How long have lasers been around

Apollo program. The round-trip travel time of the pulse provided a measurement of the distance to the Moon. Later, ruby laser beams sent out and received by telescopes measured distances to the Moon with a precision of about three centimeters—a great use of the ruby laser's short pulses.

When the first laser appeared, scientists and engineers were not really prepared for it. Many people said to me—partly as a joke but also as a challenge—that the laser was "a solution looking for a problem. And many different laser types and applications came along quite soon.

At IBM's research laboratories in Yorktown Heights, New York, Peter Sorokin and Mirek Stevenson demonstrated two lasers that used techniques similar to Maiman's but with calcium fluoride, instead of ruby, as the lasing substance. This produced continuous radiation at low power but with a very pure frequency and the narrowest possible beam.

Then came semiconductor lasers, first made to operate in by Robert Hall and his associates at the General Electric laboratories in Schenectady, New York.

Semiconductor lasers now involve many different materials and forms, can be quite small and inexpensive, and are by far the most common type of laser. They are used, for example, in supermarket bar-code readers, in optical-fiber communications, and in laser pointers.

By now, lasers come in countless varieties. They include the "edible" laser, made as a joke by Schawlow out of flavored gelatin but not in fact eaten because of the dye that was used to color it , and its companion the "drinkable" laser, made of an alcoholic mixture at Eastman Kodak's laboratories in Rochester, New York. Natural lasers have now been found in astronomical objects; for example, infrared light is amplified by carbon dioxide in the atmospheres of Mars and Venus, excited by solar radiation, and intense radiation from stars stimulates laser action in hydrogen atoms in circumstellar gas clouds.

This raises the question: why weren't lasers invented long ago, perhaps by when all the necessary physics was already understood, at least by some people? What other important phenomena are we blindly missing today? Maiman's paper is so short, and has so many powerful ramifications, that I believe it might be considered the most important per word of any of the wonderful papers in Nature over the past century.

Lasers today produce much higher power densities than were previously possible, more precise measurements of distances, gentle ways of picking up and moving small objects such as individual microorganisms, the lowest temperatures ever achieved, new kinds of electronics and optics, and many billions of dollars worth of new industries. The U. Kelleher cites multiple areas that need improvement, beginning with the ability to eliminate wrinkles and improve skin tone and texture.

The common patient complaint of excessively oily skin still needs to be resolved. The ability of lasers to safely, comfortably and substantially eliminate unwanted fat is lacking.

Laser treatment of non-melanoma skin cancer is in its infancy and not widely used. Laser treatment of melanoma is essentially nonexistent. Energy-based devices continue to advance; more developments are coming from different parts of the world, especially Asia.

We use combination treatments more widely today and have moved from face to off-face targets e. Another area of potential benefit is the ability to in vivo image tissue with lasers.

Susan Van Dyke, M. Examples include steroids to reduce hypertrophic scars, minoxidil to stimulate hair growth, bimatoprost to promote pigmentation, platelet rich plasma to enhance healing and trigger collagen and elastin productions, hydroquinone to reduce melasma, and post-inflammatory hyperpigmentation.

BTL and Sciton. Pozner reports no relevant disclosures. What amazing new uses might be discovered for use in medicine, communications, scientific research — or warfare? Radio was soon put to use, but the same techniques could not be used with radiation of shorter wavelengths. A method for amplifying light had its origins in an idea Einstein developed in Looking deeply into the new theory of quantum physics, he predicted that rays could stimulate atoms to emit more rays of the same wavelength.

But engineers had little notion how to manipulate atoms, and for decades the idea seemed a theoretical curiosity of no practical interest. Scientists and engineers pushed radio techniques to ever shorter wavelengths. By , ingenious devices could generate rays with wavelengths of a centimeter or less.

They were swiftly pressed into service to detect enemy airplanes. By the start of the 20th century, scientists understood that light rays could be thought of as electro- magnetic waves — similar to radio waves, but with much shorter wavelengths.

A spectrum chart shows various forms of electromagnetic radiation. The only difference between one ray and another is the length of its wave. We can also say the frequency is different, the frequency being the number of waves that pass a point each second as the ray moves through space.

The spectrum is drawn so that the wavelength is reduced by a large factor at each major division. Rays with shorter wavelengths can carry more information and more energy. Scientists boasted that radar had won the war and the atomic bomb had ended it. What might physicists create next? As the Cold War against the Soviet Union got underway, the US government poured ever larger funds into basic and applied research.

Detecting not only military but civilian applications, corporations and entrepreneurs heaped their own money on the pile. Industrial and university laboratories proliferated. It was from this fertile soil that the laser would grow. Townes: Of course, the nuclear bomb I think surprised people It changed the style, and the amount of money available, and the energy with which physics was pursued. And it made jobs in universities for people.

Many of my friends from Caltech had taken jobs [in the s] teaching high school even, teaching in junior colleges certainly — very good men teaching in junior college, working in the oil fields, working in industry. And suddenly after the war, why, there were jobs for them in the universities, and many of them became quite prominent. It wasn't for lack of ability that they were teaching in junior colleges. It's just that there were no jobs. Aaserud: The laboratory that you turned to at Columbia was funded by the [U.

