Fabrication and Experiment of Diffractive Phase Element That Implements Wavelength Demultiplexing and Focusing

Abstract

Recently, the diffractive optics has extensively attracted interest of researchers because diffractive optical elements (DOE’s) can incorporate several optical functions in a single optical element.[1–4] This is important in a number of areas such as integrated optics, optical computing, optical sensors, and so on. For example, one can design diffractive optical elements to perform wavelength multiplexing/demultiplexing, and focusing. Various designs and fabrication schemes for DOE’s that modulate only the phase of an incident lightwave have been proposed. In this paper we present the design and fabrication of diffractive phase element (DPE) that incorporates simultaneous wavelength demultiplexing and focusing in the optical system illuminated by a light beam with three wavelength components. Optical lithography and reactive-ion etching are used to fabricate the surface-relief structure with 8 levels. Experiments demonstrate the feasibility of three wavelength demultiplexing and focusing simultaneouslly.