Key Takeaways & Executive Findings
- •• Demonstrated room-temperature electrically injected lasing in regrowth-free GaN-based photonic-crystal surface-emitting lasers (PCSELs) grown on sapphire substrates. • Achieved a low threshold current density of 13.7 kA/cm2, indicating efficient device performance. • The regrowth-free approach simplifies fabrication and reduces cost compared to conventional regrowth methods, while maintaining device quality. • This work advances GaN-based PCSELs for applications in visible light communication, laser illumination, and other fields requiring compact, high-brightness sources.
Abstract
Photonic crystal surface emitting lasers (PCSELs) utilize the Bragg diffraction of two-dimensional photonic crystals to achieve a single-mode output with a high power and a small divergence angle, and has recently attracted much attention. In 2023, Kyoto University reported GaAs-based 945 nm PCSELs with a continuous-wave (CW) single-mode output power of exceeding 50 W, and a narrow beam divergence angle of 0.05°, demonstrating a brightness of 1 GW·cm−2·sr−1, which rivals those of the existing bulky lasers. As compared with GaAs/InP-based materials, the emission wavelength of GaN-based materials is shorter, covering the spectrum from visible light to deep ultraviolet, which brings great promise to GaN-based PCSELs for various important applications, such as material processing, laser illumination, underwater communication, visible light communication, chip-scale atomic clock, laser medical treatment and so on. However, the development of GaN-based PCSELs is hindered by its small refractive index, immature regrowth and device fabrication processing technology. So far, only Kyoto University and Canon Corporation have achieved room-temperature (RT) electrically pumped lasing of GaN-based PCSELs with air holes retained via regrowth approach, which would inevitably degrade the material quality, complicate the fabrication process, and increase manufacturing costs. Compared to the regrowth-based methods, the regrowth-free approach reduces the fabrication complexity while maintaining the device performance, offering a cost-effective solution for mass production. In this letter, we reported regrowth-free GaN-based PCSELs grown on sapphire substrate, and demonstrated the RT electrically pumped lasing of GaN-based PCSELs with a threshold current density of 13.7 kA/cm2.
1. Introduction
Photonic crystal surface emitting lasers (PCSELs) utilize the Bragg diffraction of two-dimensional photonic crystals to achieve a single-mode output with a high power and a small divergence angle, and has recently attracted much attention. In 2023, Kyoto University reported GaAs-based 945 nm PCSELs with a continuous-wave (CW) single-mode output power of exceeding 50 W, and a narrow beam divergence angle of 0.05°, demonstrating a brightness of 1 GW·cm−2·sr−1, which rivals those of the existing bulky lasers.
As compared with GaAs/InP-based materials, the emission wavelength of GaN-based materials is shorter, covering the spectrum from visible light to deep ultraviolet, which brings great promise to GaN-based PCSELs for various important applications, such as material processing, laser illumination, underwater communication, visible light communication, chip-scale atomic clock, laser medical treatment and so on. However, the development of GaN-based PCSELs is hindered by its small refractive index, immature regrowth and device fabrication processing technology. So far, only Kyoto University and Canon Corporation have achieved room-temperature (RT) electrically pumped lasing of GaN-based PCSELs with air holes retained via regrowth approach, which would inevitably degrade the material quality, complicate the fabrication process, and increase manufacturing costs.
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Tong Xu, Meixin Feng, Xiujian Sun, Rui Xi, Xinchao Li, Shuming Zhang, Qian Sun, Xiaoqi Yu, Kanglin Xiong, Hui Yang, Xianfei Zhang, Zhuangpeng Guo, Peng Chen (2025). Room-temperature electrically injected GaN-based photonic-crystal surface-emitting lasers. SinoTechIntel Verified Research. https://doi.org/10.1088/1674-4926/25070031
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Frequently Asked Questions
What is the main achievement of this paper?
The paper reports the first regrowth-free GaN-based photonic-crystal surface-emitting lasers (PCSELs) that achieve room-temperature electrically injected lasing, with a threshold current density of 13.7 kA/cm2.
What is the significance of the regrowth-free approach?
The regrowth-free approach simplifies the fabrication process, reduces manufacturing costs, and avoids the material quality degradation associated with regrowth methods, making it more suitable for mass production.
What are the potential applications of GaN-based PCSELs?
GaN-based PCSELs can be used in material processing, laser illumination, underwater communication, visible light communication, chip-scale atomic clocks, and laser medical treatment, among others.
How does this work compare to previous GaN-based PCSELs?
Previous GaN-based PCSELs required a regrowth process to retain air holes, which complicated fabrication and degraded material quality. This work demonstrates a regrowth-free method that maintains device performance while simplifying fabrication.
What is the threshold current density achieved in this study?
The threshold current density is 13.7 kA/cm2, which is competitive for GaN-based PCSELs and indicates efficient lasing at room temperature.
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