Propagation length

The propagation length of a SPP mode, Sspp, is the distance over which the field falls to 1/e of its initial value, and it is given by Sspp = where /c is the imaginary part of the SPP wavevector 

From Eq. (1.177) we can observe that for a long propagation length we require a large negative real part of the relative permittivity of the metal, , and a small imaginary part, so that the absorptive nature of metals in the visible and near-lR places considerable restrictions on the construction of photonic components or circuits based on SPPs. 

In addition, we see that the SPP propagation length is significantly greater than the SPP wavelength. This allows surface plasmon-polaritons to be manipulated by wavelength scale gratings and other periodic surface structures [7,12,14]. 

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It must be noted that the echoes that arrive at the receiver do not have the same intensity, as the propagation lengths of the waves are different. Thus, a weighting must be applied, according to the signal power. The weighting factors are calculated by the following set of equations ... 

We note in passing that the spectral method can be regarded as a special case of FD with L = 1, for which the uncertainty principle dictates that the spectral resolution is inversely proportional to the propagation length. In FD, the spectral resolution is enhanced beyond the uncertainty principle, because of the diagonalization of the Hamiltonian in the subspace spanned by multiple filtered vectors. 

Fig. 6. Evolution of the generation efficiency as a function of propagation length (for perfect phasematching) in the lossless and a few lossy cases...

The introduction of a metal, which usually exhibits high absorptions, onto or close to a waveguide was a revolutionary idea. Critical voices only mentioned malfunctioning because of the extremely high losses expected and, therefore, the small possible propagation lengths. 

Up to now, no significant conversion efficiencies q = PiJ co where P is power at given frequency, were reported. This is mainly due to the poor overlap integral, limited propagation length caused by the nonoptimized propagation properties of polymeric waveguides, and limited values of ( (-2cu,cu,cu) susceptibility. 

In a conventional RWG biosensor, the binding signals typically represent the averaged response of the binding at a defined area, as predetermined by the size of illumination light (e.g., 100 pm) as well as the distance of the propagation length... 

The fast dynamics of oscillatory electrochemical reactions often require a temporal resolution considerably better than video frequency. In the studies discussed in the next section, cameras with a full-frame transfer architecture that allows the recording of about 1000 frames per second were used. The spatial resolution is limited by the propagation length of... 

FlG. 12.1. Experimental Otto configuration for (a) single prism ATR measurements and (b) double prism measurement of propagation length L. Prism are spaced a variable distance g above surface (from (6)). 

Spectral dependencies of the effective index, attenuation, and propagation length of a surface plasmon supported by gold, silver and aluminum are shown in Fig. 4. 

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