William R. Bennett Jr., a physicist and inventor who helped develop the first gas laser nearly 50 years ago at Bell Laboratories, died on June 29, at his home in Haverford, Pa, at the age of 78. Bennett and a team of researchers, including Donald R. Herriott and Ali Javan, assembled the very first gas laser by trapping helium and neon in a pressurized tube. They then agitated the gases’ atoms with an electrical current. Both ends of the tube were fixed with mirrors that redirected the resulting particles of light, sending them out in a concentrated and continuous infrared beam. Javan and Bennett received a patent for the gas laser in 1964. Bennett found that gas lasers, such as the helium-neon (HeNe), had advantages over those using solid materials. So in the following years, Bennett and others experimented with argon, krypton, xenon and similar gases and studied the qualities and burning power of their laser beams, giving ways to countless applications and breakthroughs, such as CD players, supermarket scanners, surgical tools and weapons navigation systems, to name a few. He left Bell Laboratories and in 1962 joined the newly formed department of physics and applied science at Yale. There, he continued his laser research, studied musical sound, and looked into possible health effects of power lines and electromagnetic fields, a risk he believed to be significantly overrated. William Ralph Bennett Jr. was born on Jan. 30, 1930, in Jersey City. He graduated from Princeton and went on to receive a doctorate in physics from Columbia in 1957.In 1964, he was named a professor of physics and applied science at Yale, and remained there for the rest of his career. From 1981 to 1987, he was master of Silliman College at Yale. He became a professor emeritus of engineering, applied science and physics in 1998 and retired in 2000. Bennett authored eight books, twelve patents and over 120 research papers over the span of his career.