Normal-incidence reflection

Each reflector contributes a reflection along a raypath to the surface, defined by the normal incidence reflection point (shortest travel time)... 

Measured normal incidence reflectances of a-SiC for incident electric field perpendicular to the hexagonal axis are shown in Fig. 9.6 these are unpublished measurements made in the authors laboratory, but they are similar to those pubhshed by Spitzer et al. (1959). Also included in this figure are both sets of optical constants—n, k and e, e"—calculated from the best fit of a one-oscillator model to the experimental data. Note that the model curve is almost a perfect representation of the data over the entire range shown for this solid, the technique of fitting data with a one-oscillator model is both a simple and accurate method for extracting optical constants. 

In the region between to, and to, which for SiC is between about 800 and 1000 cm-1, the reflectance is high not because of large k but because of small n. If n = 0, the normal incidence reflectance is nearly 100% only for the undamped oscillator (y = 0) is the reflectance actually 100%, but solids like SiC approach this rather closely. If the damping constant y in (9.20) is set equal to zero, the real part of the dielectric function becomes... 

Fig. 9.2. Normal incidence reflectivity for various XUV/SXR mirrors. All of the mirrors, except the SiC mirror, are multilayer-coated. The solid lines show the theoretical values and the plots are measured data...

Fig. 2.2. Polarized transmittance (dashed line) and near-normal-incidence reflectance (continuous line) spectra of highly stretch-oriented PPV...

Usually, the absorption coefficient of the conducting crystals is so high that producing a crystal sufficiently thin and suitable for absorption measurements presents a great difficulty. If this is so, the bulk optical constants of a solid may be computed from the normal-incidence reflectivity of that material over an extended range of frequencies, followed by a Kramers-Kronig analysis of the measurements [12,14]. In this method the real, n, and imaginary, k, parts of the complex index of refraction... 

Figure 1 Polarized near-normal-incidence reflection spectra of TEA(TCNQ)2 at room temperature in the far-infrared and infrared region. The spectra show the details for three light polarizations 1, parallel to the TCNQ chains 2 and 3, perpendicular to the chains (2 being within and 3 perpendicular to the alternating layers of TCNQ and TEA molecules). (From Ref. 18.)...

Figure 4. Polyethylene the normal incidence reflectivity (----------) and optical absorption coefficient (-----) computed from the dielectric function of Figure 3 (1)...

In Fig. 1 the three normal incidence reflectance components are shown in the range from the infrared to 25000 cm ... 

Figure 17.1.9 Dependence of the real and imaginary components of the optical-frequency dielectric constant of gold on the energy of incident photons. The normal-incidence reflectivity of gold in air is shown in the inset. [From D. M. Kolb and J. D. E. McIntyre, Surf. ScL, 28, 321 (1971), with permission.]...

The structure in the reflectivity can be understood in terms of band structure features i.e. ifom the quantum states of the crystal. The normal incident reflectivity from matter is given by... 

These tables list the index of refraction n, the extinction coefficient k, and the normal incidence reflection f (( ) = 0) as a function of photon energy E, which is expressed in electron volts (eV). To convert the energy in eV to the wavelength in pm, use X = 1.2398/ E. To compute the dielectric function e = + ie from the complex... 

For any two opaque (absorbing) media, the normal incidence reflectivity is... 

It must be emphasized that the short attenuation length and low normal-incidence reflectivity of materials in the EUV range present very difficult problems regarding fabricating single-surface mirrors or lenses. The main solution to this problem is the use of multilayer reflectors. Absent these reflectors, EUV lithography as currently practiced would not be possible. 

Figure 14.5 Calculated normal Incidence reflectivity curve for a molybdenum-silicon multilayer mirror with number of bIlayers 50. The molybdenum thickness Is 2.7 nm and the silicon thickness Is 4.2 nm. (Reprinted with permission from Ref. 44. 2009 McGraw-Hill.)...

Figure 8.6. Measured normal incidence reflectivity of two-layer Jaumann RAM using PPy treated cotton cloth composite layers. Reprinted with permission from ref 84.

Breiland, W. G., and K. P. Killeen. 1995. A virmal interface method for extracting growth rates and high temperature optical constants from thin semiconductor films using in situ normal incidence reflectance. Journal of Applied Physics 78(11 ) 6726-6736. 

Hou, H. Q., W. G. Breiland, B. E. Hammons, and H. C. Chui. 1996. In situ growth rate measurements by normal-incidence reflectance during MOCVD growth. Electrochemical Society Proceedings 96(2) 27-35. 

Fig. 14 Normal incidence reflection spectra for PTS, TCIXJ, ETCD belokr the phase transition, and ETCD above the phase transition.

Fig. 137. Near-normal incidence reflectivity of CeCu at 5 K. and at 300 K. The inset shows the profile of the density of states near the Fermi level as inferred from experimental data. (After Marabelli et al. 1988.)...

The absorption coefficient o( ) and normal-incidence reflectivity R E) can be written as... 

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