Laser diodes single crystal materials

Figure 9.41 shows a diode junction for generating the inverted population combined with a Fabry-Perot resonant cavity. When the junction is forward biased, one can obtain laser emission from such a structure. To get some of fhe Hght out of the cavity at least one, and often both, of the mirrors are only partially reflecting. It turns out to be easy to fabricate such mirrors in a single crystal material such as a semiconductor... 

Figure C2.16.2 shows tire gap-lattice constant plots for tire III-V nitrides. These compounds can have eitlier tire WTirtzite or zincblende stmctures, witli tire wurtzite polytype having tire most interesting device applications. The large gaps of tliese materials make tliem particularly useful in tire preparation of LEDs and diode lasers emitting in tire blue part of tire visible spectmm. Unlike tire smaller-gap III-V compounds illustrated in figure C2.16.3 single crystals of tire nitride binaries of AIN, GaN and InN can be prepared only in very small sizes, too small for epitaxial growtli of device stmctures. Substrate materials such as sapphire and SiC are used instead.

Materials. Single crystals of Sn-doped n-GaAs of orientation (100) were obtained from Laser Diode Lab, Inc. with the following... 

It drops off in relation to l/r3, the radius of the ion in the crystal. A three-body exchange process has too low a probability to be of practical value in an Anti-Stokes phosphor. If we reexamine the calculated free-ion energy level diagram, we notice that Yb3+ has a single energy level with no adjacent levels to which relaxation could occur. Therefore, if we add this ion to our material, we should be able to obtain a phosphor which functions as an Anti-Stokes material. The energy level of Yb3+ lies at 10,300 cm-i (9710 A). It just happens that the output of a GaAsrSi laser diode occurs at 9500 500 A. 

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