Each photon carries a polarization state, shown as a point on the equator of the Bloch sphere
(a qubit representation). Firing photons at an analyzer set at angle φ relative to the polarization
angle θ, each individual photon either passes whole or is blocked — there is no "partial" photon —
but the pass probability follows Malus's law.
P(pass) = cos²(θ − φ)
|ψ⟩ = cos(θ)|H⟩ + sin(θ)|V⟩
Single-photon outcome ~ Bernoulli(P)
- Polarization angle θ — sets the photon source's polarization state (arrow on the Bloch equator and beam color).
- Analyzer angle φ — rotates the polarizing filter disk the photons must pass through.
- Photon emission rate — how many photons per second are fired toward the analyzer.
- Run / Pause — starts or freezes the photon stream so you can inspect the current state.
Real-world relevance: this is exactly the mechanism behind quantum key distribution (BB84 protocol)
and Bell-inequality tests confirming quantum entanglement, both built from single-photon polarization
measurements like this one.