We numerically investigate the dynamic control over the spontaneous emission rate of quantum emitters using tunable hyperbolic metamaterials (HMMs). The dispersion of a metal–dielectric thin-film stack at a given frequency can undergo a topological transition from an elliptical to a hyperbolic dispersion by incorporating a tunable metal or dielectric film in the HMM. This transition modifies the local density of optical states of the emitter and, hence, its emission rate. In the visible range, we use an HMM consisting of TiN and ${{\rm Sb}_2}{{\rm S}_3}$ and show considerable tunability in the Purcell enhancement and quantum efficiency as ${{\rm Sb}_2}{{\rm S}_3}$ phase changes from amorphous to crystalline. Similarly, we show tunable Purcell enhancement in the telecommunication wavelength range using a ${\rm TiN}/{{\rm VO}_2}$- HMM. Finally, tunable spontaneous emission rate in the mid-IR range is obtained using a ${\rm graphene}/{\rm MgF}_2$ HMM by modifying the graphene conductivity through changing its chemical potential. We show that using a metal nitride (for the visible and NIR HMMs) and a fluoride (for the mid-IR HMM) is important to get an appreciable change in the effective permittivity of the thin-film multilayer stack.

中文翻译：

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使用可调双曲超材料动态控制自发发射率

我们在数值上研究了使用可调双曲线超材料（HMM）对量子发射器自发发射速率的动态控制。通过在HMM中加入可调节的金属或介电膜，金属-介电薄膜叠层在给定频率下的色散会经历从椭圆形到双曲线的色散拓扑变化。该转变改变了发射器的光学状态的局部密度，并因此改变了其发射速率。在可见范围内，我们使用了由TiN和$ {{\ rm Sb} _2} {{\ rm S} _3} $组成的HMM，并在赛尔增强和量子效率方面表现出相当可调谐性，为$ {{\ rm Sb} _2} {{\ rm S} _3} $相从无定形变为结晶。同样，我们显示了使用$ {\ rm TiN} / {{\ rm VO} _2} $ -HMM在电信波长范围内可调的赛尔增强。最后，使用$ {\ rm石墨烯} / {\ rm MgF} _2 $ HMM通过改变石墨烯的化学势来改变石墨烯的电导率，从而获得中红外波段的可调自发发射速率。我们表明，使用金属氮化物（用于可见光和近红外HMM）和氟化物（用于中红外HMM）对于使薄膜多层堆叠的有效介电常数发生明显变化很重要。