Monday, 29 August 4:00pm – 5:00pm

This seminar will be delivered in Chemistry Lecture Theatre 4 and Online Zoom Please email chemistry.researchsupport@sydney.edu.au for zoom link and password.

Speaker: Yun Li; The University of Sydney

Supervisor: A/Prof. Girish Lakhwani

Title: Design of Laser Structures and Configurations With Solution Processed Active Materials

Abstract: Solution processed lasers have seen significant progress in recent years and offer solutions to low-cost, simple fabrication, tunable light sources for myriad of applications including integrated lab-on-chip devices, spectroscopy, and sensing. For practical application, compact electrically driven lasers are desired. However major hurdles currently stunt progress into injection lasers. In the case of organic injection lasers, statistical triplet exciton formation limits the inversion density and introduces excited-state absorption loss, while accompanied by losses from injection electrodes. In addition, degradation at the high excitation densities required to achieve lasing must be addressed if such devices are to ever see commercialization.

Modifications to existing injection architectures for improving optical confinement are explored, and demonstrated through optical characterization, notably through a reduction in amplified spontaneous emission threshold. Pure optical pumping schemes circumvent issues with injection lasers and are explored in detail with new excitation schemes proposed. Pure gain-coupled distributed Bragg lasers are explored via a projection optical system with binary masks, and proximity contact phase-shift masks. We explore lasing through conformal contact of a patterned PDMS stamp with an active film. Additionally, Higher-order Bragg lasers fabricated to the 400^th Bragg order are explored with respect to lasing thresholds and output characteristics as a potentially more cost-effective alternative to conventional lower order lasers in niche applications.