Stankevič Valdemar, Karosas Jonas, Gečys Paulius
Opt Lett. 2023 Aug 15;48(16):4404-4407. doi: 10.1364/OL.498853.
This manuscript presents a simple approach to the manufacturing and optimization of a multilevel phase-only diffractive conical lens (Fresnel axicon or "fraxicon"). The method for recording deep type I modifications in fused silica was established and its ability proven. We showed the prospects and limitations of elements processed using this method. The fine and advanced parameters optimization allowed us to get a compensation mechanism for almost uniform refractive index change for each separate layer. The maximum diffraction efficiency of the fraxicon for a wavelength of 515 nm was ∼80%. The measured Bessel beam depth of field was compared with commercially available conical lens axicons and showed good agreement.
本手稿介绍了一种制造和优化多层纯相位衍射圆锥透镜（菲涅耳轴棱锥或“分数轴棱锥”）的简单方法。建立了在熔融石英中记录深I型改性的方法并证明了其能力。我们展示了使用该方法加工元件的前景和局限性。精细和先进的参数优化使我们能够获得一种补偿机制，使每个单独层的折射率变化几乎均匀。分数轴棱锥在515 nm波长下的最大衍射效率约为80%。将测量的贝塞尔光束景深与市售圆锥透镜轴棱锥进行了比较，结果显示吻合良好。
