Xu, Yunfei; Li, Weijiang; Ma, Yu; Lu, Quanyong; Zhang, Jinchuan; Zhai, Shenqiang; Zhuo, Ning; Liu, Junqi; Liu, Shuman; Cheng, Fengmin; Wang, Lijun; Liu, Fengqi Source: Journal of Semiconductors, v 45, n 6, June 2024; ISSN: 16744926; DOI: 10.1088/1674-4926/23120010; Article number: 062401; Publisher: Institute of Physics

Author affiliation:

Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Beijing; 100083, China

Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing; 100049, China

Division of Quantum Materials and Devices, Beijing Academy of Quantum Information Sciences, Beijing; 100193, China

Abstract:

We demonstrated a scheme of phase-locked terahertz quantum cascade lasers (THz QCLs) array, with a single-mode pulse power of 108 mW at 13 K. The device utilizes a Talbot cavity to achieve phase locking among five ridge lasers with first-order buried distributed feedback (DFB) grating, resulting in nearly five times amplification of the single-mode power. Due to the optimum length of Talbot cavity depends on wavelength, the combination of Talbot cavity with the DFB grating leads to better power amplification than the combination with multimode Fabry−Perot (F−P) cavities. The Talbot cavity facet reflects light back to the ridge array direction and achieves self-imaging in the array, enabling phase-locked operation of ridges. We set the spacing between adjacent elements to be 220 μm, much larger than the free-space wavelength, ensuring the operation of the fundamental supermode throughout the laser's dynamic range and obtaining a high-brightness far-field distribution. This scheme provides a new approach for enhancing the single-mode power of THz QCLs.