Higher order modes and crystallographic axis angular dependence of propagation in anisotropic pbn using a spectral matrix method

1987 ◽  
Author(s):  
Ayman A. Mostafa ◽  
Clifford M. Krowne ◽  
Kawthar A. Zaki
Keyword(s):  
Angular Dependence ◽  
Matrix Method ◽  
Higher Order ◽  
Crystallographic Axis ◽  
Spectral Matrix ◽  
Higher Order Modes

scholarly journals Numerical Investigation of the System-Matrix Method for Higher-Order Probe Correction in Spherical Near-Field Antenna Measurements

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Thorkild B. Hansen
Keyword(s):  
Condition Number ◽  
Matrix Method ◽  
Near Field ◽  
Higher Order ◽  
Normal Matrix ◽  
Identity Matrix ◽  
System Matrix ◽  
Higher Order Modes ◽  
Near Field Scanning ◽  
Least Squares Approach

The system-matrix method for higher-order probe correction in spherical near-field scanning is based on a renormalized least-squares approach in which the normal matrix closely resembles the identity matrix when most of the energy of the probe pattern resides in the first-order modes. This method will be “stressed-tested” in the present paper by employing probes for which up to 49% of the pattern energy resides in the higher-order modes. The condition number of the resulting normal matrix will be computed, and its “distance” from the identity matrix displayed. It is also shown how the condition number of the normal matrix can be further reduced.

scholarly journals Electrical characterisation of higher order spin wave modes in vortex-based magnetic tunnel junctions

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Alex. S. Jenkins ◽  
Lara San Emeterio Alvarez ◽  
Samh Memshawy ◽  
Paolo Bortolotti ◽  
Vincent Cros ◽  
...  
Keyword(s):  
Spin Wave ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Higher Order ◽  
Spin Torque ◽  
Micromagnetic Simulations ◽  
Higher Order Modes ◽  
Spin Diode ◽  
Super High Frequency ◽  
Wave Modes

AbstractNiFe-based vortex spin-torque nano-oscillators (STNO) have been shown to be rich dynamic systems which can operate as efficient frequency generators and detectors, but with a limitation in frequency determined by the gyrotropic frequency, typically sub-GHz. In this report, we present a detailed analysis of the nature of the higher order spin wave modes which exist in the Super High Frequency range (3–30 GHz). This is achieved via micromagnetic simulations and electrical characterisation in magnetic tunnel junctions, both directly via the spin-diode effect and indirectly via the measurement of the coupling with the gyrotropic critical current. The excitation mechanism and spatial profile of the modes are shown to have a complex dependence on the vortex core position. Additionally, the inter-mode coupling between the fundamental gyrotropic mode and the higher order modes is shown to reduce or enhance the effective damping depending upon the sense of propagation of the confined spin wave.

scholarly journals Design of large mode area all-solid anti-resonant fiber for high-power lasers

2021 ◽  
Vol 9 ◽  
Author(s):  
Xin Zhang ◽  
Shoufei Gao ◽  
Yingying Wang ◽  
Wei Ding ◽  
Pu Wang
Keyword(s):  
High Power ◽  
Single Mode ◽  
Higher Order ◽  
Coupling Scheme ◽  
Resonant Coupling ◽  
Higher Order Modes ◽  
Mode Loss ◽  
Fiber Mode ◽  
Power Needs ◽  
Mode Area

Abstract High-power fiber lasers have experienced a dramatic development over the last decade. Further increasing the output power needs an upscaling of the fiber mode area, while maintaining a single-mode output. Here, we propose an all-solid anti-resonant fiber (ARF) structure, which ensures single-mode operation in broadband by resonantly coupling higher-order modes into the cladding. A series of fibers with core sizes ranging from 40 to 100 μm are proposed exhibiting maximum mode area exceeding 5000 μm2. Numerical simulations show this resonant coupling scheme provides a higher-order mode (mainly TE01, TM01, and HE21) suppression ratio of more than 20 dB, while keeping the fundamental mode loss lower than 1 dB/m. The proposed structure also exhibits high tolerance for core index depression.

On the higher-order modes in rectangular-groove guide

1996 ◽  
Vol 17 (11) ◽  
pp. 1957-1967 ◽  
Author(s):  
W. M. Shi ◽  
K. F. Tsang ◽  
C. N. Wong ◽  
W. X. Zhang
Keyword(s):  
Higher Order ◽  
Higher Order Modes ◽  
Groove Guide ◽  
Rectangular Groove
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