tance between them can be controlled by the parameters of the extrusion process. The possibility of obtaining strictly ordered structures is especially important for the IR wave guide applications of the composite.
We studied the optical properties of the composite. It was concluded that the films are opaque in visible light. Transparency of the films increases dramatically as the wavelength increases and reaches 89.3 % in the far-IR (at 25 lm wavelength).
It can be seen (Fig. 2) that the non-oriented structure is highly transparent in the broad middle-and far-IR bands of the spectrum. The peaks seen on the spectrum are inherent for polyethylene. IR light scattering by the spherical glass particles makes diffuser applications of the composite possible. The films were successfully used as laser shaping diffusers that smooth and homogenize laser sources and provide uniform light.
The films with oriented structure show distinct polarization properties in the far IR. Films of 100 lm in thickness demonstrated 80 % polarization at 10.6 lm wavelength. At the same time the transparency of the oriented films is not yet satisfactory. We concentrate our efforts on the improvement of this parameter.
The optical properties of composites of high percentage (near 40 %) of chalcogenide glass are of greatest interest. It can be seen (Fig. 3) that a high percentage of chalcogenide glass makes the composite opaque not only to visible light but to the near-and middle-IR (partially) as well. At the same time the composite is highly transparent in the far-IR. Such properties make the composite especially suitable as the filtering elements of detector units.
Optical measurements have given conclusive evidence that the controlled structure of composite obtained by varying the extrusion parameters gives rise to controlled IR optical properties, and that the requirements of various IR-optics applications can be met.
Our work has demonstrated that the new composites based on polyethylene and chalcogenide glasses offer promising optical properties. The composites under investigation can be made into flexible films that have controlled structure: from spherical particles of chalcogenide glass of 1±2 lm dispersed in a polymer matrix, to highly oriented structures. Oriented films demonstrate pronounced polarization properties in the far-IR. Such oriented films can be used as IR polarizers, waveguides, and immersion materials. Effective flexible optical filters transparent in IR and opaque in the UV and visible bands of the spectrum could be based on such composites.