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Low Energy Optics
During the past few years, we have developed various techniques to investigate
the frequency dependent conductivity and dielectric constant of (mainly)
highly conducting materials over broad frequency range. The focus of
our technique development effort is on the low frequency response, at
frequencies below what conventional optical methods cover. Various resonant
cavities enclosed, and composite resonators with high quality factors
have been designed and built in the microwave and millimeter wave spectral
range, operating at various frequencies between 2.5 and 150 GHz, where
resonant techniques are necessary to investigate the perturbation due
to the specimens. Various configurations are employed and these depend
on the sample geometry and measurement frequency among other factors.
A so-called coherent source spectrometer, based on semiconductor and
on Backward Wave Oscillator (BWO) sources and on a quasioptical arrangement
has recently been constructed. We have acquired a range of Impatt oscillators
in the 2 - 7 cm-1 range, while external magnetic field driven BWO sources
cover the entire submillimeter wave range up to 25 cm-1. A few years
ago, we have also acquired a Bruker IFS 113v Fourier Transform spectrometer
which operates from 15 to 5500 cm-1.
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Conventional optics
In the UV and visible, a Beckman Coulter DU 640 Spectrophotometer is
used. This is complemented by a Perkin Elmer IR spectrometer. A Bruker
IFS 113v Fourier Transform spectrometer operates from 15 to 5500 cm-1
spectral range.
