A Do-It-Yourself Quantum Eraser: What you will need for the experiment

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A very dark room.
Polarizing film. Plain gray, high-quality film ("experimental grade") gives the best results; avoid film tinted with a color (see this page for some places that sell film). You need to cut it into six squares, each about two inches on a side. The box on page 94 describes what polarizers do to photons.
A laser, such as a laser pointer. If yours emits polarized light, align its polarization at 45 degrees from the vertical. If your laser is not polarized, include a polarizer at 45 degrees immediately after the laser at every step. Use a rubber band to keep the laser turned on.
A thin, straight piece of wire, such as from an unused twist tie or a straightened staple. The thinner the better.
Some tinfoil and a pin to poke a hole in it. The light that goes through the pinhole will expand outward, forming a narrow, conical beam. The pinhole makes the patterns dimmer but may improve the results if the room is dark enough.
Some stands to hold the laser and polarizers in place. These could be as low-tech as cereal boxes.
A screen to display the final patterns. The bare wall will do if it is plain enough; otherwise use a sheet of paper.

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