Facilities‎ > ‎

microRaman Laboratory

Labram Aramis Jobin Yvon Horiba microRaman system:

The LabRAM Aramis is an integrated confocal microRaman system. The confocal microscope is coupled to a 460mm-focal length spectrograph equipped with a PC-controlled four interchangeable gratings-turret. The different excitation wavelengths (532 and 633 nm) are supplied by two internal lasers and eventually by an external additional laser. In the range between 450 nm and 850 nm, the wavenumber accuracy is ±1 cm-1 with the 1800 l/mm grating.

Technique description:

Raman spectroscopy is a non-destructive analysis technique that can be used to identify the chemical bonding of different materials and identify their molecular symmetry. Raman spectroscopy works by illuminating a sample with the monochromatic light of a laser and analyzing the spectral shift of the incident light as diffused from the sample. For investigation of small areas, the laser can be passed through an optical microscope, thus reducing the sample area. This technique is generally referred to as micro-Raman. On the incoming path, the laser beam is reflected towards the microscope by the means of special spectral filter, used in injection/rejection mode. On the return path to the spectrograph, the Raman back-scattered light is fully transmitted through the filter towards the confocal slit-hole located at the entrance of the spectrograph. The spectrograph disperses the polychromatic Raman signal onto the CCD multichannel detector.

Technical Data:

 Laser sources  He-Ne 632.8 nm
 DPSS 532 nm
 Drop off stokes edge  <150 cm-1
 Coupling options  Point-mode
 Spectral range  450 – 850 nm
 Spectrograph  450 mm focal length
 Gratings  Turret: 300 l/mm, 600 l/mm, 1200 l/mm, 1800 l/mm
 Standard objectives  10X, 50X, 100X
 Detector  Air-cooled CCD 1024*256 VIS

Figure 1: microRaman system