Pulsed swept-source FDML-MOPA laser with kilowatt picosecond pulses around 1550 nm

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Laser Technology

Background:

• Swept-source lasers are crucial for high-speed imaging techniques like multiphoton microscopy.
• Current methods like SLIDE achieve kilohertz rates, but longer wavelengths offer benefits for deep tissue penetration.
• Shortwave infrared (SWIR) microscopy is advantageous for deep tissue imaging and LiDAR applications.

Purpose of the Study:

• To develop a novel swept-source laser operating around 1550 nm.
• To achieve high-speed wavelength agility and high peak power for nonlinear excitation.
• To demonstrate the laser's potential for advanced imaging and ranging applications.

Main Methods:

• Utilized a Fourier-domain mode-locked (FDML) laser operating at a 326 kHz sweep rate.
• Employed a master oscillator power amplifier (MOPA) configuration with erbium-doped fiber amplifiers (EDFAs) for pulse amplification.
• Achieved picosecond pulse modulation and amplified continuous wave (cw) output to several kilowatts peak power.

Main Results:

• Demonstrated a swept-source laser around 1550 nm with high-speed wavelength agility.
• Achieved high peak power pulses (several kilowatts) suitable for nonlinear excitation.
• Successfully performed third-harmonic generation (THG) imaging on harmonic nanoparticles at a 10 MHz pulse excitation rate.

Conclusions:

• The developed FDML-MOPA laser source offers unique performance parameters for nonlinear microscopy, spectroscopy, and ranging.
• This fiber-based system provides a reliable and cost-effective solution for advanced photonic applications.
• The laser's capabilities pave the way for enhanced deep tissue imaging and LiDAR technologies.