Dual-output fs/ps burst-mode laser for megahertz-rate rotational coherent anti-Stokes Raman scattering

Area of Science:

• Laser Spectroscopy
• Nonlinear Optics
• Physical Chemistry

Background:

• Coherent anti-Stokes Raman scattering (CARS) is a powerful technique for chemical analysis.
• High repetition rates are crucial for increasing CARS signal acquisition speed.
• Existing laser systems have limitations in achieving high-speed, hybrid femtosecond/picosecond operation.

Purpose of the Study:

• To develop a novel burst-mode laser system for hybrid femtosecond/picosecond (fs/ps) rotational coherent anti-Stokes Raman scattering (RCARS).
• To achieve megahertz repetition rates for fs/ps RCARS.
• To demonstrate the system's capability for rapid chemical species detection.

Main Methods:

• Development of a burst-mode laser system utilizing a common femtosecond oscillator.
• Simultaneous generation of time-synchronized 1061 nm (274 fs) and 1064 nm (15.5 ps) pulses.
• Demonstration of two-beam fs/ps RCARS in nitrogen (N2) at a 1 MHz repetition rate.

Main Results:

• The system successfully generated synchronized fs and ps pulses with high peak powers.
• Achieved a 1 MHz repetition rate for fs/ps RCARS, an order of magnitude higher than previous burst-mode systems.
• Obtained a high signal-to-noise ratio (SNR) of 176 in N2 detection at room temperature.

Conclusions:

• The developed burst-mode laser system enables high-repetition-rate fs/ps RCARS.
• This technology significantly advances the speed of CARS-based measurements.
• The system holds potential for rapid, in-situ chemical analysis and diagnostics in various applications.