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In recent years there has
been a sharp increase in the number and form of analyses to which
Raman spectroscopy has been applied. The introduction of small
bench-top spectrometer systems has certainly opened up the fields of
study. However, on the back of the renewed interest in the Raman
technique, ever more demanding applications have arisen.
For this reason the next
generation of Research grade instruments incorporate much of the
cutting edge technology found in the bench-top systems, but also
provide the higher performance required for samples which prove
difficult or impossible to analyse with more routine instrumentation.
The T64000 system is
designed to provide a versatile platform for Raman analysis. It has
an integrated triple spectrometer design for unprecedented optical
stability. The instrument incorporates the proven technology of the
confocal LabRam Raman microprobe. The mechanical coupling is rigid
and stable. The optical coupling is efficient and throughput is
limited only by theoretical considerations.
High stray light rejection
Holographic notch filter
technology provides a very good solution to laser rejection for
visible wavelengths in many applications.
However, there are
acknowledged limitations to the use of these filters for work close
in to the laser line. Even with specially developed low frequency
accessories(4) with many difficult samples it is still often
impossible to obtain reliable data at 10 , 20 or 30 cm-1.
In using the double
subtractive configuration of the T64000, it is possible to obtain
spectral information very close in to the laser line. The subtractive
mode is ideal for studying such detail as LA modes in polymer systems
and crystal lattice modes.

Spectrum of a proprietary
SiGe material in which it is possible to observe spectral bands down
as low as 4 cm-1.
Ultra high resolution
With the use of the
ultra-high resolution triple
additive configuration
of the T64000 triple system, it is possible to very accurately study
the position of Raman bands.
This is of particular
importance for the measurements of stress in semiconductor materials
such as GaN, SiC and diamond where stress induced shifts in the order
of 0.1 cm-1 are often studied. The high resolution also offers the
level of accuracy required for the authentication and certification
of materials for Raman standards.

Raman analysis of stressed
GaN in the solid phase. Identification of shifts in the Raman
spectral features in the order of 0.2 cm-1 are observed.
Below shows the difference
in spectral resolution between a single spectrometer and that of the
triple additive mode. It can be clearly seen that for such
applications it is necessary to acquire the data at a high resolution
not achievable with a small focal length single spectrometer.


Single spectrometer technology
With the final mode of
operation, the direct spectrograph entrance,
the system can be used with holographic notch filter technology and
as a more conventional single spectrometer based system. The high
throughput of the large optical components means that it is then
ideal for Raman mapping and even remote probe forms of analysis.

Raman Mapped image of
Stressed Silicon interface using Single direct path operation.
Summary
The list of applications
to which the T64000 can be applied is impressive including, thin
films, solid state devices, biological chemistry and techniques such
as UV, resonance Raman, PL and laser fluorescence.
In Summary, for demanding
applications and work which requires high laser rejection, high
spectral resolution and the obvious advantages of a continuously
variable laser filter, the triple spectrometer system is an
invaluable tool. With the introduction of the latest technology from
the smaller bench-top systems it can also be applied to more general
routine analysis. The T64000 heralds a new era for new and more
versatile high grade research Raman instrumentation.
Click
here for further specifications
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