Measuring Prisms: Multiple Wavefront Channels in One Setup
Prisms assemblies are difficult optical elements to measure. Back reflections from multiple surfaces and multiple channels make laser interferometry incapable of making these measurements. Spectrally Controlled Interferometry (SCI), available from Apre Instruments, offers an easy-to-use, accurate method to measure these components for the first time.
A laser light source interferometer (for example a laser Fizeau) creates fringes from every back-reflecting surface. In some prism assemblies these fringes are created in multiple channels and are superimposed, producing confused interference patterns that are impossible to measure.
SCI can selectively isolate the interference cavity of interest for easy and accurate measurement. As opposed to white light “delay line” interferometers, SCI is easy to align prior to measurement, using its long coherence alignment mode.
An article discusses the following types of prism stacks easily measured by SCI:
- Imaging System Prism Stack
- Displacement Measuring Interferometer Components
- RGB Prism Combiners
To read the complete article, click here.