Group Laboratories
Raman Lab
The Raman Laboratory has a Jobin Yvon T64000 triple spectrometer, with macro and
microscope entraces, plus an additional entrance to the spectrometer via a notch filter.
With three grating sets and two entrance set ups we are able
to perform optical studies between 250 and 1500 nm. Two different detectors are available,
an open electrode CCD for the UV and visible range and an InGaAs diode array for the
near infrared. A motorized table allows automatic mappings, line scannings or signal
variations in depth. A galvanometric linescanning can provide the complete spectra of
a line by using the second dimension of the CCD, i.e. a collection of 512 spectra can be
taken at the time. A micro-cryostat from Cryovac allows the low-temperature measurements
at the Raman system.
Two lasers supply different monochromatic wavelengths to the Raman Lab
or any other system by means of optical fibers. The Spectrum 70 is a laser with a
Kr and Ar mixture to provide several colors in the visible range from the violet
to the red. The SABRE is an Argon laser with 30 W of total power (6 W in the UV),
and the typical lines of the Argon. This laser has a deep UV line at 275 nm. An UV
prism monochromator at the exit of the laser eliminates the plasma lines. We have two
additional laser diodes. A low-price 532 nm laser and a YAG laser with spectroscopic
quality, this last to perform Raman measurements in the near infrared region.
Optical constants
In this laboratory we can carry on optical measurements (transmission, reflectance,
photoluminescence, etc) in the optical range from 180 to 2500 nm. The set up consists
of a simple spectrometer TRIAX 190 with three gratings, spectral lamps (deuterium,
mercury or halogen) and different detectors (back-illuminated CCD, a nitrogen cooled
InGaAs detector, an avalanche silicon photodiode or a two-Peltier stated PbS cell) to
cover the mentioned spectral range. A closed-cycle cryostat allows us to perform measurements
between 6 and 300 K. A high temperature cell allows to extend the range of optical or
photo-transport measurements to 1500 degrees Centigrades.
Magneto-optics
The magnetic field lab is equipped with a 14 T magnet of Cryogenic Ltd.,
with optical access. The temperature in the sample cryostat ranges from 2 to 300 K.
For transport measurements we use a switching system and
a software program to carry on electrical measurements as a function of temperature
or magnetic field automatically.
For the magnetooptics we are installing a simple spectrometer with 800 mm focal length
equipped with a CCD and a notch filter.
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