Reflections on Forty Years
of Optical SETI --
Looking Forward and Looking Backward
Charles H. Townes
Picture by Tom McDonough, The Planetary
When, in early 1961, interstellar communication with lasers was
first discussed, it was met with interest but not enthusiasm. The
scientific community was thinking of laser powers in the kilowatt range (which
had not yet been actually achieved) and telescopes of maximum diameter 200
inches. Now there are lasers of average power 106 watts, pulsed
power 1015 watts, and telescopes of diameter 10 meters. Just
what technology an advanced extrasolar civilization would have is still
debatable, but on earth communication with lasers is growing rapidly and now
"Optical SETI" seems to many a likely prospect. In
addition to increased power and variety of lasers, with expectation of further
growth, the easy use of short pulses alleviates the need for high spectral
resolution required by CW laser communication, and gives high signal to
noise ratios. Such changes in our own technology and views over only
a few decades obviously stimulate open-mindedness about the state of
technical developments and communication in any external civilization. And
what are the resulting speculations?
Optical SETI, 1961, lasers, communications, technology, history.
Principal Author Biography
||Born in Greenville, S.C.
||Receives a B.A. and a B.S. from Furman
||Receives an M.A. from Duke University.
|| Joins Bell Labs on West Street, N.Y.C., after receiving his Ph.D. degree in physics from the California Institute of
|| Becomes an associate professor of physics at Columbia
|| Meets Arthur L.
Schawlow, who comes to Columbia University on a fellowship and works as a research assistant to
|| Becomes a professor of physics at Columbia and executive director of the Columbia Radiation
|| Conceives if the idea of a maser (similar ideas occur independently to A. Prokhorov and N. Basov in Moscow and J. Weber of the University of
|| Becomes chairman of Columbia's Physics
|| Builds the first maser with J. P. Gordon and H. J. Zeiger at
||Co-authors the book Microwave Spectroscopy with
|| Serves as a Bell Labs consultant in the field of solid-state
|| While serving as a consultant to Bell Labs, begins working with Schawlow on the principles of a device -- the laser -- that could operate at wavelengths a thousand times shorter than the
||Proposes with Schawlow in a paper published in the
December Physical Review that the principles of the maser could be extended to the optical regions of the spectrum using an incoherent pump
|| Becomes vice-president and director of research for the Institute for Defense Analysis in Washington, D.C.
|| Receives with Schawlow a patent for the invention of the laser. The first working laser is built by
Theodore Maiman at Hughes Aircraft Company using ruby at 0.69
||Co-authors paper with R. N.
Schwartz titled: "Interstellar and Interplanetary Communication by Optical Masers"
an April issue of Nature. This
is the first description of the optical approach to SETI.
|| Shares the Nobel Prize in Physics 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."
|| Becomes Institute Professor at MIT.
|| Becomes University Professor of Physics at the University of California at
|| Becomes University Professor of Physics, Emeritus, at the University of California at
||Participated in SPIE's OSETI
||Will participates in SPIE's
OSETI III Conference which marks the 40th
anniversary of Optical SETI.
Principal Author Affiliation
Space Sciences Laboratory
University of California,
Berkeley, CA 94720-7450
||Reserved for Slideshow