Traditional drug detection technique is highly accurate but time consuming and labor intensive. Raman spectroscopy (RS) is a fast and non-destructive detection technique that provides detailed information on chemical composition, phase and morphology, crystallinity and molecular interaction of the sample. The current Raman spectrometer is mainly based on the use of Gaussian light, providing with good signal to noise ratio for a thin or transparent sample. However, owing to the scattering effect, the Gaussian beam will become diffuse in the scattering medium. This makes it not conducive to in vivo or deep imaging. Utilizing the long focusing characteristics and self-reconstructing properties of Bessel beam, we here presented a new scheme for RS, which used a Bessel beam as the excitation light. The Bessel beam-based RS was first verified with the standard samples, and then comparatively tested on several drugs. Taking the acetaminophen as the test sample, we compared the Bessel beam-based RS with the traditional Gaussian beam based one with or without a scattering medium. With the addition of a scattering medium, the signal-to-noise ratio of Raman spectra based on Bessel beam decreases less than that based on the Gaussian light, which demonstrated the great potential of the use of Bessel beam in in vivo or deep RS. This study provides great value for in vivo applications of Raman spectroscopy.
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