[ 1930-31 | 1931-40 | 1940-46 | 1946-76 | 1976-2010 | Future Outlook ]

George R. Harrison Spectroscopy Laboratory History

The history of the Spectroscopy Laboratory falls naturally into five divisions: its founding by George R. Harrison in the Physics Department (1930-1931), basic spectroscopic research on atomic structure (1931-1940), national defense activities (1940-1946), research activities as an Interdepartmental Laboratory under the direction of Richard C. Lord (1946-1976), and the expansion of the Laboratory research activities under the direction of Michael S. Feld (1976-2010).

Founding of the Spectroscopy Laboratory (1930-31)
When George R. Harrison moved from Stanford University to become Professor of Experimental Physics at MIT in 1930, he was asked by MIT's President, Karl T. Compton, also a physicist, to indicate his needs for space in the new Eastman Research Laboratories (Building 6), then under construction. These needs included space for a Rowland circle of 10-meter diameter and a large 21-foot vacuum spectrograph. The two men concluded that these needs could not be met in the Eastman building, and they decided to put up an additional building adjacent to the main research laboratories, especially designed to house spectroscopic equipment. Compton was personally involved in the design and oversaw its construction. This building, the Spectroscopy Laboratory (Building 6A), was completed in 1931, a full year before the adjacent Eastman Research Laboratories were finished. It is believed to be the first building constructed entirely for the purpose of conducting spectroscopy research. Its windowless walls are more than four feet thick and effectively isolate the interior from external thermal variations. The floors are also isolated from external vibrations. In view of its massive construction, it is surprising to realize that the Laboratory was built somewhat as an afterthought.

As the Laboratory was an appendage of the Physics Department, all of its staff members were physicists. In addition to Drs. Harrison and Compton, they included Associate Professor J.C. Boyce and two instructors, Dr. John Wulff, who later became Professor of Metallurgy, and Dr. Henry M. O'Bryan, who later took a research position at Sylvania. Two graduate research assistants, Walter E. Albertson and Donald Weaver, had come with Harrison from Stanford; the former, after earning a Ph.D., remained in the Laboratory for several years and did fine work analyzing the spectra of complex rare earth atoms. Although the Laboratory was just founded, it had many visitors from other laboratories in the United States and abroad, who worked on special problems for which the unique equipment developed in the Spectroscopy Laboratory was needed. This tradition continues to the present day.

Atomic Spectroscopy & MIT Wavelength Tables (1931-1940)
In its early years, the Spectroscopy Laboratory became famous under Professor Harrison's leadership for its contributions to atomic spectroscopy, namely the analysis of complex spectra, with some emphasis on qualitative and quantitative analysis of materials.

During this period, Harrison became interested in developing special machines for diminishing the complex and tedious labor of converting spectroscopic data to usable form. The bottleneck in determining atomic energy levels turned out to be the precision of wavelength measurements, for which six- or seven-figure accuracy was required. Harrison designed and constructed the first automatic comparator for measuring spectral line wavelengths with high speed and precision.

By 1934 this instrument was able to scan, compute and record up to 2000 seven-figure wavelengths from a 20-inch photographic spectrum in 120 seconds. Thus, the Laboratory began the accumulation of thousands of feet of 35mm motion picture film containing intensity traces as a function of wavelength to the stated accuracy of seven figures. This spectroscopic data eventually resulted in the MIT Wavelength Tables.

These tables, first published in 1939, by the MIT Press, contain 110,000 seven-figure wavelengths assigned to their elements of origin, in accordance with the measurements in the Spectroscopy Laboratory as well as those given in the literature, and are still in daily use in laboratories throughout the world. A second and slightly enlarged edition was published in 1969 with assistance from the National Bureau of Standards.

A second major development in the 1930s was the application of a new type of electromagnet, designed by Professor Francis Bitter of the Physics Department, to high-field Zeeman effect studies. Many rare earth and other complex spectra were studied in magnetic fields of up to 100,000 gauss, and new orders of magnetic separation of spectral lines became available at static fields up to 2.5 times as intense as those previously attainable. This magnet proved to be a particularly powerful tool for determining atomic quantum numbers and spectral structure. Many of these spectral traces and photographs were provided to analysts such as W.F. Meggers and C.C. Kiess of the National Bureau of Standards and numerous other workers.
Starting in 1933, the Spectroscopy Laboratory hosted a six-week summer course in spectroscopy for visitors from academia and industry. At the end of the summer, the Spectroscopy Laboratory held the Summer Conference on Spectroscopy, which drew an international attendance of about 200 researchers. The published reports of these conferences had a substantial impact on the field of quantitative emission spectroscopy. In 1942, this conference was discontinued because of the World War II.

Furthermore, Harrison recognized the value of cooperative work with researchers in other fields to which the new techniques of spectroscopy could be applied, especially in the departments of Chemistry, Biology and Metallurgy.

National Defense Research (1940-46)
During the period from 1940 to 1946, many of the Laboratory's scientists became occupied with national defense and war work, and their spectroscopic research projects were gradually reduced. During much of this time, the Laboratory's facilities were used for spectrochemical analysis for the Manhattan Project, and many thousands of uranium samples collected from the first atomic reactor at the University of Chicago were analyzed with the help of the 10-meter grating spectrograph. During the war, Harrison served as Chief of the Optics Division of the National Defense Research Committee, and became acquainted with a vast array of scientists engaged in the war effort, including Richard C. Lord, a physical chemist specializing in infrared and Raman spectroscopy. This widening of horizons was to have important consequences in the post-war future of the Laboratory.

