Raman Spectrometer Laboratory

Objective

In Geological Material Analysis:
Chemical identification, characterization of molecular structure, effect of bonding, environment and stress
In Chemistry:
Phase identification, Characterization of molecular structure
In biology/medicine:
As a non-invasive diagnostic tool, Biochemical information, Protein conformation
In material science
Material characterization
In physics
Electron phonon interaction
Electronic resonance effect in phonons
Dynamics of fractal network
Behaviour of Acoustic phonon
Surface science
In art
For restoration/conservation
Other fields, where the technique is used extensively
Biosecurity
Display Technologies
Environmental
Food & Beverages
Forensic
Industrial Process
Nanotechnology
Cosmetics
Photovoltaic / Solar Cell

Equipment & Details

RAMAN SPECTROMETER

Excitation source: Argon-Krypton mixed ion gas laser. MODEL 2018 RM (Make Spectra Physics, USA)
Spectrometer: MODEL T64000 (Make Jobin Yvon Horiba, France)
Detector: Thermoelectric cooled front-illuminated 1024 256 CCD. MODEL SynpseTM (Make Jobin Yvon Horiba, France)
Collection Optics: Optical Microscope MODEL BX41 (Make Olympus, Japan)

TECHNICAL SPECIFICATIONS

Basic Configuration Optical Diagram for the Spectrometer

Axial entrance slit
Aberration-corrected holographic grating
Fixed mirror
Intermediate slit
Fixed mirror
Aberration corrected holographic grating
Slit to spectrograph
Manual intermediate slit
Fixed mirror
Aberration corrected holographic grating
Fixed mirror

Round plates: Fixed mirrors

Presently Available Configuration: Single Monochromator Configuration (Double Subtractive Mode)

The double subtractive foremonochromator is used as an tunable filter in the spectral range defined by the scanning mechanism and the gratings. A polychromatic radiation enters the first monochromator through the entrance slit S1 and is dispersed by the grating G1. The exit slit of the first monochromator (entrance slit of the 2nd monochromator) Si1/2 selects a bandpass between l₁ and l₂. The grating G2 in the 2nd monochromator recombines all the dispersed radiations on the exit slit Si2/3 giving again a polychromatic radiation, but limited to only the spectral range between l₁and l₂. The polychromatic radiation selected by the foremonochromator between l₁ and l₂ is dispersed by the grating G3 of the spectrograph. The spectrum is acquired with a multichannel detector which is mounted in the plane of the exit image or with a monochannel detector through an exit slit. See following diagram.

Focal length of the spectrometer for present configuration: 640mm

Low frequency: < 100 cm^-1

Step size: 0.00066 nm (0.03 cm^-1)

Grating: 1800 grooves/mm

Grating efficiency curve

Table for dispersion and resolution

Wavelength of excitation source (nm)	Corresponding wavenumber (cm^-1)	Dispersion (cm^-1/mm)	Total dispersion on CCD chip* (cm^-1)	Dispersion /pixel (cm^-1)**	Resolution (Min. 3 pixels to define a peak) (cm^-1)
400	25000	46.55	1210.3	1.18	3.54
500	20000	27.83	723.58	0.71	2.13
600	16667	17.86	464.36	0.45	1.35
700	14286	11.53	299.78	0.29	0.87

*dimension of the chip 26 mm´26 mm ** CCD format 1024´256

Basic specification for the CCD

CCD format: 1024´256 Front illuminated open electrode CCD

Pixel size: 26 mm´26 mm

Quantum efficiency

Basic specification for the laser

Wavelength and Maximum Power

Wavelength of excitation source (nm)	Laser Power at laser head (mW)	Power on the sample using 10´ objective (mW)
487.986	200	15
514.532	220	15
647.088	220	22

(note: it is only power not power density on the sample)

Collection optics

Visible confocal microscope with X-Y manual mechanical stage

and a revolver equipped with 3 achromatic objectives

10´ visible, NA= 0.25, WD=10.6 mm

50´ visible, NA= 0.75, WD=0.37 mm

100´ visible, NA= 0.90, WD=0.21 mm

Measurements will be carried out at room temperature

PURCHASE SOURCE:

Institute Funding, Year Of Installation September 2011

Sample Details

SAMPLES PREPARATION FOR MEASUREMENTS

Sample Preparation Required: Nil

Please bring a micropipette or a special spatula, if they are required to handle the sample.
VOLATILE SAMPLES ARE STRICTLY PROHIBITED.

POWDERED SAMPLE WILL BE ENTERTAINED ONLY WITH 10´ MICROSCOPE OBJECTIVE.