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Achieving both high power and high-quality beam pattern has been a longstanding challenge for terahertz (THz) quantum-cascade (QC) lasers largely due to their use of subwavelength metallic waveguides. Recently, the vertical-external-cavity surface-emitting laser (VECSEL) concept was demonstrated for the first time in the THz range and for a QC-laser. This is enabled by the development of an amplifying...
We have demonstrated THz quantum-cascade metasurface vertical external cavity surface emitting lasers (VECSELs) using a variety of metasurfaces. The dependence of the laser spectrum on the metasurface design parameters is analyzed via simulation and experiment.
We report THz quantum-cascade vertical-external-cavity surface-emitting-lasers (VECSELs) with up to 60 mW of power at 3.3 THz at 77 K. High quality, directive, near-diffraction limited, Gaussian beams are observed.
A composite right/left-handed metamaterial waveguide for terahertz quantum-cascade lasers is presented. Left handed (backward wave) propagation is confirmed by using the waveguide as a leaky-wave antenna where directional beams at angles of −4° and −63° are experimentally observed at excitation frequencies 2.59 and 2.48 THz, respectively.
We present a scheme for achieving active composite right/left handed (CRLH) transmission line metamaterial waveguides in the THz by loading THz QC-laser metal-metal waveguides with sub-wavelength capacitive and inductive structures. We discuss our progress in using transmission-line metamaterial concepts for the engineering of THz active leaky-wave antennas that provide amplification and exhibit beam...
A one-dimensional metamaterial waveguide for terahertz quantum-cascade lasers is presented that tailors laser radiation to a low-divergence beam with frequency-dependent direction. The demonstrated prototype exhibits narrow (FWHM ∼ 15°) surface emission (40° from broadside) at 2.74 THz.
We report a novel tuning mechanism based on a “wire-laser” with subwavelength transverse dimensions(w≪λ). By manipulating the waveguided mode propagating outside the cavity, frequency tuning of ∼137GHz (3.6%) is demonstrated from a single-laser device at ∼3.8THz.
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