US Patent 7884942 Probe apparatus and terahertz spectrometer

A probe apparatus includes a first focusing lens and a second focusing lens. The first focusing lens is arranged on a surface of a base to which a terahertz excitation beam is applied, the surface being opposite to the surface to which terahertz excitation beam is applied, with the lens axis deviated from the center of a point at which the terahertz excitation beam is applied. The second focusing lens is arranged on a surface of a base to which a terahertz detected beam is applied from a source of the terahertz excitation beam, the surface being opposite to the surface to which the terahertz detected beam is applied, with the lens axis deviated from the center of a point at which the terahertz detected beam is applied, in a direction opposite to the direction in which the lens axis of the first focusing lens is deviated.