Nature 285, 388 - 390 (05 June 1980); doi:10.1038/285388a0

Frequency of the methane-stabilized He−Ne laser at 88 THz measured to 3 parts in 10¹¹

D. J. E. Knight^*, G. J. Edwards, P. R. Pearce & N. R. Cross

National Physical Laboratory, Teddington, Middlesex TW11 0LW, UK
^*Present address: Bureau International des Poids et Mesures, F-92310 Sèvres, France.

We have measured the frequency of methane-stabilized laser at 88 THz (3.39 µm) (ref. 1), by method which largely eliminates the uncertainties contributed by lower-frequency lasers used as transfer oscillators. This result is primarily of interest for proposed new definition of the metre in which the speed of light in vacuum (c ₀) would be kept constant and reference would be m de to the standard of time and frequency². For this re son our measurement has been referred to the me an frequency of five small portable, stabilized lasers of similar design that re used as wavelength standards^3,4. We estimate the me an frequency of the laser ensemble to have been (88, 376, 181, 616 3) kHz. The estimated standard deviation comes within about factor of 2 of the reproducibility of the lasers themselves. This result therefore demonstrates degree of accuracy that would permit the choice of definition of the metre in which c ₀ was kept constant, without substantial loss of accuracy compared with choosing definition based on the wavelength of selected stabilized laser.

References

1.	Barger, R. L. & Hall, J. L. Phys. Rev. Lett. 22, 4−8 (1969). | Article | ISI | ChemPort |
2.	Com. Consult. Definition Metre (Com. Int. Poids Mesures) 5th Session (1973); 6th Session (1979).
3.	Jolliffe, B. W., Kramer, G. & Chartier, J.-M. IEEE Trans. Instrum. Meas. IM-25, 447−450 (1976).
4.	Felder, R., Jolliffe, B. W. & Chartier, J.-M. Rapport BIPM/79-7 (Bureau International des Poids et Mesures, F-92310 Sèvres, France, 1979).
5.	Evenson, K. M., Wells, J. S., Petersen, F. R., Danielson, B. L. & Day, G. W. Appl phys. Lett. 22, 192−195 (1973). | Article | ISI | ChemPort |
6.	Blaney, T. G., Edwards, G. J., Jolliffe, B. W., Knight, D. J.E. & Woods, P. T. J. Phys. D9, 1323−1330 (1976). | ISI | ChemPort |
7.	Blaney, T. G. et al. Proc. R. Soc. A355, 61−68; 89−114 (1977). | ISI | ChemPort |
8.	Layer, H. P., Deslattes, R. D. & Schweitzer, W. G. Jr, Appl. Optics 15, 734−743 (1976). | ISI | ChemPort |
9.	Woods, P. T., Shotton, K. C. & Rowley, W. R. C. Appl. Opt. 17, 1048−1054 (1978). | ISI | ChemPort |
10.	Knight, D. J. E. et al. in Proc. 6th Vavilov Conf. on Nonlinear Optics, Akademgorodok, Novosibirsk, USSR, June 1979 (in the press).
11.	Blaney, T. G., Cross, N. R., Knight, D. J. E., Edwards, G. J. & Pearce, P. R. J. Phys. D (in the press).
12.	Eisenhart, C. Natn. Bur. Stand. (U. S.), Spec. Publ. 343, 509−518 (1971).
13.	Domnin Yu., S., Koshelyaevskii, N. B., Tatarenkov, V. M. & Shumyatskii, P. S. Pis'ma v Zh. Eksp. Teor. Fiz. (USSR) 30, 273−5 (1979).