Figure 3
SLM-based experimental setup for 3D chiral microstructures in isotropic material. (a) The femtosecond laser is expanded using a telescope (lenses L1–L2) to match the aperture of the SLM, after its polarization and power are controlled using a half-wave plate (HW1) and a polarizer (P). The Gaussian beam, reflected by a mirror (M), is modulated by an SLM, which displays a designed hologram. Subsequently, the desired first-order diffraction beam is selectively introduced into the microscope system via an iris (I) positioned at the focal plane of the lenses (L3 and L4). A half-wave plate (HW2) behind the SLM is used to rotate the polarization. Experimental setup: DM, dichroic mirror; S, sample. (b) Finally, the diffracted beam is focused onto a sample located under the focal plane of a × 100 microscope objective (OBJ), and a chiral microstructure is achieved. (c) The beam, which is modulated by designed holograms (first row) with different topological charges that can be positive or negative, illuminates the sample. Then, the intensity pattern (second row) and optical micrograph of the polymer (third row) can be measured using a charge-coupled device. After developing, top-view (fourth row) and 45° tilted (fifth row) SEM images of chiral microstructures are realized. (Scale bar, 2 μm)
