Charles H. Townes, a renowned physicist who invented the laser and the maser, died in Oakland, California on Tuesday at the age of 99. Townes’ inventions earned him the Nobel Prize in physics in 1964.
Laser stands for Light Amplification by Stimulated Emission of Radiation. Masers are similar, but use microwaves instead of light. The laser and the maser are the basis for numerous products in our everyday lives: CD and DVD players, barcode scanners, speed guns, medical and astronomical tools.
Here’s how a laser works: Light is produced byexciting electrons inside atoms and releasing photons, particles of light. White light from the sun or a light bulb is full of different colors of light, or different wavelengths, all of which are moving out of sync.
A laser tube takes a single wavelength of light and corrals those excited electrons and photons. The laser forces them to move in sync. Then it can direct those photons in a single beam.
Los Angeles Times reporters Charles Piller and Thomas H. Maugh II compare it to a group of soldiers marching across a bridge:
“While the footsteps of the crowd have little effect on the bridge, the combined footfalls of the soldiers have much greater impact, causing the bridge to shake and tremble. Similarly, the coherent light from a laser carries much more power than simple white light, allowing it to burn through flesh or even steel,” they write.
The idea for the maser and the laser goes back to Einstein in 1917, but scientists thought it was impossible. Townes thought of the idea while sitting on a park bench in Washington, D.C. in 1951. He imagined a flash of light exciting ammonia molecules in a tube. After sketching the idea out, he returned to Columbia University. For the next three years, he worked with his brother-in-law physicist Arthur Schawlow to develop the first maser in 1954.