Development of a time-gated system for Raman spectroscopy of biological samples

Abstract

A time gating system has been constructed that is capable of recording high quality Raman spectra of highly fluorescing biological samples while operating below the photodamage threshold. Using a collinear gating geometry and careful attention to power conservation, we have achieved all-optical switching with a one picosecond gating time and 5% peak gating efficiency. The energy per pulse in this instrument is more than 3 orders of magnitude weaker than previous reports. Using this system we have performed proof-of-concept experiments on a sample composed of perylene dissolved in toluene, and the stem of a Jasminum multiflorum plant, the latter case being particularly important for the study of plants used in production of cellulosic biofuels. In both cases, a high SNR spectrum of the high-wavenumber region of the spectrum was recorded in the presence of an overwhelming fluorescence background.

Raman difference spectroscopy: a non-invasive method for identification of oral squamous cell carcinoma

“…Recent efforts have been made to remove the underlying fluorescence background from the spectral data in an effective manner and adequate Raman instrumental systems or data processing regimes have been introduced. Computational approaches primarily focus on the polynomial fit method or Fourier transformation of the acquired data [50][51][52], whereas time-resolved Raman spectroscopy and polarization modulation have been described in literature regarding instrumental approaches [53,54].…”

Microspectroscopy as applied to the study of wood molecular structure

“…Some 10 years ago, a fluorescence rejection device was developed (Everall et al 2001;Matousek et al 1999Matousek et al , 2001, which effectively suppresses fluorescence background of biological samples (Knorr et al 2010). This instrument is based on a high throughput optical Kerr shutter separating Raman light from fluorescence in the time domain.…”

Label‐Free Molecular Imaging of Biological Cells and Tissues by Linear and Nonlinear Raman Spectroscopic Approaches

“…Data collection approaches for background corrections include time gating to separate the rapid Raman scattering from the slower fluorescence, [15] shifted subtracted Raman spectroscopy (SSRS), [16] shifted excitation Raman difference spectroscopy (SERDS), [17] and multi-excitation Raman spectroscopy. Thef requently used wavelength of 785 nm offers ac ompromise between low fluorescence,r easonable Raman scattering intensities,a nd quantum efficiency of CCD detectors.However,even with 785 nm excitation, the fluorescence background from some samples still interferes.Data processing methods have been developed to correct fluorescence background variations (see Section 1.3).…”