Visible continuum pulses based on enhanced dispersive wave generation for endogenous fluorescence imaging

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Laser Physics

Background:

• Nonlinear microscopy often relies on specific laser wavelengths.
• Ti:sapphire oscillators typically operate in the near-infrared, limiting visible-light applications.
• Endogenous fluorescence imaging requires efficient excitation sources.

Purpose of the Study:

• To generate broadband visible continuum pulses for nonlinear microscopy.
• To enable simultaneous imaging of NADH and tryptophan in biological tissues.
• To extend the accessible wavelength range for nonlinear microscopy.

Main Methods:

• Utilized a 100-fs Ti:sapphire oscillator and nonlinear photonic crystal fiber.
• Employed enhanced dispersive wave generation in the anomalous dispersion region.
• Optimized fiber length to minimize continuum pulse width.
• Generated broadband (500-700 nm) high-power (150 mW) continuum pulses.

Main Results:

• Successfully generated broadband visible continuum pulses (500-700 nm).
• Achieved simultaneous two-photon microscopy imaging of NADH and tryptophan in mice tissues.
• Demonstrated the utility of generated pulses for visible-wavelength nonlinear microscopy.

Conclusions:

• The developed method extends nonlinear microscopy to the visible wavelength range.
• This technique is valuable for applications requiring visible laser pulses, overcoming limitations of traditional Ti:sapphire oscillators.
• Enables advanced endogenous fluorescence imaging of biological samples.