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Updated: Jul 7, 2026

Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
Superluminal and slow light propagation in a room-temperature solid
Matthew S Bigelow1, Nick N Lepeshkin, Robert W Boyd
1Institute of Optics, University of Rochester, Rochester, NY 14627, USA. mbigs@optics.rochester.edu
Abstract:
We have observed both superluminal and ultraslow light propagation in an alexandrite crystal at room temperature. Group velocities as slow as 91 meters per second to as fast as -800 meters per second were measured and attributed to the influence of coherent population oscillations involving chromium ions in either mirror or inversion sites within the crystal lattice. Namely, ions in mirror sites are inversely saturable and cause superluminal light propagation, whereas ions in inversion sites experience conventional saturable absorption and produce slow light. This technique for producing large group indices is considerably easier than the existing methods to implement and is therefore suitable for diverse applications.
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