Anomalous Dispersion of Light in the R Lines of Ruby and the Refraction Shift of the Spectrum Produced by a Laser

Pil Hyon Kim, Susumu Namba

Brent L. Bean

M. D. Galanin, Aleksandr M Leontovich, Zoya A Chizhikova

Rajitha Papukutty Rajan, Hans Riesen

Studies about light propagation have been undertaken for more than a century. It is now well established that any material that has normal or anomalous dispersion generates slow or fast light. In this paper, we demonstrate an experimental technique to rapidly switch between slow and fast light in ruby. The experiment utilizes transient holeburning to create drastic variation in refractive index of ruby to produce slow as well as fast light. Transient hole-burning involves the depletion of the ground state leading to a highly populated excited state by single frequency laser excitation. This leads to a hole in the absorption spectrum when readout by a laser. We observed a delay of 29 ns and advancement of -11 ns in an external magnetic field of B║c = 12 mT corresponding to a group velocity of c/961 and negative group velocity of –c/365 respectively.

Jerald R. Izatt, Harold A. Daw, Mitchell,Robert C.

High-resolution measurements have been made of the anomalous dispersion associated with the two Stark components of the R sub l absorption line in ruby. These preliminary measurements suggest that the R sub l dispersion obeys the Kronig-Kramers relations; however, it is superposed on a background which is itself anomalous because the refractive index increases with increasing wavelength. These measurements cover a wavelength interval of about 0.5 A, and the change in background index is of the order of 0.001 while the R sub l dispersion curve deviates from the background value by about 0.0001 at the maximum. A second surprising feature of the measurements is the observation that coherent radiation from a ruby laser, which was used to illuminate the ruby sample, is absorbed less in traversing the sample than would be expected on the basis of absorption measurements made with incoherent light. Highly accurate measurements have been made of the temperature dependence of the ruby laser emission between 63K and 116K and in a second interval between 196K and 207K. Light shielding is described which has been designed and tested to minimize pump light and ruby fluorescence at the detector in experiments with the sample optically pumped. (Author)

Jerald R. Izatt, Brent L. Bean, Harold A. Daw

The real and imaginary parts of the complex index of refraction in the R-line region of ruby have been measured near liquid-nitrogen temperature with sufficient resolution that the R-line doublet structure was well resolved. A modification of the usual Babinet compensator technique was used for the refractive-index measurements, which were found to correlate with the absorption measurements as predicted by the Kramers-Kronig relations. An attempt at direct quantitative verification of the dispersion relations for an optically pumped sample is also described.