Photothermal deflection spectroscopy of chalcogenide glasses

Abstract

Photothermal deflection spectroscopy has been applied to optical absorption measurements in As 2 S 3 , Se, and As-S glasses. The spectroscopic method is demonstrated to be suitable for evaluation of small absorption in thin samples, while its accuracy is affected by light scattering. For As 2 S 3 , as-evaporated films give higher residual absorption than those of the bulk. In the As-S system, As 2 S 3 shows the most prominent weak absorption tail, and As 17 S 83 exhibits a peculiar spectrum. The origins of these features are discussed.

Two-photon absorption spectroscopy of As2S3 glass

“…In contrast, ␣ smaller than ϳ1/5 cm Ϫ1 (ប р1.9 eV) could not be evaluated accurately, since the longest sample employed in the present experiment was 5 cm. Accordingly, ␣ was evaluated using photothermal deflection spectroscopy, 26 the result being consistent with that reported for As 2 S 3 optical fibers. 19 Figure 1 shows typical light pulses obtained with ͑a͒ infrared light ͑ប ϭ1.17 eV and I 0 ϭ430 MW/cm 2 ͒ and ͑b͒ subgap light ͑2.16 eV and 82 MW/cm 2 ͒.…”

“…This energy is roughly the same with the characteristic energy of the weakabsorption tail, 200-300 meV, 3 which appears at around ប Ϸ1.5 eV, the actual shape in the present sample being shown by the dashed line. 26 This approximate coincidence implies that the two-photon absorption process in As 2 S 3 is governed by the states which give rise to the absorption tail. The process is probably resonantly enhanced by the states, 23 for which theoretical calculations including transition probabilities remain.…”

Two-photon optical absorption in amorphous materials

“…2 shows the two-photon absorption spectrum for As 2 S 3 , with a one-photon spectrum replotted from Ref. [23]. Note that the two spectra are obtained for samples prepared from a single ingot, so that a reliable comparison can be made.…”

Optical properties and applications of chalcogenide glasses: a review

“…The absorption coefficient and the band gap can be calculated using the transmission data. Photothermal deflection spectroscopy (PDS) has been used [10] to measure low optical absorption coefficients of chalcogenide glasses in the form of thick samples as well as films. PDS has been applied to optical absorption measurements in, for example, As 2 S 3 and As-S glasses [10].…”