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Shao D, Yao C, Fu Z, Wan W, Li Z, Cao J. Terahertz quantum cascade lasers with sampled lateral gratings for single mode operation. FRONTIERS OF OPTOELECTRONICS 2021; 14:94-98. [PMID: 36637779 PMCID: PMC9743838 DOI: 10.1007/s12200-020-1083-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/01/2020] [Indexed: 06/17/2023]
Abstract
In this paper, we presented single mode terahertz quantum cascade lasers (THz QCLs) with sampled lateral grating emitting approximately 3.4 THz. Due to strong mode selection, the implementation of sampled lateral grating on THz QCL ridges can result in stable single longitudinal mode emission with a side-mode suppression ratio larger than 20 dB. The measured peak power of the grating laser is improved by about 11.8% compared to the power of devices with uniform distributed feedback gratings. Furthermore, the far-field pattern of the presented device is uninfluenced by grating structures.
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Affiliation(s)
- Dixiang Shao
- Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Chen Yao
- Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Zhanglong Fu
- Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Wenjian Wan
- Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Ziping Li
- Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Juncheng Cao
- Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China.
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Biasco S, Garrasi K, Castellano F, Li L, Beere HE, Ritchie DA, Linfield EH, Davies AG, Vitiello MS. Continuous-wave highly-efficient low-divergence terahertz wire lasers. Nat Commun 2018; 9:1122. [PMID: 29549267 PMCID: PMC5856764 DOI: 10.1038/s41467-018-03440-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 02/14/2018] [Indexed: 11/20/2022] Open
Abstract
Terahertz (THz) quantum cascade lasers (QCLs) have undergone rapid development since their demonstration, showing high power, broad-tunability, quantum-limited linewidth, and ultra-broadband gain. Typically, to address applications needs, continuous-wave (CW) operation, low-divergent beam profiles and fine spectral control of the emitted radiation, are required. This, however, is very difficult to achieve in practice. Lithographic patterning has been extensively used to this purpose (via distributed feedback (DFB), photonic crystals or microcavities), to optimize either the beam divergence or the emission frequency, or, both of them simultaneously, in third-order DFBs, via a demanding fabrication procedure that precisely constrains the mode index to 3. Here, we demonstrate wire DFB THz QCLs, in which feedback is provided by a sinusoidal corrugation of the cavity, defining the frequency, while light extraction is ensured by an array of surface holes. This new architecture, extendable to a broad range of far-infrared frequencies, has led to the achievement of low-divergent beams (10°), single-mode emission, high slope efficiencies (250 mW/A), and stable CW operation.
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Affiliation(s)
- Simone Biasco
- NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy
| | - Katia Garrasi
- NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy
| | - Fabrizio Castellano
- NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy
| | - Lianhe Li
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, LS2 9JT, UK
| | - Harvey E Beere
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
| | - David A Ritchie
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Edmund H Linfield
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, LS2 9JT, UK
| | - A Giles Davies
- School of Electronic and Electrical Engineering, University of Leeds, Leeds, LS2 9JT, UK
| | - Miriam S Vitiello
- NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy.
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Wienold M, Röben B, Schrottke L, Sharma R, Tahraoui A, Biermann K, Grahn HT. High-temperature, continuous-wave operation of terahertz quantum-cascade lasers with metal-metal waveguides and third-order distributed feedback. OPTICS EXPRESS 2014; 22:3334-3348. [PMID: 24663624 DOI: 10.1364/oe.22.003334] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Currently, different competing waveguide and resonator concepts exist for terahertz quantum-cascade lasers (THz QCLs). We examine the continuous-wave (cw) performance of THz QCLs with single-plasmon (SP) and metal-metal (MM) waveguides fabricated from the same wafer. While SP QCLs are superior in terms of output power, the maximum operating temperature for MM QCLs is typically much higher. For SP QCLs, we observed cw operation up to 73 K as compared to 129 K for narrow (≤ 15 μm) MM QCLs. In the latter case, single-mode operation and a narrow beam profile were achieved by applying third-order distributed-feedback gratings and contact pads which are optically insulated from the intended resonators. We present a quantitative analytic model for the beam profile, which is based on experimentally accessible parameters.
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