Apr 9, 2025
11:45am - 12:00pm
Summit, Level 4, Room 427
Tung Dang1,Donghyo Hahm1,Changjo Kim1,Valerio Pinchetti1,Victor Klimov1
Los Alamos National Laboratory1
Tung Dang1,Donghyo Hahm1,Changjo Kim1,Valerio Pinchetti1,Victor Klimov1
Los Alamos National Laboratory1
Microlasers are essential components of complex integrated photonic circuits. Most commercially available microlasers are based on epitaxially grown III-V semiconductors, which exhibit excellent optical and electrical properties and high reliability. However, their integration with silicon-based microelectronic circuits is challenging due to material compatibility issues. Colloidal quantum dots (CQDs) show great promise as active gain materials for integrated photonics due to their solution processability. Unlike conventional semiconductors, CQD layers can be directly deposited on various substrates using simple coating techniques such as spin coating, inkjet printing, or drop-casting.
Recent advances in CQD research have demonstrated their utility as low-threshold laser materials with remarkable robustness and stability.
1,2 In this study, we utilized custom-designed CQDs to prepare micro-ring/disk lasers using standard photolithography and dry etching techniques. When optically excited, CQD-based microlasers exhibit low-threshold (~10 μJ cm
-2) whispering gallery mode lasing. We applied similar fabrication techniques to incorporate microring resonators into high-current density electroluminescent structures. The developed devices exhibit strong dual-band electroluminescence due to the band-edge (1S) and first excited (1P) electronic states. This indicates the realization of population inversion in the QD medium. The next step is to achieve a net positive overall gain by optimizing the design of our fully stacked devices to enhance the modal gain and, in parallel, reduce the parasitic optical loss. The expected result of this work will be an electrically excited microring laser.
1. Lim, J., Park, YS. & Klimov, V. Optical gain in colloidal quantum dots achieved with direct-current electrical pumping.
Nature Mater 17, 42–49, 2018.
2. Hahm, D.
et al. Liquid-State Semiconductor Lasers Based on Type-(I+ II) Colloidal Quantum Dots.
Nature Mater. (accepted), 2024.