Level 0 · Phenomena · Unit 2 of 3

Mach–Zehnder interferometer

about 5 min · Free · No sign-in needed

A photon meets a half-silvered mirror, a beam splitter. If you looked right after it, you would find the photon in the upper path half the time and in the lower path half the time. Two mirrors bring the paths together at a second beam splitter, and two detectors, D0 and D1, count where photons end up. Photons are sent one at a time. Predict first.

1. Predict
2. Run
3. Rules
4. Redraw
5. Explain
6. Done

Prediction 1 of 2

Simulated

Predict first, then run it.

Paths

Both paths openBlock the upper pathBlock the lower path

Run the experiment to see the result.

Both paths are open. What do D0 and D1 show after many photons?About half at each: each photon takes one path, and each splitter is 50:50.Every photon at D0, none at D1.Each photon splits in two, so each detector receives half a photon.

Clears this unit's progress and drawing record on this device.