A device for generating terahertz radiation. The device comprising a dipole generating layer, a coupling block and an extraction block. The coupling block is transparent to laser light and is in contact with the surface of the dipole generating layer to couple light from a laser to the surface of the dipole generating layer, when the device is in use. The extraction block is located in contact with the surface of the dipole generating layer to provide an emission extraction surface. The refractive indices of the dipole forming layer, the coupling block and the extraction block are substantially equal. In this way, the dipole which is generated upon illumination of the dipole generating layer by a laser, has an axis which is not perpendicular to the emission.