Invited Article: Ultra-broadband terahertz coherent detection via a silicon nitride-based deep sub-wavelength metallic slit
Invited Article: Ultra-broadband terahertz coherent detection via a silicon nitride-based deep sub-wavelength metallic slit
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DOI：
10.1063/1.5052628
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发表时间：
2018-11
期刊：
影响因子：
5.6
通讯作者：
A. Tomasino;R. Piccoli;Y. Jestin;Sebastien Delprat;M. Chaker;M. Peccianti;M. Clerici;A. Busacca;L. Razzari;R. Morandotti
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文献类型：
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作者：
A. Tomasino;R. Piccoli;Y. Jestin;Sebastien Delprat;M. Chaker;M. Peccianti;M. Clerici;A. Busacca;L. Razzari;R. Morandotti
我们提出了一种新型的与CMOS兼容的器件，旨在执行超短太赫兹脉冲的固态偏置相干检测，即具有至少20年宽的无间隙带宽。这种结构依赖于位于两个平行铝垫之间的1微米宽的狭缝孔径，嵌入1微米厚的氮化硅层中，并沉积在石英基板上。我们发现，这种装置可以探测到超宽带太赫兹脉冲，只使用了几十纳焦耳的前所未有的低光探测器能量。这是由于氮化硅的非线性系数比前几代使用的非线性材料二氧化硅高一个数量级以上。此外，由于铝垫之间的距离减小，通过施加极低的外部偏置电压(几十伏的数量级)，可以在狭缝内产生非常高的静电场，这大大提高了所检测到的太赫兹波形的动态范围。这些结果为在由高重复频率激光振荡器和低噪声、低电压发生器供电的紧凑型和小型化太赫兹系统中集成固态超宽带检测铺平了道路。
We present a novel class of CMOS-compatible devices aimed to perform the solid-state-biased coherent detection of ultrashort terahertz pulses, i.e., featuring a gap-free bandwidth at least two decades-wide. Such a structure relies on a 1-µm-wide slit aperture located between two parallel aluminum pads, embedded in a 1-µm-thick layer of silicon nitride, and deposited on a quartz substrate. We show that this device can detect ultra-broadband terahertz pulses by employing unprecedented low optical probe energies of only a few tens of nanojoules. This is due to the more than one order of magnitude higher nonlinear coefficient of silicon nitride with respect to silica, the nonlinear material employed in the previous generations. In addition, due to the reduced distance between the aluminum pads, very high static electric fields can be generated within the slit by applying extremely low external bias voltages (in the order of few tens of volts), which strongly enhance the dynamic range of the detected THz waveforms. These results pave the way to the integration of solid-state ultra-broadband detection in compact and miniaturized terahertz systems fed by high repetition-rate laser oscillators and low-noise, low-voltage generators.