tutorials on optics and photonics.
Working on a real part rather than a concept? See the Guides.
Refractive Index & the Sellmeier Equation
Why light slows down in glass, how dispersion works, and how the Sellmeier equation captures it. The foundation for every coating calculation.
How Anti-Reflection Coatings Work
Why every lens, solar panel, and pair of glasses has an invisible coating — and the physics that makes it work.
Fresnel Equations & Brewster's Angle
Why glass reflects 4% of light, its angle dependence, and why polarized sunglasses work.
Thin-Film Interference: From Soap Bubbles to Optical Coatings
How a layer thinner than a wavelength of light creates vivid colors, kills reflections, or acts as a mirror.
Jones Matrices and Polarization States: A Practical Guide
Describe polarization with Jones vectors, manipulate it with Jones matrices. Interactive E-field visualization, Malus's law demo, and Poincaré sphere.
Birefringence
Why some crystals split light in two, how wave plates work, and the one equation that ties it all together.
How High-Reflector Mirrors Work: Metal Coatings vs. Quarter-Wave Stacks
From 95% silver mirrors to 99.99% dielectric stacks — how quarter-wave interference creates nearly perfect reflectors.
Fabry-Perot Interferometers & Optical Resonators
How two mirrors create a precision wavelength filter. Airy function, finesse, finesse budget, and resonator stability.
Gaussian Beams and the ABCD Matrix
How laser beams propagate, focus, and expand — and how a single 2×2 matrix predicts the beam through any optical system.
The Q-Factor of Optical Cavities
What Q means physically, how to compute it from mirror reflectance and cavity length, and how it connects to finesse and photon lifetime.
Waveguide Modes and Photonic Integration
How light gets trapped in a waveguide, which modes can exist, and why SOI, SiN, and LNOI platforms behave so differently. Interactive slab mode solver and platform comparison.
Diffraction Gratings: From the Grating Equation to Echelle Spectrographs
Hold a CD under a lamp and tilt it. That rainbow is diffraction — the same physics that powers every spectrometer.
Ring Resonators in Photonics
From single-ring notch filters to Kerr frequency combs — how a loop of waveguide does the work of a Fabry-Perot cavity.
Optical Aberrations: The Five Seidel Terms on a Single Lens
Spherical aberration, coma, astigmatism, field curvature and distortion, traced live on one biconvex lens, plus the two color terms and what reshaping the glass can and cannot fix.
Chromatic Aberration and the Achromatic Doublet
Why blue and red focus at different distances, what the Abbe number measures, and how a crown against a flint cancels color, computed live on a real doublet.
Correcting Aberrations: The Cooke Triplet, Stop Shift and the Petzval Sum
It takes three pieces of glass to cancel the five: the 1896 Cooke triplet read one surface at a time, what moving the aperture stop buys, and the blur that survives it.