The Measurement of Fundamental Constants (Metrology) and Its Effect on Scientific and Technical Progress
It is perhaps appropriate that in this year 1975, which marks the centenary of the Systeme Metrique and that of the Bureau International des Poids et Mesures, scientific activity in the field of Metrology appears to be flourishing. This is witnessed on the one hand by the number, range and quality of the contributions to this Symposium and, on the other, by the importance which most of the 44 Governments affiliated to the BIPM attach both to their Basic Laboratories and to the network of technical centers engaged in developing measuring methods and in disseminating their results to all levels of the various branches of industry. Should this state of affairs be considered a happy but ephemeral stage in the march of science, or does it represent a tendency of fundamental importance in the evolution of science and technology ? Enough is now known about the history of civilization for us to affirm that, even since the Renaissance, Metrology has payed an ever greater part in both scientific and civic activities.
Impact of Atomic Physics on Fundamental Constants
This report offers one experimentalist’s outlook on the constants area especially from the perspective of atomic physics. There are many recent reviews of selected areas of such work in addition to the well-known periodic overall studies including least squares adjustments. My intent is neither to offer the scientific depth of the specialized reviews nor to even approach the technical scope of an overall adjustment.
Frequency Stabilization of the 3.39-µm Laser on a CH4 Line
Theoretical and experimental studies on a primary standard of wavelength and frequency in the infrared are reported. The 3.39-μm He-Ne laser is tuned to the center of the absorption line of methane which is assigned to the F1(2) component of the P(7) branch of the v3 band. The absence of Stark and Zeeman effects under the highest fields tested, the strong absorption at 63.2°K as well as at 78°K, and the separation from other lines are excellent features for a high degree of absolute stability and reproducibility. A method of automatic frequency control of the He-Ne laser at the line-center of methane is described.