Spatiotemporal focusing through a multimode fiber via time-domain wavefront shaping

Area of Science:

• Optics and Photonics
• Fiber Optics
• Nonlinear Optics

Background:

• Controlling ultrashort optical pulses is crucial for advanced imaging and spectroscopy.
• Multimode fibers offer potential for flexible light delivery but typically degrade pulse quality.

Purpose of the Study:

• To demonstrate the shaping of femtosecond optical pulses for controlled output from a multimode fiber.
• To investigate the potential for nonlinear fluorescent imaging using shaped pulses transmitted through a multimode fiber.

Main Methods:

• Shaping femtosecond optical pulses in time and delivering them in a single spatial mode into a multimode fiber.
• Utilizing a square-core step-index multimode fiber for pulse propagation.
• Employing raster scanning at the fiber output to create an image.

Main Results:

• An ultrashort pulse was successfully generated at a predefined focus at the output of the multimode fiber.
• Raster scanning of the ultrashort pulse was achieved, demonstrating imaging capabilities.
• Experimental results closely aligned with numerical simulations.

Conclusions:

• Femtosecond pulse shaping enables controlled ultrashort pulse generation and scanning at the output of multimode fibers.
• This technique shows promise for nonlinear fluorescent imaging applications, with flexible single-mode fiber connectivity.
• The findings validate the proposed method for advanced optical imaging through multimode systems.