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CPP: Chemische Physik und Polymerphysik

CPP 11: Light induced phenomena II

CPP 11.3: Vortrag

Montag, 7. März 2005, 11:45–12:00, TU C230

Holographic recording of more-dimensional gratings in photo-sensitised PMMA — •Rafael Meinhardt¹, Ansgar Draude¹, Hilmar Franke¹, and Roger A Lessard² — ¹Universität Duisburg-Essen, Abteilung Duisburg, Laboratorium für angewandte Physik, Lotharstr. 1, 47048 Duisburg — ²COPL, departement de physique, university Laval, G1K7P4, Quebec, Canada

Volume phase holography is used for the recording of refractive-index patterns with the symmetry of a photonic crystal. As a recording material solid plates of PMMA, containing up to 10 wt% of residual monomer MMA doped with different photo-initiators have been used. Light-intensity patterns could be transferred into refractive-index patterns using the mechanism of the photo-induced residual polymerisation.

The recording has been performed via 2 different ways. First a consecutive method using a 2-beam holographic set-up was applied: While the first pattern is developing the sample is turned by an arbitrary angle and a second grating with a different lattice-constant was recorded. Three of such steps lead to a 3-dimensional grating.

For the second single-step method we used the interference of up to 4 beams. Simulations showed different more-dimensional light-intensity patterns depending on the orientation and the polarisation of the beams’ wave-vectors.

The obtained gratings are characterised using a goniometer, different diffracted orders may be indexed according to their (h,k,l) Miller’s indices. For the single-step method we were able to verify experimentally the simulated photonic structures.