Spectroscopy on Vertical Microcavities for the Mid-Infrared

Abstract

Mid-infrared microcavities from IV-VI semiconductors (lead salts) are investigated by infrared transmission measurements. Epitaxial Pb 1--x Eu x Te/EuTe multilayers with an refractive index contrast of more than 80% are used as Bragg interference mirrors with a very large mirror stop band width. Therefore, the polarization splitting of cavity modes which are strongly detuned in respect to the center of the mirror stop band can by studied. It is found to show a quadratic dependence as function of the detuning energy. Furthermore, by inspecting the ratio between the width and the height of cavity resonances, the absorption edge of ordered, self-organized PbSe quantum dots is clearly detected.