Developing on-chip, DC powered THz sources with tuneable output frequency for sensing and ultra-fast computing

THz电磁辐射广泛应用于高分辨率成像、无线通信、皮肤癌筛查、化学分析等领域。典型的THz源具有复杂的设置或低温等限制，阻碍了尺寸的缩小，因此具有许多潜在的应用。本文提出利用自旋电子学或自旋电子学来开发具有可调谐输出频率的片上直流供电THz源。自旋电子太赫兹发射器的制造方法与工业协议兼容，它在室温下工作，是全电的，并且可以扩展到纳米尺度。在这里我们举两个例子：100 GHz以上的无线：这些设备可以应用于开发高分辨率雷达，用于汽车驾驶员辅助（透过雾和雨）和交通协调。现有的商业产品达到了Silicon Radar（https：//siliconradar.com/）的雷达收发器达到亚太赫兹范围（高达300 GHz）。化学分析：许多化学元素在太赫兹频率下具有独特的特征。到目前为止，非接触式太赫兹光谱主要用于研究它们，需要昂贵的设备，并且不允许空间分辨率低于~ 1 mm。有可能通过廉价的全电动设备在芯片上进行相同的分析，从而可以获得几个数量级可实现的空间分辨率将是一个巨大的收获。超快计算：在过去的二十年里，由于云计算、移动的连接以及人工智能和自动驾驶等越来越多的数据密集型技术，数据交换出现了爆炸式增长。处理如此大量的数据给数据中心带来了巨大的压力，并要求更快、更紧凑的存储器。器件的工作频率和它们的面密度决定了计算能力。虽然第二数量在过去几十年中稳步增加，但时钟速度在过去二十年中一直保持在几GHz。拥有片上和CMOS兼容的THz源将提供一种将工作速度提高几个数量级的方法。

THz electromagnetic radiation is used in a variety of fields including high-resolution imaging, wirelesscommunication, skin cancer screening, chemical analysis, etc. Typical THz sources have limitations ofcomplex setups or low temperature, etc. hindering size shrinking down and consequently, manypotential applications.Here we propose to use spintronics, or spin-electronics, to develop on-chip, DC powered THz sourceswith tuneable output frequency. The spintronic THz emitter is simple to fabricate with methodscompatible with industrial protocols, it works at room temperature, it is all-electrical, and it is scalabledown to the nanometre scale. Realising it would attract enormous interests for its potentialapplications.Here we give two examples:Wireless above 100 GHz: These devices could find applications for the development of high resolutionradars for automotive applications for driver's assistance (see through fog and rain) and trafficcoordination. Existing commercial products reach as the radar transceivers by Silicon Radar(https://siliconradar.com/) reach the sub-THz range (up to 300 GHz).Chemical analysis: Many chemical elements have distinguished signatures at THz frequencies. So far,contactless THz spectroscopy has mainly been used to study them, requiring expensive equipment andnot allowing space resolution below ~ 1 mm. Having the possibility to bring the same analysis on-chipvia a cheap, all-electrical device that allows gaining several orders of magnitude in the achievablespace resolution would be an enormous gain.Ultra-fast computing: The past twenty years have seen an explosion of data exchange due to cloudcomputing, mobile connectivity and increasingly data-intensive technologies such as artificialintelligence and autonomous driving. The processing of this huge amount of data is putting a greatstrain on data centres and demands faster and more compact memories. The operating frequency ofthe devices together with their areal density is what determines computational power. While thesecond quantity steadily increased in the past decades, the clock speed has remained pinned at a fewGHz for the past twenty years. Having on-chip and CMOS-compatible THz sources would offer a way topush the working speed up by several orders of magnitude.