Magnetically driven Terahertz spectral filters and their applications

如今，非线性光学领域令人印象深刻的创新为实现新的可靠的太赫兹（THz）源和探测器铺平了道路，直到最近，才有了完全可操作的设备。该合作研发项目是由我们与两个工业合作伙伴Novacam Technologies Inc.和QPS Photronics Inc.合作提出的，旨在证明一系列用于操纵太赫兹波的新型设备的可行性和有效性。特别地，我们建议在太赫兹频率范围内演示磁驱动的可调谐频谱滤波器。这种装置将依赖于PI先前演示的双线太赫兹波导。主要思想是直接将布拉格光栅（BG）写入波导的金属结构上，从而作为宽带太赫兹传播脉冲的陷波（即抑制）滤波器。为了进一步调整这种滤波器的中心频率和线宽，我们将提议将我们的设备与一种特殊的磁性材料结合起来，这种材料被称为铁磁流体，它在太赫兹范围内大部分是透明的。铁磁流体具有受外部静磁场偏置时折射率发生改变的特性。通过将这些材料嵌入到BG的结构中，我们将最终实现一个滤波器，其光谱响应可以根据施加的外部磁场实时（即动态）修改，从而允许太赫兹脉冲带宽的低损耗重塑。我们相信，我们打算在该项目中开发的紧凑且价格合理的动态调谐太赫兹频谱滤波器将在即将到来的太赫兹成像和下一代高速无线通信领域发挥关键作用，这将包括建筑物内外短距离的高速宽带无线数据传输。此外，这些设备已经为我们的工业合作伙伴创造了巨大的兴趣，他们打算通过提供控制太赫兹辐射的前沿产品，大幅增加他们在不断增长的太赫兹市场上的存在。该项目的成果将使加拿大能够增加其在不断增长的信息通信技术市场的全球份额，尤其是在成像和信号处理等新兴领域。

Nowadays, impressive innovations in the field of nonlinear optics have paved the way for the realization of new reliable Terahertz (THz) sources and detectors and, only recently, fully operating devices. The aim of this collaborative Research and Development project, proposed in collaboration with our two industrial partners Novacam Technologies Inc. and QPS Photronics Inc., is to demonstrate the feasibility and effectiveness of a series of novel devices engineered for the manipulation of THz waves. In particular, we propose to demonstrate a magnetically driven tunable spectral filter in the THz frequency range. Such a device will rely on the two-wire THz waveguide previously demonstrated by the PI. The main idea is to directly write a Bragg grating (BG) onto the metallic structure of our waveguide, thus acting as notch (i.e., rejection) filter for the broadband THz propagating pulse. With the aim of further tuning the central frequency and the linewidth of such a filter we will propose to combine our device with a particular class of magnetic materials, named Ferrofluids, which are mostly transparent in the THz range. Ferrofluids have the property to change their refractive index when biased by an external static magnetic field. By embedding such materials in the structure of the BG, we will finally achieve a filter whose spectral response can be modified in real-time (i.e., dynamically), in function of the applied external magnetic fields, thus allowing a low loss reshaping of the THz pulse bandwidth. We believe that the compact and affordable dynamically tuned THz spectral filters we intend to develop in this project will play a key role in the forthcoming fields of THz imaging and next-generation high-speed wireless communications, which will consist of high speed broadband wireless data transfer within and outside buildings on short distances. Furthermore, such devices have already created a significant interest for our industrial partners who intend to significantly increase their presence on the growing THz market, by providing leading-edge products for the manipulation of THz radiation. The project results will allow Canada to increase its global share of the growing ICT market, above all in the burgeoning areas of imaging and signal processing.