What is the International Day of Light?

At Esco Optics, we supply a wide array of clientele with precision optics ranging from lenses, prisms and windows, to high-precision, 1/10 wave flat coated mirrors. Every day we work with our customers to achieve groundbreaking results.

May 16^th, known as “The International Day of Light”, is a special day to everyone in the photonics industry. This occasion celebrates Theodore Maiman, who successfully operated the first laser on May 16th 1960. His laser was a scientific achievement that lead to the rapid advancement of many new technologies in the fields of communications, aerospace, and biomedical research, to name just a few.

In honor of Maiman’s breakthrough work, let us examine his greatest achievement. By today’s standards, his laser was simple. The first component was a polished aluminum cylinder. In one part of this cylinder was housed a simple power source and switch that was then connected to a fused quartz flash lamp located further down the cylinder. The lamp itself was originally developed for the photography industry and was an off-the shelf, readily available item. Lastly, was the inclusion of a ruby crystal and some mirrors.

Ruby is a key component because ruby crystal is mostly aluminum oxide where some aluminum atoms are replaced with chromium atoms. It’s the addition of chromium that gives ruby its rich red color. After the ruby is cut and formed into a rod, it is then surrounded by a quartz flash tube as shown in the figure below. The power supply provides electricity, illuminating the tube which, in turn, excites the chromium atoms as they absorb the incident photons. The excited atoms become ionized as their electrons jump from their ground state to one of higher potential.  When the electrons fall back to their ground state, they emit photons at a frequency specific to the atomic structure of the chromium atom. These photons are then directed back and forth between a mirror placed at either end of the cylinder, one with near 100% reflectivity and another which is partially reflective. The emitted photons passing back and forth in the chamber in conjunction with the energy from flash lamp then work to amplify the ionization of additional chromium atoms, greatly intensifying the light.  Finally, those photons which leave the chamber through the partially reflective mirror are what we see as laser light.

Maiman's achievement cannot be understated. It is now 60 years since his discovery and lasers, mostly taken for granted, are a part of our daily lives - fiber optic signals race information around the world in fractions of a second, laser range finding and mapping gives us unprecedented detail of our natural world, surgical procedures using lasers are now commonplace…we have automated welding systems, driverless cars, guided smart missiles, and of course, microchips incorporated in countless electronic devices…all are made possible by lasers. It was Maiman's success in advancing light technology that fundamentally changed our daily lives forever.

So next May 16th, after you've said the rhymes about April showers bring May flowers and you've celebrated Star Wars Day on May the 4th (be with you) and then on May 6th after you've cursed yourself for drinking too many Margarita's on Cinco De Mayo. Remember, that international day of light is coming up and we should all take note to celebrate science and the discoveries that further advancements for all of us.