| Under vibrational strong coupling (VSC) conditions, Rabi splitting coincides with periodic ripples in the Raman background, which are indicative of cavity length. Analytical findings suggest that the frequency of these ripples can estimate cavity length. A proportional relationship exists between the number of periodic peaks and the optical cavity length, providing an indirect measurement method. Although the broadening of mode peaks in the free spectral range (FSR) of Raman spectra introduces systematic errors at the level of 10-2 in cavity length determination, this deviation is significantly below the sensitivity threshold (10-1 level) required for cavity length modulation in VSC detection. Therefore, it does not substantially affect the probing of VSC effects. During VSC measurements, cavity length is calculated concurrently, facilitating in situ detection. Additionally, when the cavity length was fixed, any changes in the cavity contents led to frequency shifts in the FSR mode peaks of the Raman spectrum, enabling real-time monitoring of chemical reaction rates. Research findings revealed that VSC could catalyze the hydrolysis of para-nitrophenyl acetate (PNPA), offering both qualitative and quantitative insights into the reaction process, and significantly enhancing the hydrolysis rate of PNPA by one to two orders of magnitude. These observations have significant implications for detecting molecular reaction processes under VSC conditions. |
