An organic MNA crystal phase modulator

A prototype transverse phase modulator employing the organic electrooptic MNA (2-methyl-4-nitroaniline) crystal is described. The design configurations and performance characteristics are presented. MNA was purchased as a fine greenish-yellow powder and was purified by multiple sublimations under low pressure. Purified MNA powder was subsequently saturated in acetone. To start growth, the beaker of filtered solution was placed in the dessicator with an equal volume of toluene on the bottom. The vapors of the solvent would fill the sealed vessel and get reabsorbed into the liquids. In the process, toluene molecules displaced the MNA ones, forcing them to precipitate out into crystalline form. Under controlled conditions of stable temperature and vapor exchange rate, large quality samples were obtained