Femtosecond pulse propagation at exciton resonance: polariton beats and optical precursor

Summary form only given. We perform pulse propagation experiments at the Z/sub 3/-exciton resonance of CuCl, and observe polariton beats and an optical precursor clearly. The exciton in CuCl has very large oscillator strength and long decay time. With increasing input-pulse intensity, polariton beats are strongly suppressed. We confirmed these experimental results with Lorentzian oscillator model and obtained good agreement.