Time-Dependent Optical Spectroscopy of Polariton Systems Having a Minimum Group Velocity

If a pulse of light is transmitted through a slab of material whose polariton dispersion curve has a minimum value for the group velocity [$\omega \mathrm{}\left(q\right)\mathrm{}$ has an inflection point], then the intensity of emergent light will oscillate before decaying, in accordance with the properties of the Airy function. The effect is linear in the applied field of the incident light. Application is made to the $A(n=1\mathrm{})\mathrm{}$ exciton-polariton of CdS, with no adjustable parameters.