Cryogenic amplifier with low input-referred voltage noise calibrated by shot noise measurement<xref rid="cpb_27_6_060702_fn1" ref-type="fn">*</xref><fn id="cpb_27_6_060702_fn1"> <label>*</label> <p>Project supported by the National Natural Science Foundation of China (Grant No. 11474008), the National Key Research and Development Program of China (Grant No. 2016YFA0300904), and the National Basic Research Program of China (Grant No. 2011CBA00106).</p> </fn>

Cryogenic amplifier with low input-referred voltage noise calibrated by shot noise measurement* *

Project supported by the National Natural Science Foundation of China (Grant No. 11474008), the National Key Research and Development Program of China (Grant No. 2016YFA0300904), and the National Basic Research Program of China (Grant No. 2011CBA00106).

Yang Wuhao^†, Wei Jian

(color online) (a) Voltage noise spectrum for different current bias of the Al/AlO_x/Al tunneling junction at 4.6 K, which is measured by our cryogenic amplifier with Au-1447 amplifier. Current bias varies from 0 μA to 1 μA in 0.05-μA steps. Inset: Zoom-in of the voltage noise spectrum in the frequency bin we pick with linear axis, 2.0 MHz to 2.1 MHz (black rectangle). (b) The bias dependence of the voltage noise power of the Al/AlO_x/Al tunneling junction at 4.6 K measured by our cryogenic amplifier with Au-1447 amplifier.