Extension of the Jones matrix formalism to higher-order transverse modes

2006 ◽  
Vol 32 (1) ◽  
pp. 83 ◽  
Author(s):  
Andreas Voss ◽  
Marwan Abdou Ahmed ◽  
Thomas Graf
2010 ◽  
Vol 18 (21) ◽  
pp. 21540 ◽  
Author(s):  
Andreas Voss ◽  
Marwan Abdou-Ahmed ◽  
Thomas Graf

1999 ◽  
Vol 5 (3) ◽  
pp. 32 ◽  
Author(s):  
S. Wolff ◽  
D. Messerschmidt ◽  
H. Fouckhardt

1997 ◽  
Vol 14 (9) ◽  
pp. 2290 ◽  
Author(s):  
D. Han ◽  
Y. S. Kim ◽  
Marilyn E. Noz

2015 ◽  
Vol 12 (111) ◽  
pp. 20150734 ◽  
Author(s):  
M. Menzel ◽  
K. Michielsen ◽  
H. De Raedt ◽  
J. Reckfort ◽  
K. Amunts ◽  
...  

The neuroimaging technique three-dimensional polarized light imaging (3D-PLI) provides a high-resolution reconstruction of nerve fibres in human post-mortem brains. The orientations of the fibres are derived from birefringence measurements of histological brain sections assuming that the nerve fibres—consisting of an axon and a surrounding myelin sheath—are uniaxial birefringent and that the measured optic axis is oriented in the direction of the nerve fibres (macroscopic model). Although experimental studies support this assumption, the molecular structure of the myelin sheath suggests that the birefringence of a nerve fibre can be described more precisely by multiple optic axes oriented radially around the fibre axis (microscopic model). In this paper, we compare the use of the macroscopic and the microscopic model for simulating 3D-PLI by means of the Jones matrix formalism. The simulations show that the macroscopic model ensures a reliable estimation of the fibre orientations as long as the polarimeter does not resolve structures smaller than the diameter of single fibres. In the case of fibre bundles, polarimeters with even higher resolutions can be used without losing reliability. When taking the myelin density into account, the derived fibre orientations are considerably improved.


2020 ◽  
Vol 128 (8) ◽  
pp. 1151
Author(s):  
С.А. Блохин ◽  
М.А. Бобров ◽  
Н.А. Малеев ◽  
А.Г. Кузьменков ◽  
В.М. Устинов

The static characteristics of 850 nm-range vertical-cavity surface-emitting lasers (VCSEL) based on strained InGaAs/AlGaAs quantum wells were studied in the wide range of oxide current aperture sizes and the origins of their anomalous behavior at large gain-to-cavity detuning was analyzed. The higher-order modes localized at the periphery of the oxide current aperture can appear in the studied VCSELs due to the lateral carrier spreading in the quantum wells and the specific profile of the oxide aperture (leading to the formation of a two-stage effective waveguide). Inhomogeneous carrier injection over the current aperture area in wide-aperture lasers leads anomalous start of lasing via high-order transverse modes, and the subsequent transition to the classical lasing via low-order modes with an increase in the current is due to a change of the gain-to-cavity detuning with an increase in the internal laser temperature. Anomalous lasing via higher-order modes in the case of narrow-aperture VCSELs becomes possible due to the increase in diffraction losses at the edge of the oxide current aperture for the fundamental mode, while the subsequent switching to the two-mode lasing is due to not only a decrease in the gain-to-cavity detuning, but also the thermal lens effect.


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