公开(公告)号：US20170242158A1

公开(公告)日：2017-08-24

申请号：US15316799

申请日：2015-06-10

Applicant: Element Six Technologies Limited

Inventor： Alexander MUHR ,  Yevgeny Vasilievich YeANOIKIN ,  Daniel James TWITCHEN

IPC: G02B1/118 ,  G02B5/30 ,  G02B1/02

CPC classification number: G02B1/118 ,  G02B1/02 ,  G02B5/3083

Abstract: An optical element comprising: synthetic diamond material; and an optical surface pattern formed directly in at least one surface of the synthetic diamond material, wherein the optical surface pattern comprises a plurality of projections separated by trenches, the projections spaced apart with a periodicity d, wherein the periodicity d is between 65 and 99% of a zeroeth order diffraction limit above which non zeroeth diffraction orders are observed at an operating wavelength λ, wherein the optical surface pattern has a fill fraction in a range 0.1 to 0.6, the fill fraction defined as [area of projection in one periodic unit]/[area of the periodic unit], and wherein the optical element has an absorption coefficient measured at room temperature of ≦0.2 cm−1 at a wavelength of 10.6 μm.