Army] Signal Corps, I think you said? Townes: It was a joint services laboratory, but under the responsibility of the Signal Corps primarily That laboratory had been working on magnetrons [for radar] during the war, you see, and they had also started some measurements on the absorption of microwaves by water. They'd made some good measurements, but at high pressure, atmospheric pressure.

I'd been working at low pressure where you could get narrow lines Navy] particularly but other services stepped in to help the universities and help them keep going, and they were interested in the further development of magnetrons.

In a way, that was the job of that laboratory still, after the war, to develop higher frequency magnetrons.

The armed services felt that anything in that general area, good physics in that general area was fair game, and that's of course what the university was interested in. Already in the s scientists could have built a laser. They had the optical techniques and theoretical knowledge — but nothing pushed these together.

The push came around from an unexpected direction. Short-wavelength radio waves, called microwaves, could make a cluster of atoms vibrate in revealing ways a technique called microwave spectroscopy. Radar equipment left over from World War II was reworked to provide the radiation.

Townes: Rabi has very strong ideas. Rabi is a very wise man in many ways and I admire him, but he also — he has very strong opinions. And I know perfectly well what Rabi's thinking was. I believe I know perfectly well what his thinking was. He felt molecules were really not very interesting, and not really physics; that's chemistry, and it's not really physics.

Real physics is nuclei, high energy physics. And solid state even he felt wasn't very interesting. Columbia never had very much solid state physics. But Columbia had a microwave lab, being well-supported by the armed services and the Signal Corps, and he felt he needed some notable research going on in the microwave lab.

This was an active field and interesting a lot of people, but I think he kind of looked down on it as kind of dirty stuff, that molecules are too complicated, and not fundamental and so on. But it's OK, it's pretty good, and so, he needed a person like me. So that's the reason I got hired. Now, it was a good opportunity in that they already had equipment there and a big laboratory and it was well run and well financed, and I could go ahead and work.

Charles Townes of Columbia University had studied molecules as a physicist in the s, and during the war he had worked on radar as an electronics engineer. The Office of Naval Research pressed him and other physicists to put their heads together and invent a way to make powerful beams of radiation at ever shorter wavelengths.

In he found a solution. Under the right conditions — say, inside a resonating cavity like the ones used to generate radar waves — the right kind of collection of molecules might generate radiation all on its own. Townes gave the problem to Herbert Zeiger, a postdoctoral student, and James P.

Gordon, a graduate student. By they had the device working. Townes: We'd had enough meetings that we had really surveyed everything that was going on, surveyed our own ideas. And so I was beginning to feel that, well, we may be coming to an end as to what we could usefully do immediately. And I was a little discouraged that nobody had turned up There were new things, but there was just no clear solution.

Then we were having a meeting in Washington. That was the occasion when I sort of tried to think back over things, and what it was that might, might possibly work, and why other things weren't working. And that was where the possibility of the maser occurred to me Engineer or scientists behind the project: Gordon Gould.

Description of Milestone: Gordon's notebook would be the first time the acronym Laser was used but also noted some basics concepts for building one. This notebook would become the focus of a year court battle for the patent rights to the technology. Gould discussed his ideas with ith physicist Charles Townes , who advised him to write his thoughts down and have it notarized, which he did. Gould was under the impression he should have a working model prior to applying for a patent and was beaten to it by Townes and physicist Arthur Schawlow who had filed a similar application, meaning his eventual application was rejected.

Gould would finally win his case in to be awarded the first patent for a laser. The importance of the laser innovation or milestone: This was the first successful assembly of a complete laser device. It would be the first of many more to come. Theodore, a physicist at Hughes Research Laboratories in Malibu, California, built the first laser using a cylinder of mand-made ruby 1 cm in diameter and 2 cm long.

Each end was coated with silver to make them reflective and help them serve as a Fabry-Perot resonator. Description of Milestone: After serving some time in the navy, Theodore earned his B. After successfully completed it in the summer of he turned his attention to the development of a laser. After successfully building a working laser, he had his achievements published in Nature in and went on to found the Korad Corporation to develop and build high-powered laser equipment.

This company would become a market leader and in supplied their equipment was used as the lunar laser ranging equipment. The importance of the laser innovation or milestone: The Helium-Neon He-Ne laser was the first laser to generate a continuous beam of light at 1. This laser would find many applications in telecommunications, internet data transmission, holography, bar-code scanners, medical devices and many more.

Javan was able to see how a population inversion can be created in a gas discharge by selective, resonant energy transfer. This was key to his invention of the first gas laser, the He-Ne laser, which was also the first continuous wave laser. The importance of the laser innovation or milestone: This was the first time laser technology was used to treat a human patient. It would pave the way for an explosion in future innovation in laser technology for use in surgery and medical treatment.

Engineer or scientists behind the project: Dr. Charles J. Campbell and Charles J. Description of Milestone: Dr. Koester of the American Optical Co. The treatment utilized an American Optical Ruby Laser to destroy a retinal tumor.

This tumor, an Angioma , was destroyed with the use of a single pulse that lasted a thousandth of a second. The procedure was incredibly fast and considerably more comfortable for the patient when compared to conventional treatment using 1,watt Xenon arc lamps of the time. In the years to come, the ruby laser was used in various medical treatments. The importance of the laser innovation or milestone: The semiconductor injection laser was a revolution in laser technology at the time.