title: Sequentially shifted excitation Raman spectroscopy: novel algorithm and instrumentation for fluorescence-free Raman spectroscopy in spectral space.
abstract: A novel Raman spectrometer is presented in a handheld format. The spectrometer utilizes a temperature-controlled, distributed Bragg reflector diode laser, which allows the instrument to operate in a sequentially shifted excitation mode to eliminate fluorescence backgrounds, fixed pattern noise, and room lights, while keeping the Raman data in true spectral space. The cost-efficient design of the instrument allows rapid acquisition of shifted excitation data with a shift time penalty of less than 2 s. The Raman data are extracted from the shifted excitation spectra using a novel algorithm that is typically three orders of magnitude faster than conventional shifted-excitation algorithms operating in spectral space. The superiority of the instrument and algorithm in terms of background removal and signal-to-noise ratio is demonstrated by comparison to FT-Raman, standard deviation spectra, shifted excitation Raman difference spectroscopy (SERDS), and conventional multiple-shift excitation methods.
authors.affiliation: Department of Chemistry, Old Dominion University, Norfolk, VA 23529, USA. jcooper@odu.edu
authors.forename: John B
authors.initials: JB
authors.lastname: Cooper
authors.forename: Mohamed
authors.initials: M
authors.lastname: Abdelkader
authors.forename: Kent L
authors.initials: KL
authors.lastname: Wise