Fabrication of diffractive optical elements using a single optical exposure with a gray level mask

Abstract

Articles you may be interested in X-ray mask fabrication technology for 0.1 μm very large scale integrated circuits General aspheric refractive micro-optics fabricated by optical lithography using a high energy beam sensitive glass gray-level mask A method for mass fabrication of environmentally rugged monolithic diffractive optical elements ͑DOEs͒ is demonstrated. A one-step optical exposure, with a gray level mask, was used to produce analog resist profiles that were transferred into their substrates using chemically assisted ion beam etching in a single etching step. The described procedure allows mass fabrication of DOEs without the tedious multiple exposure and etching steps commonly used in multilevel DOE fabrication. To generate a multilevel DOE in an optical substrate, only a single exposure using a gray level mask and a single etching step are necessary. The fabrication method presented will reduce processing time and increase manufacturability, which will result in a general cost reduction per element.

Process development and application of grayscale lithography for efficient three-dimensionally profiled fiber-to-waveguide couplers

“…The production of three-dimensionally profiled micro-scale devices has been described in the literature for some time [18][19][20][21] . However, a drawback common to many of these techniques is the limitation of the device features to a discrete number of height levels.…”

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“…13 In recent years, with the advent of HEBS glass, gray-scale masks were extensively introduced and investigated in the area of continuous phase diffractive optical elements fabrication. [13][14][15] Because the HEBS mask produces varying transmittance to represent the designed phase pattern for different etching depths, gray-scale masks are being used to replace the conventional binary masks. It is known that the latter necessitates strict requirements on multimask alignment.…”

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