Enhanced nonlinear interactions in one-dimensional photonic crystals: polarization mode conversion

2002 ◽  
Author(s):  
B.J. Eggleton ◽  
R.E. Slusher
Keyword(s):  
Photonic Crystals ◽  
Mode Conversion ◽  
Nonlinear Interactions ◽  
Polarization Mode ◽  
One Dimensional

scholarly journals Interaction of equivalence ratio fluctuations and flow fluctuations in acoustically forced swirl flames

2021 ◽  
pp. 175682772110155
Author(s):  
Vincent Kather ◽  
Finn Lückoff ◽  
Christian O. Paschereit ◽  
Kilian Oberleithner
Keyword(s):  
Equivalence Ratio ◽  
Transfer Functions ◽  
Transport Model ◽  
Mode Conversion ◽  
Fuel Injector ◽  
One Dimensional ◽  
Flow Fluctuations ◽  
Non Linear ◽  
Non Local ◽  
Acoustic Forcing

The generation and turbulent transport of temporal equivalence ratio fluctuations in a swirl combustor are experimentally investigated and compared to a one-dimensional transport model. These fluctuations are generated by acoustic perturbations at the fuel injector and play a crucial role in the feedback loop leading to thermoacoustic instabilities. The focus of this investigation lies on the interplay between fuel fluctuations and coherent vortical structures that are both affected by the acoustic forcing. To this end, optical diagnostics are applied inside the mixing duct and in the combustion chamber, housing a turbulent swirl flame. The flame was acoustically perturbed to obtain phase-averaged spatially resolved flow and equivalence ratio fluctuations, which allow the determination of flux-based local and global mixing transfer functions. Measurements show that the mode-conversion model that predicts the generation of equivalence ratio fluctuations at the injector holds for linear acoustic forcing amplitudes, but it fails for non-linear amplitudes. The global (radially integrated) transport of fuel fluctuations from the injector to the flame is reasonably well approximated by a one-dimensional transport model with an effective diffusivity that accounts for turbulent diffusion and dispersion. This approach however, fails to recover critical details of the mixing transfer function, which is caused by non-local interaction of flow and fuel fluctuations. This effect becomes even more pronounced for non-linear forcing amplitudes where strong coherent fluctuations induce a non-trivial frequency dependence of the mixing process. The mechanisms resolved in this study suggest that non-local interference of fuel fluctuations and coherent flow fluctuations is significant for the transport of global equivalence ratio fluctuations at linear acoustic amplitudes and crucial for non-linear amplitudes. To improve future predictions and facilitate a satisfactory modelling, a non-local, two-dimensional approach is necessary.

TE Transmittance properties of one-dimensional symmetric quinary photonic crystals

2021 ◽  
Vol 68 (3) ◽  
pp. 125-133
Author(s):  
Hassan S. Ashour ◽  
Mazen M. Abadla ◽  
Khedr M. Abohassan
Keyword(s):  
Photonic Crystals ◽  
One Dimensional

scholarly journals One-dimensional ZnSe/ZnS/BK7 ternary planar photonic crystals as wide angle infrared reflectors

2021 ◽  
Vol 22 ◽  
pp. 103882
Author(s):  
Khedr M. Abohassan ◽  
Hassan S. Ashour ◽  
Mazen M. Abadla
Keyword(s):  
Photonic Crystals ◽  
Wide Angle ◽  
One Dimensional

Single Defect in Finite one Dimensional Photonic Crystals

2012 ◽  
Vol 614-615 ◽  
pp. 1629-1632
Author(s):  
Gang Xu ◽  
Yun Sun
Keyword(s):  
Photonic Crystals ◽  
Transmission Coefficient ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Defect Mode ◽  
Transmission Peak ◽  
Reflection And Transmission ◽  
One Dimensional ◽  
Single Defect ◽  
Reflection And Transmission Coefficient

Applying transfer matrix method, we get reflection and transmission coefficient of finite one dimensional photonic crystals. At the same time, we consider the position influence of single defect. We find the frequency of defect mode is same, but the height of transmission peak is not same when single defect is in different position of crystal. The transmission peak is maximum when the defect is in center of finite one dimensional photonic crystals.

scholarly journals Light propagation in tunable exciton-polariton one-dimensional photonic crystals

2016 ◽  
Vol 94 (12) ◽  
Author(s):  
E. S. Sedov ◽  
E. D. Cherotchenko ◽  
S. M. Arakelian ◽  
A. V. Kavokin
Keyword(s):  
Photonic Crystals ◽  
Light Propagation ◽  
One Dimensional
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