Development of new near-infrared filters based on the "sandwich" polymer-chalcogenide glass-polymer composites

A new generation of filters are presented that are ideal for blocking visible light while passing near-infrared radiation. These filters are based on the novel use of selenium-based chalcogenide glasses with a low softening point on the one hand, and thermoplastic polymers on the other hand. A technology was developed that allows "sandwich" structures to be obtained, which include thin layers of polymers and chalcogenide glasses. The technology permits the cutoff edge of filters to be controlled with high accuracy, This can be done either by varying components of the "sandwich" or by varying the thickness of the chalcogenide glass layer.