Two-Photon Interferometry I: Biphoton Interference

Z. Y. Ou

Yanhua H. Shih, Morton H. Rubin, Alexander V. Sergienko

R. M. Stevenson, A. J. Hudson, R. J. Young +4 more

We demonstrate optical interferometry beyond the limits imposed by the photon wavelength using 'triggered' entangled photon pairs from a semiconductor quantum dot. Interference fringes of the entangled biphoton state reveals a periodicity half of that obtained with the single photon, and much less than that of the pump laser. High fringe visibility indicates that biphoton interference is less sensitive to decoherence than interference of two sequential single photons. The results suggest that quantum interferometry may be possible using a semiconductor LED-like device.

Stevenson, RM, Hudson, AJ, Young, RJ +6 more

We demonstrate optical interferometry beyond the limits imposed by the photon wavelength using 'triggered' entangled photon pairs from a semiconductor quantum dot. Interference fringes of the entangled biphoton state reveals a periodicity half of that obtained with the single photon, and much less than that of the pump laser. High fringe visibility indicates that biphoton interference is less sensitive to decoherence than interference of two sequential single photons. The results suggest that quantum interferometry may be possible using a semiconductor LED-like device. (C) 2007 Optical Society of America

Yanhua H. Shih

Two-photon interferometry started to play an important role in quantum optics since 1980’s. In that time, Dirac was criticized to be mistaken because he stated in his book, The Principles of Quantum Mechanics , that “photon only interferes with itself. Interference between two different photons never occurs”. Two-photon interference was considered as the interference between two photons. In fact, neither classical theory nor quantum theory suggested the interference between different photons. Classical theory views optical interference the result of coherent superposition between electromagnetic waves. The two-photon interference picture provided reasonable interpretation to that observation too: under the condition of complete overlapping, when the two biphoton amplitudes superpose in phase the joint-detection of the two distant photodetectors reaches its maximum counting rate as the sign of “correlation”. When the optical path difference is increased from zero to unbalanced values, a coincidence curve of “dip” is observed.