Colorless gradient-index cylindrical lenses with high numerical apertures produced by silver-ion exchange

Abstract

Colorless gradient-index cylindrical lenses with high numerical apertures in slabs 200-1000 µm thick have been fabricated by silver-sodium ion exchange in a specially developed glass. The lenses with numerical apertures of 0.6 are characterized by index profiles and by spherical and chromatic aberration. On-axis focusing properties and the application to the collimation of high-power laser diode bars are discussed.

Arrays of microlenses with variable focal lengths fabricated by restructuring polymer surfaces with an ink-jet device

“…Molding and casting optical materials are very common [4][5][6]: In these techniques, the fabrication of a template has to be accomplished previous to the manufacturing of the microlenses. For template production, various techniques such as photolithography [7], ion exchange [8] or LIGA processes [9] are used. Arrays of microparticles have been used recently as template to fabricate microlenses [4,10], as well as irradiation of sol-gels with UV light [11].…”

Assembly of a photonic wavelength-division multiplexing device using laser-based soldering

“…A common way for the production of GRIN optics is ion exchange between the glass and a molten salt bath. By embedding ions, such as silver or lithium, into the glass or by removing them from it different profiles of the refractive index can be produced, allowing for both focusing and diverging lenses [8].…”

The effect of RO (R=Mg, Ca, Ba and Zn) on physical properties of Na2O/Al2O3/B2O3/SiO2 glasses for the preparation of gradient index micro lenses

“…After a first ion exchange carried out in an AgNO 3 -containing salt melt, an uniform Ag 2 O-concentration in the whole volume of the glass rod is obtained and nearly 90% of the Na 2 O is replaced by Ag 2 O. During the second ion exchange step in a NaNO 3 -containing salt melt, the required profile in the refrective index is adjusted by diffusion of silver ions from the glass towards the molten salt [8][9][10][11]. This required profile is nearly parabolic, where the refractive index and the silver concentration in the center are larger than in the outer parts of the rod.…”

“…This required profile is nearly parabolic, where the refractive index and the silver concentration in the center are larger than in the outer parts of the rod. One of the main problems associated with the preparation procedure is the tendency of silver ions to be reduced at elevated temperatures caused by impurities in the glass (e.g., As 3+ , Fe 2+ and Sb 3+ ) which is favoured by the presence of non-bridging oxygen in the glass structure [11][12][13][14][15]. The reduction of silver ions and the formation of colloids of metallic silver leads to a colouration from yellow to black.…”