Localization of Nonblinking Point Sources Using Higher-Order-Mode Detection and Optical Heterodyning: Developing a...

Area of Science:

• Optics and Photonics
• Super-resolution Microscopy
• Quantum Optics

Background:

• Fluorescence microscopy relies on stochastic blinking for super-resolution, limiting its use for nonblinking systems.
• Coherent Raman experiments often involve nonblinking molecular systems, posing a challenge for traditional super-resolution techniques.

Purpose of the Study:

• To develop and generalize optical heterodyning for subdiffraction-limited imaging of nonblinking point emitters.
• To establish a theoretical framework for estimating localization limits considering realistic noise sources.

Main Methods:

• Exploitation of optical heterodyning to detect higher-order transverse electromagnetic (TEM) modes carrying displacement information.
• Development of a theoretical model incorporating shot noise, background noise, and Gaussian noise to determine practical localization limits.
• Experimental demonstration using a laser as a surrogate for point emitters, analyzing localization precision with Fisher information and Cramér-Rao lower bound.

Main Results:

• Super-resolution localization of point emitters demonstrated, achieving precision 2-3 orders of magnitude smaller than the point-spread function size.
• A theoretical estimation limit for localization parameters was established under realistic noise conditions.
• The method shows promise for localizing multiple emitters and nonblinking molecular systems.

Conclusions:

• Optical heterodyning offers a viable alternative for super-resolution imaging of nonblinking systems, expanding beyond fluorescence-based methods.
• The developed theoretical framework provides a practical guide for optimizing localization precision.
• This technique has the potential to significantly broaden the scope of super-resolution measurements in various scientific fields.