High quality factor manganese-doped aluminum lumped-element kinetic inductance detectors sensitive to frequencies below 100 GHz
High quality factor manganese-doped aluminum lumped-element kinetic inductance detectors sensitive to frequencies below 100 GHz
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DOI：
10.1063/1.4984105
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发表时间：
2017-01
影响因子：
4
通讯作者：
G. Jones;B. Johnson;M. Abitbol;P. Ade;S. Bryan;H.-M. Cho;P. Day;D. Flanigan;K. Irwin;D. Li;P. Mauskopf;H. McCarrick;A. Miller;Y. Song;C. University;Cardiff University;A. S. University;S. N. Laboratory;Jet propulsion Laboratory;S. University;U. California
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作者：
G. Jones;B. Johnson;M. Abitbol;P. Ade;S. Bryan;H.-M. Cho;P. Day;D. Flanigan;K. Irwin;D. Li;P. Mauskopf;H. McCarrick;A. Miller;Y. Song;C. University;Cardiff University;A. S. University;S. N. Laboratory;Jet propulsion Laboratory;S. University;U. California
对毫米波光子敏感的铝集总元件动感电感探测器 (LEKID) 已被证明具有较高的品质因数，使其高度灵敏且可复用。铝的超导间隙限制了铝 LEKID 的光子频率高于 100 GHz。锰掺杂铝 (Al-Mn) 具有可调的临界温度，因此如果在薄膜中添加锰时内部品质因数保持足够高，对于对 100 GHz 以下频率敏感的 LEKID 来说可能是一种有吸引力的材料。为了进行研究，我们测量了 Al-Mn LEKID 的一些关键特性。使用沉积在 500 µm 厚的高电阻率浮区硅基板上的 40 nm 厚的 Al-Mn 薄膜制造了原型八元件 LEKID 阵列。锰含量为 900 ppm，测得的 Tc = 694 ± 1mK，谐振频率接近 150 MHz。通过在 65 至 250 mK 之间的不同浴温下测量前向散射参数 S21，我们确定我们制造的 Al-Mn LEKID 的内部品质因数大于 2 × 105 ，这对于毫米波天体物理观测来说足够高。在测量这些设备的黑暗条件下，分数频率噪声频谱显示出一个浅斜率，该斜率取决于浴温度和探测音幅度，这可能是两级系统噪声。当探测器在未来的测量中用毫米波照射时，预期的白光子噪声应该在低频噪声中占主导地位。 LEKID 对 1550 nm 发光二极管发出的光脉冲做出响应，我们使用这些光脉冲确定准粒子寿命为 60 µs。
Aluminum lumped-element kinetic inductance detectors (LEKIDs) sensitive to millimeter-wave photons have been shown to exhibit high quality factors, making them highly sensitive and multiplexable. The superconducting gap of aluminum limits aluminum LEKIDs to photon frequencies above 100 GHz. Manganese-doped aluminum (Al-Mn) has a tunable critical temperature and could therefore be an attractive material for LEKIDs sensitive to frequencies below 100 GHz if the internal quality factor remains sufficiently high when manganese is added to the film. To investigate, we measured some of the key properties of Al-Mn LEKIDs. A prototype eight-element LEKID array was fabricated using a 40 nm thick film of Al-Mn deposited on a 500 µm thick high-resistivity, float-zone silicon substrate. The manganese content was 900 ppm, the measured Tc = 694 ± 1mK, and the resonance frequencies were near 150 MHz. Using measurements of the forward scattering parameter S21 at various bath temperatures between 65 and 250 mK, we determined that the Al-Mn LEKIDs we fabricated have internal quality factors greater than 2 × 105 , which is high enough for millimeter-wave astrophysical observations. In the dark conditions under which these devices were measured, the fractional frequency noise spectrum shows a shallow slope that depends on bath temperature and probe tone amplitude, which could be two-level system noise. The anticipated white photon noise should dominate this level of low-frequency noise when the detectors are illuminated with millimeter-waves in future measurements. The LEKIDs responded to light pulses from a 1550 nm light-emitting diode, and we used these light pulses to determine that the quasiparticle lifetime is 60 µs.