# Transfer of Phase Information between Optical and Microwave Fields via an Electron Spin

## TL;DR

This paper demonstrates the coherent transfer of phase information between microwave and optical fields using a nitrogen vacancy center in diamond, highlighting the role of dark states for quantum state transfer in solid-state systems.

## Contribution

It introduces a method for transferring phase information between microwave and optical fields via electron spins in diamond, advancing quantum communication capabilities.

## Key findings

- Successful transfer of phase information between microwave and optical fields
- Identification of dark states as crucial for coherent coupling
- Potential for full quantum state transfer in solid-state systems

## Abstract

We demonstrate the coherent coupling and the resulting transfer of phase information between microwave and optical fields in a single nitrogen vacancy center in diamond. The relative phase of two microwave fields is encoded in a coherent superposition spin state. This phase information is then retrieved with a pair of optical fields. A related process is also used for the transfer of phase information from optical to microwave fields. These studies show the essential role of dark states, including optical pumping into the dark states, in the coherent microwave-optical coupling and open the door to the full quantum state transfer between microwave and optical fields in a solid-state spin ensemble.

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Source: https://tomesphere.com/paper/1705.00093