Optical flats are flat glass discs with one face ground and polished to a high degree of flatness.
They are most commonly used as test plates to evaluate the accuracy of flat surfaces. Holding the precision face of an optical flat against a test surface under monochromatic light creates a fringe pattern, which is visible through the back surface of the flat. This fringe pattern describes the contour of the test surface.
The MSL Optical Workshop manufactures and calibrates optical flats out of Fine Annealed Pyrex, Fused Silica and Zerodur up to 300 mm in diameter.
We also evaluate, refurbish and calibrate old optical flats.