Abstract The problem of the character of the oscillation phase at different points of the wave field of a system of two point and isotopically emitting sources is discussed. This issue is considered for the points located on the surfaces of the maxima and minima of the interference picture. It is also shown that on the surfaces of the amplitude extrema, the in-phase or antiphase oscillations are determined by the multiplicity of the sum of the path of the waves to the wavelength. The distribution of phase points in various plane cuts is investigated.
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.
We propose a two-photon subwavelength interference scheme for classical light in which multiple quantum-like entangled two-photon paths play an essential role. These entangled two-photon paths are introduced through a specially designed source composed of many point sources
j with
j's complex amplitude being a superposition of modes ${e}^{i{\ensuremath{\phi}}_{j}}$ and ${e}^{i{\ensuremath{\phi}}_{j}^{(1)}}$, where ${\ensuremath{\phi}}_{j}$ and ${\ensuremath{\phi}}_{j}^{(1)}$ are temporally random phases but satisfying ${\ensuremath{\phi}}_{j}+{\ensuremath{\phi}}_{j}^{(1)}={\ensuremath{\phi}}_{0}$, with ${\ensuremath{\phi}}_{0}$ being either a constant or a random phase in time. Interference between the entangled two-photon paths could lead to second-order subwavelength interference of an object put in front of the source plane. In a proof-of-principle experiment, by using a spatial light modulator to modulate the wave front of a coherent light, we have generated such a source and observed subwavelength interference of a double-slit mask via two-photon measurement.