Filters for ν_2 band of CO_2: monitoring and control of layer deposition

Abstract

Two types of multilayer interference filter are required for temperature sounding the earth's atmosphere. In relation to the 668-cm(-1) nu(2) band of CO(2) these are narrowband (4 cm(-1) wide for the Q branch, 10 cm(-1) for the R branch) or isolation (~60 cm(-1) wide for the complete center of the band). Difficulty in manufacturing the filters for NIMBUS-SCR and -PMR spaceflight has indicated a need for improvement in the monitoring and control of the deposition of layers, and the paper describes a realization of this. The consequent effect on filter performance (utilizing a particular combination of layer materials) is described.

Increments at the Interface between Layers during Infra-red Filter Manufacture

“…The manufacturing status for these items is satisfactory [9] and descriptions of typical performance are given elsewhere [10,11] . ACKNOWLEDGMENTS We are grateful for much stimulation by users of precision infra-red multilayer optical components, particularly those for spaceflight temperaturesounding and for spin-flip laser spectroscopy .…”

Infrared optical coatings for the EarthCARE Multispectral Imager

“…The practical implementation of these requirements necessitated the use of substrate materials with limited opportunity for optical reworking. Hence, meticulous attention during each processing stage was crucial, requiring precision substrate fixtures, deposition plant engineering, high thermal contact conductance, and reproducible operating parameters to control the layer thickness accuracy at the elevated temperatures [6] . All substrate materials were manufactured and supplied by ULO Optics Ltd., UK.…”

Photocatalytic Layer-by-Layer Coatings for Degradation of Acutely Toxic Agents

“…This band is present in an IR-fingerprint of ethylene as the ν 7 band, but may also be a result of chloroethylene present in the vapor. 25 The increase in absorbance at 668 cm -1 is indicative of the ν 2 band of carbon dioxide, 26 suggesting the increasing presence of one of the final products throughout the duration of the test. The conclusion can then be drawn that even in a saturated atmosphere the surface of the titania remains active for at least 30 min.…”