| 摘要 |
A multibeam optical system that employs a laser source emitting a laser beam, a diffractive beam-dividing element that diffracts the laser beam emitted from the laser source to be divided into a plurality of diffracted beams exiting at different diffraction angle, and a compensating optical system. compensating optical system, which is afocal and consists of a first group and a second group, arranged at the position where beams divided by a diffractive beam-dividing element are incident thereon. The compensating optical system has a characteristic such that the angular magnification thereof is inversely proportional to the wavelength of the incident beam. The angular difference among the diffracted beam caused by the wavelength dependence of the diffractive beam-dividing element can be reduced when the beams transmit the compensating optical system.
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