| Autor: |
McCann PC; Department of Chemistry, The University of Tokyo, Tokyo 113-0033, Japan., Hiramatsu K; Department of Chemistry, The University of Tokyo, Tokyo 113-0033, Japan.; Research Center for Spectrochemistry, The University of Tokyo, Tokyo 113-0033, Japan.; PRESTO, Japan Science and Technology Agency, Saitama 332-0012, Japan., Goda K; Department of Chemistry, The University of Tokyo, Tokyo 113-0033, Japan.; Department of Bioengineering, University of California, Los Angeles, California 90095, United States.; Institute of Technological Sciences, Wuhan University, Wuhan, Hubei 430072, China. |
| Abstrakt: |
Fluorescence-encoded vibrational spectroscopy has become increasingly more popular by virtue of its high chemical specificity and sensitivity. However, current fluorescence-encoded vibrational spectroscopy methods lack sensitivity in the low-frequency region, which if addressed could further enhance their capabilities. Here, we present a method for highly sensitive low-frequency fluorescence-encoded vibrational spectroscopy, termed fluorescence-encoded time-domain coherent Raman spectroscopy (FLETCHERS). By first exciting molecules into vibrationally excited states and then promoting the vibrating molecules to electronic states at varying times, the molecular vibrations can be encoded onto the emitted time-domain fluorescence intensity. We demonstrate the sensitive low-frequency detection capability of FLETCHERS by measuring vibrational spectra in the lower fingerprint region of rhodamine 800 solutions as dilute as 250 nM, which is ∼1000 times more sensitive than conventional vibrational spectroscopy. These results, along with further improvement of the method, open up the prospect of performing single-molecule vibrational spectroscopy in the low-frequency region. |
