Fabrication of ultrahigh-precision hemispherical mirrors for quantum-optics applications

Abstract

High precision, high numerical aperture mirrors are desirable for mediating strong atom-light coupling in quantum optics applications and can also serve as important reference surfaces for optical metrology. In this work we demonstrate the fabrication of highly-precise hemispheric mirrors with numerical aperture NA = 0.996. The mirrors were fabricated from aluminum by single-point diamond turning using a stable ultra-precision lathe calibrated with an in-situ white-light interferometer. Our mirrors have a diameter of 25 mm and were characterized using a combination of wide-angle single-shot and small-angle stitched multi-shot interferometry. The measurements show root-mean-square (RMS) form errors consistently below 25 nm. The smoothest of our mirrors has a RMS error of 14 nm and a peak-to-valley (PV) error of 88 nm, which corresponds to a form accuracy of λ/50 for visible optics.

High-Density Qubit Wiring: Pin-Chip Bonding for Fully Vertical Interconnects

“…This method is based on rectangular coaxial ribbon cables attached to micro-sized pins, forming coaxial transmission lines by means of an interposer block; the tip of each pin is bonded vertically to mating pads on the quantum chip using In. The quantum chip is patterned with a square array of [5,30] µm thick circular pads made from In with d pad ∈ [100, 200] µm; the In pads can be fabricated above an underlying Al thin film, or other films. Each pad is electrically connected to an on-chip Al (or Nb) trace used to reach a qubit.…”

“…2 (c)]. The channel (groove) is fabricated by means of single-point diamond turning (SPDT) [30], which provides extremely high nanometric accuracy and precision and allows to trench narrow channels in Cu and possibly other materials. The aspect ratio of our channels is at a minimum ∼ 140 µm/1 mm = 0.14, which is not terribly hard to achieve with SPDT.…”

A novel sandwich structured wheel to achieve mirror finish in grinding of a mould steel

“…These components, such as optical products, require high surface quality for optimal performance. However, achieving this high-quality standard often involves multiple processing steps, resulting in lengthy processing time and high costs [1]. Therefore, there is a need to research and develop more efficient processing tools and methods to reduce processing time and costs while maintaining the required high-quality standards.Traditional machining operations for the mould steel parts can be classified into two major categories: grinding and polishing.…”