English

Strong Reverse Saturation and Fast-Light in Ruby

Optics 2023-02-01 v1

Abstract

We observe a strong reverse saturation of absorption in ruby at a wavelength of 473 nm. With an intensity-modulated laser, we observe that the peaks of the pulses appear more than a hundred microseconds earlier than the reference signal. A theoretical model based on coherent population oscillation would suggest a fast-light effect with an extremely large and negative group index of (1.7±0.1)×106-(1.7\pm0.1)\times 10^6. We propose that this pulse advancement can also be described by time-dependent absorption of ruby. Our study helps to understand the nature of the fast- and slow-light effects in transition-metal-doped crystals such as ruby and alexandrite.

Keywords

Cite

@article{arxiv.2301.13300,
  title  = {Strong Reverse Saturation and Fast-Light in Ruby},
  author = {Akbar Safari and Cara Selvarajah and Jenine Evans and Jeremy Upham and Robert W. Boyd},
  journal= {arXiv preprint arXiv:2301.13300},
  year   = {2023}
}
R2 v1 2026-06-28T08:27:28.971Z