Fig. 1. Schematic of femtosecond laser micromachining system

Fig. 2. Birefringent micrographs of lines by femtosecond laser writing under different pulse energies. (a) GeO2 glass; (b) silica glass; (c) formation thresholds of nanogratings within GeO2 glass

Fig. 3. Optical micrographs and birefringence intensity distribution. (a) Optical micrographs of lines within GeO2 glass by femtosecond laser writing under different pulse durations; (b) laser-induced birefringence intensity versus pulse duration and pulse energy

Fig. 4. Optical retardance wthin GeO2 glass induced by femtosecond laser versus pulse energy for different repetition rates

Fig. 5. Optical retardance induced by femtosecond laser versus pulse density for different repetition rates. (a) 50 kHz; (b) 100 kHz; (c) 200 kHz; (d) 500 kHz

Fig. 6. Polarization diffraction grating. (a) Orientation distribution of nanograting; (b) distribution of optical retardance; (c) distribution of azimuthal angle; (d) intensity and polarization distributions of 532 nm lasers with different polarizations after vertical transmittance from polarization diffraction grating

Fig. 7. Computer-generated geometric phase Fourier hologram by femtosecond laser writing. (a) Experimental light path for image reconstruction; (b)original portrait of Confucius; (c) computer-generated hologram of portrait of Confucius; (d) hologram with orientation along slow axis written within GeO2 glass; (e) reconstructed image by structure written within GeO2 glass