Spectrally-broad coherent anti-Stokes Raman scattering hyper-microscopy utilizing a Stokes supercontinuum pumped at...

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Spectroscopy

Background:

• Coherent anti-Stokes Raman scattering (CARS) microscopy is a powerful label-free imaging technique.
• Traditional CARS microscopy often requires complex setups and multiple lasers.
• Expanding the accessible vibrational frequency range is crucial for comprehensive molecular analysis.

Purpose of the Study:

• To demonstrate a simplified spectral-focusing based CARS (SF-CARS) hyper-microscopy system.
• To achieve broad vibrational frequency probing using a single laser source.
• To reduce instrumental complexity for multimodal CARS microscopy.

Main Methods:

• Utilized a single Ti:Sapphire femtosecond laser operating at 800 nm.
• Employed a commercial supercontinuum-generating fiber module.
• Generated a broad Stokes supercontinuum by power tuning the fiber module with long/chirped pump pulses.

Main Results:

• Achieved probing of vibrational frequencies from 630 cm⁻¹ to 3250 cm⁻¹.
• Generated a Stokes supercontinuum with significant spectral power between 800 nm and 940 nm.
• Enabled convenient access to lower vibrational frequencies in the fingerprint spectral region.

Conclusions:

• The developed SF-CARS hyper-microscopy system simplifies multimodal CARS microscopy.
• The approach expands the spectral capabilities of established SF-CARS techniques.
• This method offers a more accessible and versatile tool for vibrational spectroscopy.