  We demonstrate a compact two-chip terahertz-emitting vertical-external-cavity
surface-emitting laser (TECSEL) source, which provides 1-THz output based on
intracavity frequency conversion of dual-wavelength emission in a
periodically-poled lithium niobate crystal. The type-I frequency conversion
scheme at room temperature highly benefits from the power-scaling possibilities
in a multichip cavity with intracavity powers in excess of 500 W.
