Fine-tuning the etch depth profile via dynamic shielding of ion beam

Abstract

We introduce a method for finely adjusting the etch depth profile by dynamic shielding in the course of ion beam etching (IBE), which is crucial for the ultraprecision fabrication of large optics. We study the physical process of dynamic shielding and propose a parametric modeling method to quantitatively analyze the shielding effect on etch depths, or rather the shielding rate, where a piecewise Gaussian model is adopted to fit the shielding rate profile. We have conducted two experiments. In the experiment on parametric modeling of shielding rate profiles, its result shows that the shielding rate profile is significantly influenced by the rotary angle of the leaf. And the experimental result of fine-tuning the etch depth profile shows good agreement with the simulated result, which preliminarily verifies the feasibility of our method.

Multi-grating design for integrated single-atom trapping, manipulation, and readout

“…The length of the grating part is 8 µm with 18 grooves. The etching depth increases from 20 nm to 280 nm linearly, which can improve the diffraction efficiency of the grating [44]. Around the working wavelengths of 780 nm and 850 nm, the refractive index of Si 3 N 4 and SiO 2 are set as 1.9935 and 1.45, respectively.…”

Surface modeling for optical fabrication with linear ion source

“…Reactive ion etching (RIE) is a useful method in the fabrication of diffraction optics. Recently we fabricated large-aperture BSGs by the RIE process, where the ion beam emitted from linear ion source scans over BSGs along a linear guide meanwhile the rotary leaf scans along the elongated footprint of ion beam, thus the spatial distribution of etch depths is finely adjusted for improving the diffractive uniformity of BSG [14,15]. Now we try to exploit more applications by combining optical fabrication technique with linear ion source and the aforementioned surface modeling method.…”