A material that differs from ruby only in the slight impurity that gives the material its color. It is useful because of its high refractive index, low dispersion, and exceptional hardness.
SPHERICAL VS. ASPHERIC LENSES
HOW THEY’RE USED IN IMAGING APPLICATIONS
Optical Lenses are often categorized by their shape. Two common surface shapes are spherical and aspherical. Each offers unique characteristics that make it suitable for different use cases.