Charles Townes

1. Charles Townes The Laser

2. What is a Laser? L ight A mplification by S timulated E mission of R adiation

3. How does it work? When atoms are stimulated by some energy source, its electrons absorb the energy and go into a higher quantum level. These electrons then try to go back to their original levels, releasing their energy in the form of a photon of light. Figures 1 and 2 show this phenomenon. A laser uses this principal within its tube, to manipulate and control the light emission. Since a normal flashlight uses a same principal as that in figures 1 and 2, it is important to note how a laser differs. Lasers are: Monochromatic: Having the same color of light Coherent: The photons have same wave phase Directional: The path of the photons are very similar These properties are attained through the mirrors found in the laser Fig 2 Fig 1

4. How does it work? 2 Fig 1 Fig 2 After the photons are released, they bounce around in the laser tube until their orientations cause them to bounce between the full reflective mirror on one end and a partial reflective one. As these photons are doing this, they are also colliding with other atoms causing their electrons to release photons which happen to have he same wavelength (color) and phase as the the photon that impacted it, this is known as stimulated emission. Finally, these photons which are oriented by the mirrors will go through the partial reflected one in a intense column of light that is highly directional, and whose photons are of the same wavelength and phase. Figure1 shows how the photons are traveling against the mirrored surface of the tube. Figure 2 shows the photons finally leaving the tube all traveling in the same direction.

5. Why are Lasers important? • Cd players • Barcode scanners • Eye surgery • Weapon guidance • Fiber optic communications • Laser Printers • Laser telescopes • Are just a few of the current uses with many more being developed • every day!

6. Who’s idea was the Laser? • Charles Hard Townes • Born July 28, 1915 in Greenville, S.C • Bachelor of Science degree in physics and Bachelor of Arts degree in Modern Languages from Furman University by the age of 19. • Master of Arts degree in Physics at Duke University • Ph.D. degree from The California Institute of Technology with a thesis on isotope separation and nuclear spins

7. Microwave Amplification by Stimulated Emission of Radiation Before Townes developed the laser, he worked on and developed the maser. This device is basically the same science as the laser except it operates on the microwave band instead of the optical. This device has been used in things like the atomic clock and electronic amplifiers for radio telescopes. His breakthrough idea on how to make shorter waves using atoms not only gave rise to the impressive laser but he is also credited to the development of the maser. Although the technology is similar, each has found its own uses in modern society. What else did he do?

8. What is he doing now? • Currently Charles Townes works as a graduate professor at the University of California at Berkeley, where he lives with his wife and four daughters. • In 1998 he was celebrated at the 40th anniversary of the laser which was held by bell labs. • He also is an active member with america’s youth as well its graduate students. He has given talks with young student audiences about his life in an attempt to inspire and amaze.

9. Timeline 1915- Born 1939 - Joins Bell Labs 1948 - Becomes an associate professor of physics at Columbia University. 1950 - Becomes a professor of physics at Columbia and executive director of the Columbia Radiation Laboratory 1953 - Builds the first maser with J. P. Gordon and H. J. Zeiger at Columbia. 1957 - Works with A.L.Schawlow on the theory of the laser based on the principles of the maser 1959-61 - Becomes vice-president and director of research for the Institute for Defense Analysis in Washington, D.C. 1960 - Receives with Schawlow a patent for the Laser. 1964 -- Shares the Nobel prize with A. Prokhorov and N. Basov of the Lebedev Institute in Moscow for "fundamental work in the field of quantum electronics which has led to the construction of oscillators and amplifiers based on the maser-laser principle.” 1966 - Becomes Institute Professor at MIT. 1967 - Becomes University Professor of Physics at the University of California at Berkeley. 1986 - Becomes University Professor of Physics, Emeritus, at the University of California at Berkeley.

10. Conclusion Today, lasers are found in many aspects of our lives. We cannot even go the buy groceries without noticing their impact on modern society. As time goes on people will find more and more uses for this simple yet important light making device. The next time one see a laser in use, remember that at one time a man named Charles H. Townes dreamed about it before it was ever created. Although, many did not believe his inventions would have much use, even he could not have predicted how important it has become.