A metrology device, such as an ellipsometer, includes a light source that
produces a pulsed electromagnetic beam, such as a flash bulb or pulsed
laser, and a spatially dependent polarizing element that introduces a
spatially dependent retardation in the light beam. The use of a pulsed
light source is advantageous over a continuous light source, as a pulsed
light source generates less heat, is stronger, lasts longer, and does not
need the use of a mechanical shutter. The use of a spatially dependent
polarizing element advantageously eliminates the use of temporally
dependent moving polarization modulation elements, thereby allowing the
use of a pulsed light source. Downstream of the spatially dependent
polarizing element are the analyzer and a multi-element detector that may
be synchronized with the pulsed electromagnetic beam to detect after one
or several pulses of light have been emitted from the pulsed light
source.