scholarly journals Total Reflection of Two Guided Waves for Embedded Trapped Modes

AIAA Journal ◽  
2021 ◽  
Vol 59 (1) ◽  
pp. 131-139
Author(s):  
Xiwen Dai
Keyword(s):  
Guided Waves ◽  
Total Reflection ◽  
Trapped Modes

Guided Waves

2019 ◽  
pp. 249-284
Author(s):  
B. D. Guenther
Keyword(s):  
Plane Wave ◽  
Guided Waves ◽  
Unit Length ◽  
Numerical Aperture ◽  
Geometric Theory ◽  
Wave Theory ◽  
Total Reflection ◽  
Dimension Theory ◽  
Coupling Energy ◽  
Propagation Of Light

Use a one-dimension theory based on the normal to a plane wave to evaluate the propagation of light in a dielectric layer. If the ray strikes the walls of the guide it must meet the condition for total reflection. The theory, called the zigzag model, is not a “pure” geometric theory because we use the properties of interference and of phase change upon total reflection that we derived using wave theory. The theory predicts that the rays propagating down the guide can only strike the walls at discrete angles. These angles are the modes of the guide. The theory allows us to calculate the number of bounces/unit length the ray can make. We show limitaitons on coupling energy into the guided modes and the numerical aperture of a mode. We discuss losses and dispersion in the guide and introduce photonic crystals that allow hollow guides to be constructed.

Trapped modes and scattering for oblique waves in a two-layer fluid

2014 ◽  
Vol 753 ◽  
pp. 427-447 ◽  
Author(s):  
M. I. Romero Rodríguez ◽  
P. Zhevandrov
Keyword(s):  
Scattering Problem ◽  
Total Reflection ◽  
Unperturbed System ◽  
Trapped Modes ◽  
Theoretical Understanding ◽  
Transmission Coefficients ◽  
Trapped Mode ◽  
Geometric Conditions ◽  
Small Height ◽  
Incident Waves

AbstractThe system describing time-harmonic motions of a two-layer fluid in the linearised shallow-water approximation is considered. It is assumed that the depth is constant, with a cylindrical protrusion (an underwater ridge) of small height. For obliquely incident waves, the system reduces to a pair of coupled ordinary differential equations. The values of frequency for which wave propagation in the unperturbed system is possible are bounded from below by a cutoff, to the left of which no propagating modes exist. Under the perturbation, a trapped mode appears to the left of the cutoff and, if a certain geometric requirement is imposed upon the shape of the perturbation (for example, if the ridge is a rectangular barrier of certain width), a trapped mode appears whose frequency is embedded in the continuous spectrum. When these geometric conditions are not satisfied, the embedded trapped mode transforms into a complex pole of the reflection and transmission coefficients of the corresponding scattering problem, and the phenomenon of almost total reflection is observed when the frequency coincides with the real part of the pole. Exact formulae for the trapped modes are obtained explicitly in the form of infinite series in powers of the small parameter characterising the perturbation. The results provide a theoretical understanding of analogous phenomena observed numerically in the literature for the full problem for the potentials in a two-layer fluid in the presence of submerged cylinders, and furnish explicit formulae for the frequencies at which total reflection occurs and the trapped modes exist.

Attenuated Total Reflection Studies of Honeycomb Nanoporous GaN Thin Films

2015 ◽  
Vol 1108 ◽  
pp. 9-14
Author(s):  
Sook Fong Cheah ◽  
Sai Cheong Lee ◽  
Sha Shiong Ng ◽  
Fong Kwong Yam ◽  
Abu Hassan Haslan ◽  
...  
Keyword(s):  
Thin Film ◽  
Room Temperature ◽  
Guided Waves ◽  
Honeycomb Structure ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Effective Medium Model ◽  
Surface Phonon Polariton ◽  
Atr Spectroscopy ◽  
Good Agreement

In this work, room temperature polarized infrared attenuated total reflection (ATR) spectroscopy was employed to characterize a nanoporous GaN thin film with honeycomb structure. Prominent ATR dips due to the surface phonon polariton (SPP) and guided waves of nanoporous GaN thin film were observed. Both SPP resonance and guided waves were detected in the p-polarized ATR spectrum while only guided waves were detected in the s-polarized ATR spectrum. The ATR results were compared with the theoretical spectra generated by means of effective medium model. Good agreement was achieved between the measured and theoretical spectra. Finally, the thickness and porosity of porous layer were determined unambiguously.

Contribution of x-ray total reflection to the background intensity in EPMA

1990 ◽  
Vol 48 (2) ◽  
pp. 202-203
Author(s):  
Werner P. Rehbach ◽  
Peter Karduck
Keyword(s):  
Atomic Number ◽  
Target Material ◽  
Total Reflection ◽  
Background Intensity ◽  
X Rays ◽  
Characteristic Radiation ◽  
X Ray

In the EPMA of soft x rays anomalies in the background are found for several elements. In the literature extremely high backgrounds in the region of the OKα line are reported for C, Al, Si, Mo, and Zr. We found the same effect also for Boron (Fig. 1). For small glancing angles θ, the background measured using a LdSte crystal is significantly higher for B compared with BN and C, although the latter are of higher atomic number. It would be expected, that , characteristic radiation missing, the background IB (bremsstrahlung) is proportional Zn by variation of the atomic number of the target material. According to Kramers n has the value of unity, whereas Rao-Sahib and Wittry proposed values between 1.12 and 1.38 , depending on Z, E and Eo. In all cases IB should increase with increasing atomic number Z. The measured values are in discrepancy with the expected ones.

Determination of some heavy metals (Fe, Cu, Zn and Pb) in blood by total reflection X-ray fluorescence

2003 ◽  
Vol 107 ◽  
pp. 203-206 ◽  
Author(s):  
M. Bounakhla ◽  
A. Doukkali ◽  
K. Lalaoui ◽  
H. Aguenaou ◽  
N. Mokhtar ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Total Reflection ◽  
X Ray

On birefringence phenomena, associated with total reflection

1973 ◽  
Vol 34 (5-6) ◽  
pp. 335-340 ◽  
Author(s):  
B. Julia ◽  
A. Neveu
Keyword(s):  
Total Reflection
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