Radiation mode coupling

When the SRI is equal to the cladding one, the cladding layer becomes an infinitely extended medium and thus supports no discrete cladding modes. In this case, a broadband radiation mode coupling occurs with no distinct attenuation bands8. 

Koyamada, Y., Numerical analysis of core mode to radiation mode coupling in long period fiber gratings, IEEE Photon. Technol. Lett. 2001, 13, 308 310... 

B2.5.351 after multiphoton excitation via the CF stretching vibration at 1070 cm. More than 17 photons are needed to break the C-I bond, a typical value in IR laser chemistry. Contributions from direct absorption (i) are insignificant, so that the process almost exclusively follows the quasi-resonant mechanism (iii), which can be treated by generalized first-order kinetics. As an example, figure B2.5.15 illustrates the fonnation of I atoms (upper trace) during excitation with the pulse sequence of a mode-coupled CO2 laser (lower trace). In addition to the mtensity, /, the fluence, F, of radiation is a very important parameter in IR laser chemistry (and more generally in nuiltiphoton excitation) ... 

In the 2-D periodic metallic structure, coupling between radiation modes and surface plasmons is described by... 

The couplings within the sub-systems consisting of the atomic states and the two radiation modes corresponding to at most a single excitation are shown in Fig. 7. The set of collective states can be separated into groups with specific excitation numbers n+, ii- in the two polarization modes. 

Straight FBGs Back-couples to a core mode o Tilted Back-couples to radiation modes 1 l... 

A synchrotron radiation source, with its thousand-fold improvement in brightness over thermal sources, higher stability, and ouqmt IR spectroscopy, enables reflectivity changes to be measured from IRRAS with absolute baseline accuracy of 0.2% over a broad frequency range and with a spectral shape reproducibility of 0.01% in acquisition times of 100 s down to 50 cm and with 1 cm resolution. These advantages of synchrotron radiation were used in an IRRAS study of mode coupling in the CO-Cu(lOO) system [23]. 

Mode coupling Interaction of modes resulting in the transfer of light intensity between the guided (core) modes and the radiation (cladding) modes. 

Another fundamental process in semiconductors that may contribute to the observed power-independent linewidth is light scattering. Among the many scattering mechanisms that have been observed in GaAs, those that are related to a random process (i.e., carrier density variations, temperature fluctuations, etc.) and produce radiation that couples to the laser mode may increase the noise in the mode above that due to spontaneous emission. However, as opposed to the spontaneous light, the on-line scattered component will increase with the power in the mode above threshold and therefore contribute a power-independent phase fluctuation rate. Various Rayleigh... 

Nevertheless, the fields of the perturbed fiber at position z can be described by a superposition of the fields of the complete set of bound and radiation modes of the unperturbed fiber. An individual mode of the set does not satisfy Maxwell s equations for the perturbed fiber, and hence the perturbed fields must generally be distributed between all modes of the set. This distribution varies with position along the fiber and is described by a set of coupled mode equations, which determine the amplitude of every mode [1-3],... 

The scalar propagation constant Pj is determined from the eigenvalue equation. We have ignored the continuum of radiation modes in Eq. (27-1) since we shall be considering coupling between bound modes only. 

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