Optics & Light
Reflection, refraction, lenses, prisms, and diffraction patterns
- NewSchool
Eye: Myopia & Hyperopia
Reduced eye + glasses; retina blur cue; presets and suggested ΔP.
- NewUniversity / research
Fresnel vs Fraunhofer
Slit diffraction: N = a²/(λL); Cornu spiral; Fresnel integral vs sinc².
- NewSchool
Three Polarizers (paradox)
P₁–P₂–P₃ Malus chain; crossed P₁⊥P₃ plus P₂ at 45° lets light through.
- NewSchool
Airy Disk & Rayleigh Limit
Circular aperture Fraunhofer pattern; first dark ring; two-point resolution.
- NewSchool
Optical Bench (sandbox)
Up to 4 elements: thin lenses, vertical mirrors, wedge δ; paraxial ray trace.
- NewSchool
Telescope & Microscope (2 lenses)
Kepler / Galileo / microscope presets; paraxial rays, M, f_obj/f_eye hint.
- NewSchool
Whispering Gallery (Rays)
Circular mirror: shallow chords refocus acoustic energy opposite the source (geometric optics).
- NewUniversity / research
Fiber Bragg Grating
λ_B = 2 n_eff Λ; Lorentzian toy reflectivity vs λ and probe wavelength.
- NewSchool
Laser Speckle
Random phased waves: |Σ e^{i(k·r+φ)}|² grain pattern (qualitative).
- NewUniversity / research
Bragg’s Law (X-ray)
2d sin θ = nλ vs θ; crystal planes and constructive reflection (schematic).
- NewKids
Kaleidoscope
N-fold rotation + optional mirror: one bead etches a symmetric mandala trail.
- NewSchool
Coffee-Cup Caustics
Parallel beam, circular cup segment, reflected-ray density on a table line.
- NewSchool
Soap Film (Minimal Surface)
Non-planar wire: discrete Laplace relaxation on z; iridescent mesh — Plateau sketch.
- NewSchool
CD / Grating Rainbow
Lines/mm and incidence: scalar grating orders painted as λ-colored fans.
- NewSchool
Moiré (Line Gratings)
Two translucent rulings: spacing, tilt, shift — spatial beats and envelopes.
- NewSchool
Fiber: Numerical Aperture
NA from n_core, n_clad; acceptance angle and bend loss cue.
- NewSchool
Fiber Bend & TIR Loss
Curved core: outer-wall incidence vs θ_c; tight R leaks (meridional sketch).
- NewUniversity / research
Evanescent Wave (TIR)
Beyond θ_c: penetration depth scale in the rarer medium vs λ.
- NewSchool
Retina & Diffraction
Order-of-magnitude θ ~ λ/D and cone spacing scale.
- NewSchool
Pinhole Camera
Camera obscura: similar triangles, image size h_i = h_o · v/u.
- NewSchool
Rainbow in a Droplet
Snell in a sphere: primary (1× internal reflection ~42°) and secondary (2× ~51°, reversed spectrum); scan b/R and n.
- NewSchool
Rayleigh Sky (blue)
Scattered intensity ∝ λ⁻⁴; compare blue vs red and qualitative sky gradient.
- NewSchool
Inferior Mirage (hot road)
n(y) gradient above hot asphalt: rays bend — sky light looks like a wet patch.
- School
Reflection
Flat, concave, and convex mirrors with auto-drawn ray diagrams.
- FeaturedSchool
Refraction
Light crossing boundaries. Snell's law with angle measurements.
- School
Total Internal Reflection
Find the critical angle. Fiber optics analogy.
- FeaturedSchool
Lens Simulator
Converging and diverging lenses with ray diagrams and image formation.
- NewSchool
Simple Eye (Thin Lens)
P_total = P_eye + P_glasses; 1/v = P − 1/u vs retina; blur cue.
- NewSchool
Thin Lens Equation
Hyperbola d_i(d_o), pole at d_o = f, schematic + 1/d check.
- NewSchool
Prism & Dispersion
White light through a prism creating a rainbow spectrum.
- NewSchool
Thin-Film Interference
Wedge fringes: n, d, θ; cos²(δ/2) colors and I(λ) at mid thickness.
- NewSchool
Newton’s Rings
Spherical lens on flat glass: air-film thickness fringes; optional π phase on reflection.
- NewSchool
Anti-Reflection Coating
Air–film–glass at normal incidence: R(λ) from two-interface interference; quarter-wave design.
- NewUniversity / research
Michelson Interferometer
I(Δ) = V cos²(πΔ/λ); tilt fringes; coherence length envelope.
- NewUniversity / research
Mach–Zehnder Interferometer
Two-beam recombination; I ∝ cos²(πΔ/λ) vs one-arm OPD; schematic + fringe plot.
- NewUniversity / research
Fabry–Pérot Cavity / Etalon
Airy transmission T(L), finesse F, free spectral range FSR = λ/(2n), linewidth ΔL ≈ FSR/F; animated cavity-length scan.
- NewUniversity / research
Gaussian Beam & q-Parameter
Waist w₀, Rayleigh range z_R, Gouy phase ζ(z), and ABCD propagation through a thin lens; w(z) and q at observation plane.
- NewUniversity / research
Fourier Optics 4f System
Object → lens → Fourier plane → spatial filter (low/high-pass) → lens → image; 2D FFT with circular aperture in spectrum.
- NewUniversity / research
Zernike Wavefront Aberrations
Defocus, astigmatism, coma, spherical Zernike modes on a circular pupil; PSF via FFT, Strehl ratio and Maréchal estimate.
- NewUniversity / research
Optical Tweezers (Gradient Trap)
Gaussian trap U(r), stiffness k ∝ P/w₀², overdamped Langevin bead with Stokes drag and thermal Brownian jitter; ⟨r²⟩ trace.
- NewUniversity / research
1D Photonic Crystal Bandgap
Alternating n₁/n₂ bilayers; TE transfer-matrix T(λ), R(λ); stop bands where |Tr(M_period)/2|>1 vs period Λ.
- NewUniversity / research
Sagnac (Ring) Interferometer
Δφ ∝ Ω·A/λ for counter-propagating beams in a rotating loop — optical gyro idea.
- NewSchool
Brewster Angle
tan θ_B = n₂/n₁; R_p→0; θᵢ+θₜ=90°; Fresnel R_s, R_p vs θᵢ.
- NewSchool
Fermat's Principle
OPL = n₁AP+n₂PB vs hit point; minimum = Snell path.
- NewSchool
Chromatic Aberration
Cauchy n(λ); thin-lens f(λ); paraxial rays R/G/B.
- School
Diffraction
Single and double slit with interference patterns.
- Kids
Color Mixing
Additive (RGB) and subtractive (CMY) interactive color mixing.
- NewSchool
Polarization (Malus)
Two polarizers. Rotate θ, see I = I₁ cos²θ and extinction.
- NewUniversity / research
Birefringence (Calcite sketch)
Two scalar Snell paths for n_o and n_e — double refraction cartoon (not full optic-axis walk-off).
- NewUniversity / research
Holography (Recording principle)
Toy 2D interference |E_ref + E_obj|²: fringes encode phase; readout diffraction not simulated.