Modulation of Optical Spatial Coherence

Synopsis

Dominating on the correlations between fluctuations of electromagnetic fields (the degree of optical spatial coherence) at the micrometer scale has many complexities. Dongfang Li and Domenico Pacifici have used surface plasmon polaritons (traveling electromagnetic waves along a metal-dielectric or metal-air interface) at the slit positions of Young’s double-slit interferometer as a method to combine the random fluctuations of the incident electromagnetic fields. Modifying the separation distance between the two slits has achieved strong tunability of the complex degree of spatial coherence of light. Therefore, the light can be transformed from completely incoherent to almost totally coherent or the opposite way, by using surface plasmon polaritons (SPPs).