Surface relief holograms and holographic optical elements in sensitized polystyrene

Poly(tBOC)styrene is a sensitive (<0.5-mJ/cm 2 ) photodeformable holographic medium that supports high-efficiency surface relief gratings and moderate efficiency index gratings. The development of the holograms is especially simple, requiring only that the medium be heated to ~100°C for 2 min. The diffraction efficiency for the first order in reflection is higher than 10% for spatial frequencies below 500 lines/mm, but there is no regime where a linear relationship exists between exposure and efficiency. This medium is eminently suitable for the production of holographic optical elements intended for use in the ultraviolet. An off-axis zone plate made by aluminizing a relief hologram fully depletes the zero-order beam and produces a first-order focused spot within 30 % of the diffraction limit. Such tightly focused beams can be used for ablating patterns in many materials.