Measurement of the photonic de Broglie wavelength of a two-photon wavepacket

Summary form only given. J. Jacobson et al. (1995) have shown theoretically that the measured de Broglie wavelength of an object is dependent on its internal structure. A fourth-order Young interference experiment is done to demonstrate a practical way to measure the photonic de Broglie wavelength of a two-photon wavepacket. Light in the two-photon state generated collinearly in the process of spontaneous parametric down-conversion. By modifying the transverse field profile of the pump laser beam that generates the two-photon beam we demonstrate experimentally and theoretically that it is possible to measure the de Broglie wavelength of the constituents parts of the wavepacket, the de Broglie wavelength of the two-photon wavepacket (biphoton) as a whole and an undefined intermediate de Broglie wavelength between the two cases.