Abstract

High-speed Raman spectroscopy has become increasingly important for analyzing chemical dynamics in real time. To address the need, rapid-scan Fourier-transform coherent anti-Stokes Raman scattering (FT-CARS) spectroscopy has been developed to realize broadband CARS measurements at a scan rate of more than 20,000 scans/s. However, the detection sensitivity of FT-CARS spectroscopy is inherently low due to the limited number of photons detected during each scan. In this Letter, we show our experimental demonstration of enhanced sensitivity in rapid-scan FT-CARS spectroscopy by heterodyne detection. Specifically, we implemented heterodyne detection by superposing the CARS electric field with an external local oscillator (LO) for their interference. The CARS signal was amplified by simply increasing the power of the LO without the need for increasing the incident power onto the sample. Consequently, we achieved enhancement in signal intensity and the signal-to-noise ratio by factors of 39 and 5, respectively, compared to FT-CARS spectroscopy with homodyne detection. The sensitivity-improved rapid-scan FT-CARS spectroscopy is expected to enable the sensitive real-time observation of chemical dynamics in a broad range of settings, such as combustion engines and live biological cells.

© 2017 Optical Society of America

Highly sensitive Fourier-transform coherent anti-Stokes Raman scattering spectroscopy via genetic algorithm pulse shaping

Matthew Lindley, Julia Gala de Pablo, Ryo Kinegawa, Kotaro Hiramatsu, and Keisuke Goda
Opt. Lett. 46(17) 4320-4323 (2021)

Highly sensitive single-beam heterodyne coherent anti-Stokes Raman scattering

Bernhard von Vacano, Tiago Buckup, and Marcus Motzkus
Opt. Lett. 31(16) 2495-2497 (2006)

Heterodyne coherent anti-Stokes Raman scattering (CARS) imaging

Eric O. Potma, Conor L. Evans, and X. Sunney Xie
Opt. Lett. 31(2) 241-243 (2006)

Fourier-transform coherent anti-Stokes Raman scattering microscopy

Jennifer P. Ogilvie, Emmanuel Beaurepaire, Antigoni Alexandrou, and Manuel Joffre
Opt. Lett. 31(4) 480-482 (2006)

Stimulated Raman scattering microscopy and spectroscopy with a rapid scanning optical delay line

Ruoyu He, Zhiping Liu, Yongkui Xu, Wei Huang, Hong Ma, and Minbiao Ji
Opt. Lett. 42(4) 659-662 (2017)