On the Young's Interference Pattern

Ping Wang

Alexander Shaw, Trevor G. Vrckovnik, Billy Thorpe +1 more

This experiment explores the quantum phenomenon known as the Quantum Eraser, using a variation of Young’s Double Slit experiment. Young’s Double Slit experiment demonstrates that light acts as a wave by creating an interference pattern when diffracted through two slits. If one measures which of the two slits the photons pass through, then the interference pattern is replaced by a single bright spot, as would be expected for particle-like behaviour. The “Quantum Eraser” eliminates the measurement on the photons, thereby reintroducing the interference pattern observed in Young’s original experiment. The experiment’s first stage saw Young’s Double Slit experiment recreated and an interference pattern was observed. Upon adding two orthogonally polarized filters, the photon’s path was measured, and the interference pattern was removed. By then adding a third filter which was polarized 45O relative to both other polarisers, the interference pattern was somewhat restored. For each experiment, the heights of the peaks in the interference patterns were compared to each other to examine the quality of the reproduced interference pattern based on the original double slit interference pattern. This comparison gave a quantitative result that demonstrated that the Quantum Eraser was able to restore the interference pattern to within 5 standard errors, thereby exemplifying the effect that changing the measurement conditions affects the final measurement.

G. Girieud, Silvania F. Pereira

An analysis of Young’s interference experiment for single cycle pulses showing the time evolution of the interference pattern due to two square apertures is obtained in the Fresnel regime. The fact that the diffraction pattern from each aperture is not constant in time has consequences on the interference pattern. We have also analyzed the changes in the spectrum at different regions at the observation plane. This position-dependent spectrum results in frequency beating of the interference pattern for the case of two apertures.

P. N. Ghosh

Derek N. Stacey

The author demonstrates a relationship between the pattern of straight interference fringes formed in Young's experiment and the circular fringes produced at infinity by a Michelson interferometer. The two patterns can both be considered to be produced by the interference of light from two coherent point sources. It is shown that the pattern given by these sources on a large sphere centred midway between them reduces to Young's fringes in the vicinity of zero path difference and to the Michelson pattern in the vicinity of maximum path difference.

RAYLEIGH