A multi-object spectral imaging instrument (Vol. 44 No. 6)

Fluorescent microbeads are tracked using a camera. A series of slits displayed on a DMD deflect light into a spectrometer and are updated to follow the microbeads. Spectra are obtained in real time from a CCD image of the slits after dispersion from a prism.

Imaging spectrometers acquire three-dimensional spectral data cubes (x, y, λ) to enable chemical imaging in fields ranging from microscopy and biomedicine to remote sensing. Traditional systems, employing time-sequential recording of the complete data cube, cannot record time-varying phenomena and are optically highly inefficient. Our technique enables spectra to be recorded in real time from a programmable sparse array of spots within a microscope sample. Real-time computer-controlled manipulation of the spot array enables tracking and video-rate spectroscopy of these points with the very high optical efficiency. This is achieved with a digital micro-mirror device (DMD) that deflects light from the sparse multiple points in the sample into a slitless spectrometer consisting of a dispersive prism and CCD camera. We demonstrate real-time spectra of multiple fluorescent microbeads in aqueous solution as they diffuse in the sample.

G. M. Gibson, M. Dienerowitz, P. A. Kelleher, A. R. Harvey and M. J. Padgett, ‘A multi-object spectral Imaging Instrument’, J. Opt. 15, 085302 (2013)