In this chapter the fabrication of optical elements will be explored. Traditional optical systems employ refractive and reflective elements to move light from object space to image space. It is these elements that will be examined in more detail in the ensuing pages. Refractive lenses are typically made of glass, plastic, or crystalline materials. Their shape determines the refraction of rays as the rays pass through the front and back surfaces of the lens. Reflective surfaces are typically made of a coated glass or metallic substrate. The shape of the coated surface determines the direction in which rays are reflected from the surface. To systematically control the refraction and reflection of the rays, the surfaces have a prescribed shape and should be smoothly varying to well below the wavelength of light. Failure to meet this smoothness requirement introduces scatter and stray light into the system, degrading performance. Based on these observations, the shape of the surface and the material it is made of are critical to the performance of the optical system. This chapter describes common optical surface shapes and materials used in various optical systems, as well as provides an overview of different fabrication techniques to generate these surfaces. More complex structures such as diffractive elements have recently become more prevalent in optical design. However, the design and fabrication these elements are beyond the scope of this text.
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