The invention describes a system for the measurement of volume holograms
on a wafer scale that permits high-resolution and high throughput
measurement of grating parameters. The invention uses a collimated beam
of a fixed wavelength light source that is transmitted through the wafer
to be tested. The transmitted beam is imaged with a lens onto a sensor.
The sensor is used to measure the beam power under a variety of
conditions, including without a wafer in place, so that the various
measurements can be used to determine grating characteristics. The
measurement data produced includes values for grating spacing, tilt
angle, and diffraction efficiency with a high spatial resolution.