Refractive index of air

Small air bubbles also scatter light because the refractive index of air is about 1.0, whereas the refractive index of most polymers is approximately 1.5. Air bubbles in films are sometimes usehil in increasing opacity but the efficiency in scattering light is much less than for mtile Ti02 because the difference in refractive index is much smaller. 

Fig. 2 Surface plasmon resonance device in the Kretschmann configuration, so is the refractive index of prism, ei is the refractive index of thin metal film (usually Au or Ag), 62 is the refractive index of air, and 0 represents the critical angle...

The first non-linear effect at play in the propagation of high-power laser pulses is Kerr self-focusing [35,36]. For high fluences, the refractive index of air depends on the incident intensity ... 

Figure 3.37. A schematic diagram of an optical flbre showing propagation of light beams deflned by the numerical aperture of the flbre and the refractive indices and 2 of the core and cladding materials Hq is the refractive index of air. Adapted from Boisde and Harmer (1996).

The frequency is independent of the medium in which radiation propagates, but the speed of light and the wavelength are inversely proportional to the refractive index (n) of the medium. This is to say, X = Xq I n and c = Cf I n. The refractive index of air is abont 0.03% greater than 1 (the refractive index of vacuum), and therefore it is often approximated as 1. 

Most compilations of refractive indexes provide data in terms of liquation f>-14. Such data are readily converted to refractive indexes with vacuum as a reference by multiplying by the refractive index of air relative to a vacuum. That is,... 

A PSi microcavity was exposed to the saturated vapor of ethanol. The ethanol substitutes the air inside the pores and leads to a rise in a progressive monotonic red shift of the interference pattern of the PL spectrum. Moreover, the PL intensity of the cavity peak oscillates over time. Both effects are sequences in the progressive change of the refractive index of air and ethanol. Large, repeatable and selective red-shifts in the reflectivity spectra of PSi microcavities have been registered following exposure to... 

J.C. Owens Optical refractive index of air Dependence on pressure, temperature and composition. Appl. Opt. 6, 51 (1967)... 

For single-layer PS on silicon substrate, the optimal ARC effect (zero net reflection) is fulfilled under two conditions. First, refractive index of the ARC layer (narc) is equal to the square root of the refractive index of silicon (nsi = 3.84), i.e., Uan = (noiisi) = 1.96 (no = 1 is the refractive index of air). Second, the optical thickness of the ARC to be equal to a quarter of the wavelength (Xmin), i.e., (Harcdarc) = min/4. Calculated thickness of ARC layer is 83 nm at = 650 nm. Experimental realization of single-layer ARC on silicon of 60 % porosity and 105 nm thickness reduces the effective reflectance up to 7.3 % in the range 400-100 nm (Strehlke et al. 1999 Table 1). 

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