Fiber laser system for standoff coherent Raman spectroscopy

Area of Science:

• Optics and Photonics
• Spectroscopy
• Chemical Sensing

Background:

• Coherent anti-Stokes Raman scattering (CARS) is a powerful spectroscopic technique for molecular identification.
• Traditional CARS systems can be bulky and complex, limiting their field applicability.
• Standoff detection requires robust and portable instrumentation capable of analyzing targets from a distance.

Purpose of the Study:

• To present a compact fiber laser system for standoff detection of chemical and biological species.
• To demonstrate the system's capability in acquiring high-resolution Raman spectra for identification.
• To assess the system's performance at relevant standoff distances and integration times.

Main Methods:

• Utilizing an ytterbium fiber laser and a hollow-core photonic crystal fiber to generate broadband pump/Stokes pulses for CARS.
• Acquiring high-resolution Raman spectra in the fingerprint region (600-1600 cm⁻¹) for target analytes.
• Operating the system at standoff distances of 2 meters with integration times of 8 milliseconds.

Main Results:

• Successful acquisition of high-resolution Raman spectra for toluene, dimethyl methylphosphonate, and sodium dipicolinate.
• Demonstration of effective spectral fingerprinting for identification of chemical and biological simulants.
• Validation of the system's performance at a 2-meter standoff distance with rapid 8 ms integration times.

Conclusions:

• The developed fiber laser system offers a compact and effective solution for standoff detection and identification.
• Fiber laser technology facilitates the implementation of portable CARS systems for real-world applications.
• The system's ability to rapidly acquire detailed spectral information enhances security and safety protocols.