极低温下高灵敏太赫兹探测阵列的信号读出

Readout of high-sensitive terahertz detector arrays at low temperature

太赫兹(THz)波段的高灵敏探测器在诸多前沿领域中有着巨大的应用价值。超导量子电容探测器(QCD)是一种在THz波段具备单光子探测能力的高灵敏直接探测器,且可实现大规模阵列。对阵列而言,可靠的读出技术是其性能发挥的基本保障。本研究利用零差读出技术进行了QCD信号读出与表征。微波同相正交(IQ)混频器是零差读出电路的重要组成元件,故对IQ混频器进行了详细表征与校准,通过排除其不平衡性对探测器信号读出的影响,提高了测量的可靠性。在此基础上,对QCD的THz响应信号进行了测量,结果显示QCD响应信号与理论预期结果高度一致。此外,所构建的零差读出电路还可用于高灵敏超导微波动态电感探测器(MKID)阵列等极低温(15 mK以下)探测器的信号读出,为高灵敏THz探测器的开发奠定了良好的基础,具有较高的应用价值。

High-sensitive detector arrays in terahertz(THz)band have great application value in many fields.Quantum capacitance detector(QCD)is one kind of direct detectors with single-photon detection and array capabilities in THz band,which uses frequency division multiplexing,and the array readout technology is relatively simple.For high-sensitive detector arrays,reliable readout technology is the basic guarantee for its superior performance.In this study,QCD signal is measured and characterized by homodyne readout technique.As microwave in-phase quadrature-phase(IQ)mixer is an important component of the homodyne readout circuit,the IQ mixer is characterized and calibrated,and its measurement reliability is improved by eliminating the impact of its imbalance on signal readout.Under this calibration method,the quantum capacitance response signal of QCD is measured,and the results show that the QCD response signal is periodic,which is highly consistent with the expected quantum capacitance effect.In addition,the constructed readout circuit can also be used for signal readout of extremely low temperature(below 15 mK)detectors such as microwave kinetic inductance detector(MKID)arrays,which lays a good foundation for the development of high-sensitive THz detector arrays and has good application value.