Structure grating

The first observations on the development of periodic modulations were made on Pt surfaces annealed in vacuum in the temperature range 920 to 1300C[9J. The 1-dimensional grating structures were made by mechanically ruling portions of gratings on polycrystalline Pt specimens. Annealing caused extensive... 

Figure 16.12 shows the effect of pitch size on the directional emission spectra of SPGCE for three differoit grating structures. The resultant angular (fisposion is about -35°—5° for device with pitch size of 500 nm while for pitch size of 800 nm is limited to -10° 10°. 

Figure 16.13 The SP-

Figure 16.16 The experimental PL emission obtained from a sample with grating structure riiows SPGCE diagram in directional emissi( i spectra.

Positive tone resins based on a photoacid generator and either a random copolymer of tetrahydropyranyl methacrylate and methyl methacrylate [137] or random copolymers of tetrahydropyranyl methacrylate, methyl methacrylate, and t-butyl methacrylate (180) were used for fabrication of 3D microchannel structures [264], Simple placed channels connected to cubic or prismatic trenches, which are open to the surface as well as optical grating structures, comprise a set of several parallel channels placed about 10 pm below the surface with connecting reservoirs on both ends. They were fabricated by positive TP microlithography (Fig. 3.75) [264]. 

Figure 3.104. Emission of the circular grating structure below (dotted line) and above (solid line) the lasing threshold excited at 1.64 eV. (From Ref. [174] with permission of Wiley-YCH.)...

Sensors Based on Resonances in Diffraction Grating Structures. 81... 

Fig. 93 Profilometer scans of blazed grating structures ablated into polyimide. The profile shape depends on the corrections for the polymer response, i.e., etch rate per pulse at a given fluence. REPRINTED WITH PERMISSION OF [Ref. 322], COPYRIGHT (2001) Elsevier Science...

A technological approach to decrease the threshold of DFB lasers is the use of first-order grating structures instead of second-order DFB lasers. As can be seen in Table 12.1, this experiment was performed with three material systems, two low molecular weight based G-H systems and with the conjugated polymer MeLPPP. In all cases the laser threshold was reduced significantly - on average by a decade. 

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