Invention of the Laser (1960): Theodore Maiman's Ruby Laser

The invention of the laser came on 16 May 1960, when the physicist Theodore Maiman produced the first pulses of laser light from a small ruby crystal at Hughes Research Laboratories in Malibu, California. His device built on decades of theory, from Albert Einstein’s idea of stimulated emission to the maser of the 1950s and the laser proposal of Charles Townes and Arthur Schawlow. Within a few decades, lasers had become part of medicine, industry, communications and everyday life.

Background: from Einstein to the maser

The laser rests on a process called stimulated emission. In 1917 Albert Einstein showed that, in addition to absorbing and spontaneously emitting light, an excited atom could be “stimulated” by an incoming photon to release a second photon identical in direction, frequency and phase. Einstein’s work built on the quantum ideas that began with Max Planck in 1900.

For decades stimulated emission seemed only a curiosity, because in ordinary matter most atoms sit in low-energy states and absorb light rather than amplify it. To get amplification, physicists needed a “population inversion”, in which more atoms are in an excited state than in a lower one.

The first device to achieve this was the maser (Microwave Amplification by Stimulated Emission of Radiation). Charles Townes, with James Gordon and Herbert Zeiger at Columbia University, operated an ammonia maser in 1953–54. In the Soviet Union, Nikolay Basov and Aleksandr Prokhorov developed similar ideas independently. Masers proved useful as very sensitive amplifiers for radio astronomy and communications.

The race to make an optical maser

In 1958 Townes and his brother-in-law Arthur Schawlow, then at Bell Telephone Laboratories, published a landmark paper, “Infrared and Optical Masers”, in Physical Review. They explained how the maser principle could work with light, using a gain medium between two parallel mirrors so that light bounced back and forth and was amplified on each pass.

At about the same time Gordon Gould, a graduate student at Columbia, had written down similar ideas in a notebook in November 1957, coining the word “laser”. He had the pages notarised, which later supported decades of patent battles. Several laboratories, including Bell Labs, IBM, the defence firm TRG and Hughes, began racing to build the first working device. Most researchers expected the first laser to use a gas or a metal vapour, such as the potassium vapour that Townes had proposed.

Maiman’s ruby laser

Theodore Maiman, a physicist at Hughes Research Laboratories, had worked on ruby masers. Many experts, including Schawlow, believed ruby was a poor candidate for an optical laser, because measurements suggested it converted absorbed light too inefficiently. Maiman made his own measurements, concluded that the earlier figures were wrong, and pressed ahead with a simple design.

He used a synthetic pink ruby rod about 1 centimetre across and 2 centimetres long, with its ends coated in silver to form mirrors, one with a small opening to let light out. Around it he placed a coiled, high-power xenon flash lamp of the type used in photography, inside a reflective cylinder. The intense flash pumped the chromium atoms in the ruby into excited states.

On 16 May 1960 Maiman and his assistant Irnee D’Haenens raised the flash lamp’s power past a threshold. The red light from the ruby suddenly became more intense, narrowed in colour and was emitted as a beam, the signature of laser action. The device produced brief pulses of deep red light at a wavelength of about 694 nanometres.

Announcement and controversy

Maiman submitted a short paper to Physical Review Letters, which turned it down. He then sent a brief report to the British journal Nature, which published it on 6 August 1960 under the title “Stimulated Optical Radiation in Ruby”. Hughes had already announced the achievement at a press conference in New York on 7 July 1960.

Some newspapers immediately described the device as a “death ray”, an image that annoyed Maiman. His assistant reportedly joked that the laser was “a solution looking for a problem”, a phrase that circulated widely in the early 1960s because practical uses were not yet obvious.

Other lasers followed quickly. In November 1960 Peter Sorokin and Mirek Stevenson at IBM built a laser using uranium in calcium fluoride. In December 1960 Ali Javan, William Bennett and Donald Herriott at Bell Labs operated the first gas laser, using helium and neon, which shone continuously rather than in pulses. Semiconductor lasers were demonstrated in 1962.

Key people

• Theodore Maiman (1927–2007), physicist at Hughes who built the first working laser.
• Charles Townes (1915–2015), inventor of the maser and co-author of the 1958 laser proposal; Nobel Prize 1964.
• Arthur Schawlow (1921–1999), co-author of the 1958 proposal; Nobel Prize 1981.
• Gordon Gould (1920–2005), who coined the word “laser” and after long legal battles won important laser patents from 1977.
• Ali Javan (1926–2016), Iranian-American physicist who led the team that built the first gas laser.

Consequences and legacy

Lasers took several years to find wide practical use, but they eventually transformed many fields. Doctors used them in eye surgery from the 1960s. Supermarket barcode scanners appeared in 1974, compact discs in 1982, and fibre-optic communication, which carries most of the world’s internet traffic, depends on semiconductor lasers. Industry uses lasers to cut, weld and measure; scientists use them for spectroscopy, timekeeping and the detection of gravitational waves. Since the Apollo 11 Moon landing in 1969 left reflectors on the lunar surface, laser pulses fired from Earth have measured the Moon’s distance to within centimetres.

The invention also became a classic case study in disputed credit. Townes and Schawlow had the published theory, Gould had an early notebook, and Maiman had the first working device. Courts, patent offices and prize committees reached different conclusions about each claim.

Myths and facts

Myth: the first laser produced a continuous beam. Maiman’s ruby laser emitted brief pulses of light, each lasting a fraction of a millisecond. Continuous laser beams came later in 1960 with the helium-neon gas laser.

Myth: lasers were invented as weapons. Newspaper talk of “death rays” in 1960 had little to do with the device itself, which produced only modest pulses of red light. The laser grew out of basic physics research on microwave amplifiers and spectroscopy, and its main uses have been in science, medicine, industry and communications.

Myth: one person invented the laser. The first working laser was Maiman’s, but the underlying theory came from Einstein, Townes, Schawlow, Basov and Prokhorov, and Gould made an important early proposal. The laser is better seen as the product of a scientific community than of a lone inventor.

Timeline

• 1917: Albert Einstein describes stimulated emission of radiation.
• 1954: Charles Townes’s group at Columbia University reports the first working maser.
• 1957, November: Gordon Gould records the laser concept and the word “laser” in his notebook.
• 1958, December: Schawlow and Townes publish “Infrared and Optical Masers”.
• 1960, 16 May: Theodore Maiman operates the first laser at Hughes Research Laboratories.
• 1960, 7 July: Hughes publicly announces the ruby laser.
• 1960, 6 August: Maiman’s report appears in Nature.
• 1960, December: The first helium-neon gas laser operates at Bell Labs.
• 1964: Townes, Basov and Prokhorov share the Nobel Prize in Physics.

Why it matters

Maiman’s ruby laser turned a theoretical idea into a working tool and opened an entirely new field of technology. Lasers now underpin global communications, modern manufacturing, medicine and precision science, making the small ruby rod of 1960 one of the most consequential inventions of the twentieth century.