| 摘要 |
PROBLEM TO BE SOLVED: To provide a spatial frequency reproducing device which improves an effective resolution by improving an intra-plane resolution, further improving an out-of-plane resolution with respect to a height or refractive index distribution and accurately reproducing spatial frequency information that a measurement object has, by acquiring a spatial frequency which cannot be acquired by a normal image forming optical system.SOLUTION: Irradiation light of a laser light source 21 is made incident to an acoustic optical element 23, and split into two beams which are proximate to each other while being modulated to frequencies different from each other. The two beams are scanned by a two-dimensional scanning device 26 in a two-dimensional manner, and an objective lens 31 irradiates a measurement object G1 with the two beams. Reflection light from the measurement object G1 is received by a light-receiving element 29, photoelectric conversion is performed thereon and while changing an amplification factor in accordance with frequencies of electric signals as a result of the photoelectric conversion, a signal comparator 33 amplifies the signals and creates a difference signal or a sum signal of the amplified signals. A phase difference or a strength difference of the difference signal or the sum signal is calculated and a data processing part 34 obtains a measurement. |
