Photonic crystals (PCs) are artificial micro-nano structures composed of two dielectric materials with different refractive indices arranged periodically and have a photonic bandgap (PBG) capable of regulating electromagnetic waveguides with different frequencies. Meanwhile, the PBG band range can be regulated by changing the structural parameters of PCs to regulate light-matter interaction. Tamm plasmon polaritons (TPPs) are an energy localized plasmon resonance mode at the interface of metal and medium, which causes troughs in the bandgap in the reflection spectrum. The research on optical Tamm states (OTSs) provides a new way to precisely control light at the nanoscale and has many applications in enhancing light-matter interaction. Although the OTSs have been applied to metamaterials and optical sensors, the high radiative loss of the Tamm states in “PC-Metal” can not be ignored. Additionally, since the metal layer is an isotropic medium, both transverse electric (TE) and transverse magnetic (TM) waves can generate Tamm states at the interface. Therefore, anisotropic media should be added to the structure to regulate the polarization characteristics of Tamm states for studying the dispersion of Tamm states in different incident polarization directions. Generally, we hope to design a low loss structure containing PCs and metasurface to research the dispersion of Tamm states in different polarization directions.

We design the composite structures of “PC-Metal-PC” and “PC-Metal”, and fabricate the experimental samples by electron beam evaporation and focused ion beam (FIB) etching respectively. The reflection spectra of the samples are measured by angular-resolved microscopic spectrometer (ARMS) and compared with the simulation results of the FDTD (finite-difference time-domain) solution. The quality factor is directly proportional to the ratio of frequency and half-height width. As the frequency of the Tamm states of the two structures is the same, the size relationship of the quality factor of the two structures can be qualitatively compared only by comparing the half-height width. By employing the FDTD solution to calculate the electric field and dielectric constant distribution of the two structures, the quality factor size of the two structures can be quantitatively calculated, and the plane wave size of the two structures can be compared by the electric field distribution. Meanwhile, the “PC-Metasurface-PC” composite structure is designed to explore the polarization of Tamm states. The samples are processed experimentally and the reflection spectra in different polarization directions are measured by ARMS, with the results compared with the simulation results. The variation of reflection spectra with incident polarization angles is observed and recorded.

In the reflection spectrum, the “PC-Metal-PC” structure has a smaller half-height and width than the “PC-Metal” structure, indicating that the “PC-Metal-PC” structure has a larger quality factor and lower radiative loss. In the electric field and dielectric constant distribution diagram, the plane wave radiated by “PC-Metal-PC” is smaller than that of “PC-Metal”, which can also prove that the former has a lower radiative loss. After quantitative calculation, the quality factor of “PC-Metal-PC” is about three times higher than that of “PC-Metal”. The addition of a layer of PCs effectively improves the quality factor and reduces the radiative loss of the structure. The reflection spectrum measurement of “PC-Metasurface-PC” in different polarization directions shows that there are Tamm states in the PBG of the reflection spectrum of TE polarization, but not in the PBG of the reflection spectrum of TM polarization. The reflection spectrum of the incident light is measured from 0° to 90°. When the polarization direction is 0°, there is no Tamm state. The Tamm state in the PBG becomes clearer with the increasing polarization angle, and the Tamm state is most clear and easy to distinguish at 90°.

To solve the problem of low quality factor and high radiative loss of Tamm states at the interface of PCs and metal, we design the composite structure of “PC-Metal-PC”, measure the reflection spectrum of the two models in FDTD, and calculate the field intensity and dielectric coefficient distributions of the two structures. The result shows that the “PC-Metal-PC” can increase the quality factor of the structure and reduce the radiative loss of the structure. By designing a composite structure of “PC-Metasurface-PC”, the reflection spectra of different incident polarization angles are measured. The results show that anisotropic metasurface controls the polarization characteristics of Tamm states. When the polarization direction of the incident light is parallel to the direction of the metasurface, the metasurface is dielectric and there is no Tamm state in the reflection spectrum. When the polarization direction is not parallel to the metasurface, the dielectric property of the metasurface is weakened and the metal property is enhanced, with Tamm states in the reflection spectrum. Our study can be adopted to regulate the dispersion of Tamm states by employing the polarization angle of incident light as the degree of freedom and to research the light-matter interaction in nonlinear optics and quantum optics. Our proposed idea can open up a new way for developing new photonic devices and sensors by utilizing the characteristics of Tamm state coupling and provide a new solution for adopting anisotropic metasurface to regulate electromagnetic waves.