Electronically Controlled Dual-Wavelength Switchable SRS Fiber Amplifier in the NIR-II Region for Multispectral...

Area of Science:

• Biomedical Optics
• Laser Physics
• Materials Science

Background:

• Photoacoustic microscopy (PAM) offers high-resolution, non-invasive imaging with optical absorption contrast.
• Multispectral PAM requires light sources with high repetition and switching rates, microjoule pulse energy, and nanosecond durations.
• A gap exists in suitable light sources, especially for the near-infrared-II window.

Purpose of the Study:

• To develop and demonstrate a novel all-fiber-based light source for efficient multispectral photoacoustic microscopy.
• To address the need for a light source with specific parameters for advanced PAM applications.

Main Methods:

• Designed and constructed a custom all-fiber laser system.
• Utilized digitally addressed semiconductor seed lasers and stimulated Raman scattering amplification.
• Achieved arbitrary pulse sequences at 1168.4 nm and 1202.1 nm, with a 100 kHz switching rate between wavelengths.

Main Results:

• The developed light source delivers >3 μJ, 2 ns pulses at a 200 kHz repetition rate.
• Demonstrated arbitrary wavelength sequencing and 100 kHz switching between 1168.4 nm and 1202.1 nm.
• Successfully performed high-resolution multispectral photoacoustic microscopy on three polymer samples.

Conclusions:

• The custom all-fiber light source meets the stringent requirements for efficient multispectral PAM.
• This technology enables advanced spectroscopic analysis and high-resolution imaging in the near-infrared-II window.
• The demonstrated system is suitable for various applications requiring multispectral photoacoustic imaging.