2s exciton-polariton revealed in an external magnetic field

We demonstrate the existence of the excited state of an exciton-polariton in a semiconductor microcavity. The strong coupling of the quantum well heavy-hole exciton in an excited 2s state to the cavity photon is observed in non-zero magnetic field due to surprisingly fast increase of Rabi energy of the 2s exciton-polariton in magnetic field. This effect is explained by a strong modification of the wave-function of the relative electron-hole motion for the 2s exciton state.Comment: 5 pages, 5 figure

Angular dependence of giant Zeeman effect for semimagnetic cavity polariton

The observation of spin-related phenomena of microcavity polaritons has been limited due to the weak Zeeman effect of nonmagnetic semiconductors. We demonstrate that the incorporation of magnetic ions into quantum wells placed in a nonmagnetic microcavity results in enhanced effects of magnetic field on exciton-polaritons. We show that in such a structure the Zeeman splitting of exciton-polaritons strongly depends on the photon-exciton detuning and polariton wave vector. Our experimental data are explained by a model where the impact of magnetic field on the lower polariton state is directly inherited from the excitonic component, and the coupling strength to the cavity photon is modified by an external magnetic field

Relative Reflection Difference as a Method for Measuring the Thickness of the Exfoliated MoSe₂ Layers

We propose a method for measuring the thickness of the exfoliated MoSe₂ layers deposited on Si/SiO₂ substrate, based on the reflectance measurements performed with laser light illumination at two different wavelengths: red and green from confocal microscope at room temperature. We demonstrate the correlation between the number of layers in a flake and the value of its relative reflection difference. We applied the transfer matrix method to calculate the reflectivity and verify our experimental results. The approach proposed by us allows for fast and automatic verification of the exfoliated MoSe₂ layers thickness on large areas of the substrate