An optical metamixer
An optical metamixer
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发表时间：
2017-10
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通讯作者：
Sheng Liu;P. Vabishchevich;A. Vaskin;J. Reno;G. Keeler;M. Sinclair;I. Staude;I. Brener
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作者：
Sheng Liu;P. Vabishchevich;A. Vaskin;J. Reno;G. Keeler;M. Sinclair;I. Staude;I. Brener
混频器是一种非线性设备，可组合电磁波以产生新频率的波。混频器是现代射频技术中无处不在的组件，广泛应用于微波信号处理。用于光频率的多功能混频器的开发仍然具有挑战性：此类设备通常依赖于弱非线性光学过程，因此必须满足相位匹配条件。在这项工作中，我们利用基于 GaAs 的电介质超表面来演示光学混频器，该混频器可以同时生成涵盖紫外到近红外 (NIR) 光谱范围的 11 个新频率。我们的方法结合了强大的固有材料非线性、增强的电磁场和宽松的相位匹配要求，允许同时发生七种不同的非线性光学过程。具体来说，当由两个飞秒近红外脉冲泵浦时，我们观察到二次、三次和四次谐波的产生、和频的产生、双光子吸收引起的光致发光、四波混频和六波混频。这种超紧凑的光学混频器可以在生物学、化学、传感、通信和量子光学领域实现多种应用。
A frequency mixer is a nonlinear device that combines electromagnetic waves to create waves at new frequencies. Mixers are ubiquitous components in modern radio-frequency technology and are widely used in microwave signal processing. The development of versatile frequency mixers for optical frequencies remains challenging: such devices generally rely on weak nonlinear optical processes and, thus, must satisfy phase matching conditions. In this work, we utilize a GaAs-based dielectric metasurface to demonstrate an optical frequency mixer that concurrently generates eleven new frequencies spanning the ultraviolet to near-infrared (NIR) spectral range. Our approach combines strong intrinsic material nonlinearities, enhanced electromagnetic fields, and relaxed phase-matching requirements, to allow seven different nonlinear optical processes to occur simultaneously. Specifically, when pumped by two femtosecond NIR pulses, we observe second-, third- and fourth-harmonic generation, sum-frequency generation, two-photon absorption induced photoluminescence, four-wave mixing, and six-wave mixing. Such ultracompact optical mixers may enable a plethora of applications in biology, chemistry, sensing, communications and quantum optics.