Linear Avalanche HgCdTe Arrays for Photon Counting AO Wavefront Sensing

自20世纪90年代中期以来，自适应光学（AO）技术已经彻底改变了光学和红外（IR）波长的地基观测天文学。大气对自然或激光引导星星波前的扭曲的精确感知对于实现望远镜的衍射极限至关重要。夏威夷大学的Donald Hall博士建议，通过生产适度格式的阵列并在望远镜上展示其用于波前传感的光子计数性能，来适应并优化通过国家在空间和军事LADAR方面的大量投资开发的AO波前传感传感器。为了实现这一目标，该技术利用了碲镉汞独特的线性雪崩特性，碲镉汞已经是1 - 5微米波段天文学的首选材料，也是生产近红外天文学大型阵列的技术基础。该项目将混合32 x32阵列的碲镉汞线性模式雪崩光电二极管，以优化64输出读出。这些混合器将以高量子效率计数波长在0.85和2.5微米之间的单个近红外光子，帧速率接近100 KHz，并且其基本泊松统计没有退化。我们的目标是生产超过一千个读出管芯，并使几十个高质量的杂交阵列可用于初步表征，然后部署在望远镜AO system.While拟议的调查有可能彻底改变AO波前传感和科学的各个方面，它使地面望远镜，它几乎没有挖掘表面的更广泛的应用，超越天文学。调查还将包括潜在的太阳能应用，并可能使日冕AO传感。 最后，社会将受益于该技术的发展，其应用超越天文学，以及令人兴奋的科学发现，它将成为可能。开发和建造原型摄谱仪的资金由NSF的天文科学部通过其先进技术和仪器计划提供。

Since the mid 1990's, Adaptive Optics (AO) techniques have revolutionized ground-based observational astronomy at optical and infrared (IR) wavelengths. The precise sensing of the atmosphere's distortion of the wavefront from a natural or laser guide star is crucial to achieving a telescope's diffraction limit. Dr. Donald Hall of the University of Hawaii proposes to adapt, and optimize for AO wavefront sensing, sensors developed through the nation's substantial investment in space and military LADAR by producing modest format arrays and demonstrating their photon counting performance for wavefront sensing at the telescope. To achieve this, the technique utilizes the unique linear avalanche properties of HgCdTe, a substance already the material of choice for astronomy in the 1 - 5 micron waveband and the technology base for production of large format arrays for near-IR astronomy. The project will hybridize 32x32 arrays of HgCdTe linear-mode avalanche photo-diodes to an optimized 64-output readout. These hybrids will count individual near-IR photons with wavelengths between 0.85 and 2.5 microns with high quantum efficiency, at frame rates approaching 100 KHz, and with no degradation of their fundamental Poisson statistics. The goal is to produce over a thousand readout dies and to make several dozen high-quality hybridized arrays available for initial characterization followed by deployment in telescope AO systems.While the proposed investigation has the potential to revolutionize AO wavefront sensing and all aspects of the science it enables on ground based telescopes, it barely taps the surface of broader applications that extend beyond astronomy. The investigation will also encompass potential solar applications and likely enabling coronal AO sensing. Finally, society will benefit from the development of the technique, its application beyond astronomy, and the exciting scientific discoveries it will make possible.Funding for development and construction of the prototype spectrograph is being provided by NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.