Optical metrology

Lens features have been getting too small to properly characterise – but metrology providers are catching up, finds Andy Extance

Keely Portway looks at some of the latest advances in light-based test and measurement techniques

Verifying the surface quality of optics has long relied on a visual, non-quantitative approach, finds Jessica Rowbury

Aspheres and other freeform optics are becoming more commonly used in areas like consumer electronics - but, as these lenses move further away from rotational symmetry, can the metrology equipment to test them cope? Tom Eddershaw finds out