The goal of optical testing is to determine if a lens, mirror or optical system is good enough. Naturally, there are many ways to answer this question. The methods discussed on our pages range from very simple to the most powerful available.
Simple Lens or Mirror
Even for a simple lens or mirror, a number of measurements can be made. A few of these are listed below along with the appropriate device for the test.
- Surface curvature – Spherometer
- Refractive Index – Abbe Refractometer
- Thickness and diameter – Micrometer, Dial Indicator or Calipers
- Centration – Micrometer, Calipers or a Specialized Instrument
- Back Focal Length – Optical Bench + Microscope
- Focal length – Optical Bench + Nodal Slide
- Surface Form Accuracy – Interferometer or Profilometer
- Surface Roughness – Scatterometer or Profilometer
Optical System
After all of the lenses and mirrors for an optical system have been assembled, the optical system must be tested as a whole. Often the primary concern is image quality – is the image really sharp? The following tests can be used to answer this question quantitatively.
- Resolution Chart Testing
- MTF Testing
- Shack-Hartmann Testing
- Interferometric Testing
Many other test methods exist, but the ones listed above are some of the most common. If you have questions about optical testing, feel free to contact us for a consultation. Our phone number is (651)315-8249, or you can use our Contact Form to reach us.