Pixel super-resolution interference pattern sensing via the aliasing effect for laser frequency metrology

TL;DR

This paper introduces a novel optical super-resolution technique using Fourier aliasing and sensor rotation to resolve sub-micrometer interference patterns, enabling high-precision laser wavelength measurement beyond traditional limits.

Contribution

The authors present a simple, compact method combining a standard image sensor and Fourier analysis to achieve super-resolution and precise wavelength sensing without specialized equipment.

Findings

Resolved periodicities of ~3/μm surpassing Nyquist limit

Achieved wavelength resolving power over 100,000

Demonstrated simple sensor rotation for absolute frequency determination

Abstract

The superposition of several optical beams with large mutual angles results in sub-micrometer periodic patterns with a complex intensity, phase and polarization structure. For high-resolution imaging thereof, one often employs optical super-resolution methods such as scanning nano-particle imaging. Here, we report that by using a conventional arrayed image sensor in combination with 2D Fourier analysis, the periodicities of light fields much smaller than the pixel size can be resolved in a simple and compact setup, with a resolution far beyond the Nyquist limit set by the pixel size. We demonstrate the ability to resolve periodicities with spatial frequencies of ~3/$\mu$m, 15 times higher than the pixel sampling frequency of 0.188/$\mu$m. This is possible by analyzing high-quality Fourier aliases in the first Brillouin zone. In order to obtain the absolute spatial frequencies of the interference patterns, we show that simple rotation of the image sensor is sufficient, which modulates the effective pixel size and allows determination of the original Brillouin zone. Based on this method, we demonstrate wavelength sensing with a resolving power beyond 100,000 without any special equipment