Sub-diffraction-limit realization and micro-displacement measurements via complex Gaussian-correlated beam

Highlights: • A special correlated partially coherent beam, the complex Gaussian-correlated (CGC) beam, is used to realize sub-diffraction-limit. • The minimum resolution distance of four symmetrical pinholes can achieve at least 0.05 times the classical Rayleigh limit by using the CGC beam. • Not only realize sub-diffraction-limit, this approach can also be used in sub-Rayleigh displacement measurements. Overcoming the Rayleigh diffraction limit has been a longstanding focus in optical field. In this paper, a complex Gaussian-correlated beam was used as the illumination source, which renders the minimum resolution distance of four symmetrical pinholes at least 0.05 times the Rayleigh diffraction limit. In addition, the method was applied in displacement measurements, which can measure a displacement below the Rayleigh diffraction limit. The theoretical results show that the complex Gaussian-correlated beam has a great potential to realize sub-diffraction-limit and micro-displacement measurements.