Patent ID: 8502986
Filing Date: 2013-08-06
Classification: G01B

Abstract:
1. A lightwave interference measurement apparatus comprising: a wavelength-variable laser configured to periodically perform wavelength scanning between a first reference wavelength λ a wavelength-fixed laser configured to emit light beam having a third reference wavelength λ a wavelength reference element configured to be able to set a wavelength of the light beam emitted from the wavelength-variable laser to the first reference wavelength λ a light beam splitting element configured to split the light beams emitted from the wavelength-variable laser and the wavelength-fixed laser into reference light beam and light beam under test; a phase detector configured to detect a phase based on an interference signal of the reference light beam that is reflected on a reference surface and the light beam under test that is reflected on a surface under test; and an analyzer configured to sequentially determine an interference order of the third reference wavelength λ