Micro-optics includes a family of optical components that are fabricated by modern micromachining, such as optical lithography, direct laser and e-beam writing, and reactive ion etching. In the past decade, micro-optics has emerged as a powerful tool for realizing various optical functions that have not previously been possible or feasible using conventional optical elements. Elements utilizing either refractive or diffractive surfaces are now found in applications ranging from laser beam shaping in laser material processing to optical interconnects in telecom applications. In general terms, one of the major strengths of microoptics as compared to conventional optics lies in the fact that micro-optics allows integration of large, complex optical systems into a much more compact form. Additionally, the emergence of replication techniques such as injection molding allows the lowest cost mass production of micro-optical elements.
This chapter presents the basic concepts of light deflection in micro-optics and the main fabrication technologies. The history is summarized in Sec. 3.2. Section 3.3 presents the basic functionalities. The fabrication methods are then divided into technologies based on binary optics masks (Sec. 3.4), resulting in N-level staircase profiles, and analog technologies (Sec. 3.5). Section 3.5 includes elements that have a continuous surface profile and replication techniques. Not discussed in this chapter are waveguides, gradient index optics, and active devices.Micro-optical components, testing, and applications will be discussed in detail in Chapter 5 of this book.
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