Fig. 1. (a)(c) Secondary electron images and (b)(d) backscattering electron images of silica glass surface polished close to the depth of focal spot[11]

Fig. 2. Nanograting structure. (a) SEM image along the incident light direction[20]; (b) schematic diagram of the spatial structure[23]

Fig. 3. Relationship between minimal period of nanogratings and incident laser wavelength[26]

Fig. 4. Influence of laser repetition rate on material modification within fused silica[33]

Fig. 5. Influence of incident pulse number on nanograting growth[33]

Fig. 6. Analysis of lines imprinted in fused silica by laser pulses with different polarizations. (a) Optical microscope photograph; (b) polarizing microscope photograph; (c) transmitted light intensity corresponding to lines under polarizing microscope; (d) cross-sectional photograph of lines[38]

Fig. 7. Variance of optical path retardation with pulse duration for nanogratings in different glass versus light with wavelength of 633 nm[41]

Fig. 8. Evolution from nanopore array to single nanopore with the laser intensity decreasing[44]

Fig. 9. Secondary electron images of cleaved sample surfaces in the modified regions in GeO2 glass created by femtosecond laser pulse with a pulse energy of (a) 0.2 μJ and (b) 0.4 μJ; (c) schematic diagram of nanograting structure in GeO2 glass[49]

Fig. 10. (a) TEM image and (b) high resolution SEM image and diffraction pattern of femtosecond laser-induced nanostructures; (c) schematic diagram of nanostructures[50]

Fig. 11. (a) SEM image of nanograting formed in AF 32 glass surface; distributions of light retardation values in (b) silica glass, (c) AF 32 glass, and (d) Borofloat 33 glass versus pulse energy and duration under the conditions of 3 μm/s laser scanning speed and 100 kHz pulse repetition rate[52]

Fig. 12. (a) Evolution of nano-plasma into nano-plane[27]; (b) schematic diagram of local field enhancement around a nano-plasma[19]

Fig. 13. Schematic diagram of forming self-trapped excitons and decaying to semi-permanent point defects[26]

Fig. 14. Schematic diagram of realizing three-dimensional rotation of nanogratings by PFT femtosecond pulses[56]

Fig. 15. (a) Concept map of exciting surface plasma wave at interface between laser modified and unmodified areas of porous glass; (b) relationship between calculated period of surface plasma wave and electron density[58]

Fig. 16. (a) SEM image of nanograting after polishing and etching and (b) schematic diagram of nanograting forming process for parallel scanning (upper) or perpendicular scanning (lower)[61]

Fig. 17. (a) Schematic diagram and (b) photograph of nanofluidic device; fluorescent images of nanochannel arrays with width of (c) 50 nm and (d) 200 nm, respectively[45]

Fig. 18. Readout process in 5D optical storage. (a) Birefringence measurement of the data record in three separate layers; (b) enlarged 5×5 dot array; (c) retardance distribution retrieved from the top data layer; (d) slow axis distribution retrieved from the top data layer; (e) enlarged normalized retardance matrix; (f) enlarged normalized slow axis matrix; (g) binary data retrieved from (e); (h) binary data retrieved from (f)[65]

Fig. 19. (a) Distribution along optical axial direction of polarization diffraction grating; (b) slow axis orientation and corresponding phase modulation for two circular polarizations across the dashed line in (a); (c) phase distribution for light passing through polarization diffraction grating; (d) far-field intensity and polarization distributions for differently polarized light passing through gratings; (e) radially or azimuthally polarized optical vortexes splitted by polarization diffraction grati

Fig. 20. Schematic diagram of nanograting distribution in (a) quarter- and (b) half-wave polarization converters; femtosecond-laser-written radial polarization converters for (c) circular and (d) linear incident polarizations[74]

Fig. 21. (a)-(d) Variation of retardation values in nanogratings with etching time under different manufacture conditions; (e) images of retardation values in nonagratings after corrosion with different time[79]