Focusing metasurface quantum-cascade laser with a near diffraction-limited beam.
A terahertz vertical-external-cavity surface-emitting-laser (VECSEL) is demonstrated using an active focusing reflectarray metasurface based on quantum-cascade gain material. The focusing effect enables a hemispherical cavity with flat optics, which exhibits higher geometric stability than a plano-plano cavity and a directive and circular near-diffraction limited Gaussian beam with M2beam parameter as low as 1.3 and brightness of 1.86 × 106Wsr-1m-2. This work initiates the potential of leveraging inhomogeneous metasurface and reflectarray designs to achieve high-power and high-brightness terahertz quantum-cascade VECSELs.
Luyao
L
Xu
Daguan
D
Chen
Tatsuo
T
Itoh
John L
JL
Reno
Benjamin S
BS
Williams