CW Lasers History
Despite our range of fiber lasers being relatively new and innovative, and featuring the most modern advancements in laser technology, lasers themselves, and CW lasers, have a rather detailed history.
We’ve touched upon the basics of this history here, with a particular focus on CW.
The history of the laser
Before turning our attention to CW lasers in particular, it’s worth talking about the origin of lasers themselves. The first true realisation of a working laser was in 1960, discovered by Theodore Maiman at Hughes Research Laboratories.
However, this was based on any theoretical foundations and hypotheses that came before this; with the famous Albert Einstein being the first one to lay the foundations for a working laser all the way back in 1916.
In short, his proposal suggested that photons could stimulate the emission of other identical photons from atoms that had been excited. There were some reports of stimulated emission in 1928, but there wasn’t enough evidence at the time for scientists to give it their full attention.
In 1940 it was suggested that a stimulated emission could be achieved using gas, and in 1951 this was taken a step further when it was suggested that the same stimulated emissions could be achieved at microwave frequencies.
These suggestions, coming from Americans and Russians, created something of a race to create the laser, similar to the “Star Wars” race of the Regan era. However, there were two initial problems which needed to be overcome:
- How could one excite a population inversion?
- What was the active medium that could be used?
Various methods were tried, such as optical pumping of a vaporized alkali metal, or the pumping of an impurity atom with a solid. Suggestions were again made of exciting gas using electricity, but progress for these methods was slow.
The invention of the laser
It was Maiman, who we spoke about earlier, that made the breakthrough. He began to investigate using ruby as the medium, as he had a history of creating a compact microwave laser that used ruby crystals.
Other scientists disagreed with him, telling him it would never work, but his own calculations and measurements said otherwise. He tested his theory on May 16, 1960, and unveiled his working invention on July 7, 1960. He unveiled it at a convention in New York, and many were stunned by the success of the project.
After this, things moved rather rapidly for the world of lasers, with scientists testing different methods and innovations for a working laser.
The birth of the continuous wave laser
It was on December 12, 1960, that both the first gas laser and the first continuous wave laser were born. Three scientists, Ali Javan from Bell Labs, William Bennet and Donald Herriott made the discovery, with helium being the gas that was used.
This version of a CW laser was extremely close to the concept originally coined of a continuous coherent optical oscillator, but it was still much longer than what had been originally included in the plans.
From this discovery, other low-gain CW lasers would naturally come much more easily. Two other scientists (there are many scientists involved in the discovery and development of the laser!) later designed a confocal resonator, which helped to increase cavity alignment.
After the helium-neo laser became more widely available, which offered a much more coherent beam, this cavity alignment became even easier to achieve.
In 1963 Bell Labs identified several gas laser lines in gas discharges, with the most important of these being the 632.8-nm line of helium-neon. Alan White and Dane Rigden, two scientists from Bell Labs, spent long hours and weekends working to refine this helium-neon laser.
After much work, they had created the first CW laser that had a visible beam, and it’s hardly surprising that this was of much excitement to the scientific community. From here, developments and innovations happened at a rapid pace.
Two more scientists (surprise!), named Leo F. Johnson, and Kurt Nassau, again from Bell Labs, began working with neodymium-doped solid state lasers, moving away from the use of gas.
They were then able to use this type of laser for CW laser machines at room temperature; the very first time this had been done for a solid. Later, in 1964, the first crystal CW laser was used from Nd-YAG. Then, in 1990, there was an explosive growth in the use of fiber optic lasers which brings us to the modern day versions of the fiber CW lasers that we use here at SPI Lasers with all their applications!
Find out more about the history of CW lasers
Above, we’ve gone a little further than just scratching the surface when it comes to the history of CW lasers, but there’s still a wealth of information available to the avid reader. If you are interested in reading a more detailed history, please follow this useful link here. Also, we have available our CW glossary of terms and CW FAQs.