1. Why is glass used in quantum devices?
It offers precise machining, high breakdown threshold, excellent dielectric properties, electro-magnetic inactive, low/adjustable CTE (depending on glass type), vacuum compatibility, optical access, and dimensional precision for ion traps or vapor cells.
2. What tolerances are required for ion traps in glass?
Sub-micron accuracy ensures stable electric fields and particle confinement and allows to precisely define fine structures such as electrodes and trenches.
3. Can glass integrate optical and electrical paths?
Yes, refractive optics such as mirrors or lenses can coexist with metallized features for hybrid quantum architectures. Additionally, laser-inscribed waveguides can be added for beam routing. Currently, waveguides are optimized for telecom wavelengths, but ongoing development work is devoted to extend the wavelength range to more specific quantum wavelengths (1760 nm, 700-800 nm, 400-500 nm)
4. How is hermetic sealing achieved for quantum cells?
Laser welding provides leak-free encapsulation. At the moment, Laser welding takes place at ambient pressure, but ongoing development work is devoted to the progress of the welding process into vacuum.
5. Which glass materials suit quantum optics?
Fused silica offers high optical performances, low birefringence and low thermal expansion for cryogenics operation.
6. Are through-glass vias possible?
Yes, femtosecond laser drilling and etching enable precise TGV formation. Additional metal deposition can make the TGVs conductive with sub-Ohm resistance.
7. Can optical cavities be formed inside glass?
3D microfabrication allows integrated resonators and cavities.
8. Is glass compatible with cryogenic temperatures?
Yes, fused silica maintains excellent stability at cryogenic conditions.
9. How does surface roughness affect quantum performance?
Smooth surfaces minimize scattering and noise in optical and electric fields.
10. Is wafer-level scaling feasible for quantum devices?
Yes, glass substrates can be batch-processed for array-based systems.
