Thomas Miller has joined LightLab Imaging as chairman and CEO, effective March 25. Paul Magnin will remain president and become COO. Lightlab specializes in optical coherence tomography for medical and biological applications.   . . .   EMCORE Corp. announced its sale of a Discovery 125 (D125) metalorganic chemical vapor deposition research and small-scale production reactor to Albany NanoTech (ANT) of the University at Albany, State University of New York. The reactor will be incorporated into ANT compound semiconductor research facilities to support research in gallium nitride and related III-nitride materials.