We demonstrate a free-space amplitude modulator for mid-infrared radiation (λ ≈ 9.6 μm) that operates at room temperature up to at least 20 GHz (above the −3 dB cutoff frequency measured at 8.2 GHz). The device relies on the ultrafast transition between weak- and strong-coupling regimes induced by the variation of the applied bias voltage. Such transition induces a modulation of the device reflectivity. It is made of a semiconductor heterostructure enclosed in a judiciously designed array of metal–metal optical resonators, that—all-together—behave as an electrically tunable surface. At negative bias, it operates in the weak light–matter coupling regime. Upon application of an appropriate positive bias, the quantum wells populate with electrons, and the device transitions to the strong-coupling regime. The modulator transmission remains linear with input radio frequency power in the 0–9 dBm range. The increase in optical powers up to 25 mW exhibit a weak beginning of saturation a little bit below.

中文翻译：

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基于光-物质耦合超快电切换的超快 (≈10 GHz) 中红外调制器


我们展示了一种用于中红外辐射 (λ ≈ 9.6 μm) 的自由空间调幅器，它在室温下工作，频率至少高达 20 GHz（高于在 8.2 GHz 测量的 -3 dB 截止频率）。该器件依赖于由所施加的偏置电压的变化引起的弱耦合状态和强耦合状态之间的超快转变。这种转变引起器件反射率的调制。它由半导体异质结构制成，封装在精心设计的金属-金属光学谐振器阵列中，这些谐振器总体上表现为电可调表面。在负偏压下，它在弱光-物质耦合状态下工作。在施加适当的正偏压后，量子阱中充满电子，并且器件转变为强耦合状态。调制器传输在 0–9 dBm 范围内与输入射频功率保持线性。光功率增加到 25 mW 时，饱和度开始较弱，略低于 25 mW。