| 摘要 |
PURPOSE:To obtain a frequency analyzer which is made small-sized and improved in resolution, by providing one geodesic lens and providing a linear waveguide group in the condensing part of a laser beam. CONSTITUTION:The laser beam going toward the center of a lens 11 from a circle 12 which indicates positions to which lengths from the center of a geodesic lens 11 are twice as long as the focal length of the lens 11 is collimated near the center of the lens 11 and is condensed on a position symmetrical with respect to a point on the circle 12. If the centers of the sectors of SAW electrodes 13 are placed on the circle 12, the laser beam has a plane wave shape near the center of the lens, and electrodes function as a diffraction grating to diffract the laser beam. The angle of diffraction depends upon the wavelength of SAW, namely, the frequency of an AC voltage. The laser beam is condensed when passing the latter half part of the lens 11 and reaches the entrance of a linear waveguide group 14 on the circle 12. The laser beam is not diffused by the waveguide group 14 but the angle of diffraction is extended, and it is detected by a detector array 8 to obtain frequency analysis of the AC voltage. Thus, the frequency analyzer which is made small-sized and has the resolution improved is obtained. |
