Toward continuous-wave operation of organic semiconductor lasers

TLDR

Continuous‑wave lasing from organic semiconductor films is highly desirable for practical applications but remains a challenging objective. The authors achieved low‑threshold surface‑emitting organic distributed‑feedback lasers by using a high‑gain, high‑quantum‑yield thin film without triplet absorption losses and a mixed‑order grating, and by applying a simple encapsulation that reduces thermal degradation and ablation. The study demonstrates low‑threshold quasi‑continuous‑wave operation at 80 MHz and 30 ms long‑pulse excitation, showing that continuous‑wave organic semiconductor laser technology is achievable through gain‑medium and device‑architecture engineering.

Abstract

The demonstration of continuous-wave lasing from organic semiconductor films is highly desirable for practical applications in the areas of spectroscopy, data communication, and sensing, but it still remains a challenging objective. We report low-threshold surface-emitting organic distributed feedback lasers operating in the quasi-continuous-wave regime at 80 MHz as well as under long-pulse photoexcitation of 30 ms. This outstanding performance was achieved using an organic semiconductor thin film with high optical gain, high photoluminescence quantum yield, and no triplet absorption losses at the lasing wavelength combined with a mixed-order distributed feedback grating to achieve a low lasing threshold. A simple encapsulation technique greatly reduced the laser-induced thermal degradation and suppressed the ablation of the gain medium otherwise taking place under intense continuous-wave photoexcitation. Overall, this study provides evidence that the development of a continuous-wave organic semiconductor laser technology is possible via the engineering of the gain medium and the device architecture.