Quantum Dot FRET Cascade

This simulator visualises a Förster resonance energy transfer (FRET) relay through a chain of four quantum dots of increasing size and decreasing bandgap. Each pumped exciton starts at the smallest, highest-energy donor dot and, at every step, stochastically either hops non-radiatively to the next dot in the chain or decays where it sits — with the real distance-dependent probability E(r) = 1 / (1 + (r/R₀)⁶) and transfer rate k_FRET = (1/τ_D)·(R₀/r)⁶ that govern real dipole–dipole energy transfer. Tune the dot spacing, Förster radius and donor lifetime to see how a few nanometres of separation can make or break a multi-step energy-transfer cascade, and watch the measured cascade efficiency converge toward the theoretical E³ prediction as more excitons are pumped through.