Circularly Polarized Stimulated Emission from a 2D Chiral Cavity Based on ACD Organic Thin-Films

Tzu-Ling Chen^1*, Li-Zhi Lin¹, Ling-Qi, Huang¹, Yi-Jan Huang¹, Francesco Zinna², Gennaro Pescitelli², Laura A. Aronica², Lorenzo di Bari², Randall H. Goldsmith³

¹Photonics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
²Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Pisa, Italy
³Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA

* Presenter:Tzu-Ling Chen, email:tlc@nycu.edu.tw

A recently developed nonreciprocal organic chiral thin film has shown significant potential for generating circularly polarized (CP) light. In this study, we integrated the film into a free-space dye laser system by coating one of the cavity mirrors with the chiral material. This configuration successfully produced direct CP laser emission with a degree of circular polarization (DOCP) reaching up to 0.6 while the degree of polarization (DOP) approaching 0.8. The observed ellipticity is experimentally confirmed to stem from the chiral film, leading to asymmetric cavity losses between right- and left-circularly polarized light. Comprehensive polarimetric characterization revealed that the generated light exhibits a dynamic level of circularity, which initially increases and then decreases with changes in pump energy. We also present a simple laser pulse evolution model to explain this behavior.

Keywords: chiral, circular dichorism, stimulated emission, laser, polarization