Optical characterisation of locally modified areas in quarziodine glass

The focal length and numerical aperture of a modified region of a complex structure in the volume of a porous glass plate are estimated. It is shown that when sintering a porous glass plate with a modified region, the complex structure of the modified region is retained. An assessment of the focal length and numerical aperture of a modified region of a complex structure in a quartz-shaped glass plate is carried out. It was found that sintering a porous glass plate with a modified area in a furnace contributes to a significant decrease in the focal length and an increase in the numerical aperture to 0.9.