Patent ID: 7236293

Claim:
A frequency converter using an optical excitation surface plasma, comprising: a substrate in which an optical excitation surface plasma is produced and is for transmitting an input wave; an output part, including a waveguide, to total-reflect or substantially total-reflect the input wave and to allow the output Wave to pass through by setting a cutoff frequency of the waveguide to be larger than a maximum frequency of the input wave; a high-frequency transmission line formed on the substrate and having first and second sides, including a matching part to the waveguide of the output part at the second side in order to improve matching properties; and an optical delay circuit to give a transmission time difference to a laser beam and for irradiating the substrate with the laser beam, wherein: the input wave is inputted from the first or the second side of the high-frequency transmission line and is reflected at the second side, the laser beam is made incident on the optical delay circuit, the laser beam is made to reach the high-frequency transmission line while the transmission time difference occurs according to a position of the high-frequency transmission line in a line direction by the optical delay circuit, the laser beam optically produces the surface plasma in the substrate through the optical delay circuit to short-circuit the high-frequency transmission line, the input wave reflected at the second side of the high-frequency transmission line is further reflected by the surface plasma, this reflection point is moved to the second side of the high-frequency transmission line to perform frequency conversion of the input wave based on a principle of a Doppler effect, and a frequency-converted output wave is outputted from the output part through the matching part of the second side of the high-frequency transmission line.