Constantes optiques des halogénures de césium a basses températures dans l'infrarouge lointain

Cesium Iodide (Csl)

“…The term (1 + k2/rt 2) is negligible except when close to the resonance on the high-frequency side. The two models used in the reflectivity analysis [4,5] give n and k values that can differ by up to 50%. The thinnest crystal used in Ref.…”

“…These results show k to be fairly smooth below the resonance, but Love et al's accurate low-temperature measurements on KI crystals up to 10 cm long [11] show that two-phonon structure can be observed in these materials. The Kramers-Kronig values [4] are tabulated, since they are more directly obtained, but these are supplemented with Lorentz-model values [5] in the wings. [3] did not transmit between 56cm -1 and 94 cm -1.…”

“…In the wide transparent region from 67/~m (150cm -~) to 0.25/~m (40,000 cm-1), Li [6] has tabulated very accurate values of n. Starting with the 297 K data of Rodney [7], which Li reduced to 293 K, and using the infrared absorption peak at 161.29/~m (detailed earlier [4]), together with the seven known absorption peaks in the vacuum ultraviolet, Li where 2 is in/~m. Values from Eq.…”

Cesium Bromide (CsBr)

“…Vergnat et al [10] found refractive indices and extinction coefficients for the Cs halides at 290, 80, and 25 K from analysis of reflection measurements in the 200 to 1000/xm spectral region. Their static value for n at 290 K was 2.56, which equals Dianov and Irisova's 2-mm interferometric value at 300 K. The CsBr sample used was a single crystal.…”