US 12,405,168 B2
Phase difference measuring device, beam output apparatus and phase difference measuring method
Koichi Hamamoto, Tokyo (JP); Tomoya Morioka, Tokyo (JP); Shingo Nishikata, Tokyo (JP); Hiroyuki Daigo, Tokyo (JP); and Noriaki Miyanaga, Osaka (JP)
Assigned to MITSUBISHI HEAVY INDUSTRIES, LTD., Tokyo (JP); and INSTITUTE FOR LASER TECHNOLOGY, Osaka (JP)
Appl. No. 17/915,009
Filed by MITSUBISHI HEAVY INDUSTRIES, LTD., Tokyo (JP); and Institute for Laser Technology, Osaka (JP)
PCT Filed Feb. 16, 2021, PCT No. PCT/JP2021/005586
§ 371(c)(1), (2) Date Sep. 27, 2022,
PCT Pub. No. WO2021/199737, PCT Pub. Date Oct. 7, 2021.
Claims priority of application No. 2020-061991 (JP), filed on Mar. 31, 2020.
Prior Publication US 2023/0152163 A1, May 18, 2023
Int. Cl. G01J 9/02 (2006.01); G02B 5/30 (2006.01); G02B 5/32 (2006.01)
CPC G01J 9/02 (2013.01) [G02B 5/3083 (2013.01); G02B 5/32 (2013.01); G01J 2009/0261 (2013.01)] 16 Claims
OG exemplary drawing
 
1. Phase difference measuring device comprising:
a phase conversion device configured to convert a first laser beam that passes therethrough, so that the first laser beam includes a phase distribution of one cycle in an azimuth direction in a cross section of the first laser beam that has passed therethrough included in an arbitrary virtual plane perpendicular to an optical axis of the first laser beam; and
a detection device configured to detect an azimuth angle of an intensity centroid of an interference pattern and detect an inter-beam phase difference of a second laser beam with respect to the first laser beam based on the azimuth angle for a measurement of the inter-beam phase difference,
wherein the interference pattern is generated by a shaped detection beam in a cross section of a detection beam,
wherein the cross section of the shaped detection beam is a circle having a predetermined radius and having a center at a point, where the cross section of the detection beam and an extension line extended along an optical axis from an optical axis of the phase conversion device intersect,
wherein the cross section is perpendicular to an optical axis of the detection beam,
wherein a part outside the circle is masked,
wherein the detection beam is obtained by combining a first partial intensity laser beam and a second partial intensity laser beam on a same optical path,
wherein the first partial intensity laser beam has at least a part of an intensity component of the first laser beam that has passed through the phase conversion device, and
wherein the second partial intensity laser beam has at least a part of an intensity component of a second laser beam derived from a laser beam as seed light from which the first laser beam derives.