Picosecond spectroscopy of polaritons in anthracene crystals. I. Preresonant scattering

• Published in: Journal of luminescence Vol. 35; no. 5; pp. 267 - 275
• Main Authors: Aaviksoo, J., Freiberg, A., Reinot, T., Savikhin, S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 1986; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Infrared and raman spectra and scattering; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Physics; Picosecond; Time resolution; Anthracene; Exciton; Experimental study; Polariton; Condensed benzenic compound; Organic compounds; Preresonance Raman scattering
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/0022-2313(86)90050-5

The resonant secondary emission spectrum of anthracene crystals is investigated by applying simultaneous time and frequency resolution. Under preresonant excitation the secondary emission of polaritons has an essentially nonexponential time behavior that depends strongly on the excitation frequency. At larger detunings the “Raman-like” lines, shifting together with excitation, have “fast” and a “slow” component, which correspond to different channels in populating the final polariton states. It is shown that such preresonant excitation can create a long-lived (≈1 ns) population of excitonic polaritons in the crystal. Group velocity plays the main role in the polariton dynamics.