Fabrication and evaluation of a dimension-reduction fiberoptic system for chemical imaging applications

A novel system for rapid chemical imaging is described and evaluated. The system operates via single-frame spectroscopic chemical imaging with high spectroscopic resolution using a second-generation dimension-reduction fiberoptic array. Images are focused onto a rectangular array of square close-packed 25 mu m cross-sectional f/2 optical fibers that are drawn into a linear distal array with serpentine ordering. The distal end is then imaged with an f/2 spectrograph equipped with a holographic grating and a gated intensified charge-coupled device (ICCD) camera for analysis. Software is used to extract the spatial/spectral information contained in a single ICCD image and deconvolute it into wavelength-specific univariate reconstructed images or position-specific spectra that span an 86 nm wavelength space using our present grating. A description of the fabrication of the dimension-reduction array is given as well as a zero-order reconstruction of a binary target and single-wavelength image reconstructions of a laser-induced plasma. The system is evaluated for spatial and spectral resolution, throughput, image brightness, resolving power, depth of focus, and channel cross talk. Treatment of the spectroscopic data obtained from the ICCD images for use in potential chemical imaging applications is discussed. (C) 1999 American Institute of Physics. [S0034-6748(99)05106-0].