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.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1364/OE.22.003334 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
30 years of the quantum cascade laser.
Commun Phys
December 2024
Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, Zürich, 8093 Zürich Switzerland.
It was January 1994, when the first quantum cascade laser (QCL) displayed laser action in Bell Laboratories. During these 30 years the QCL evolved incessantly, from a lab curiosity to the main on-chip source of coherent radiation in the Mid-IR and THz ranges. The journey has seen an impressive development of the QCL in several fields of laser physics and its applications, with a steady growth of research groups and companies worldwide.
View Article and Find Full Text PDFHarmonic quantum cascade laser terahertz frequency combs enabled by multilayer graphene top-cavity scatters.
Nanophotonics
April 2024
NEST, CNR - Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy.
Optical frequency comb synthesizers, operating in the harmonic regime, are metrological sources in which the emitted optical power is concentrated in a few modes, spaced by several multiples of the cavity free spectral range (FSR). This behavior reflects in a large correlation degree and, in principle, in an increased optical power per mode. In miniaturized quantum cascade lasers (QCLs), harmonic frequency combs (HFCs) are hence particularly attracting to explore quantum correlation effects between adjacent harmonic modes, enabled by the inherently large gain media third-order Kerr nonlinearity, even if controlled generation of stable HFCs of predefined order, is typically demanding in such electrically pumped sources.
View Article and Find Full Text PDFExtraction of the electron excess temperature in terahertz quantum cascade lasers from laser characteristics.
Nanophotonics
April 2024
Faculty of Engineering, Bar-Ilan University, Ramat Gan 5290002, Israel.
We propose a method to extract the upper laser level's (ULL's) excess electronic temperature from the analysis of the maximum light output power ( ) and current dynamic range Δ = ( - ) of terahertz quantum cascade lasers (THz QCLs). We validated this method, both through simulation and experiment, by applying it on THz QCLs supporting a clean three-level system. Detailed knowledge of electronic excess temperatures is of utmost importance in order to achieve high temperature performance of THz QCLs.
View Article and Find Full Text PDFTheoretical model of passive mode-locking in terahertz quantum cascade lasers with distributed saturable absorbers.
Nanophotonics
April 2024
TUM School of Computation, Information and Technology, Technical University of Munich (TUM), D-85748 Garching, Germany.
In research and engineering, short laser pulses are fundamental for metrology and communication. The generation of pulses by passive mode-locking is especially desirable due to the compact setup dimensions, without the need for active modulation requiring dedicated external circuitry. However, well-established models do not cover regular self-pulsing in gain media that recover faster than the cavity round trip time.
View Article and Find Full Text PDFHarmonic and Subharmonic RF Injection Locking of THz Metasurface Quantum-Cascade VECSEL.
ACS Photonics
November 2024
Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, United States.
Harmonic and subharmonic RF injection locking is demonstrated in a terahertz (THz) quantum-cascade vertical-external-cavity surface-emitting laser (QC-VECSEL). By tuning the RF injection frequency around integer multiples and submultiples of the cavity round-trip frequency, different harmonic and subharmonic orders can be excited in the same device. Modulation-dependent behavior of the device has been studied with recorded lasing spectral broadening and locking bandwidths in each case.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!