Richard C. Lord, Director (1946-1976)
In 1942, Harrison became Dean of the School of Science at MIT, and it became evident that a new Director for the Spectroscopy Laboratory was needed. In addition, Harrison felt that the Laboratory's research activities "should be expanded to other fields, in addition to physics, where spectroscopic techniques were useful." The appointment of Professor Richard C. Lord as Director of the Laboratory in July 1946 and its transfer to interdepartmental status constituted a scientific as well as administrative change. Lord, a chemist, was a specialist in the spectroscopy of polyatomic molecules, particularly in the infrared region. This part of the spectrum had not been investigated hitherto in the Laboratory, but instrumental developments during World War II had improved infrared techniques and shown the scientific value of infrared research.

After 1946, the interest of Professor Harrison, now Dean of the School of Science at MIT, turned to the development of spectroscopic instrumentation. In 1949, he invented the echelle spectrograph, which combines very high resolution with broad spectral range. He developed engines for the ruling of diffraction gratings under interferometric control, by which gratings of unprecedented size (as large as 400 x 600 mm) and optical performance were produced.

During Lord's tenure from 1946 to 1976, the Laboratory established research programs in both infrared and Raman spectroscopy with substantial funding, at first from the Office of Naval Research and later from the National Science Foundation and the National Institutes of Health. Among the scientific achievements during this period were; the observation of Coriolis-activated forbidden vibrational transitions; development of tables of Coriolis coupling coefficients from symmetry arguments; synthesis and complete vibrational analysis of a large number of molecules in which deuterium replaced hydrogen; discovery and exploitation of the anomalous far-infrared spectra of ring molecules; the first vibrational analyses of the laser Raman spectra of proteins; and the important demonstration by Raman spectroscopy that the conformation of transfer RNA as determined by X-ray diffraction from a crystalline sample is the same as that in the aqueous medium existing in living cells.

Some fifty PhD theses in chemistry were based on work done in the Laboratory in this period, and a like number of postdoctoral research fellows and visiting scientists from the U.S. and 15 from foreign countries came to use its facilities. In parallel with its development of infrared techniques, especially in the demonstration of the power of diffraction gratings in "bench top" spectrometers, the Laboratory was a pioneer in the postgraduate training of research personnel in infrared spectroscopy by establishing the first summer training program in this field in 1950. In the period 1950-1972, this program introduced 2100 scientists to infrared techniques and applications.

With the arrival of Professors Charles H. Townes and Ali Javan and their associates to the Laboratory in 1962, the possibilities of using the recently invented laser in spectroscopic research began to be explored. Townes was awarded the Nobel Prize in Physics in 1964 for his contributions in the 1950s to the development of the maser and laser, and Javan had invented the gas laser in 1960. Their achievements in the Laboratory include development of a version of the Michelson-Morley experiment using infrared lasers, which gave an improved upper limit on the anisotropy of space, or the effect of "ether drift," and pioneering studies by Townes and his colleagues of the stimulated Raman and Brillouin effects. Another important achievement was the observation by Javan of the first Lamb dip and its applications to measurement of the 1.15 micron Ne²⁰-Ne²² isotope shift. This experiment marked the beginning of the field of high-resolution laser saturation spectroscopy.

Michael S. Feld, Director (1976-2010)
These and other studies made apparent the importance of lasers to spectroscopy and the study of dynamical processes in atoms and molecules. With the selection of Professor Michael S. Feld as Lord's successor in 1976, lasers become the central research tool of the Laboratory. Professor Feld received his training at the Institute, earning a PhD in physics in 1967. His special interest was the interaction of intense light fields with atoms and molecules.

Professor Feld led the Laboratory into a new era, pursuing fundamental studies and applications of lasers in various branches of science and engineering. The strong interdisciplinary emphasis is characterized by a widening set of active faculty participants from the physics, chemistry, biology and engineering departments. Major programs include high-resolution laser saturation spectroscopy, study of dynamical processes in atoms and molecules, laser chemistry, the application of lasers to nuclear physics and studies of structure and function of biological molecules using resonance Raman and other laser techniques. Achievements include the first observation of superradiance by Feld and his coworkers, and the discovery of a left-handed form of the DNA double helix by Professor Alexander Rich of the Biology Department and his colleagues, accomplished by analyzing X-ray diffraction patterns with the Laboratory's optical analog comparator. Under Feld's directorship, there was a marked increase in the number of collaborations, including colleagues from more than 10 institutions.

In 1985 Feld established the Laser Biomedical Research Center (LBRC) at the laboratory with support from the National Institutes of Health. With the LBRC, the Spectroscopy Laboratory became a leading research center in applications of spectroscopy to biomedicine. LBRC researchers developed techniques in fluorescence spectroscopy, Raman spectroscopy, multi-modal spectroscopy, and other technologies to image living cells and diagnose diseases from arteriosclerosis to breast cancer.

Future Outlook

Within this historic framework, the Spectroscopy Laboratory today is pursuing fundamental and applied research in a variety of fields. The Laboratory has wide interdisciplinary efforts and, in fact, was in the first group of MIT's interdepartmental laboratories. Currently, MIT faculty members from physics, biology, chemistry and several departments in the School of Engineering pursue research here. There is much collaborative activity, including strong interactions with outside scientists from universities and medical centers across the country.