Fig. 2. Schematic of the experiment for pump-induced Faraday rotation θ_F on graphene disks.

The frequency of the probe and pump beam is set to 3.5 THz. A quarter wave plate (λ/4 plate) is located in the pump beam path. Its rotations of −45^o and +45^o generate the left (σ⁺) - and right (σ⁻) - handed circularly polarized pump beam. The probe beam is linearly polarized in the vertical direction, the sign of θ_F denotes its direction. A wire grid polarizer is located in the probe beam path and it is aligned to 45^o with respect to the incident probe beam. The reflected and transmitted probe beams from the wire grid polarizer are guided to bolometers B2 and B1, respectively.