Quantum photonics and sensing at QCE26 counted every photon

This guide follows 15 talks on quantum photonics and sensing at IEEE Quantum Week 2026 in Toronto. Most of them treated photons and measurements as a budget to be spent with care. On the afternoon of Wednesday 16 September, in Room 718A of the Metro Toronto Convention Centre, Saikat Guha gave the closing panel of a signal-processing workshop a rule that sums up quantum photonics. Noise added at the detector can never be taken out afterwards, Guha said, so any quantum gain has to be won by working on the light before it is counted. A detector destroys the photon it registers. Each photon is therefore a coin that can be spent only once, and the only question is what it buys. Light is still the natural carrier of quantum information. A single photon barely touches its surroundings, so it can keep a quantum state intact through air, fibre or a chip at room temperature. The same aloofness makes photons hard to steer, and every mirror and splice loses a little light. Sensing turns that fragility into a strength. A quantum system that is easily disturbed makes a very fine probe, and the best-known example is the nitrogen vacancy in…