History of the Space Based Laser
Some of the history of adaptive optics is still classified and so is a dozen years of my life, so, unfortunately I can’t discuss that, and that’s unfortunate, because a lot of the development of adaptive optics into practical use that led to astronomical wide-spread use occurred there.
Adaptive optics can clear up atmospheric turbulence allowing ground-based telescopes to see with Hubble clarity.
History
Every answer on adaptive optics must mention Archimedes. The use of a large number of mirror segments each controlled by a simple technique is, of course, the source of legend if not myth. Polished metal shields could easily have accomplished the feat with a simple hole in a flat shield that could have been used to align the Sun’s spot on the ground through the hole with the line of sight to the ship viewed through the same hole. The history of determining that this myth is “plausible” is recounted here: Mythbusters were scooped — by 130 years! (Archimedes death ray)
Horace Babcock first proposed using adaptive optics in 1953, but the state of technology was not up to the task at the time. He proposed using a thin oil film bombarded with an electron beam to modulate the phase. (This was a technique used in projection TVs at the time.)
Several people working at Itek produced an elegant system for compensated imaging. Some of these people started their own companies. Some notable examples:
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In the late 1960s, work had progressed on lasers to the point that very powerful CO2 lasers were being tested as possible anti-missile weapons. Almost since the beginning of the laser, the Army was interested in its use as a missile defense. A high energy laser was being tested on ALL (Airborne Laser Laboratory) to defend against cruise missiles. One of the obvious problems was that the CO2 laser beam was absorbed enough by the air to cause heating which in turn caused thermal lensing. This whole process was called thermal blooming. That and the fact that the laser beam wavefront was not so great coming out of the laser led to a sudden renewed interest in adaptive optics.
  Darryl Greenwood Chuck Primmerman |
The Air Force turned to MIT Lincoln Laboratory for help. Darryl Greenwood and Chuck Primmerman pondered the problem, scoped out what needed to be done, worked out some of the equations, and published a couple of papers. What followed was a COAT system (Coherent Optical Adaptive Technique) and Hughes (O’Meara and Pearson) worked on the HICLAS deformable mirrors (HI power Closed-Loop Adaptive System). This system was not based on wavefront sensing. It was a multi-dither approach that resulted in limited bandwidth and for targets that were a good distance away, had severe latency issues |
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A history of adaptive optics at MIT LL was published in the 1992 Lincoln Laboratory Journal here: https://pdfs.semanticscholar.org... |
| Jim Pearson came to Pratt & Whitney Aircraft in the late 1970s and deformable mirrors (HICLAS) started to be produced there. COAT work was being done there in the field at the XLD (experimental laser device) test range in the late 1970s in support of future use on ALL-like programs. |
Jim Pearson |
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| Meanwhile, the Air Force was imaging satellites such as Skylab from its AMOS (Air Force Maui Optical Station) high on Mount Haleakala. They recognized that adaptive optics technique, which they called “compensated imaging” could give them better images of satellites, and potentially be used to discriminate ballistic missile post-boost objects optically from the ground. This history of this is given in a Lincoln Laboratory Journal Article here: http://baseballanalysts.com/arch... |
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| The HF/DF chemical laser was quickly outpacing the CO2 laser and was being planned for the DARPA Triad, a space based laser to defend against ICBMs. To correct the outgoing wavefront of the laser and segmented giant telescope mirror, adaptive optics were used sampled by Holographic Optical Elements placed on the primary mirror. A lot of ground testing of this system, including ALI (Alpha-Lamp Integration experiment) continued up to the end of the 1990s. It was successful. This work was led by Fritz Benning (Rockwell/Hughes) and Sam Williams (Lockheed/Hughes). |
Fritz Benning Sam Williams |
Meanwhile, Darryl Greenwood and Chuck Primmerman wrote a history of adaptive optics at MIT LL here: https://www.spiedigitallibrary.o...
There is an out-of-print set of adaptive optics papers edited by Jim Pearson here: Selected Papers on Adaptive Optics for Atmospheric Compensation
| The table of contents of this publication is an interesting index to who was working on adaptive optics. I should mention Dave Fried and Glenn Tyler (The Optical Sciences Corporation) as having developed a lot of theory related to the atmospheric turbulence characteristics and the requirements on an adaptive optics system to correct images or laser beams to a particular accuracy. |
David L. Fried Glenn Tyler |
| In April, 1981, compensated imaging was used from The Air Force Malabar site to examine shuttle tile damage on STS-1 for NASA. A couple of photos were mistakenly released to the press and were shown on the news Saturday morning. They were quickly and quietly withdrawn, having caused unwanted attention to the Air Force capabilities. |
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| In 1981, Julius Feinleib was thinking about the problem that a relatively bright natural star is needed as a reference to use to measure the wavefront needed to do the adaptive optics correction. It occurred to him that if a suitable star is not present, a bright laser could be focused on a layer of atmosphere and the Rayleigh scatter could be used as a reference for the wavefront sensor. This idea was immediately classified. The idea was put to use at Starfire Optical Range by the Air Force under the direction of Bob Fugate. |
 The original laser guide star at Starfire Optical Range in the 1980s.
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In 1985, Julius Feinleib and several of his staff got a patent on adaptive optics systems. Filed: December 6, 1985 Date of Patent: April 12, 1988 Assignee: Adaptive Optics Assoc., Inc. Inventors: Thomas Gonsiorowski, Julius Feinleib, Peter F. Cone, Andrew J. Jankevics, Kelsey S. Nikerson, Lawrence E. Schmutz, Anthony Vidmar, Allan Wirth
The problem with adaptive optics at that time was that you needed a reasonably bright star, say 10th magnitude, within an arc second or two of what you wanted to image. At that point, using a laser beam as an artificial “guide star” (LGS = Laser Guide Star) became the norm. The Air Force was quietly doing this at places like Sandia Optical Range, later named Starfire Optical Range in Albuquerque, New Mexico.
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In 1983, Bob Fugate, the director of the Starfire Optical Range, achieved closed loop operation with a laser guide star. In 1985, Foy and Labeyrie independently introduced the laser guide star idea in open literature. This caused a little stir at the Air Force because the subject was classified (but the authors did not know that), but the paper did not receive a lot of notice. (Foy, R. and A. Labeyrie (1985). Feasibility of adaptive optic telescope with laserprobe. ASTRON. ASTROPHYS. 152:29-31) In 1991, Fugate was successful in getting compensated imaging and laser guide star work declassified. An avid amateur astronomer, Bob was passionate about the impact that this would have on astronomy. It was a long and difficult path for getting the declassification, but the Foy and Labeyrie paper helped, and the value to astronomy was immeasurable.
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A NEW GENERATION OF HIGH RESOLUTION OPTICS WITHOUT ADAPTIVE OPTICS An imaging technique that does not use adaptive optics is getting a lot of attention these days. It is called multi-frame blind deconvolution. Image of Hubble Telescope from the ground using blind deconvolution See also: https://www.photonics.com/Articl... Issue | New Scientist (requires subscription)
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Revised: March 07, 2020 .
