CARS Signal Optimization With Convergence Compensation in Thermometry

Femtosecond chirped probe pulse (CPP) CARS technology is recognized for its non-interference, high precision, and time resolution, making it a potent tool for measuring temperature in complex combustion scenarios. However, the signal quality can be compromised by self-focusing and chromatic aberration effects. This letter proposes that multi-pulse modulation with lens combination is beneficial to optimize phase matching of focal spot intersections and increase the intensity utilization of the pulses. The study suggests using multi-pulse modulation with lens combination to enhance phase matching and pulse intensity utilization, so as to improve the signal strength by an order of magnitude. This method successfully measures temperatures in high-temperature turbulent flames at 698 K and 1394 K, offering an effective strategy for boosting CARS signal intensity and temperature measurement speed.