Replication of continuous-relief diffractive optical elements by conventional compact disc injection-molding techniques

Abstract

Continuous-relief diffractive optical elements have been replicated by use of conventional compact disc injection-molding techniques. Two continuous-relief microstructures, a blazed grating and a fan-out element, were chosen to evaluate the replication process. Original elements were fabricated by direct-write electron-beam lithography. Optical measurements and atomic force microscopy were used for investigating the replication fidelity.

Transparent thermoplastics: Replication of diffractive optical elements using micro-injection molding

“…High transparency with broad wavelength range is important in applications required to operate in both the visible and near-infrared regions. High refractive index allows smaller aspect ratios in the visible light area without compromising the optical properties of diffractive gratings [22]. Refractive index and transmittance of the sample disks at 590 nm are shown in Table 2.…”

Influences on the Fabrication of Diffractive Optical Elements by Injection Compression Molding

“…Diffractive elements with binary or continuous structures and feature sizes in the (sub-) micrometer range can be fabricated [13,14]. Results show that the replication of the micro-structures is highly depending on the molding parameters.…”

Isopropanol/water as a developer for poly(dimethylglutarimide)

“…For example, PMGI can be used to create lift-off profiles with thicknesses greater than 10 m. 8 In addition to being used as a resist, PMGI has also been used as an optical material in microfabricated optical devices [15][16][17] and as both a structural layer and a sacrificial layer in surface micromachining. [18][19][20][21] Depending on the formulation, PMGI has a glasstransition temperature of approximately 190°C.…”

“…10 PMGI is a long chain polymer and is susceptible to a number of radiation sources. Exposure methods for PMGI include deep UV, 2,3,5,11,22 electron beam, 6,7,14,16,17 and proton beam. 23 All of these methods create main-chain scissons, which reduce the average molecular weight of the polymer, and therefore increase solubility.…”

“…This makes PMGI, with 254-nm irradiation, a good candidate for grayscale lithography applications. Additionally, combined with PMGI's existing applications for micro-optics,[15][16][17] PMGI should thus be considered for refractive optical components.…”