Abstract
A free-electron laser oscillator has been operated above threshold at a wavelength of 3.4 μm.
- Received 17 February 1977
DOI:https://doi.org/10.1103/PhysRevLett.38.892
©1977 American Physical Society
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Letters from the Past - A PRL Retrospective
2008 marked PRL’s 50th anniversary. As part of the celebrations a collection of milestone Letters was started. The collection contains Letters that have made long-lived contributions to physics, either by announcing significant discoveries, or by initiating new areas of research.