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In the effective mass approximation, single-particle, excitonic states, and interband and intraband transitions in CdSe nanoplatelet are considered in the presence of an external axial uniform electrostatic field. It has been demonstrated that under the influence of the field, the binding energy between the electron and the hole in the nanoplatelet decreases compared to the case in the absence of the field. It is shown that with increasing electric field strength, the resonant frequencies of interband electroabsorption undergo a red shift. On the other hand, the resonance frequencies of intraband absorption shift to the region of high energies. A similar shift of photoluminescence spectrum peaks under the influence of the field has been observed. The results of theoretical calculations of the luminescence threshold frequency values are in good agreement with the corresponding experimental data. It is shown that the dependence of the optical rectification peaks on the external field is non-monotonic with pronounced maxima. [ABSTRACT FROM AUTHOR]

Herein, we theoretically demonstrate a broadband hybrid plasmonic electro-absorption optical modulator with integrated silver nanoribbons. We have examined two structures. The first one includes two layers of graphene and two layers of hexagonal boron nitride (h-BN). Silver nanoribbons are placed on the Molybdenum Disulfide ($Mo{S}_2$) layer. In the second structure, we covered the nanoribbon arrays with extra graphene, $Mo{S}_2$, and h-BN layers. The effect of the gap between the silver nanoribbons is analyzed for the effective refractive index, modulation depth (MD), Extinction Ratio (ER), Figure of Merit (FoM), and loss. The best results illustrate that the highest amount of the effective refractive index is 5.65, and the highest amount of the loss is 2.2 dB/μm in the chemical potential of 0.65 eV at the wavelength of 1.3 μm. The maximum MD and FoM are 28.37 dB/μm and 62.93 at 1.3 μm, respectively. The calculations show that this electro-absorption modulator has a modulation bandwidth of 411.25 GHz and 27.18 fJ/bit energy consumption. This modulator achieves a high MD, ER, and FoM with a small footprint and low switching voltage. The study demonstrates that the modulator can achieve a high level of modulation depth with low energy consumption and loss.