A physicist, Bennett (along with Ali Javan and Donald Herriott) developed the first gas (helium-neon) laser, at Bell Labs in New Jersey, in 1960.
Bennett called lasers “a solution looking for a problem,” but continued working with them, eventually developing at least 10. The HeNe laser was the first to be used to scan barcodes, and the argon ion laser, which Bennett invented in 1964, proved effective in medical applications, including treating blindness. When Bennett suffered from a detached retina in 1995, the treatment he received was from an argon ion laser.
Bennett was a professor of physics at Yale University for 38 years, and retired in 2000. He died from esophageal cancer at home on June 29. He was 78.