Fabrication of Binary Diffractive Lens on Optical Films by Electron Beam Lithography

Design and development of Binary Diffractive Germanium Lens by thin film deposition

“…Optical design of a refractive germanium (Plano -convex) lens using Zemax, for the wavelength band [8]- [12] µm is presented in Figure 1, Table 1. It has an effective focal length of 75 mm with a 9.09 • field of view according to the detector's dimensions (384 × 288 pixels with pixel's size 25 µm), which will be used in the measurement of the MRTD, the diameter of the lens is 33 mm.…”

“…The thickness of this layer is on the order of the incident wavelength. The phase delay is imparted to the incident wavefront by selectively removing material from the surface of the substrate [11], or adding material to the surface of the substrate using Lithography [12] or thin film deposition (coating) [2], of the same substrate's material, where the fabrication of diffractive lenses using the deposition of thin dielectric films was first demonstrated by L. D'Auria [13]. The fabrication of binary diffractive lenses by thin film deposition needs special masks, which can be produced by coating the substrate with a film of a photoresist using standard optical lithography, then transfer the mask pattern into the resist, but the disadvantage of this method is the need for high cleanness, where the presence of some particles of photoresist in the undesired places causes instability of the thin film.…”

Fabrication of Binary Diffractive Lenses and the Application to LED Lighting for Controlling Luminosity Distribution

“…The focal length of the diffractive lens is controlled by the structure of the lens, which suggests that the focal length may be independent of the curvature and index of refraction. Thus, diffractive lenses can be used as UV optical elements or thin optical elements [1].…”

“…Two types of the binary diffractive lenses are demonstrated. The one is the binary diffractive convex lens for focusing LED light [1,[12][13][14] and the other is the binary diffractive concave lens for diffusing LED light. These lensesare are fabricated by electron beam lithography (EBL) because the binary diffractive lens contains many submicron-sized structures.…”