Optically Pumped Atoms [ハードカバー]

"Optically Pumped Atoms" by Happer, Jau and Walker is a fantastic book in a well focused yet burgeoning area and represents a new milestone for modern physics. It's an incredible advancement over an old favorite and still magnificent book by Robert Bernheim, "Optical Pumping: An Introduction", that helped many of us understand the important principles while developing optically pumped magnetometers for DOD in the late 60's and later. All of Happer et al.'s chapters are extremely well written with clarity and completeness and Chapter 9 on "Radiation Forces" and Chapter 10 on "Relaxation of Polarized Atoms" are extraordinarily interesting. I especially appreciate the book's use of common symbols throughout. As the authors indicated, the MATLAB code is written for clarity but real clarity for me could have been better achieved if the authors used Mathematica to closely match their equations and symbols. The MATLAB code is not written for maximum speed and that makes it a little easier to understand the code with increased satisfaction and enjoyment. Regarding the authors' equations, there are plenty of "we can write" and "one can readily verify", etc., that leaves the details to be resolved by Harold (Hypothetical Alert Reader of Limitless Dedication: as found in Julian Schwinger's "Particles, Sources and Fields" of 1970). Although the book's diagrams are few in number, they are very helpful. For as Alice suggests in Alice's Adventures in Wonderland "what is the use of a book without pictures", I also found the diagrams used by Happer et al. to make their book easier to comprehend.

Physical perspectives in terms of applications to developing or improving actual systems are absent in this book and that is unfortunate in general but specifically for potential improvements in optically pumped magnetometers. For example, on page 30 of Electronic Design 8, April 12, 1975 there appeared an enticing story titled "Small $10 magnetometer reported a rival of bulky kilo-buck units" which was about William Happer's mini-magnetometer invention. Back in 1975, the Happer mini-magnetometer was of considerable interest because of our challenging work, at the Naval Air Development Center, to improve the optically pumped helium magnetometer for anti-submarine warfare, known as the AN/ASQ-81(V) optically pumped magnetometer. So I contacted him and the concept seemed plausible in 1975. Over three years passed and in June 1978, I contacted Happer to follow-up on his progress and decided the $10 mini-magnetometer was not going to be available in the foreseeable future. After three and a half decades it would be interesting to know the status of the Happer mini-magnetometer whose critical elements were reported to occupy "a package the size of a ball point pen".

Perhaps this excellent book by Happer et al. will rekindle efforts to successfully develop an inexpensive mini-magnetometer for operation outside a lab. Such a system could have immense value in utilizing magnetic field signatures for the detection of things like submarines to IED's or applied to the development of low frequency magnetic field signal systems capable of communicating through rock with trapped miners, situational awareness in military threat environments, and medical applications. In addition, a sensitive mini-magnetometer would have enormous value in space based systems for measuring planetary and interplanetary magnetic fields, for the geophysical exploration of planets and satellites including the Earth and our Moon, and for well or borehole logging to support special drilling operations in petroleum exploration and production, etc.

"Optically Pumped Atoms" by Happer et al. along with the equally valued and well written book "Optically Polarized Atoms" by Auzinsh, Budker and Rochester have the potential to help advance optically pumped magnetometers through improved sensitivity, reduced weight, complexity, and cost. These two books have the promise to provide more than just valuable information associated with the complexities of optical pumping. These books together perhaps offer the best detailed physical insight, background, tools, and opportunity to inspire someone to seriously look at the feasibility of achieving mini-magnetometer design and perhaps even leading the way to an optically pumped magnetometer on a chip.

Andrew Ochadlick
andrewochadlick@comcast.net