Lasers VCSEL

Vertical cavity surface-emitting lasers (VCSEL)... 

Fig. 10. Cross-sectional drawing of a vertical cavity surface emitting laser (VCSEL). Proton implantation is used to channel the current through a small active region. Light is emitted in the direction perpendicular to the plane of the wafer. This makes preparation of two-dimensional arrays quite easy.

See also Planar cavity surface-emitting laser (PCSEL) diodes Vertical cavity surface-emitting laser (VCSEL) diodes compound semiconductor-based, 22 179 Laser Doppler velocimetry (LDV), 11 784 Laser Doppler velocimeters, 11 675 Laser-drilled surgical needles, 24 206 Laser dye energy levels, 14 702-703 Laser fabrication techniques, titanium, 24 857... 

In a somewhat similar fashion, Ishii et alP- have demonstrated inkjet fabrication of polymeric microlenses for optical chip packaging. UV curable epoxy resin is deposited onto optical devices by inkjet printing. When the droplets hit the surface, they form into partial spheres due to their surface tension, and are UV-cured to form the microlens with diameters from 20 to 40 tm with /-numbers of 1.0 to 11.0. Their uniformity in a microlens array was measured to be within 1% in diameter and 3 tm in pitch (total count of 36 lenses). They have also demonstrated hybrid integration of inkjetted microlenses with a wire-bonded vertical-cavity-surface-emitting laser (VCSEL) with coupling efficiencies of 4 dB higher than without the microlens. 

Figure 4-36. Schematic of vertical cavity surface emitting laser (VCSEL).

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. 

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). 

Figure 3.32 Schematic diagrams showing the two major designs for laser diodes. Edge-emitting lasers have a quantum well, restricted to a narrow area, from which light is emitted. The cleaved edges of the semiconductor form the mirrors of the laser cavities. In vertical-cavity surface-emitting lasers (VCSELs) the reflectors are semiconductor superlattices and light is emitted from the top of the device through a transparent contact material.

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