Accession Number : ADA310568

Title :   Heterodyning Single-Photon Pairs.

Descriptive Note : Final rept. 1 Apr 93-31 Dec 95,

Corporate Author : COLUMBIA UNIV NEW YORK

Personal Author(s) : Teich, Malvin

PDF Url : ADA310568

Report Date : 05 FEB 1996

Pagination or Media Count : 10

Abstract : We have obtained theoretical and experimental second- and fourth-order interference patterns for entangled photons of different colors entering single and dual Mach-Zehnder interferometers (MZIs) in which dispersive elements have been deliberately placed. Entangled-photon pairs are a form of nonclassical light. We have observed the interference of entangled photons of different colors, in both second- and fourth-order, using coincidence detection, by sweeping the path-length difference in an interferometer (or two spatially separated interferometers). The entangled photons are created by pumping a KD*P parametric-downconverter crystal with a krypton-ion laser beam at 413 nm, creating photon pairs with center wavelengths in the vicinity of 830 nm. The coherence properties and photon statistics of this nonclassical source of light were determined. Although photon wavepackets are generally broadened, as well as delayed, by passage through dispersive optical elements, coincidence measurements made with entangled photon pairs can be free of such broadening This occurs for materials with particular dispersive behavior, as well as when the dispersion is balanced in both arms. This nonlocal behavior arises from the entanglement in the frequencies of the downconverted pair photons. We have shown that pump-frequency oscillations are present in the coincidence rate patterns for arbitrarily long path-length-difference times, confirming the robustness of this nonlocal phenomenon in the presence of dispersion. The difference-frequency oscillations, which correspond to heterodyning single-photon pairs, are also robust in the presence of dispersion, though they decay for large path-length-differences. Potential areas of applicability of twin photon beams range from photonics to visual science to computer science.

Descriptors :   *HETERODYNING, *PHOTONS, FREQUENCY, MEASUREMENT, COMPUTERS, STATISTICS, COHERENCE, LIGHT, COLORS, PATTERNS, SEPARATION, OPTICAL EQUIPMENT COMPONENTS, OSCILLATION, DISPERSIONS, INTERFEROMETERS, COINCIDENCE COUNTING, DIFFERENCE FREQUENCY, PHOTON BEAMS, COINCIDENCE RANGE FINDING.

Subject Categories : Nuclear Physics & Elementary Particle Physics
      Electricity and Magnetism
      Optics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE