In this letter, we theoretically investigate the impact of the incident light polarization on photonic spin splitting induced by the photonic spin Hall effect when a linearly polarized Gaussian beam is reflected from an air-glass interface around the Brewster angle. We calculate the spin splitting shift as a function of the incident light polarization under different incident angles. We find that a tiny variation of the incident light polarization can result in a dramatic change of the spin splitting shift, and the highest sensitivity is up to 6.8 μm/deg . The largest splitting shift can reach 5.3 μm, which is larger than the previously reported values. We also find that the direction of spin accumulation of photons with different spin directions can be switched by adjusting the incident angle around the Brewster angle when the incident light polarization is near the p-polarization. These findings may be useful for precise polarization metrology and photon modulation.
A mathematic model based on surface plasmon resonance (SPR) effect is presented to measure the nano metallic film
thickness with the coupling device of Kretschmann configuration composed of K9 prism-gold film-air. Four modulation
modes of SPR method, such as intensity, phase, wavelength and angle, are numerically analyzed. Their detection
principles, the measurement range and sensitivity of different modulation type sensors are discussed. The simulation
results show that the SPR intensity detection method has the highest measurement range and the SPR phase detection
method has the highest sensitivity. In practical applications, not only the measurement range and sensitivity, but the
optical signal processing mode, experiment devices, the complexity of the algorithm and cost factors should be
considered to research and develop the appropriate thin metallic film's thickness measurement SPR sensor with higher
sensitivity and stability.
The evanescent wave, occurred when the incident light generates total internal reflection on the interface between glass and metallic film, can raise the surface plasmon (SP) on the metallic film. SP and evanescent wave can resonate under certain angle of incidence when they have the same frequency and wave number. In this case, the power of reflection beam decreases dramatically, and the resonance peak appears in the reflection spectroscopic. The positions of resonance peaks are different when the refraction indexes of medium on the metallic film or the thicknesses of the metallic film are different. And it is found that the phase position of p-component of reflected light changes with the metal film thickness, while the phase position of s-component almost doesn’t change in the Surface Plasmon Resonance effect. S-polarized light is taken as reference and interferometry is adopted to turn the change of the phase position into the change of interference fringes position in the paper, and the film thickness can be derived from it. The simulation results indicated that, through making use of piecewise quadratic fitting on the phase data, the inaccuracy with the range of film thickness is between 30 and 80 nanometers is not more than 0.33 nm.