通过读出电流非线性实现微波动态电感探测器的可调响应度和带宽
Tunable responsivity and bandwidth in microwave kinetic inductance detectors via readout current nonlinearity
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中文总结 AI 辅助
研究通过调整读出功率和频率至接近谐振器分岔点，增强微波动态电感探测器光响应，同时减小带宽，还能通过调整激励选择反馈效应强度，可提高探测器在非本征噪声源显著时的灵敏度。
中文摘要 AI 辅助
微波动态电感探测器（MKIDs）通常用足够高幅度的微波读出信号进行读出，以充分抑制第一级放大器的噪声贡献。在高读出功率下，由于动态电感对内部循环微波电流的依赖性，探测器的谐振频率会发生改变。当信号频率低于谐振频率时，非线性频移会导致正反馈效应，这可显著提高探测器对光和微波功率的响应度。我们报告通过将读出功率和频率调至接近谐振器的分岔点，光响应增强了10倍。在此条件下，观察到谐振器带宽相应减小。我们表明通过调整激励可轻松选择反馈效应的强度，并提供了这样做的可能操作状态图。当非本征噪声源显著时，以这种模式操作MKIDs可用于提高灵敏度。
英文摘要
Microwave kinetic inductance detectors (MKIDs) are generally read out with microwave readout tones of high enough amplitude to adequately suppress the noise contribution of the first-stage amplifier. At high readout power, the detector's resonant frequency is altered as a result of the dependence of the kinetic inductance on the internally circulating microwave current. With the tone placed below the resonant frequency, the nonlinear frequency shift results in a positive feedback effect that can significantly enhance the responsivity of the detector, to both optical and microwave power. We report a factor of 10 enhancement in optical response by tuning the readout power and frequency to close to the resonator's bifurcation point. A corresponding decrease in the bandwidth of the resonator is observed under these conditions. We show that the strength of the feedback effect can be easily selected by adjusting the excitation, and provide a map of possible operational states to do so. Operation of MKIDs in this mode could be used to improve sensitivity when non-intrinsic noise sources are significant.
