Fig. 1. Defocusing problem in TPP-LDW processing. (a) Schematic of TPP-LDW setup; (b) mechanism of focus defocusing

Fig. 2. Influence of focus defocusing in large-scale micro-nano structure fabrication. (a) Scanning electron microscope (SEM) image of large-scale micro-nano wire mesh fabrication; (b)(c) detailed images of different locations; (d)‒(f) schematic of impact of defocus on voxel position

Fig. 3. Variation of two-photon fluorescence image with focus position near photoresist-substrate interface. (a) Two-photon fluorescence image at different focal points; (b) fitting curves of variance change of image gray value

Fig. 4. Fluorescence image processing results and focus compensation principle. (a) Processing results of fluorescence images at different positions and corresponding two-photon processing results; (b) schematic diagram of angle of focus scanning plane and substrate plane; (c) compensating effect diagram based on rotation path and projection path

Fig. 5.

Micro-nano wire structure array fabrication results based on fluorescence imaging analysis of proactive defocus compensation. (a) SEM image of processing result; (b)‒(e) atomic force microscope (AFM) 3-dimensional morphologies of micro-nano wires local structure; (f)‒(i) AFM transverse profiles of micro-nano wires at places A, B, C and D in Fig. (a)

Fig. 6. Large-scale gradient structure fabrication based on active defocusing compensation by fluorescence imaging analysis. (a) Scale gradient double-needle structure nanowire based on focus axial position modulation; (b) variation of linewidth at needle tip structure; (c) scale gradient double-needle structure based on focus position and fabrication speed modulation; (d) AFM 3-dimensional morphology image of needle tip in Fig. (c); (e) cross-section profile of needle tip in Fig. (c)

Fig. 7. Large-scale fabrication of complex gradient structure based on active defocusing compensation by fluorescence imaging analysis. (a) SEM image of periodic topology; (b) enlarged view of structure at beginning; (c) enlarged view of structure at edge