What's it about?
This paper will first detail where slope error originated from, what it represents and the role it plays in optical performance. The three attributes that make up a complete slope error specification will be discussed along with examples of a complete slope error specification. Finally, it will conclude with techniques for measuring slope error.
1. SLOPE ERROR: A REFINEMENT OF FORM ERROR
Specifying an optical component begins with choosing a combination of mechanical dimensions, optical material and surface shape to satisfy an existing system performance requirement1. Deviation from the nominal effects system performance.
Looking specifically at surface shape, deviation falls into one of two categories: uniform and nonuniform deviation. Uniform deviation is where the as-manufactured surface is uniformly offset relative to nominal, and power in spherical surfaces would be an example. Nonuniform deviation is anything else, and it can have a periodic or random structure. The broad term “irregularity” is applied here, and it represents...