US 12,135,444 B2
Terahertz wave optical element and method for producing terahertz wave optical element
Shohei Hayashi, Hamamatsu (JP); Tetsushi Shimomura, Hamamatsu (JP); and Hiroyasu Fujiwara, Hamamatsu (JP)
Assigned to HAMAMATSU PHOTONICS K.K., Hamamatsu (JP)
Filed by HAMAMATSU PHOTONICS K.K., Hamamatsu (JP)
Filed on Jun. 14, 2023, as Appl. No. 18/209,718.
Application 18/209,718 is a continuation of application No. 17/116,189, filed on Dec. 9, 2020, granted, now 11,774,651.
Claims priority of application No. 2019-230456 (JP), filed on Dec. 20, 2019.
Prior Publication US 2023/0324591 A1, Oct. 12, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. G02B 5/18 (2006.01); G02B 27/00 (2006.01); G02F 1/39 (2006.01); G02B 3/08 (2006.01)
CPC G02B 5/1871 (2013.01) [G02B 5/1809 (2013.01); G02B 5/1857 (2013.01); G02B 5/1876 (2013.01); G02B 27/0025 (2013.01); G02F 1/39 (2013.01); G02B 3/08 (2013.01); G02F 2203/13 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A terahertz wave optical element comprising:
a substrate having a surface provided with an uneven structure that changes a phase of a terahertz wave,
wherein the uneven structure includes a plurality of unevenness forming portions formed of protruding portions extending from the surface that are periodically arranged,
the uneven structure includes a plurality of regions where the plurality of unevenness forming portions are arranged,
a height of the unevenness forming portion in a thickness direction of the substrate and a width of the unevenness forming portion in a direction orthogonal to the thickness direction differ for each of the regions,
outer end portions of the uneven structure in the thickness direction are located on the same plane,
the plurality of regions are formed of N, N is an integer of 2 or more, regions including a first region to an Nth region that are arranged along a predetermined direction, and
an effective refractive index of each of the plurality of regions is further decreased in a stepwise manner as the region is shifted from the first region toward the Nth region.