Diffusers are devices that are designed to spread or scatter light. Many different types of diffusers are readily available in the commercial and scientific industries, but most are designed with a specific application in mind. Thus, when attempting to use a diffuser in an unconventional way, it is important to understand how it will behave in the system it will be used in. One example is a diffuser in a coherently illuminated, wide field of view system such as a laser spot tracker. For some diffusers, coherent illumination and/or off-axis illumination can have a major impact on their diffusing properties, which may or may not be acceptable to system performance. This project evaluates the pros and cons of several types of diffusers in order to identify the most effective solution based on the parameters of a system, using a laser spot tracker as an example. First, three diffusers are down selected from the list based on their refractive and diffractive properties. Next, the candidates are evaluated analytically and/or experimentally to characterize their behavior when illuminated by a collimated laser over a wide range of incident angles. Results suggest that a computer generated diffractive diffuser is the most flexible design option for the described laser spot tracker, but some drawbacks such as diffraction efficiency and maximum diffusion angle do need to be considered. This selection method can be extended to serve as a guide for making the proper diffuser choice in many different applications.
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