A 1645 nm end-pumped dual-channel Er:YAG vector laser that could generate two cylindrical vector (CV) beams simultaneously with different polarization orders is demonstrated. The laser is designed in a two-arm structure, wherein each arm places a q-plate (QP) to introduce intra-cavity spin-orbital angular momentum conversion, leading to the oscillation of two various CV modes in two arms, and finally output along two directions, respectively. The favorable experimental results illustrate high power stability and polarization mode purity. Furthermore, an additional setup is built to demonstrate the potential of the proposed dual-channel CV laser in data transmission. By placing additional acousto-optic modulators, the output dual CV modes are encoded to represent different digital symbols and achieve successful data transmission in free space.
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http://dx.doi.org/10.1364/OL.542437 | DOI Listing |
A 1645 nm end-pumped dual-channel Er:YAG vector laser that could generate two cylindrical vector (CV) beams simultaneously with different polarization orders is demonstrated. The laser is designed in a two-arm structure, wherein each arm places a q-plate (QP) to introduce intra-cavity spin-orbital angular momentum conversion, leading to the oscillation of two various CV modes in two arms, and finally output along two directions, respectively. The favorable experimental results illustrate high power stability and polarization mode purity.
View Article and Find Full Text PDFOptical misalignment between transmitter and receiver leads to power loss and mode crosstalk in a mode division multiplexing (MDM) free-space optical (FSO) link. We report both numerical simulations and experimental results on the propagation performance of two typical vector beams, C-point polarization full Poincaré beams (FPB), and V-point polarization cylindrical vector beams (CVB), compared to homogeneous polarization scalar vortex beams (SVB) under optical misalignment. The FSO communication performance under misalignment using different transmit beams is evaluated in terms of power loss, mode crosstalk, power penalty, etc.
View Article and Find Full Text PDFFree-space optical (FSO) communication has the advantages of large bandwidth and high security and being license-free, making it the preferred solution for addressing the "last kilometer" of information transmission. However, it is susceptible to fluctuations in the received optical power (ROP) due to atmospheric turbulence and pointing errors, resulting in the inevitable free-space optical communication transmission performance degradation. In this work, we experimentally verified the turbulence resistance of the cylindrical vector beam (CVB) over a 3 km long free-space field trial link.
View Article and Find Full Text PDFBMC Ophthalmol
January 2025
Medical Laboratories Techniques Department, College of Health and Medical Techniques, Al-Mustaqbal University, Babylon, 51001, Iraq.
Purpose: To compare the prevalence, magnitude, and type of astigmatism among patients with different Duane Retraction Syndrome (DRS) types.
Method: This retrospective cross-sectional study reviewed the records of 312 DRS patients. Patients were categorized into DRS Types 1, 2, 3, and bilateral cases.
Sensors (Basel)
December 2024
Institute of Communications Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
A core dielectric cylindrical rod wrapped in a dielectric circular pipe whose outer surface is enclosed by a helical conducting strip grating that is skewed along the axial direction is herein analyzed using the asymptotic strip boundary conditions along with classical vector potential analysis. Targeted for use as a cylindrical holographic antenna, the resultant field solutions facilitate the aperture integration of the equivalent cylindrical surface currents to obtain the radiated far fields. As each rod section of a certain skew angle exhibits a distinct modal attribute; this topology allows for the distribution of the cylindrical surface impedance via the effective refractive index to be modulated, as in gradient-index (GRIN) materials.
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