Remotely-sensed atomic magnetometry

Thesis (M.S.)--Boston UniversityCoherent population trapping (CPT) effects can be realized with frequency mod- ulated lasers and compact vapor cells of alkali metals such as Rubidium-87. Using these optical resonances, one can readily measure the hyperfine separation of this three-level atom. In the presence of a magnetic field, the Zeeman effect causes magnetic sublevels of these hyperfine ground states to split; the frequency of such splitting can be measured in an ensemble of Rubidium atoms with the magnetometer we have constructed. While other groups have constructed magnetometers based on these effects, none to our knowledge have investigated the capability to measure magnetic fields remotely. Most atomic-optical magnetometers,colocate the transmit and receive optical system with the vapor cell itself or require fiber optics at the location of the cell; our free-space technique with a reflective geometry lends itself to measurement at distances greater than could be achieved with those methods. We have developed a laboratory FM laser spectrometer that interrogates CPT resonances to measure magnetic fields with the vapor cell not necessarily co-located with the spectrometer. Its intrinsic linewidth (in the presence of transit-time broadening) is less than 30 kilohertz, which allows measurements on the order of 2 microtesla. We present results concerning the accuracy of the magnetometer at about one meter of standoff distance, and describe considerations for measurements at longer distances

Summary of Research 1994

The views expressed in this report are those of the authors and do not reflect the official policy or position of the Department of Defense or the U.S. Government.This report contains 359 summaries of research projects which were carried out under funding of the Naval Postgraduate School Research Program. A list of recent publications is also included which consists of conference presentations and publications, books, contributions to books, published journal papers, and technical reports. The research was conducted in the areas of Aeronautics and Astronautics, Computer Science, Electrical and Computer Engineering, Mathematics, Mechanical Engineering, Meteorology, National Security Affairs, Oceanography, Operations Research, Physics, and Systems Management. This also includes research by the Command, Control and Communications (C3) Academic Group, Electronic Warfare Academic Group, Space Systems Academic Group, and the Undersea Warfare Academic Group