Han Yiping

Characteristic of laser diode beam propagation through a collimating lens.

A mathematical model of a laser diode beam propagating through a collimating lens is presented. Wave propagation beyond the paraxial approximation is studied. The phase delay of the laser diode wave in passing through the lens is analyzed in detail. The propagation optical field after the lens is obtained from the diffraction integral by the stationary phase method. The model is employed to predict the light intensity at various beam cross sections, and the computed intensity distributions are in a good agreement with the corresponding measurements.

Electromagnetic Scattering of a High-Order Bessel Trigonometric Beam by Typical Particles

The scattering of an electromagnetic high-order Bessel trigonometric beam by several typical homogeneous dielectric particles is investigated. The incident beam is represented by the vector expressions in Cartesian coordinates. The scattering problems involving homogeneous dielectric particles are formulated with the surface integral equation method. As an example, the effects of the beams parameters on the differential scattering cross section for a sphere are analyzed in detail. Then the numerical results for the scattering of a high-order Bessel trigonometric beam by three typical nonspherical particles, including a spheroid, a cylinder, and a cube, are presented.

Numerical Investigation on Scattering of an Arbitrarily Incident Bessel Beam by Fractal Soot Aggregates

Scattering of an arbitrarily incident Bessel beam by fractal soot aggregates is numerically investigated. The incident beam is described by the vector expressions of the zero-order Bessel beam in combination with rotation Euler angles. The scattering problems involving fractal soot aggregates are formulated with a hybrid vector finite element-boundary integral-domain decomposition method. Some numerical results are included to show the scattering behaviors of fractal soot aggregates when they are illuminated by Bessel beams.