Catastrophic optical damage (COD) is a failure mode of high-power semiconductor lasers. It occurs when the semiconductor junction is overloaded by exceeding its power density and absorbs too much of the produced light energy, leading to melting and recrystallization of the semiconductor material at the facets of the laser. This is often colloquially referred to as "blowing the diode." The affected area contains a large number of lattice defects, negatively affecting its performance. If the affected area is sufficiently large, it can be observable under optical microscope as darkening of the laser facet, and/or as presence of cracks and grooves. The damage can occur within a single laser pulse. A laser diode is a laser where the active medium is a semiconductor p-n junction similar to that found in a light-emitting diode. ... A p-n junction is formed by combining N-type and P-type semiconductors together in very close contact. ... In engineering, specific power (sometimes also power per unit mass or power density) refers to the amount of power delivered by an energy source, divided by some measure of the sources size or mass. ... In physics, melting is the process of heating a solid substance to a point (called the melting point) where it turns into a liquid. ... Insulin crystals Recrystallization is an essentially physical process that has meanings in chemistry, metallurgy and geology. ... Semiconductor materials are insulators at absolute zero temperature that conduct electricity in a limited way at room temperature (see also Semiconductor). ... Crystalline solids have a very regular atomic structure: that is, the local positions of atoms with respect to each other are repeated at the atomic scale. ...

Catastrophic optical damage is one of the limiting factors in increasing performance of semiconductor lasers. It is the primary failure mode for AlGaInP/AlGaAs red lasers. [1] Aluminium gallium indium phosphide (AlGaInP, also AlInGaP, InGaAlP, etc. ... Aluminium gallium arsenide (also Aluminum gallium arsenide) (AlxGa1-xAs) is a semiconductor material with very nearly the same lattice constant as GaAs, but a larger bandgap. ...

Short-wavelength lasers are more susceptible to COD than long-wavelength ones.

The typical values for COD in industrial products range between 12-20 MW/cm². The megawatt (symbol: MW) is a unit for measuring power corresponding to one million (106) watts. ...

One of the methods of increasing the COD threshold in AlGaInP laser structures is the sulfur treatment, which replaces the oxides at the laser facet with chalcogenide glasses. [2] Aluminium gallium indium phosphide (AlGaInP, also AlInGaP, InGaAlP, etc. ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Standard atomic weight 32. ... An oxide is a chemical compound containing an oxygen atom and other elements. ... A Chalcogenide glass is a glass containing a chalcogenide element (sulphur, selenium or tellurium) as a substantial constituent. ...