Dow Corning Photonics Solutions, which supplies products, technologies and services for the optical data storage, optical components and optical fiber industries, has signed a global supply agreement with Aprilis Inc., a Maynard, Mass.-based maker of holographic storage material. . . . Robert A. Cascella has been named president and COO of Hologic Inc. (Medford, Mass.), which develops medical imaging systems and digital imaging technology. . . . Cymer Inc., a San Diego, Calif.-based supplier of excimer light sources used in semiconductor manufacturing, announced today that Russell Hudyma, president of Paragon Optics Inc., has joined Cymer's scientific advisory board. Hudyma has published more than 20 papers on microlithography and related topics and teaches "Optical Design in the Ultraviolet," a popular short course at conferences sponsored by The International Society for Optical Engineering. He has published more than 20 papers on microlithography and related topics and holds or has applied for more than 30 US and foreign patents.