Example Vertical-cavity surface-emitting lasers

4-2 Example Vertical-cavity surface-emitting lasers 

A periodic arrangement of many epitaxially grown thin layers with lattice mismatch constitutes a strained-layer superlattice. An example of such a superlattice structure can be found in the vertical-cavity surface-emitting laser (VCSEL). As discussed by Choquette (2002) and Nurmikko and Han (2002), the control of layer thickness, elastic strain due to LAN to us mismatch, stress-driven crack formation and processing induced defects in the superlattice presents major scientific and technological challenges in the development of these devices. 

A VCSEL emits light in the direction normal to the surface of the layers. Proper VCSEL operation requires precise alignment of (a) the composition and thickness of the DBR layers for achieving necessary reflectance wavelengths, (b) the composition and thickness of the optical cavity and the DBR layers for achieving necessary cavity wavelength, and (c) the composition and thickness of the quan- 

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We show an example of optical component using a plana microlens array and micro-optical-bench (MOB) as in Fig. 33. This is based on vertical cavity surface emitting laser array and alignment free MOB. 

Near-field optical techniques (evanescent waves and field enhancement), as well as TPAP, facilitate the manufacture of nano-objects. The light is confined in a nanometric volume which enables high luminous power densities even low reactivity PISs can woik in these conditions. For example, although they are not very efficient in usual film photopolymerization under conventional light excitations (see below), some polymethine dye/amine systems could appear as excellent candidates as NIR PISs in TPAP for the manufacture of microtips perfectly self-aUgned on the surface of vertical-cavity surface emitting lasers (VCSELs). 

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