Vector theory of diffraction by a single-mode fiber: application to mode-field diameter measurements

Vector fields provide a mathematical framework for describing quantities that possess both magnitude and direction at every point in space. Physical phenomena such as wind flow, ocean currents, magnetic forces, and fluid motion can all be represented using vector fields. In meteorology, for example, wind may vary continuously across a geographic region, with both speed and direction changing from one location to another. To visualize this behavior on a two-dimensional map, arrows are placed at...

The divergence of a vector is a measure of how much the vector spreads out (diverges) from a point. For example, an electric field vector diverges from the positive charge and converges at the negative charge. The divergence of an electric field is derived using Gauss's law and is equal to the charge density divided by the permittivity of space. Mathematically, it is expressed as

The Bewley lattice diagram, developed by L. V. Bewley, effectively organizes the reflections occurring during transmission-line transients. It visually represents how voltage waves propagate and reflect within a transmission line, making it easier to understand the complex interactions that occur.

Curl and divergence describe two fundamental ways a vector field can behave. A vector field assigns both magnitude and direction to each point in space, such as the velocity of water flowing in a river. Leaves floating on the surface may reveal regions where the water swirls and other regions where it spreads outward or gathers inward. These motions correspond to curl and divergence.Curl measures the tendency of a vector field to rotate around a point. If leaves circle around a small whirlpool,...

In vector calculus, flux measures the total flow of a vector field through a surface. For a closed surface in three-dimensional space, this means measuring how much of the field passes outward through every point on the boundary. Directly calculating this flux can be difficult when the surface has a complicated or irregular shape. The Divergence Theorem provides a powerful alternative by relating surface flux to behavior inside the enclosed region.The Divergence Theorem states that the outward...

In the macroscopic world, objects that are large enough to be seen by the naked eye follow the rules of classical physics. A billiard ball moving on a table will behave like a particle; it will continue traveling in a straight line unless it collides with another ball, or it is acted on by some other force, such as friction. The ball has a well-defined position and velocity or well-defined momentum, p = mv, which is defined by mass m and velocity v at any given moment. This is the typical...