Femtosecond laser written waveguides in sapphire for visible light delivery

Abstract

A promising solution for scalable integrated optics of trapped-ion quantum processors are curved waveguides guiding visible light within sapphire bulk material. To the best of our knowledge, no curved waveguides were investigated in sapphire so far, and no measurements of waveguides with visible light in undoped planar sapphire substrates were reported. Here, we demonstrate femtosecond laser writing of depressed cladding waveguides in sapphire. Laser parameters, such as pulse energy, pulse duration, and repetition rate, as well as waveguide geometry parameters, were optimized to guide 728 nm light. This resulted in single-mode waveguides with a propagation loss of 1.9(3) dB/cm. The investigation of curved waveguides showed a sharp increase in total loss for curvature radii below 15 mm. Our results demonstrate the potential of femtosecond laser writing as a powerful technique for creating integrated optical waveguides in the volume of sapphire substrates. Such waveguides could be a building block for integrated optics in trapped-ion quantum processors.

References in corpus (8)

• Quantum computing with trapped ions
• An ${}^{27}$Al${}^{+}$ quantum-logic clock with systematic uncertainty below $10^{-18}$
• Femtosecond laser micromachining for integrated quantum photonics
• Fabrication and heating rate study of microscopic surface electrode ion traps
• On-chip beam rotators, adiabatic mode converters, and waveplates through low-loss waveguides with variable cross-sections
• Single-mode sapphire fiber Bragg grating
• Control of an atomic quadrupole transition in a phase-stable standing wave
• A micro-optical module for multi-wavelength addressing of trapped ions

Cited by in corpus (1)

• A comprehensive study on beam dynamics inside symmetrically chirped waveguide array mimicking the graded index media