近日，美国洛斯阿拉莫斯国家实验室Victor I. Klimov团队研究了准连续波激发下胶体量子点的低阈值激光。该项研究成果发表在2025年12月15日出版的《自然—光子学》杂志上。

胶体量子点作为一种溶液可加工、颜色可调控的激光材料具有重要发展前景。然而，目前报道的大多数量子点激光器件仍需依赖高功率飞秒激光作为泵浦源，这在实际技术应用中存在限制。

研究组通过电调制（占空比0.1-1%）的低功率连续波激光二极管作为激发源，成功实现了量子点激光发射——在77 K温度下泵浦强度仅需500 W·cm^-2，室温条件下也仅需3.6 kW·cm^-2即可激射。这一突破得益于(I+II)型量子点的特殊能带结构，其光学增益来源于直接/间接激子混合形成的双激子态。

此类双激子态表现出显著抑制的俄歇复合效应，从而获得数纳秒量级的长光学增益寿命。此外，得益于直接跃迁的快速辐射衰减特性，(I+II)型量子点可实现约1200 cm^-1的高材料增益。这些特性是实现连续波泵浦激光的关键所在。(I+II)型量子点同样适用于飞秒光脉冲泵浦器件，已在全堆叠电致发光器件中实现激光发射，并在量子点紧密堆积的微盘结构中实现了回音壁模式激光振荡。

附：英文原文

Title: Low-threshold lasing from colloidal quantum dots under quasi-continuous-wave excitation

Author: Hahm, Donghyo, Kim, Changjo, Dang, Tung H., Pinchetti, Valerio, Livache, Clment, Klimov, Victor I.

Issue&Volume: 2025-12-15

Abstract: Colloidal quantum dots (QDs) are promising materials for the development of solution-processed, colour-selectable lasers. However, most reported QD lasing devices rely on high-power femtosecond lasers as the pump source, which is impractical for technological applications. Here we demonstrate QD lasing using excitation from an electrically modulated (0.1–1% duty cycle), low-power continuous-wave laser diode, achieving lasing at a pump intensity just above 500Wcm2 at 77K and 3.6kWcm2 at room temperature. This achievement is enabled by type-(I+II) QDs, in which optical gain arises from hybrid direct/indirect biexcitons. These biexcitons exhibit strongly suppressed Auger recombination, resulting in a long optical gain lifetime of several nanoseconds. In addition, owing to fast radiative decay via the direct transition, type-(I+II) QDs exhibit a high material gain of approximately 1,200cm1. These properties are crucial for achieving lasing under continuous-wave pumping. Type-(I+II) QDs are also well suited for devices pumped by femtosecond optical pulses, enabling the realization of lasing in fully stacked electroluminescent devices and whispering-gallery-mode lasing in microdisks composed of densely packed QDs.

DOI: 10.1038/s41566-025-01807-w

Source: https://www.nature.com/articles/s41566-025-01807-w