# Integrated waveguides and deterministically positioned nitrogen vacancy centers in diamond created by femtosecond laser writing

## TL;DR

This paper demonstrates the fabrication of integrated diamond photonic waveguides aligned with single nitrogen vacancy centers using femtosecond laser writing, enabling on-chip quantum photonic and sensing applications.

## Contribution

It introduces a novel method to create aligned waveguides and NV centers in diamond with micron precision, combining two advanced laser-writing techniques.

## Key findings

- Successfully fabricated aligned waveguides and NV centers in diamond.
- Achieved micron-level alignment between waveguides and NV centers.
- Enabled potential for integrated quantum photonic devices.

## Abstract

Diamond's nitrogen vacancy (NV) center is an optically active defect with long spin coherence times, showing great potential for both efficient nanoscale magnetometry and quantum information processing schemes. Recently, both the formation of buried 3D optical waveguides and high quality single NVs in diamond were demonstrated using the versatile femtosecond laser-writing technique. However, until now, combining these technologies has been an outstanding challenge. In this work, we fabricate laser written photonic waveguides in quantum grade diamond which are aligned to within micron resolution to single laser-written NVs, enabling an integrated platform providing deterministically positioned waveguide-coupled NVs. This fabrication technology opens the way towards on-chip optical routing of single photons between NVs and optically integrated spin-based sensing.