Piezomodulation spectroscopy

The second approach is to use low temperature piezomodulation spectroscopy to obtain a more detailed picture of the electronic spectra. In this case, the low temperature spectrum of PTS, which is known to show excitonic interaction, is studied. 

Another approach to the investigation of the intermolecular polariton coupling, as well as to the effects of strain, is piezomodulation spectroscopy. In this experiment a periodic uniaxial stress, within the elastic regime, is applied to the sample and the optical signal is detected synchronously with the stress. The measurement can yield information on the coupling, the strain dependence of the spectra, and more extensively resolved structure (12). Because of sample size and stability, PTS was studied by piezomodulation spectroscopy at low temperature. 

Modulation spectroscopy deals with the measurement and interpretation of changes in the optical spectra when modifying the measurement conditions. This can be achieved by applying an oscillatory perturbation such as an electric (EA) or magnetic field, heat pulse (thermomodulation) or stress (piezomodulation). Since electroluminescent diodes are operated by the application of an external electric field, EA is a particularly pertinent and powerful type of spectroscopy for the study of these devices. 

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