The various laser architectures described herein provide increased gain of optical energy as well as compensation of optical phase distortions in a thin disk gain medium. The invention also provides pharmaceutically acceptable acid addition salts, optically pure enantiomers, racemates and diastereomeric mixtures of such compounds. Towards that end, a method of page decomposition comprises segmenting an image into a plurality of blocks according to an amount of information contained in each block, classifying each block according to a corresponding frequency spectrum, and refining a classification of each block.