Modulated emittance spectroscopy

Abstract

The electronic bandstructure of solids near room temperature has been successfully explored with previous versions of modulation spectroscopy. Modulation of parameters which enter into the bandstructure produce a dielectric function variation. This changes the optical observables, such as reflectance or absorptance. Modulation resonances are observed near singularities in the joint density-of-states function. These resonances must also be detectable in the emittance, an observable which also depends on the dielectric function. Thus, this work investigates the possibility of detection of optical resonances riding on the temperature derivative of the blackbody emission from a solid at high temperature. The modulated emittance was separated from the thermal background by a detection scheme utilizing a CCD and computer. The resonances were not observed because of excessive CCD noise. The existance and magnitude of the resonances was based upon results from other modulation spectroscopies.