Metrology at Edmund Optics: Measuring as a Key Component of Manufacturing

If you can't measure it, you can't make it. Edmund Optics employs a wide range of metrology equipment to guarantee that the optical components and assemblies manufactured in our global manufacturing facilities meet all published specifications. In process metrology is a critical component of Edmund’s strict ISO 9001 global quality program. This metrology is what allows Edmund to ensure the process control and repeatability required for volume production. Interferometers are utilized for high accuracy transmitted and reflected wave front measurements down to a twentieth of a wave. Edmund uses multiple interferometer configurations including stitching, large aperture, small aperture, and computer-generated hologram setups. White light interferometers also measure surface roughness and quantify group delay dispersion in ultra-fast laser optics such as our highly dispersive mirrors. Real-world group delay dispersion tends to vary from its theoretical design value more than most other specifications, making this measurement especially important. For some assemblies, such as our laser beam expanders, transmitted and reflected wavefront error is measured using Shack-Hartmann Wavefront Sensors instead of interferometers. Profilometers and coordinate measuring machines, or CMS, probe the surface of optical components to determine surface curvature, flatness, and irregularity. Profilometers have few limitations on the types of shapes they can measure, making them ideal for aspheric lens metrology. The reflective and transmissive spectral properties of optical coatings are verified through spectrophotometry. For highly reflective or transmissive optics, Cavity Ring-Down Loss Meters provide high accuracy total loss measurements with sensitivity in the parts per million at specific laser lines. The resolution and contrasts of imaging lens assemblies are tested using MTF, or modulation transfer function, test benches, reverse projection, and custom test fixtures. Differential interference contrast, or DIC microscopes, perform highly sensitive defect detection and transmissive materials such as analyzing laser damage in optical coatings and substrates. Environmental testing equipment is used in special cases to verify that components and assemblies meet the requirements for shock and vibration, humidity and immersion. Edmund utilizes many other metrology techniques including atomic force microscopes for surface roughness, and centration measurement machines for lens alignment, and autocollimators for angle verification. all of these demanding metrology systems, and the skilled technicians that operate them, ensure that Edmund optics is able to consistently meet our advertised specifications in both high and low volume production. product testing and certification reports are available upon request. to learn more about Edmund optics manufacturing and metrology capabilities please visit www.edmundmanufacturing.com.