Modal focal adaptive optics for Bessel-focus two-photon fluorescence microscopy

Area of Science:

• Biomedical Optics
• Microscopy
• Optical Engineering

Background:

• Adaptive optics (AO) enhances microscopy resolution by correcting optical aberrations.
• AO is established for circular pupils but underexplored for non-circular pupils like those in Bessel-focus two-photon fluorescence microscopy (2PFM).

Purpose of the Study:

• To introduce and validate a modal focal AO (MFAO) method for Bessel-focus 2PFM with annular pupils.
• To simplify AO implementation in microscopy systems with non-circular pupils.

Main Methods:

• Developed a modal focal AO (MFAO) method using Zernike annular polynomials.
• Implemented aberration correction using a spatial light modulator at the objective's focal plane.
• Validated MFAO with artificial and sample-induced aberrations, and in vivo imaging.

Main Results:

• MFAO achieved performance comparable to existing zonal AO methods.
• The simplified optical configuration of MFAO offers practical advantages.
• Successfully applied MFAO for in vivo imaging of zebrafish larvae and mouse brains.

Conclusions:

• MFAO expands modal AO applications to annular pupils.
• This method simplifies aberration correction at the objective focal plane.
• MFAO represents a significant advancement for AO implementation in microscopy.