https://doi.org/10.1140/epjd/s10053-021-00275-5
Regular Article – Optical Phenomena and Photonics
Controlling negative refractive index of degenerated three-level 
-type system by external light and magnetic fields
Vinh University, 182 Le Duan Street, Vinh City, Vietnam
Received:
17
July
2021
Accepted:
16
September
2021
Published online:
1
October
2021
We have achieved the negative refractive index for the probe light in a degenerated three-level -type atomic medium under electromagnetically induced transparency. The width of the frequency band of the negative refractive index can be changed by adjusting the coupling light intensity, while the position of the frequency band of the negative refractive index can be shifted to low or high frequency region by varying the coupling light frequency or the external magnetic field. Furthermore, the positive refractive index for a given probe frequency can be converted to the negative refractive index and vice versa by adjusting the strength or the sign of the magnetic field. This means that we can use the external magnetic field as a “knob” to control the sign of the refractive index of the material which can obtain the desired material with positive or negative index.
© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2021
