Origin of emission from square-shaped organic microlasers

¹ Laboratoire de Photonique Quantique et Moléculaire, ENS Cachan, Centrale Supélec, CNRS, Université Paris-Saclay - F-94235 Cachan, France
² Department of Applied Physics, Yale University - New Haven, CT 06520, USA
³ Surface du Verre et Interfaces, UMR 125 CNRS/Saint-Gobain Recherche - 39 quai Lucien Lefranc, F-93303 Aubervilliers, France
⁴ Laboratoire de Photonique et Nanostructures, CNRS UPR20 - Route de Nozay, F-91460 Marcoussis, France
⁵ Centre de Mathématiques et de leurs Applications, ENS Cachan, CNRS, Université Paris-Saclay - F-94235 Cachan, France
⁶ Département de Physique, Université de Liège - 4000 Liège, Belgium
⁷ Université Paris-Sud, Laboratoire de Physique Théorique et Modèles Statistiques, CNRS UMR 8626 Orsay, F-91405, France

^(a) lebental@lpqm.ens-cachan.fr

Received: 22 January 2016
Accepted: 15 March 2016

Abstract

The emission from open cavities with non-integrable features remains a challenging problem of practical as well as fundamental relevance. Square-shaped dielectric microcavities provide a favorable case study with generic implications for other polygonal resonators. We report on a joint experimental and theoretical study of square-shaped organic microlasers exhibiting a far-field emission that is strongly concentrated in the directions parallel to the side walls of the cavity. A semiclassical model for the far-field distributions is developed that is in agreement with even fine features of the experimental findings. Comparison of the model calculations with the experimental data allows the precise identification of the lasing modes and their emission mechanisms, providing strong support for a physically intuitive ray-dynamical interpretation. Special attention is paid to the role of diffraction and the finite side length.