Improved theory for the polarization-dependent transverse shift of a paraxial light beam in free space

Spatial distribution of the longitudinal field component of a circularly polarized optical beam depends on the polarization handedness, which causes the lateral shift of the beam "center of gravity" when its polarization toggles. We present the generalized theory of this effect, which demonstrates its relation with the angular irradiance moments of the beam. The theory is applicable to arbitrary paraxial beams and shows that the lateral shift is the same for all cross sections of the beam.Comment: 9 pages, 2 figures. The paper is submitted to Ukr. J. Phys. Opt. It contains the refined and generalized theory of the effect first observed and explained by B. Zel'dovich et al. in 1994: polarizxation-dependent transverse shift of the focal spot obtained by focusing an asymmetric light bea

Production of Scintillation Particle Detectors With Stereolithography-Based 3D Printing

My research is to design and directly 3D print scintillator detectors. One of my main tasks was to figure out how to make test pieces as transparent as possible by sanding, cerium oxide polishing, and coating in resin. I’ve also designed and 3D printed a completely opaque cylindrical case for the photomultiplier tube (PMT). The PMT is capable of detecting light coming from a scintillator attached to its lens on a single photon level. That makes it extremely sensitive to light, so it must operate in a completely lightproof environment. I also determined ideal conditions under which resins with different amounts of scintillating ingredients can be mixed and printed. The key is to find a good temperature at which scintillating materials stay fully dissolved and don’t recrystallize so that a scintillator can be printed, but that is not too high. This allows me to 3D print liquid resin, but also ensures the resin doesn’t decompose from overheating. The next step of my research is mixing different recipes and 3D printing them to optimize for maximum detection efficiency

Subwavelength particles in an inhomogeneous light field: Optical forces associated with the spin and orbital energy flows

We analyze the ponderomotive action experienced by a small spherical particle immersed in an optical field, in relation to the internal energy flows (optical currents) and their spin and orbital constituents. The problem is studied analytically, based on the dipole model, and numerically. Three sources of the field mechanical action - energy density gradient and the orbital and spin parts of the energy flow - differ by the ponderomotive mechanism, and their physical nature manifests itself in the optical force dependence on the particle radius a. If a is much less than the radiation wavelength, the optical force behaves as a^n and integer n can be used to classify the sources of the mechanical action. This classification correlates with the multipole representation of the field-particle interaction: The gradient force and the orbital-momentum force appear due to the electric or magnetic dipole moments per se, the spin-momentum force emerges due to interaction between the electric and magnetic dipoles or between the dipole and quadruple moments (if the particle is polarisable electrically but not magnetically or vice versa). In principle, the spin and orbital currents can be measured separately by the probe particle motion, employing the special choice of particles with necessary magnetic and/or electric properties.Comment: 16 pages, 2 figures. The paper represents materials of the talk at conference "Singular Optics'12" in Sevastopol, 19 September 2012, and is designed to "Journal of Optics