3 Layer AR Coatings

One of the most typical and straightforward 3 layer deisigns is referred to as the QHQ or Quarter-Half-Quarter.  It is one of the first AR multilayer designs that is typically taught for use on glass.  It is an extremely broadband AR for use in the visible and it can get the substrate surface reflectivity down quite low.The QHQ is as follows:

glass / M 2H L

where,
    M= a QWOT of a medium index material (ex. Al2O3)
    2H = two QWOT's or a HWOT of a high index material (ex. ZrO2)
    L = a QWOT of a low index material (ex. MgF2 or SiO2)The coating performance of a QHQ that is quarterwaved at 550nm, and M = Al2O3 and H = ZrO2 is shown below:

The solid line just above 4% is the reflectance of bare glass.  The dashed line is the performance of the QHQ where the L layer is SiO2.  The blue solid line is the performance of the QHQ where the L layer is MgF2.

	Enter your search terms Submit search form
	Web www.kruschwitz.com