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Schematic of SHE of light on a graphene film. A linearly polarized beam reflects on the model and then splits into left- and right-circularly polarized light, respectively. and indicate the transverse shift of left- and right-circularly polarized components. Here, is the incident angle and the inset shows the atomic structure of graphene.
Experimental setup: The sample is a BK7 glass transferred with the graphene film. L1 and L2, lenses with effective focal length 50 mm and 250 mm, respectively. HWP, half-wave plate (for adjusting the intensity). P1 and P2, Glan laser polarizers. CCD, charge-coupled device (Coherent LaserCam HR). The light source is a 17 mW linearly polarized He-Ne laser at 633 nm (Thorlabs HRP170). The inset shows that the angle between P1 and P2 is .
Raman spectra of the samples and the graphene refractive index selection in the case of horizontal polarization. (a) Raman spectra of one, two graphene layers. (b) represents the transverse displacements under the condition of single layer graphene. We choose the thickness of one layer graphene film as 0.34 nm. The transverse shifts in the case of two layers graphene film are shown in (c). Here, the lines represent the theoretical results. The circle and triangle show the experimental results obtained from the air-prism and different graphene-prism conditions via weak measurements. The refractive index of the BK7 substrate is chosen as n = 1.515 at 633 nm.
The theoretical and experimental results of determining the layer numbers of graphene. (a) represents the theoretical transverse displacements under the condition of graphene layer numbers changing from one to five. Here, the refractive index of graphene is 3.0 + 1.149i at 633 nm. (b) describes the transverse shifts in the case of different incident angles ranging from to . The lines represent the theoretical results. The circle, square, and triangle show the experimental data obtained from three different areas of the graphene sample. (c) Raman reference data of the sample.
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