Imaging, Sensing, and Metrology

Quantum Metrology for Imaging. Inversion interferometry for superresolving point sources

Modal imaging can provide unprecedented resolution for imaging point sources, such as single-molecule fluorescent tags used to study biological samples. In principle, modal imaging  can approach quantum limits of optical resolution of point sources as quantified by Quantum Cramer Rao Bound, albeit assuming highly idealized complex quantum measurements. To utilize the potential of quantum measurements for superresolution microscopy, it is critical to understand the parameters in optical systems for realizing such quantum measurements under realistic conditions.

Our efforts focus on understanding these critical parameters and developing an optical system for superresolving two incoherent point sources (i.e. fluorophore tags) for studying biological samples. We use a Mach-Zehnder interferometer with optical field inversion to realize image inversion interferometry, in principle allowing for near quantum-optimal measurement for imaging point sources. In our work, we combine inversion interferometry with florescence microscope to image fluorescent beads acting as point sources.