Ultralow‐Threshold and High‐Quality Whispering‐Gallery‐Mode Lasing from Colloidal Core/Hybrid‐Shell Quantum Wells. Issue 13 (28th January 2022)

• Record Type: Journal Article
• Authors: Duan, Rui; Zhang, Zitong; Xiao, Lian; Zhao, Xiaoxu; Thung, Yi Tian; Ding, Lu; Liu, Zheng; Yang, Jun; Ta, Van Duong; Sun, Handong
• Is Part Of: Advanced materials. Volume 34:Issue 13(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-01-28
• Subjects: colloidal quantum wells -- compositional engineering -- monolithic microcavities -- single‐mode lasing -- ultralow threshold lasing -- whispering gallery modes; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202108884
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: The realization of efficient on‐chip microlasers with scalable fabrication, ultralow threshold, and stable single‐frequency operation is always desired for a wide range of miniaturized photonic systems. Herein, an effective way to fabricate nanostructures‐ whispering‐gallery‐mode (WGM) lasers by drop‐casting CdSe/CdS@Cd1− x Zn x S core/buffer‐shell@graded‐shell nanoplatelets (NPLs) dispersion onto silica microspheres is presented. Benefiting from the excellent gain properties from the interface engineered core/hybrid shell NPLs and high‐quality factor WGM resonator from excellent optical field confinement, the proposed room‐temperature NPLs‐WGM microlasers show a record‐low lasing threshold of 3.26 µJ cm −2 under nanosecond laser pumping among all colloidal NPLs‐based lasing demonstrations. The presence of sharp discrete transverse electric‐ and magnetic‐mode spikes, the inversely proportional dependence of the free spectra range on microsphere sizes and the polarization anisotropy of laser output represent the first direct experimental evidence for NPLs‐WGM lasing nature, which is verified theoretically by the computed electric‐field distribution inside the microcavity. Remarkably, a stable single‐mode lasing output with an ultralow lasing threshold of 3.84 µJ cm −2 is achieved by the Vernier effect through evanescent field coupling. The results highlight the significance of interface engineering on the optimization of gain properties of heterostructured nanomaterials and shed light on developing future miniaturized tunable coherent light sources. Abstract : A self‐assembled CdSe/CdS@Cd1− x Zn x S core/shell nanoplatelets‐whispering gallery mode (WGM) microlaser with ultralow‐threshold, tunable‐wavelength, and excellent photostability is proposed. Both multi‐ and single‐mode high quality factor WGM lasing are achieved with ultralow thresholds. The results highlight the significance of interface engineering on the optimization of gain properties of heterostructured nanomaterials and shed light on developing future miniaturized tunable coherent light sources.