Wavelength guide

The guide wavelength (Xg) is related to the free space wavelength (X) and the tube dimensions as given by Eq. 1. 

Guide wavelength The distance over which the fields of propagating modes repeat themselves in a waveguide. 

Attenuation vs. guide wavelength for several different material systems with different feature sizes. 

The guide wavelength can differ markedly from the free-space wavelength A and so wavelengths measured on this basis must be carefully corrected. This requires an absolute identification of the mode in question, which is not so in the Fabry-Perot resonator case, where modes with fixed values of p and / reappear with the same periodicity (very nearly) as do modes with any other fixed values of p and /. For example in Fig. 3.4, which is a cavity scan made with a circular metallic waveguide laser of 19mm diameter, many different periodicities... 

Fig. 3.4. Segment of a cavity scan, or Laser Resonator Interferogram , in this case for a waveguide laser. Despite the many peaks only two distinct laser transitions are involved — at 447 /im and 1306 fim free space wavelength. The marked features have the following guide wavelengths A and B — 447 //m, C—1310 //m, D— 1346/im. The gas was ethyl chloride and the pump line 10J728. Adapted from [3.9] by the author.

Figure Bl.26.15. The Del/Psi trajectory for silicon dioxide on silicon with angle of mcidence ( )j = 70° and wavelength X = 6328 A (Tompkins FI G 1993 A Users Guide to Ellipsometry (San Diego, CA Academic)).

Biegert, J., Diels, J.-C., and Milonni, P. W., 2000, Bi-chromatic 2-photon coherent excitation of sodium to provide a dual wavelength guide star. Optics... 

Once the wavelength dependence of the molecular form factor F(nqo) is known from the reasonable model of layer organization, the ratios r /ti may be calculated. The value of these ratios (for example, T2/T1, T3/T1) give a good guide to the sharpness of the distribution function f(z) - for an ideal crystal f(z) would be an array of delta-functions and T2 = Ti = = = 1. From the... 

The length L of the precession field is measured in meters, the guide field H in Oersted and the wavelength X in Angstrpm. 

---