Two-dimensional grating

Figure 1.11. A series of ten pmrs of photographs that show the effects of spatial filtering on the image of a two-dimensional grating. Each photograph shows (a) the diffraction pattern and (b) the resulting image. (Continued, pp. 24-27)...

Peng S, Morris G (1996) Experimental demonstration of resonant anomalies in diffraction from two-dimensional gratings. Opt Lett 21 549-551... 

Now imagine a two-dimensional grating, as in Figure 4.6. There are lines of letter Rs which do not correspond to those defining the unit cell (the smallest asymmetric unit). The situation is analogous to that in a carefully planted forest, where if the trees are all planted in rows and the distance between trees in... 

The short end of the tuning range was lim- 2) A two-dimensional grating has been used in ited by the available grating substrates. this case [85],... 

Equation (3) can be used to relate 0 to / Only the first order (n = 1) is significant for roughness wavelength. BRDF can now be interpreted as the ability of each / to scatter light. If BRDF is plotted versus a Ap scale it may be independent of 0 and proportional to / If the surface behaves in this way the BRDF is shift invariant (11). In the general case for scatter out of the PLIN the following two dimensional grating equations apply ... 

A two-dimensional grating gives a much more compheated pattern, from which it is possible to deduce the spacings between the two sets of ruhngs and the angle between them. In the same way, the diffraction pattern... 

Fig. 8.16 A two-dimensional grating structure in a PDMS film as imaged by an AFM ((a),...

The potential of LA-based techniques for depth profiling of coated and multilayer samples have been exemplified in recent publications. The depth profiling of the zinc-coated steels by LIBS has been demonstrated [4.242]. An XeCl excimer laser with 28 ns pulse duration and variable pulse energy was used for ablation. The emission of the laser plume was monitored by use of a Czerny-Turner grating spectrometer with a CCD two-dimensional detector. The dependence of the intensities of the Zn and Fe lines on the number of laser shots applied to the same spot was measured and the depth profile of Zn coating was constructed by using the estimated ablation rate per laser shot. To obtain the true Zn-Fe profile the measured intensities of both analytes were normalized to the sum of the line intensities. The LIBS profile thus obtained correlated very well with the GD-OES profile of the same sample. Both profiles are shown in Fig. 4.40. The ablation rate of approximately 8 nm shot ... 

The DFB grating concept was extended to higher dimensions. Two-dimensional (2D) gratings can be made in a variety of forms, from the simple overlapping of two orthogonal gratings up to concentric rings, or more complicated structures. In modern theory, they can be treated as 2D photonic crystals. 

Because a CCD is a two-dimensional array of pixels, it is possible to create a double-beam instrument with a single detector. Coupled in an optical design with an imaging grating, the output of two fibers may be imaged simulfaneously and separately onto the CCD and both spectra readout by the electronics. 

Color Plate 24 Polychromator for Inductively Coupled Plasma Atomic Emission Spectrometer with One Detector for All Elements (Section 21-4) Light emitted by a sample in the plasma enters the polychromator at the upper right and is dispersed vertically by a prism and then horizontally by a grating. The resulting two-dimensional pattern of wavelengths from 165 to 1 000 nm is detected by a charge injection device detector with 262 000 pixels. All elements are detected simultaneously. [Courtesy TJA Solutions, Franklin, MA.J... 

Figure 10.5 Two-dimensional domain grating tailored in a RbTiOPC>4 crystal.

The SERS spectra from an organic analyte deposited on the substrate were found to show a enhancement factor of 104, which is comparable to the enhancement obtained from two-dimensional silver gratings produced by electron beam lithography by Kahl et al. [39]. Like the self-assembled three-dimensional opal gratings, the templated gratings provide clear practical advantages over ordered substrates produced by more complex and expensive methods. The results reported are summarized in Table 10.2. From the... 

---