A new method of probing mechanical losses of coatings at cryogenic temperatures
Serge Galliou, Samuel Deléglise, Maxim Goryachev, Leonhard Neuhaus, Gianpietro Cagnoli, Salim Zerkani, Vincent Dolique, Xavier Vacheret, Philippe Abbé, Laurent … 展开作者
Serge Galliou, Samuel Deléglise, Maxim Goryachev, Leonhard Neuhaus, Gianpietro Cagnoli, Salim Zerkani, Vincent Dolique, Xavier Vacheret, Philippe Abbé, Laurent Pinard, Christophe Michel, Thibaut Karassouloff, Tristan Briant, Pierre-François Cohadon, Antoine Heidmann, Michael E. Tobar, Roger Bourquin
A new method of probing mechanical losses and comparing the corresponding deposition processes of metallic and dielectric coatings in 1-100 MHz frequency range and cryogenic temperatures is presented. The method is based on the use of extremely high-quality quartz acoustic cavities whose internal losses are orders of magnitude lower than any available coatings nowadays. The approach is demonstrated for Chromium, Chromium/Gold and a multilayer tantala/silica coatings. The ${\rm Ta}_2{\rm O}_5/{\rm Si}{\rm O}_2$ coating has been found to exhibit a loss angle lower than $1.6\times10^{-5}$ near 30 {\rm MHz} at 4 {\rm K}. The results are compared to the previous measurements.
Frequency stability of cryogenic silicon cavities with semiconductor crystalline coatings
采用低温参考腔的现有技术的光学振荡器在性能上受到与反射镜涂层的机械耗散相关联的布朗热噪声的限制。最近，结晶Al $_{1-x}$ Ga $_{x}$ As/GaAs涂层已成为改善涂层热噪声的有希望的候选者。我们测量了两个全结晶的低温参考腔的频率噪声，该参考腔具有Al $_{0.92}$ Ga $_{0.08}$ As/GaAs光学涂层。我们报告先前未测量的双折射噪声与反相关的频率波动之间的偏振模式的结晶涂层，并确定变量，影响其大小。比较两个低温参考腔之间的双折射噪声揭示了一组现象学的缩放与腔内功率和模式面积。我们实现了一个询问方案，消除了这两个偏振模式的同时探测噪声。这种消除后剩余的残余噪声大于两个腔的热噪声限制，但仍低于先前测量的等效谐振器与介电涂层的不稳定性。虽然这些新的噪声机制的来源还不清楚，我们证明，晶体涂层可以提供稳定性和灵敏度的谐振器采用介电涂层的竞争力。
Cryogenic Mechanical Loss of GaAs/AlGaAs Crystalline Coatings
Syracuse University（雪城大学）；Cardiff University（卡迪夫大学）；Hobart William Smith Colleges（霍巴特威廉史密斯学院）；California Institute of Technology（加州理工学院）；University of Arizona（亚利桑那大学）
NTL-amplified cryogenic light detectors with optically transparent electrodes
INFN, Sezione di Milano Bicocca（意大利国家核物理研究所米兰比可卡分部）；Dipartimento di Fisica ”G.Occhialini”, Università degli Studi di Milano - Bicocca（米兰比可卡大学G.奥恰利尼物理系）；INFN, Sezione di Pavia（意大利国家核物理研究所帕维亚分部）
Detrapping and retrapping of free carriers in nominally pure single crystal GaP, GaAs and 4H-SiC semiconductors under light illumination at cryogenic temperatures
