Photonics Dictionary

In the most general sense, the resistance of a solid surface to damage.

A measurement of the hardness of a material as determined by the penetration depth of a diamond stylus under a specified amount of pressure.

Material hardness scale that is used to characterize the scratch resistance of various materials. This surface hardness evaluation is determined by scratching the surface to be tested with 10...

Rockwell hardness (Rc) refers to a method for measuring the hardness of a material, primarily metals, using an indentation test. It is named after the Rockwell scale, which was developed by Stanley...

A test similar to the Knoop hardness test, but used for fractured material. The indenter is a square-based pyramid-shaped diamond.

The penetrating capacity of x-rays that is an inverse function of the wavelength.

A doubly refracting mineral used to produce polarizing prisms. It is uniaxial negative and in the trigonal division of the hexagonal system of crystals. Its indices are e = 1.486, w = 1.658; its...

Usually a dielectric coating on glass or plastic optics; a coating that is comparable in hardness to glass itself.

Optical materials refer to substances or compounds specifically chosen for their optical properties and used in the fabrication of optical components and systems. These materials are characterized by...

Sapphire crystal refers to a transparent, single-crystal form of aluminum oxide (Al2O3) known as corundum. It is one of the hardest known materials, second only to diamond on the Mohs scale of...

Sapphire optical fiber is a type of optical fiber made from single-crystal sapphire, which is a form of aluminum oxide (Al2O3) that is highly transparent in the infrared region of the electromagnetic...

A sapphire window refers to a transparent optical component made from sapphire crystal. Sapphire is a single-crystal form of aluminum oxide (Al2O3) that is highly prized for its exceptional optical...

An instrument used to test the hardness of various materials. It measures the pressure on a standard point that is necessary to scratch the material.