A dispersive nanoSQUID magnetometer for ultra-low noise, high bandwidth flux detection
A dispersive nanoSQUID magnetometer for ultra-low noise, high bandwidth flux detection
复制标题
用于超低噪声、高带宽通量检测的色散 nanoSQUID 磁力计
DOI：
--
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
I. Siddiqi
中科院分区：
文献类型：
--
作者：
E. Levenson;R. Vijay;N. Antler;I. Siddiqi
我们描述了一种分散的纳米级超导量子干涉装置（nanoSQUID）磁强计，该磁强计由两个可变厚度的铝弱链路约瑟夫森结和片上电容器并联组成。当直接耦合到50 Ω传输线时，这种排列形成了一个非线性振荡器，具有可调谐的4-8 GHz谐振频率，质量因子Q = 30。在近谐振微波载波信号存在的情况下，低频磁通输入产生的边带很容易用微波反射计检测到。如果载流子激励足够强，则磁强计也显示参数增益，导致最小有效磁通噪声为30 nΦ0 Hz−1/2，瞬时带宽为20 MHz。如果在磁力计后面加上一个近量子噪声限制的约瑟夫森参数放大器，我们可以在不影响灵敏度的情况下将带宽增加到60 MHz。这种高灵敏度和宽带宽的结合，没有片上耗散，使该器件非常适合经典和量子自旋动力学的局部传感。
We describe a dispersive nanoSQUID (nanoscale superconducting quantum interference device) magnetometer comprised of two variable thickness aluminum weak-link Josephson junctions shunted in parallel with an on-chip capacitor. This arrangement forms a nonlinear oscillator with a tunable 4–8 GHz resonant frequency with a quality factor Q = 30 when coupled directly to a 50 Ω transmission line. In the presence of a near-resonant microwave carrier signal, a low frequency flux input generates sidebands that are readily detected using microwave reflectometry. If the carrier excitation is sufficiently strong, then the magnetometer also exhibits parametric gain, resulting in a minimum effective flux noise of 30 nΦ0 Hz−1/2 with 20 MHz of instantaneous bandwidth. If the magnetometer is followed with a near-quantum-noise-limited Josephson parametric amplifier, we can increase the bandwidth to 60 MHz without compromising sensitivity. This combination of high sensitivity and wide bandwidth with no on-chip dissipation makes this device ideal for local sensing of spin dynamics, both classical and quantum.