Fabrication of molded chalcogenide-glass lens for thermal imaging applications.

With the recent development of less costly uncooled detector technology, expensive optics are among the remaining significant cost drivers. As a potential solution to this problem, the fabrication of IR lenses using chalcogenide glass has been studied in recent years. We report on the fabrication of a molded chalcogenide-glass lens for car night vision and on the evaluation of the lens. The moldability of chalcogenide glass was characterized through transcription properties of the mold's surface. In addition, both IR transmittance and x-ray diffraction patterns of the molded chalcogenide-glass lens were evaluated to verify the compositional and structural stability of the glass material under the given molding conditions.

Photoluminescence of ZnO in metal ion exchanged zeolite Y.

The photoluminescence of nano-sized ZnO in metal-ion-exchanged zeolite Y (ZnO/M-FAU, M = Na, Ca, Er) was investigated. ZnO/M-FAU was prepared by exposing Er(3+)- or Ca(2+)-exchanged Na-FAU to Zn vapor and to air at 723 K. The ZnO formation in the M-FAU showed a change in intensity in the (220), (311) and (331) lines, but no indication of ZnO peaks. In the EDXS and ICPAES analyses, it was found that the molar ratio of Zn/Si was linearly related to the exchanged amount of metal ions, and that the slope of the Zn/Si to the metal/Si was in the order of ZnO/Na-FAU < ZnO/CaNa-FAU < ZnO/ErNa-FAU. In the photoluminescence spectra of all the ZnO/M-FAU samples, peaks were observed at around 380 nm (3.2 eV) and 530 nm (2.5 eV) of ZnO. In ZnO/ErNa-FAU sample, the reabsorption of Er3+ at 520 nm and its emission at 650 nm were observed at the 530 nm peak of ZnO, which can be explained in terms of the interaction of ZnO with Er3+ in the FAU. In the case of ZnO/CaNa-FAU, the peak at around 380 nm was broaden to a longer wavelength, which is supposed to have been caused by emission peak of (CaO)x(ZnO)y. In addition, there were some indications of interaction between Na+ ZnO in ZnO/Na-FAU and the ZnO that was doped with Na+. From the result, it is suggested that ZnO particles were formed in the cavities that interacted with the ions in the zeolites.

Effect of temperature on the molding of chalcogenide glass lenses for infrared imaging applications.

We examine the effect of temperature on the molding of chalcogenide glass for infrared (IR) lens fabrication and evaluate a molded chalcogenide glass lens. Both the adhesion of the chalcogenide glass to the mold's surface and lens breakage depended on the initial heating temperature and on the molding temperatures in the glass molding process. In addition, the molded chalcogenide glass lens was evaluated based on transcription characteristics of the mold's surface, IR transmittance, and x-ray diffraction patterns. From the analysis results, we verified that the chalcogenide glass lens for IR imaging application could be fabricated by well-controlled temperature conditions.