- Rapid Communication
- Access by Xinjiang University
Sensitive detection of Doppler-free two-photon-excited 2S positronium by spatially separated photoionization
Phys. Rev. A 44, R5(R) – Published 1 July, 1991
DOI: https://doi.org/10.1103/PhysRevA.44.R5
Abstract
Using a spatially filtered pulsed laser at 486 nm we have photoexcited positronium to the 2S state and detected it via a delayed and spatially separated 532-nm photoionization pulse. We have extended our observations down to low 486-nm power to explore the possibility of a cw measurement of the positronium 1S-2S interval. A model calculation taking into account the velocity distribution of the 235-K positronium from an oxygenated cold Al(111) target, the parameters of the laser beams, and the nonlinear excitation probability explains our data. The same model indicates that a cw measurement is presently feasible.
References (7)
- For a general reference, see J. R. Sapirstein and D. R. Yennie, in Quantum Electrodynamics, edited by T. Kinoshita (World Scientific, Singapore, 1990), p. 560.
- Steven Chu, Allen P. Mills, Jr., and John L. Hall, Phys. Rev. Lett. 52, 1689 (1984).
- K. Danzmann, M. S. Fee and Steven Chu, Phys. Rev. A 39, 6072 (1989).
- M. S. Fee, K. Danzmann, and Steven Chu (unpublished).
- A. P. Mills, Jr., et al., Phys. Rev. Lett. 66, 735 (1991).
- R. H. Howell, R. A. Alverez and M. Stanek, Appl. Phys. Lett. 40, 751 (1982); A. P. Mills, Jr., et al., Rev. Sci. Instrum. 60, 825 (1989).
- D. H. McIntyre and T. W. Hänsch, Phys. Rev. A 36, 4115 (1987).