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The quantized photonic spin Hall effect (PSHE) in the strained graphene-substrate system is predicted under a sub-Tesla external magnetic field, which is two orders of magnitude smaller than required to produce the quantized effect in the conventional graphene-substrate system. It is found that in-plane and transverse spin-dependent splittings in the PSHE, exhibit different quantized behaviors and are closely related to the reflection coefficients. Unlike the quantized PSHE in the conventional graphene-substrate system formed by the splitting of real Landau levels, the quantized PSHE in the strained graphene-substrate system is attributed to the splitting of pseudo-Landau levels caused by the pseudo-magnetic field and the lifting of valley degeneracy of the n ≠ 0 pseudo-Landau levels induced by the sub-Tesla external magnetic field. At the same time, the pseudo-Brewster angles of the system are also quantized with the change of Fermi energy. The sub-Tesla external magnetic field and the PSHE appear as quantized peak values near these angles. The giant quantized PSHE is expected to be used for direct optical measurements of the quantized conductivities and pseudo-Landau levels in the monolayer strained graphene.

We theoretically investigate the temperature-dependent Goos-Hanchen (GH) shifts in a symmetrical graphene-cladding waveguide (SGCW). The GH shifts in SGCW present a quasi-periodic tendency near the resonance angle with the change of temperature, which can mainly be attributed to the temperature dependence of the guiding layer’s thickness, instead of the graphene intraband conductivity and guiding layer’s refractive index. Importantly, tiny temperature fluctuations can cause significant deviations in GH shifts, and the deviations can be efficiently improved by adjusting the Fermi energy. Therefore, we propose a high-sensitivity temperature sensing scheme based on GH shifts in the SGCW, and the maximum sensitivity can reach up to −2.2 × 105 μ m/ ° C. These researches may open avenues for applications of optical temperature sensors.

We study the Goos-Hanchen (GH) effect in a graphene-substrate system comprehensively by using the transfer matrix method. It is revealed that the magnitude and sign of GH shifts are closely related to the imaginary part of graphene conductivity in the case of the fixed refractive index of substrate, while the Brewster angle position is largely influenced by the real part of conductivity. Further studies show that the position of Brewster angle keeps invariable when the Fermi energy exceeds 0.4 eV, and the magnitude and sign of GH shifts at a certain Brewster angle are changed only by Fermi energy. On the basis of these findings, a scheme to control the positive and negative GH shifts precisely is proposed and demonstrated by instances. We first adjust the refractive index of substrate to control the Brewster angle position under the condition of the Fermi energy exceeding 0.4 eV, and then adjust the Fermi energy to make the GH shift approach target value. Finally, we apply these precise control properties of GH shift to design a refractive index detector with adjustable sensitivity coefficient. These researches may have potential applications in refractive index sensor with high sensitivity and precise measurement of graphene parameters.

In modern optics, there are two general models to describe the behavior of light in graphene: the zero-thickness model and the slab model. The difference in physical phenomena predicted by the two models is very small, which is hardly distinguished by traditional measurement methods. Therefore, which model can describe the light–matter interaction in graphene more exactly is still a challenging issue. In this work, based on the sensitive optical phenomenon called the photonic spin Hall effect, the small difference can be magnified to a detectable level by the weak-value amplification. The experimental results show that the zero-thickness model can more accurately describe the interaction between light and monolayer or bilayer graphene, while the case of more than two layers, which can no longer be regarded as two-dimensional thickness, should be described by the slab model. Our results may provide information on light interacting with graphene for future investigation in photonics and optoelectronics.

We systematically study the lattice-dependent spin Hall effect of light (SHEL) in a Weyl semimetal (WSM) by considering left-handed polarization of the incident beam, and propose a new simple method to sense the lattice spacing precisely. It is revealed that the lattice spacing plays as essential a role as the Weyl points separation in the influences on the SHEL, and the variations of SHEL shifts are closely related to the real part of Hall conductivity. Specifically, the SHEL shifts increase to the peak values first and then decrease gradually with the increase of lattice spacing, and a quantitative relationship between the SHEL and the lattice spacing is established. By simulating weak measurement experiments, the lattice-dependent SHEL shifts are amplified and measured in desirable accuracies. Subsequently, we propose a method of precisely sensing the lattice spacing based on the amplified SHEL shifts. These researches provide theoretical basis for manipulating the SHEL in WSMs, and may open the possibility of fabricating the WSM parameter sensors.

We systematically study the role of Weyl cone tilting in the spin Hall effect of light (SHEL) in doped Weyl semimetals (WSMs), and propose a new scheme to determine the type of a WSM and to sense the tilt degree of Weyl cones precisely. It is found that in the case of a small amount of doping, the SHEL in type-I WSMs shows almost no dependence on the tilt degree of Weyl cones, while the SHEL in type-II WSMs is extremely sensitive to variations in the degree of tilt. However, in the case of a large amount of doping, not only the SHEL in type-II WSMs but also the SHEL in type-I WSMs show strong dependences on the tilt degree. These trends are mainly attributed to the variation of the real part of the Hall conductivity with the tilt degree. Remarkably, by using a quantum weak measurement, the tiny SHEL shifts can be amplified and detected to a desirable accuracy. Based on the obviously different tilt-dependent characteristics of amplified SHEL shifts in WSMs, we propose a new scheme to determine the type of a WSM and to sense the tilt degree precisely. By adjusting the doping level, the sensing sensitivity can reach up to 1461.55 µm per degree of tilt. This study may provide an application reference for the fabrication of WSM parameter sensors and other topological photoelectric devices.

We propose a tunable and high-sensitivity temperature-sensing method via weak-value amplification of Goos–Hanchen (GH) shifts in a graphene-coated system. The GH shifts were sensitive to the temperature, which was mainly attributed to the variations in the substrate’s refractive index with the temperature. By introducing the weak-value amplification technique, a temperature-sensing method was produced, in which the sensing sensitivity was two orders of magnitude higher and could be effectively manipulated by adjusting the amplified angle. The sensitivity was improved by regulating the graphene’s Fermi energy. Based on these findings, we obtained a maximum sensitivity of 1 . 3 × 1 0 5 nm/ ∘ C by using the appropriate Fermi energy and amplification angle. These studies expand the practical applications of GH shifts, and provide the potential for developing high-sensitivity temperature sensors based on weak-value amplification.