基于奇异光学束缚态的古斯-汉欣位移增大

Increase of Goos-Hänchen Shift Based on Exceptional Optical Bound States

作为一类具有代表性的光学共振模式,光学束缚态已被用于大幅增大古斯-汉欣位移。然而,在大多数的研究工作中,人们利用的是透射型的束缚态来增大古斯-汉欣位移。因此,古斯-汉欣位移的峰值位于透射谱的极大值(即反射谱的极小值)处,对应的反射率很低,这不利于实验测量与实际应用。本综述阐述了本课题组在近年来利用两种奇异的光学束缚态增大古斯-汉欣位移的研究情况。第一种光学束缚态为四部分光栅-波导复合结构中的连续谱准束缚态。古斯-汉欣位移的峰值位于反射谱的极大值处,反射率高达100%。第二种束缚态为光子晶体异质结中的界面态。界面态的反射率可由光子晶体的虚相位的失配程度进行灵活调节。古斯-汉欣位移的峰值虽位于反射谱的极小值处,但反射率仍可达到97.6%。这两种奇异的光学束缚态在大幅增大古斯-汉欣位移的同时,保持了较高的反射率,这克服了传统增大古斯-汉欣位移的方法的低反射缺点。由于这两种奇异的光学束缚态具有较高的反射率,古斯-汉欣位移将更容易在实验上被测量到,因此后续有望将其应用在各类高性能传感器、光开关、光存储器件、波分(解)复用器件和偏振分光器件的设计中。

As a kind of typical optical resonant modes,optical bound states have been utilized to greatly increase the Goos-H?nchen shift.However,in most research work,researchers utilize transmission-type bound states to increase the Goos-H?nchen shift.Therefore,the peak value of the Goos-H?nchen shift is located at the maximum of the transmission spectrum(that is,the minimum of the reflection spectrum),and the corresponding reflectivity is very low,which is not conducive to the experimental measurement and practical application.This review describes the recent research progress of our group in using two kinds of strange optical bound states to increase the Goos-H?nchen shift.The first optical bound state is the continuum quasi bound state in the four-part grating-waveguide composite structure.The peak value of the Goos-H?nchen shift is located at the reflectance peak with 100%reflectance.The second bound state is the interface state in the photonic crystal heterojunction.The reflectivity of the interface state can be flexibly tuned by the degree of mismatching between the imaginary phases of photonic crystals.Although the peak value of the Goos-H?nchen shift is located at the reflectance dip,the reflectance can still reach 97.6%.These two strange optical bound states greatly increase the Goos-H?nchen shift while maintaining a high reflectivity,which overcomes the low reflection shortcomings of the traditional method of increasing the Goos-H?nchen shift.Because these two strange optical bound states have high reflectivity,the Goos-H?nchen shift will be easier to be measured experimentally,so it is expected to be applied to the design of various high-performance sensors,optical switches,optical storage devices,wavelength division multiplexing(demultiplexing)devices,and polarization splitter devices in the future.