1. The problem statement, all variables and given/known data What are the two requirements for an anti-reflection coating? 2. Relevant equations Not sure there are any. 3. The attempt at a solution I googled the term anti-reflection coating and I found a wikipedia article on it here. http://en.wikipedia.org/wiki/Anti-reflective_coating From what I read, I'm not sure what the "requirements" would be. The only thing I found that might hint at what the answer should be is "Many coatings consist of transparent thin film structures with alternating layers of contrasting refractive index." Can anyone help out with this, or clarify what the requirements could be? This is for an electromagnetic fields course if that gives any more of a direction as to what I should be looking for.