Dome-shaped mode lasing from liquid crystals for full-color lasers and high-sensitivity detection.

In this communication, we report a new class of oscillation mode, dome-shaped mode (DSM), in liquid crystal (LC) microlasers. A record high -factor over 24 000 is achieved in LC soft-matter microlasers. We successfully presented a proof-of-concept demonstration of red, green, blue (RGB) LC-DSM microlaser pixels with a 74% broader achievable color gamut than the standard RGB color space.

Ultralow-Threshold and High-Quality Whispering-Gallery-Mode Lasing from Colloidal Core/Hybrid-Shell Quantum Wells.

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@Cd Zn 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.

Surface Depletion Effects in Bromide-Ligated Colloidal Cadmium Selenide Nanoplatelets: Toward Efficient Emission at High Temperature.

The colloidal semiconductor nanoplatelet (NPL) with broad ligand-semiconductor interface is an ideal system for surface science investigation, but the study regarding depletion effects in NPLs remains lacking. Herein we explore such effects in colloidal CdSe NPLs through Br ligation. Apart from improved brightness and red-shifted optical features, we also experimentally observed abnormal negative thermal quenching phenomena in bromide-ligated CdSe NPLs over 200 K under a cryogenic environment and up to 383 K under an ambient environment, which was absent in pristine NPLs.

Study of Complex Optical Constants of Neat Cadmium Selenide Nanoplatelets Thin Films by Spectroscopic Ellipsometry.

Knowledge of tunability of complex optical constants of colloidal CdSe nanoplatelets (NPLs) thin films is essential for accurate modeling and design of NPL-containing optoelectronic devices. Here, dielectric functions, complex optical conductivities, and absorption coefficients of a series of CdSe NPL films with a varying number of atomic layers were investigated in a combination of spectroscopic ellipsometry techniques and transmittance measurements over a broad spectral range. Fine electronic structures were deciphered from the dielectric functions.