Position and orientation estimation of fixed dipole emitters using an effective Hermite point spread function model.

Area of Science:

• Optical microscopy
• Nanoscale imaging
• Biophysics

Background:

• Accurate localization of dipole emitters is crucial for nanoscale imaging.
• Traditional methods using Gaussian spot fitting introduce significant bias for defocused emitters with tilted dipole axes.
• Existing Point Spread Function (PSF) models may not fully capture complex spot shape variations.

Purpose of the Study:

• To introduce a novel method for precise position and orientation determination of fixed dipole emitters.
• To develop an effective Point Spread Function (PSF) model for improved dipole emitter imaging.
• To eliminate localization bias in defocused emitters with tilted dipole axes.

Main Methods:

• Combination of polarimetry and spot shape detection for emitter localization.
• Development of an effective Point Spread Function (PSF) model utilizing Hermite functions.
• Comparison of the Hermite-based PSF model with Gaussian fitting for localization accuracy.

Main Results:

• The Hermite function-based PSF model accurately describes spot shape variations with dipole orientation and polarization.
• The new method achieves localization uncertainty comparable to the ideal free dipole case.
• Elimination of the massive localization bias observed with Gaussian fitting for defocused, tilted dipole emitters.

Conclusions:

• The proposed method offers computational advantages over exact vectorial descriptions.
• This technique provides robust and accurate localization for fixed dipole emitters across various orientations and signal levels.
• The Hermite-based PSF model significantly enhances the reliability of super-resolution microscopy techniques.