Optical microscope with nanometer longitudinal resolution based on a Linnik interferometer

Abstract A widefield microscope based on a Linnik interferometer was designed, constructed, and tested. The phase-shifting and polarized single-shot methods were used to measure interference patterns. Both methods use a low-coherence light-emitting diode as the light source, achieving a resolution of 10 nm in the Z direction and diffraction-limited resolution in the X and Y directions. The single-shot method is vibration-insensitive, allowing for the observation of moving objects. The simplicity and low cost of this instrument make it valuable for a wide range of applications.