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Optical absorption and fluorescence spectral imaging is performed by using the recently developed fiber-bundle image compression (FIC) technique in which an entire spectral image is collected in a single scan of a charged-coupled device (CCD) detector. Absorption imaging is demonstrated by mapping the optical absorbance of a stained microscopic lily plant stem section. Fluorescence imaging is demonstrated by mapping shifts in the ruby R1 fluorescence line to determine the pressure distribution in a microcrystalline ruby powder squeezed between two diamond surfaces. The advantages and limitations of the FIC method, relative to tunable filter and line imaging techniques, are discussed.

A new technique for rapid Raman imaging and chemical analysis of micro-composites and biomaterials, with potential applications in real-time robotic vision, automated manufacturing, and medical imaging, is described and demonstrated. The key feature of this new instrument is a fiber-optic bundle used to compress two-dimensional images onto a one-dimensional fiber stack, which serves as the entrance slit of an imaging optical spectrograph. Thus a complete Raman spectrum is simultaneously collected from every point within a sample in a single scan of a charge-coupled-device (CCD) detector. The method is demonstrated by using Raman imaging of a microscopic mixed-salt sample. Its efficiency relative to alternative Raman imaging methods is quantitatively evaluated, and potential applications in other spectral imaging measurements are discussed. Index Headings: Raman spectroscopy; Spectral imaging; Chemical imaging; Fiber optics; Chemical sensor.

A Raman probe was set up with optical fibers and a graded refractive index (GRIN) lens. It was found that the Raman background arising from optical fiber was spatially dependent, while normal Raman (NR) scattering, surface-enhanced Raman scattering (SERS), and surface-enhanced resonance Raman scattering (SERRS) were spatially independent. Spatial optimization was carried out to minimize the background interference of the optical fiber Raman probe with the use of benzoic acid as a test sample. The best configuration of the probe could also be applied to both SERS and SERRS. SER spectra of p-nitrophenol (1.0 × 10−3 M) and SERR spectra of methyl red (1.0 × 10−6 M) were obtained with the use of this probe to check its performance.