Neil C. Bruce
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Design and construction of a polarimetric scatterometer for 2D surfaces

We are currently building a scanning scatterometer to measure the polarised scattered light from a 2D rough surface. This type of surface scatters light into a hemisphere above the surface, and not a plane as is the case for a 1D rough surface (see the figure below).

	A 1D surface scatters light into a plane
	A 2D surface scatters light into a hemisphere above the mean plane of the surface

There are two types of scatterometers that can be built: a mirror scatterometer (like the one we have built) which uses optical elements to collect the scattered light and direct it to a detector, which is usually a CCD camera; and a scanning type of scatterometer which scans a detector over the area of interest. This proyect involves the design and construction of a scanning-type scatterometer to cover the full hemisphere to measure the scattered light from a 2D rough surface. The figure below shows the general design of the scatterometer.

The incident and scatter angles are controlled by two rotational motors and a third motor rotates the laser/surface assembly to cover the full hemisphere of scattered light. The system has been designed with a maximum resolution of 0.25°.