An Unofficial Account of the Beginnings of VLBI Polarimetry: From Jodrell Bank to the Event Horizon Telescope

I offer a brief and personal history of the development of polarization sensitive observations with widely separated antennas. The story starts at Jodrell Bank in the late 1960s with a 24 km baseline radio linked (but not phase stable) interferometer and reaches to the present Event Horizon Telescope (with global span and independent atomic clocks) which has just published an image of the linearly polarized radiation surrounding the black hole shadow of M87*. I was privileged to be witness to many of the developments along the way, either as an instigator, a bystander, or an unindicted co-conspirator. I am most interested in the technical developments that enabled these increasingly sophisticated observations, and in the ideas that advanced the data analysis and imaging.

Formation of Inverse Energy Flux in the Case of Diffraction of Linearly Polarized Radiation by Conventional and Generalized Spiral Phase Plates

Recently, there has been increased interest in the shaping of light fields with an inverse energy flux to guide optically trapped nano- and microparticles towards a radiation source. To generate inverse energy flux, non-uniformly polarized laser beams, especially higher-order cylindrical vector beams, are widely used. Here, we demonstrate the use of conventional and so-called generalized spiral phase plates for the formation of light fields with an inverse energy flux when they are illuminated with linearly polarized radiation. We present an analytical and numerical study of the longitudinal and transverse components of the Poynting vector. The conditions for maximizing the negative value of the real part of the longitudinal component of the Poynting vector are obtained.

Поляризационно-чувствительные регистрирующие среды для голографии на базе красителя--флуорофора lucifer yellow

Polarization-sensitive hologram media based on matrices of polyvinyl pyrrolidone and gelatin are created, containing Lucifer Yellow and Coummarine 466. A multiplexed dynamic hologram of Denisyuk is recorded in a luminescent photoanisotropic gyrotropic material, using linearly polarized radiation of the laser LSR 405 NL-50 (= 405 nm). Using the method of polarization-luminescent holography, the photoanisotropic characteristics of the beam have been measured corresponding to the reconstructed imaginary image of the object field. The polarization spectra and photoluminescence intensity spectra of the reconstructed image were measured, depending on the composition of the recording medium. The possibility of multiplex recording has been demonstrated, as well as simultaneous observation of several images of an anisotropic-gyrotropic object encoded by different emission frequencies and / or polarization state. The combination of non-destructive polarization-luminescent holographic measurement method with other luminescent spectroscopic methods significantly expands the scope of this application by increasing dramatically the overall information content of the study.

The Laser Radiation Scattering by the Small Spherical Absorbing Particles Modelling

The paper deals with the elastic light scattering on spherical absorbing particles phenomenon and the method of its quantitative description in the framework of the theory of G. Mi. An algorithm for calculating the scattered radiation relative intensity in an arbitrary direction has been developed and a modeling 3D scattering indicatrices program has been obtained. The models of 3D indicatrix scattering laser linearly polarized radiation on transparent and absorbing spherical particles are presented. The analysis of the light absorption effect on the relative angular distribution shape of the scattered radiation intensity on particles of various sizes has been carried out.The dy namics of the scattering 3D indicatrix shape on an absorbing particle as its radius changes has been visualized. The potential areas of the program practical application have been identified. The factors limiting to use program for calculations of scattering on real particles systems has been revealed.