Mirau correlation microscope

TLDR

We have built a correlation microscope using a Mirau interferometer with a thin silicon nitride film beam splitter that delivers amplitude and phase data for the reflected signal from a sample on the microscope–object plane. The device is highly vibration‑insensitive, self‑corrects for spherical and chromatic aberrations, and its imaging theory predicts transverse and range resolution that is slightly better than that of a scanning optical microscope with the same aperture.

Abstract

We have constructed a correlation microscope based on the Mirau interferometer configuration using a thin silicon nitride film beam splitter. This microscope provides the amplitude and phase information for the reflected signal from a sample located on the microscope–object plane. The device is remarkably insensitive to vibrations and is self-correcting for spherical and chromatic range aberrations of the objective. An imaging theory for the correlation microscope has been derived, which predicts accurately both the transverse resolution at a sharp edge and the range resolution for a perfect plane reflector. The range resolution is slightly better than that for a scanning optical microscope using a lens with the same aperture.