The Labram system is a confocal Raman imaging microscope system. Raman spectroscopy is a spectroscopic technique used to study vibrational, rotational, and other low-frequency modes in a system. It relies on inelastic scattering, or Raman scattering, of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range. The laser light interacts with phonons or other excitations in the system, resulting in the energy of the laser photons being shifted up or down. The shift in energy gives information about the phonon modes in the system. Infrared spectroscopy yields similar, but complementary, information.
Instruments S.A. (Jobin Yvon) LabRam 1B
Both Helium-Neon (632.8nm, 11mW) and Argon ion (514.5nm, 50mW) are available as sources. Both are polarised, enabling measurement of depolarisation ratios and studies of orientation in materials. Light is imaged to a diffraction limited spot (typically 1 micron) via the objective of an Olympus BX40 microscope. The scattered light is collected by the objective in a confocal geometry, and is dispersed onto an air cooled CCD array by one of two interchangeable gratings, 1800 lines/mm or 600lines/nm, allowing the range from 150cm-1 to 4000cm-1 to be covered in a single image, or with greater resolution in a combination of images. With the former, a spectral dispersion of 1cm-1 per pixel is achievable. The confocal, microscopic system allows measurement of powdered samples with no further sample preparation, direct measurement of liquids and solutions, as well as thin films. Spectral X-Y mapping may be performed with a precision of 0.1 micrometers. The system is furthermore equipped with a remote head which is fibre coupled to the spectrometer.