Self-Resonant u-Lasers of Colloidal Quantum Wells Constructed by Direct Deep Patterning

TL;DR

This paper reports the development of self-resonant u-lasers using colloidal quantum wells with a novel deep patterning technique that enables high aspect-ratio on-chip resonators, promising for integrated photonic circuits.

Contribution

The authors introduce a deep patterning method for fabricating high aspect-ratio colloidal quantum well resonators without damaging the nanocrystals, enabling on-chip self-resonant lasers.

Findings

Successful fabrication of patterned CQW resonators with sub-wavelength features.

The patterning process preserves the physical and chemical properties of nanocrystals.

The resulting lasers exhibit in-plane lasing with well-supported spectral characteristics.

Abstract

Here, the first account of self-resonant fully-colloidal u-lasers made from colloidal quantum well (CQW) solution is reported. A deep patterning technique is developed to fabricate well-defined high aspect-ratio on-chip CQW resonators made of grating waveguides and in-plane reflectors. CQWs of the patterned layers are closed-packed with sharp edges and residual-free lifted-off surfaces. Additionally, the method is successfully applied to various nanoparticles including colloidal quantum dots and metal nanoparticles. It is observed that the patterning process does not affect the nanocrystals (NCs) immobilized in the attained patterns and different physical and chemical properties of the NCs remain pristine. Thanks to capability of the proposed patterning method, patterns of NCs with sub-wavelength lateral feature size and micron-scale height are fabricated in the aspect ratios of 1:15 (<100 nm lateral patterned features to >1.5 {\mu}m film thickness). The fabricated waveguide-coupled laser, enabling tight optical confinement, assures in-plane lasing. The spectral characteristics of the designed CQW resonator structure are well supported with a numerical model of full electromagnetic solutions. Such directly deep-patterned self-resonant u-lasers of CQWs hold great promise for on-chip integration to photonic circuits.