All-fiber widely tunable ultrafast laser source for multimodal imaging in nonlinear microscopy

Area of Science:

• Optics and Photonics
• Laser Physics
• Materials Science

Background:

• Ultrafast lasers are crucial for scientific research and advanced imaging.
• Existing systems often require bulky components and complex operation.
• There is a need for compact, tunable, and user-friendly ultrafast laser sources.

Purpose of the Study:

• To present an all-fiber, wavelength-tunable, ultrafast laser system.
• To demonstrate its suitability for nonlinear microscopy applications.
• To highlight its compact and robust design.

Main Methods:

• Utilized soliton self-frequency shifting in an Er-doped polarization-maintaining very large mode area fiber.
• Achieved wavelength tunability over 370 nm starting from 1620 nm.
• Employed frequency doubling to extend the output range to the visible spectrum.

Main Results:

• Generated 120 fs pulses with up to 1.5 W average power directly from fiber.
• Achieved frequency-doubled output covering 810 nm to nearly 1000 nm with >500 mW average power.
• Demonstrated excellent beam quality (M² of 1.1) and high polarization extinction ratio (>40 dB).

Conclusions:

• The developed laser system is a robust, compact, and computer-controlled source.
• Its tunable output and high performance make it ideal for multimodal imaging in nonlinear microscopy.
• The all-fiber design eliminates the need for bulky external optics.