Two-photon bioimaging with picosecond optical pulses from a semiconductor laser

Area of Science:

• Biomedical Optics
• Laser Physics
• Cellular Imaging

Background:

• Two-photon bioimaging requires high-peak-power, short-wavelength light sources.
• Existing sources can be bulky, unstable, or lack sufficient power.
• Developing practical light sources is crucial for advancing bioimaging techniques.

Purpose of the Study:

• To develop a compact and stable light source for two-photon bioimaging.
• To achieve kilowatt peak power at a suitable wavelength for bioimaging applications.
• To demonstrate the utility of the developed light source in biological samples.

Main Methods:

• Utilized second-harmonic generation (SHG) to convert laser output wavelength.
• Employed a gain-switched semiconductor laser operating at 1.55 µm.
• Amplified the laser output to achieve high peak power.
• Performed two-photon fluorescence bioimaging of actin filaments in PtK2 cells.

Main Results:

• Generated kilowatt peak power optical pulses at 0.77 µm wavelength.
• Achieved a pulse duration of 5 picoseconds (ps).
• Successfully demonstrated two-photon fluorescence bioimaging of actin filaments in PtK2 cells.
• The developed light source proved to be compact and stable.

Conclusions:

• A practical and stable light source for two-photon bioimaging was successfully developed.
• The compact SHG scheme provides a viable method for generating high-peak-power optical pulses.
• The system's performance is suitable for high-resolution bioimaging of cellular structures.