Microlenses and other optical elements fabricated by laser heating of semiconductor doped and other absorbing glasses
AssigneeBrown University Research Foundation
InventorNabil M. Lawandy
Life of this patent
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Abstract
Disclosed is a method of preparing refractive microlenses in a single step, utilizing laser-induced surface structure formation in semiconductor doped glasses (SDGs). The SDG materials, in conjunction with above-bandgap wavelength laser sources, are used to fabricate lenses that operate with light of below-bandgap wavelengths. In accordance with the teaching of this invention lenses on an approximately 5-500 .mu.m diameter scale are fabricated individually or in arrays by laser irradiation of absorbing glasses. The microlenses have controllable characteristics and can be fabricated to have focal lengths as short as tens of microns. The lenses are generally parabolic or spherical in shape and are highly reproducible.
Claims7
A method for fabricating a microlens, comprising the steps of:
- providing a substrate comprised of a material that is substantially transparent at wavelengths within a first range of wavelengths, the material comprising a wavelength-selective absorber of electromagnetic radiation;
- and
- irradiating a portion of a surface of the substrate with electromagnetic radiation having wavelengths within a second range of wavelengths that are absorbed by the wavelength selective absorber such that a portion of the electromagnetic radiation is absorbed for heating and melting the material adjacent to the surface region, whereby the melted material rises up above the surface to form, when re-solidified, the microlens.
A method for fabricating an optical element, comprising the steps of:
- providing a substrate comprised of a semiconductor doped glass, the glass being substantially transparent at wavelengths within a first range of wavelengths that are longer than a bandgap wavelength of a semiconductor material that dopes the glass;
- and
- selectively illuminating a portion of a surface of the substrate with electromagnetic radiation having a wavelength within a second range of wavelengths that is equal to or shorter than the bandgap wavelength of the semiconductor material such that a portion of the electromagnetic energy is absorbed for heating and melting the glass adjacent to the illuminated portion of the surface, whereby the melted glass rises up above the surface to form, when re-solidified, an optical element.
Dependencies are inferred from the claim text.