Impurity induced far infrared absorption of CsI crystals

IMPURITY [NDUCED FAR INFRARED ABSORPTION OF CsI CRYSTALS L.GENZEL, W. PRETTL and E.SIEP

In perfect alkali halide crystals only the transverse optic phonons of zero wave vector absorb far infrared radiation in first order. The introduction of impurities in the lattice removes the translational invariance and almost all phonons become optically active. In addition to the absorption at the reststrahlen frequency, impurity induced absorption appears in the phonon band region and somet...

FAR INFRARED ABSORPTION OF CsBr AND CsI CRYSTALS DOPED WITH OH- AND OD- W. PRETTL and E. SIEP

Alkali halide crystals doped with OHand ODions exhibit in the spectral range above the two phonon absorption of the fundamental lattice vibrations (200 500 cm-l) several absorption lines, which are explained as transitions between librational levels of the OHand ODion respectively [1,2]. The fundamental librational frequency occurs at about 300 cm-l for OHand 220 cm-l for OD-. This isotope shif...

FAR-INFRARED ABSORPTION DUE TO IMPURITIES IN CsBr CRYSTALS

Far-Infrared Blocked Impurity Band Detector Development

DRS Sensors & Targeting Systems, supported by detector materials supplier Lawrence Semiconductor Research Laboratory, is developing far-infrared detectors jointly with NASA Langley under the Far-IR Detector Technology Advancement Partnership (FIDTAP). The detectors are intended for spectral characterization of the Earth’s energy budget from space. During the first year of this effort we have de...

Far-infrared Absorption by Small Particles

Detailed far-infrared (FIR) and mid-infrared (MIR) studies of aluminum small particles have been carried out. MIR absorption studies of clustered and non-clustered samples suggest that the anomalous FIR absorption does not arise from the clustering together of the individual metallic particles. The MIR absorption, which is too small to be the continuation of the anomalous FIR absorption, could ...