The concept of discovery is a powerful sentiment in science. Television’s Discovery Channel and print journalism’s Discover Magazine have folded the word into their identities, and as a child that my iconic scientist was a paleontologist, literally unearthing discoveries of the prehistoric wilderness. Just as motivating, however, is the concept of invention, and perhaps no single development of the last century has been more influential or more important than the laser. In 2010 the laser turns 50, and to celebrate, a group of organizations including the American Physical Society, the Optical Society, SPIE and IEEE Photonics Society have organized a year-long series of events this year dubbed LaserFest.
UC Berkeley has been celebrating LaserFest this past week with special exhibits and events over the weekend at the Lawrence Hall of Science, and a special lecture on Monday the 25th by Roger Falcone, Bob Byer, and Nobel laureate Charles Townes, also at the Lawrence Hall of Science.
Theodore Maiman built the first laser out of a rod of pink ruby in 1960. However, the laser’s precursor and underlying principle belongs to Townes. In 1954, he and colleagues constructed the ammonia maser, a stunning proof-of-principle device demonstrating that intense beams of light within a narrow color range could be produced. A flurry of excitement and research efforts followed aimed primarily at developing masers that could work at higher and higher frequencies of light.
As maser research matured the name changed as well. A high-frequency MASER (the acronym stands for Microwave Amplification by Stimulated Emission of Radiation) became the optical MASER. Then at a conference in 1959, Gordon Gould coined it as the LASER. (LASER is an acronym for Light Amplification by Stimulated Emission of Radiation.)” One of the conference’s organizers, Arthur Schawlow, rebutted that these new devices would be more important as oscillators rather than amplifiers, so perhaps they should really be calling it the LOSER (see the recent article in Physics Today). Curiously, substituting the O never caught on.
The laser’s influence in science and society, however, has been dramatic. We use lasers to read our hard drives and play DVDs. We use them to improve our vision. Lasers play an integral role in security systems. They are a crucial component of our ability to keep time accurately. The world’s biggest laser in Livermore could be on the verge of igniting fusion reactions. We even shot a laser at the moon, waited for it to bounce back, and used the information to calculate the moon’s distance to the Earth with unprecedented accuracy.
Time will tell what the laser’s future applications might be. Personally, I am rooting for a sign of extraterrestrial life from the Optical SETI project. The research collaboration’s website says that “A tightly focused light beam, such as a laser, can be 10 times as bright as the Sun and be easily observed from enormous distances.” Then again, if the aliens do decide to shoot a message our way via laser, let’s just hope that that they don’t decide to crank up the power so high that we all get vaporized.