Coherent anti-Stokes Raman scattering microscopy using a single-pass picosecond supercontinuum-seeded optical...

Area of Science:

• Biomedical Optics
• Spectroscopy
• Microscopy

Background:

• Coherent Anti-Stokes Raman Scattering (CARS) microscopy offers label-free vibrational contrast for biological imaging.
• Conventional CARS setups often involve complex optical arrangements for precise laser alignment.
• Developing simplified and robust CARS systems is crucial for broader adoption in scientific research.

Purpose of the Study:

• To demonstrate a simplified CARS microscopy system.
• To utilize a single-pass picosecond supercontinuum-seeded optical parametric amplifier (SCOPA) as the light source.
• To showcase the system's capability for label-free chemical imaging.

Main Methods:

• A frequency-doubled picosecond passively mode-locked Nd:YVO(4) laser was used to pump a SCOPA.
• A supercontinuum light source seeded the SCOPA, generating tunable picosecond pulses.
• The simplified setup automatically overlapped pump and Stokes beams within the SCOPA for coherent delivery to the microscope.

Main Results:

• Successful demonstration of CARS microscopy using the novel SCOPA light source.
• Acquisition of fundamental and overtone CARS images of polystyrene beads, targeting aromatic C-H stretching modes.
• Obtained CARS image of a C. elegans pharynx, visualizing aliphatic C-H stretching modes.

Conclusions:

• The developed SCOPA-based CARS microscopy system is substantially simpler than conventional setups.
• This simplified approach facilitates coherent delivery of pump and Stokes beams, enhancing imaging efficiency.
• The system's feasibility for label-free chemical imaging of biological samples was validated.