Simultaneous spatial and temporal focusing for axial scanning.

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Laser Physics

Background:

• Simultaneous spatial and temporal focusing (SSTF) is crucial for advanced optical microscopy.
• Controlling the temporal focal plane axially is essential for 3D imaging and probing.
• Existing methods often require complex dispersion pre-compensation, limiting practical applications.

Purpose of the Study:

• To demonstrate axial scanning of the temporal focal plane using SSTF.
• To investigate the relationship between group velocity dispersion and axial scanning.
• To integrate SSTF into a fiber delivery system for practical applications.

Main Methods:

• Theoretical modeling of SSTF with adjustable group velocity dispersion.
• Experimental validation using ultrashort laser pulses.
• Implementation of a fiber delivery system incorporating large mode area fiber.

Main Results:

• Axial scanning of the temporal focal plane was achieved by adjusting group velocity dispersion.
• A linear relationship was observed between dispersion and the axial shift of the temporal focal plane.
• Transform-limited pulse width was recovered at the temporal focal plane, negating the need for pre-compensation.

Conclusions:

• SSTF provides a method for axial scanning of the temporal focal plane.
• The developed technique simplifies fiber-based multiphoton imaging by eliminating dispersion pre-compensation.
• This advancement is highly promising for developing novel axial scanning multiphoton fluorescence fiber probes.