 A wavefront splitting interferometer divides a light wavefront emerging from a point or a narrow slit ( i.e. spatially coherent light ) and , after allowing the two parts of the wavefront to travel through different paths , allows them to recombine . Fig . 5 illustrates Young 's interference experiment and Lloyd 's mirror . Other examples of wavefront splitting interferometer include the Fresnel biprism , the Billet Bi @-@ Lens , and the Rayleigh interferometer . 
