# Micro-wave assisted transparency in a M-system

## TL;DR

This paper theoretically investigates a five-level M-system with microwave coupling, revealing its advantages in line narrowing and potential for phase-dependent magnetometry compared to traditional systems.

## Contribution

It introduces the concept of microwave-assisted transparency in M-systems, demonstrating their improved efficiency and line narrowing capabilities over closed loop $ ext{Lambda}$ systems.

## Key findings

- Microwave field narrows probe absorption lineshape in M-systems.
- M-systems avoid population transfer at high microwave intensities.
- Potential application in atom-based phase-dependent MW magnetometry.

## Abstract

In this work we theoretically study a five level M-system whose two unpopulated ground states are coupled by a micro-wave (MW) field. The key feature which makes M-systems more efficient in comparison to closed loop $\Lambda$ systems is the absence of MW field induced population transfer even at high intensities of the later. We examine lineshape of probe absorption as a function of its detuning in the presence of both control and MW fields. The MW field facilitates the narrowing of the probe absorption lineshape in M-systems which is in contrast to closed loop $\Lambda$-systems. Hence this study opens up a new avenue for atom based phase dependent MW magnetometry.