Use of the Talbot effect to couple the phases of lasers

Antyukhov et al. [JETP Lett. 44, 78 (1986)] first proposed that a normal and partly reflecting mirror be placed a distance a2/λ in front of a laser array to synchronize and phase lock them. Then the Talbot effect, said to produce source ‘‘self-imaging,’’ forms an ‘‘array image’’ on the array. However, a basic relation of Fresnel diffraction is now found to indicate that the method as used is inherently flawed. The Talbot effect actually introduces phase shifts into some of the reflected light which make the total output nonuniform in phase. This produces a complex amplitude pattern in Talbot planes different from the grating output. Then the various lasers will not emit in phase.