A Pathfinder Instrument for Kilopixel Heterodyne Array Receivers

太赫兹光谱系统是天文学探测器发展的最后前沿之一。在这种红外线和无线电技术的融合中，通常使用两种方法。非相干技术，包括测辐射热计和光电导体，已经被推向高达10,240像素的阵列尺寸。然而，非相干探测器不保存辐射的相位信息，因此不允许高光谱分辨率，除非它们与色散光栅或标准具组合在一起。此外，当以分散的格式使用时，非相干阵列不再能够在两个探测器维度上提供空间信息。另一方面，今天的相干探测器可以在太赫兹频率下工作，但馈电喇叭、接收器和混频器的小型化、连接化和封装成密集阵列带来了非常艰巨的技术挑战。到目前为止，相干探测器的技术水平一直是运行在350 GHz左右的像素一维阵列。亚利桑那州立大学的克里斯托弗·格罗皮是开发上述像素外差阵列团队的关键成员，他现在建议将这一开发扩展到下一个合乎逻辑的步骤，即小型(2x4像素)二维阵列。这种设备需要清除大型2-D阵列带来的几乎所有技术障碍，但规模是可管理的，材料处理技术可以负担得起的测试。凭借在超导-绝缘体-超导(SIS)混合器技术方面经验丰富的团队成员的专业知识，以及研究生(制造、组装和测试)和本科生(机械加工)的参与，Groppi计划进行为期3年的开发工作，在10米Heinrich Hertz望远镜上使用频率为660 GHz的新阵列。成功将对恒星形成区域和外部星系绘制气体物种图的效率以及遥感应用产生重大影响。这项工作的资金是由NSF的天文科学部通过其先进技术和仪器计划提供的。

The THz spectral regime is one of the last frontiers in detector development for astronomy. At this confluence of infrared and radio techniques, two general approaches are used. Incoherent techniques, including bolometers and photoconductors, have been pushed to array sizes as large as 10,240 pixels. However, incoherent detectors do not preserve phase information of the radiation, and so do not permit high spectral resolution unless they are teamed with dispersing gratings or etalons. Furthermore, when used in a dispersed format, incoherent arrays can no longer offer spatial information in both detector dimensions. Today's coherent detectors, on the other hand, can operate at THz frequencies, but the miniaturization, connectorization, and packaging of the feed horns, receivers, and mixers into a dense array pose very daunting technological challenges. To date, the state of the art in coherent detectors has been a 64-pixel 1-D array operating around 350 GHz.Dr. Christopher Groppi of the Arizona State University was a key member of the team that developed the afore-mentioned 64-pixel heterodyne array, and he now proposes to extend that development the next logical step, to a small (2x4 pixel) 2-D array. This device will need to clear nearly all of the technological hurdles that will be posed by large 2-D arrays, but on a scale that is manageable and for which materials processing techniques can be affordably tested. With the expertise of team members who are experienced in Superconducting-Insulator-Superconducting (SIS) mixer technology, and the participation of both a graduate student (fabrication, assembly, and testing) and an undergraduate student (machining), Groppi plans a 3 yr development effort capped by use of the new array at a frequency of 660 GHz at the 10-m Heinrich Hertz Telescope. Success would have dramatic implications for the efficiency with which gas species can be mapped in star-forming regions and external galaxies, as well as for remote sensing applications. Funding for this work is being provided by NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.