New photorefractive polymer composities highly sensitive at 1500 nm

Polymeric photorefractive materials have attracted much attention over the past decade due to their potential applications, especially for optical information processing. However, their practical use has until now been limited, the available photosensitizers being efficient only in the visible range. Here, the chemical development and optical investigations of a photorefractive polymeric material active at 1500 nm are described. To our knowledge, this is the first such material to be reported. A conjugated poly[(ethynediyl)(arylene)(ethynediyl)silylene] acts as both an optical chromophore, as well as charge generator and conductor. Its absorption band tails into the near-IR hence providing charge generation at the 1500 nm excitation. The photoconductivity of the composite samples was measured with a dc-method using a 1500 nm diode laser source. The electro-optical coefficient was measured with a simple reflection technique. The photorefractive response was investigated with a two-beam coupling technique. The gain of the probe beam intensity, delivered from the pumping beam, reached 40 cm-1 at the electric field strength of 650 kVcm-1 thus confirming the photorefractive nature of the grating. The gain exceeded the absorption (30 cm-1) that showed a good potential of this material for applications.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.