Deep UV Raman Spectrometer
The DUV Raman PL 200 is a more traditional, but still miniature, deep UV Raman and fluorescence spectrograph employing a TE cooled back thinned, back illuminated CCD array detector.
Key Features
- 248.6nm Excitation, Random Polarisation: Raman signatures insensitive to polarisation of target materials
- Spectrograph: 200 mm Czerny Turner with dual computer controlled 3600 g/mm (Raman) and 300, 600 or 1200 g/mm (fluorescence) holographic gratings
- Raman Resolution: <8 cm-1, 60 µm slit
- Detector: 3 stage TE cooled, back illuminated UV CCD array
A major driving motivation for deep UV Raman methods is avoidance of fluorescence obscuration or interference with Raman spectral emissions.
A second driving motivation for the DUV Raman PL 200 is the ability to detect both Raman and fluorescence emission, which provide different but complementary information about a targeted material. Raman provides information about molecular resonances while fluorescence provides information about overall electronic configuration for a material.
A third driving motivation is the ability to detect & map biological material, which is not possible with 1064 nm, 785 nm, or 532 nm Raman methods.
Deep UV excited Raman & photoluminescence spectroscopy is an emerging analytical instrument technology with vast potential for a wide range of commercial, industrial, and research applications. A major limitation of Raman spectroscopy conducted in the near UV, visible, or near IR is obscuration or interference of the Raman signals due to background fluorescence from the analyte or its background or surroundings within the laser beam interrogation spot. This interference limits the types of materials and compositions or backgrounds for which Raman spectroscopy is useful.
Autofluorescence is a phenomenon which does not occur below about 270 nm for the vast majority of materials, independent of excitation wavelength. Raman, on the other hand, is dependent on excitation wavelength and when excitation occurs below 250 nm, there exists a spectral region within which to observe over 3000 cm-1 of Raman shifted emissions without obscuration or interference from fluorescence.
The DUV Raman PL 200 provides most of the benefits capability of deep UV Raman and fluorescence systems costing 5 times more and drawing 10kW or more. Raman resolution is 8 cm-1. Fluorescence resolution is 1.2 nm.
This instrument is available in three configurations:
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- H1 Basic Instrument includes a standard XYZ manual translation stage and context camera.
- H2 Scan Instrument includes a motorized XY with manual Z stage with mapping function and context camera.
- H3 Liquids Instrument includes a cuvette holder for liquids analysis.
In addition, this instrument has options for LN2 and LHe sample cooling stages.
Raman Data That Can Be Correlated to SHERLOC
The Mars 2020 SHERLOC instrument is headed to Jezzero crater in 2020 to search for signatures of life. It is a highly advanced deep UV fluorescence and Raman spectrometer that can withstand the Mars environement and capable of generating chemical and organic maps within a mineral matrix with a mapping field of view of ~1 cm2 .
Integration of an XZY mapping stage and microscopic imager to the DUV Raman PL 200 enables the acquisition of chemical and organics maps on a mineral matrix in a similar manner to SHERLOC, using the same laser employed in SHERLOC and providing mapping over 25 cm2. As such, the Raman PL 200 is uniquely capable of generating data that can be correlated to SHERLOC, unlike any commercially available Raman instrument on the market.