Tilted Two-Dimensional Array Multifocus Confocal Raman Microspectroscopy

Abstract

A simple and efficient two-dimensional multi focus confocal Raman microspectroscopy featuring the tilted array, technique is demonstrated. Raman scattering from a 4 X 4 square foci array passing through a 4 X 4 confocal pinhole array is tilted with a periscope. The tilted array of Raman scattering signals is dispersed by an imaging spectrograph onto a CCD detector, giving 16 independent Raman spectra formed as 16 bands with different heights on the sensor. Use of a state-of-theart imaging spectrograph enables high-precision wavenumber duplicability of the 16 spectra. This high duplicability makes the simultaneously obtained spectra endurable for multivariate spectral analyses, which is demonstrated by a singular value decomposition analysis for Raman spectra of liquid indene. Although the present implementation attains only 16 measurement points, the number of points can be extended to larger than 100 without any technical leaps. Limit of patallelization depends on the interval of measurement points as Well as the performance of the optical system. Criteria for finding the maximum feasible number are discussed.