Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, USA.
Department of Electrical Engineering, City College of The City University of New York, New York, New York 10031, USA.
Phys Rev Lett. 2019 Oct 18;123(16):164102. doi: 10.1103/PhysRevLett.123.164102.
Chu's limit determines the minimum radiation quality factor Q of an electrically small resonator, and hence its maximum operational bandwidth, which is inversely proportional to its volume. This bound imposes severe restrictions in several areas of technology, from wireless communications to nanophotonics and metamaterials. We show that a suitably tailored temporal modulation of the matching network, combined with proper detuning of the feeding impedance, can overcome this limit and enable radiation over broader bandwidths, which scale as 1/sqrt[Q], ensuring at the same time stability. Our findings open opportunities for communication systems, nanophotonics, and sensor technology.
朱的限制决定了电小谐振器的最小辐射品质因数 Q，从而决定了其最大工作带宽，而带宽与体积成反比。这个限制在从无线通信到纳米光子学和超材料等多个技术领域都造成了严重的限制。我们表明，通过适当的匹配网络时间调制，并适当调整馈入阻抗的失谐，可以克服这个限制，从而实现更宽的带宽辐射，其比例为 1/√Q，同时保证稳定性。我们的发现为通信系统、纳米光子学和传感器技术开辟了机会。
