Designing High Reflectivity Omnidirectional Coating of Mirrors for Near Infrared Spectrum (700-2500 nm)

In this paper, a high reflection coating is designed depending on the variable of refractive indices for NIR spectral region (700-2500 nm) by the use of the computer program MATLAB version 7. We could find the reflective 99.62% for seven layers at the incident angels (90°, 40°) in the wavelength (1064 nm) for coatings (Si, MgF2), substrata BK7 (relatively hard borosilicate crown glass with high homogeneity), which is used for laser application such as the ND:YAG laser (1060 nm), and R=98.37% for coatings (SbSe, Na3AIF6) and substrata glass for eleven layers at ?=90° which covers the wavelength from (955.6 nm) to (1622 nm) and represents the complete range for optical telecommunication band (short (S) 1460-1530 nm, conventional (C) 1530-1560 nm and long (l)1560-1620 nm). The results show that the reflectivity of the stack increases with the number of layers in the stack, the best layer number is nine which has a reflective of 99.62% at (1060 nm), as shown in Figure 4a. Also the reflective changes with incident angel; the best angel is (40°) which gives the convergent reflective for electric and magnetic polarization 99.91% and 99.36%, respectively for the wavelength (1060 nm).