A portable double-slit quantum eraser with individual photons

Abstract

The double-slit experiment has played an important role in physics, from supporting the wave theory of light, via the discussions of the wave-particle duality of light (and matter) to the foundations of modern quantum optics. Today it keeps playing an active role in the context of quantum optics experiments involving single photons. In this paper, we present a truly portable double-slit apparatus which demonstrates both the wave-particle duality of light and the phenomenon of quantum erasing. The device can be operated either with strong laser light and screen projection, or with individual photons, in which case quantum interference and quantum erasing are detected by a photomultiplier whose pulses are rendered acoustically by means of a loudspeaker. Alternatively, the phenomena can be displayed using multimedia projection of oscilloscope traces.

Acoustic and visual display of photons: a handheld demonstration device

“…Two interference filters (10 nm bandpass, centered at 532 nm) inserted before and after the apertures prevent overloading of the PM. The apertures and filters are held in a removable collimator block [7] that is mounted onto the PM using a Hamamatsu type A10030 adapter block 6 . The collimator, PM and batteries are contained in a handheld housing (210 × 100 × 30 mm 3 ).…”

“…Two of us (TLD and AW) have developed several demonstration experiments on wave-particle duality and quantum erasing [5][6][7]. In those experiments a photomultiplier (PM) is used to detect light quanta from a strongly attenuated green (λ = 532 nm) laser pointer after their passage through a (double-slit, Mach-Zehnder or Michelson) interferometer.…”