A room temperature continuous-wave nanolaser using colloidal quantum wells

Zhili Yang,Edo Waks,Dmitri V Talapin,Matthew Pelton,Igor Fedin

doi:10.1038/s41467-017-00198-z

Abstract

Colloidal semiconductor nanocrystals have emerged as promising active materials for solution-processable optoelectronic and light-emitting devices. In particular, the development of nanocrystal lasers is currently experiencing rapid progress. However, these lasers require large pump powers, and realizing an efficient low-power nanocrystal laser has remained a difficult challenge. Here, we demonstrate a nanolaser using colloidal nanocrystals that exhibits a threshold input power of less than 1 μW, a very low threshold for any laser using colloidal emitters. We use CdSe/CdS core-shell nanoplatelets, which are efficient nanocrystal emitters with the electronic structure of quantum wells, coupled to a photonic-crystal nanobeam cavity that attains high coupling efficiencies. The device achieves stable continuous-wave lasing at room temperature, which is essential for many photonic and optoelectronic applications. Our results show that colloidal nanocrystals are suitable for compact and efficient optoelectronic devices based on versatile and inexpensive solution-processable materials.

Highlights

Colloidal semiconductor nanocrystals have emerged as promising active materials for solution-processable optoelectronic and light-emitting devices
A number of works incorporated colloidal quantum dots into nanocavities[26,27,28], but were unable to reach lasing due to rapid Auger recombination, which resulted in gain quenching
We demonstrate lasing with a threshold input power of 0.97 μW, an extremely low threshold for any laser using colloidal emitters

Summary

Introduction

Colloidal semiconductor nanocrystals have emerged as promising active materials for solution-processable optoelectronic and light-emitting devices. In addition to quantum dots, new colloidal materials such as nanorods[15, 16], nanoplatelets[17,18,19,20] and perovskite nanocrystals[21, 22] have emerged as good gain materials for room temperature amplified spontaneous emission and lasing. All of these past works required large pump powers to achieve lasing threshold due to their large cavity mode volume and high loss. Our results are an important step towards efficient on-chip light emitters and photonic integrated devices based on colloidally synthesized solution-processable materials

Methods

Results

Conclusion