Abstract
A technique for achieving molecular beam epitaxial writing of patterned GaAs epilayer structures is described. With this technique, patterned GaAs epilayer structures with controlled thickness profiles, lengthwise varying thickness, featureless and optically smooth sidewalls, and a linewidth as narrow as 10 μm were written. This technique also allows for the first time controlled variation of chemical compositions in the epilayer structure written in a lengthwise direction in the plane of the epilayer.