Films refractive index

The factor f reduces the oscillation amplitude symmetrically about R - R0, facilitating straightforward calculation of polymer refractive index from quantities measured directly from the waveform (3,). When r12 is not small, as in the plasma etching of thin polymer films, the first order power series approximation is inadequate. For example, for a plasma/poly(methyl-methacrylate)/silicon system, r12 = -0.196 and r23 = -0.442. The waveform for a uniformly etching film is no longer purely sinusoidal in time but contains other harmonic components. In addition, amplitude reduction through the f factor does not preserve the vertical median R0 making the film refractive index calculation non-trivial. 

The results of this model calculation can be used to extract unknown film properties, such as the film refractive index and thickness. Normally, however, an ellipsometer will yield only two independent observables (the two ellipsometric angles defined in equation (3.6), for example). For that reason, only two film properties can be extracted from a single measurement. If the film is nonabsorbing with a real refractive index, an ellipsometric measurement can provide the real part of the refractive index, n, and the thickness. For... 

Substrate refractive index f Waveguide film refractive index... 

Second order, polyazomethine possesses both donor and acceptor groups at the molecular level, which when aligned gives a poled polymer. Tatsuura et al. fabricated an as-deposited poled polymer film by applying anin-situ electric field during CVD and reported on the second order nonlinear optical properties of the obtained film. The polymer film refractive index was reported to be about 1.68 at 632.8 nm. Second order NLO susceptability, p, was found to be... 

Single Surfactant Systems. Relative intensity results for an equilibrium film of the block copolymer B1 in n-decane sandwiched between two water droplets at 25°C, are shown in Table II. The intensity was independent of the bulk polymer concentration within the accuracy of measurement. Assuming a constant film refractive index this implies that the film thickness is independent of surfactant concentration, and an average value of J was used for the calculation of film thickness. Coalescence occurs below a concentration of 0.1 g dm, presumably because there is insufficient... 

Film refractive index n was determined using an Abbe refractometer at room temperature. The dielectric constant e of the material at a frequency near 1 MHz is evaluated roughly from the refractive index to be e=l.ln2.[7] These results are listed in Table 1. Optically estimated e s of the nonaromatic polyimides were approximately 2.6, whereas those of semi-aromatic and aromatic polyimides were around 2.8 and 3.1, respectively.[6] The birefringence An (optical anisotropy) of sample films was evaluated by means of ellipsometry. All the nonaromatic polyimides examined in this study possessed small birefringence below 10"4. 

The first point to notice is that the contours are closed curves, a separate one for each refractive index. The A- values for the difference refractive indices necessarily all pass through the zero-thickness point which is characteristic of the n and k of the bare substrate. The thickness at which the curves cycle through this point, dr, (i.e. the thickness period) is characteristic of the film refractive index, the angle of incidence, and the wavelength. 

In multilayer production the growing Si02 film is periodically doped resulting in a sinusoidal film refractive index profile. The almost monolayer-by-monolayer growth control offers a new degree of freedom in optical coating design. 

In addition to electron diffraction, the measurement of the film refractive index also enables distinction between anatase and rutile. According to Hass [27], polycrystalline rutile films have a refractive index value of 54 = 2.70 and that of the anatase films is 546 = 2.39. 

A small packing density causes a reduction of the film refractive index, the refractive index of a porous film measured in vacuum is therefore low. On exposure to the atmosphere, however, a markedly increased value due to the sorption of water vapour, with n i0 = 1.33, is observed especially in the case of films of low refracting... 

If appropriate thin films, refractive index ni are deposited on the surfaces,... 

The spectrum of a piotein. film (refractive index of 15> v as produced by using-an ATR cell made of KRS 5 (reiracti ve indent of 2 4) If the madent radiation enters the cell crvstal at an angle of 60°C what IS the depth of penetration mto the sample... 

Ellipsometry is a technique that uses polari/.ed light to probe the dielectric properties of samples.- It is most commonly applied to the analysis of very thin films on surfaces. In ellipsometry, a polarized incident beam, often from a laser, is reflected from the film, and the reflected light is analyzed to determine a change in the state of polarization. The change in the amplitude and the phase of the reflected light are then related to properties such as film refractive index, absorptivity, optical anisotropy, and thickness. 

This means that if useful information is to be obtained from a film-substrate system, there are five parameters the complex refractive index n and k) of film (two parameters) and substrate (two parameters) and a film thickness (one parameter). Usually some parameters are known or can be assumed, such as the refractive index of the substrate material and k = 0 for a transparent film. In that case the film refractive index and thickness can be obtained from a single ellipsometric measurement. If one needs to determine more parameters, the number of free parameters can be increased by varying the angle and/or the wavelength. 

Hollow waveguide Metal/dielectric film Refractive index <1 Hollow glass waveguide Hollow sapphire at 10.6 pm... 

The wavelength of the incident light is usually also varied (spectroscopic ellip-sometry) in order to determine the three quantities characterizing the surface film (refractive index, absorption coefficient and thickness), because only two parameters can be obtained in a single measmement. 

Ellipsometry Microporous or mesoporous layers or films Refractive index scales with porosity (Tompkins and Irene 2005) (Pettersson etal. 1998)... 

Single crystal (SC) Metal/dielectric film Refractive index < 1... 

Figure 8. Change of PP film refractive index under of the various doze of gamma-irradiation...

---