HAO 2011 Profiles In Science: Dr. Steven Tomczyk

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Dr. Steven Tomczyk is a Senior Scientist Section Head in the High Altitude Observatory of the National Center for Atmospheric Research. His is an expert in the development of instrumentation for the measurement of magnetic fields in the solar corona, chromosphere and photosphere, with the goal of understanding the Sun's influence on the Earth.

Publications

(1) Tomczyk, S. , R. Casini, A. G. de Wijn, and P. G. Nelson. 2011: Wavelength-diverse polarization modulators for Stokes polarimetry. Applied Optics, 49, issue 18, 3580.

Abstract: Information about the three-dimensional structure of solar magnetic fields is encoded in the polarized spectra of solar radiation by a host of physical processes. To extract this information, solar spectra must be obtained in a variety of magnetically sensitive spectral lines at high spatial, spectral, and temporal resolution with high precision. The need to observe many different spectral lines drives the development of Stokes polarimeters with a high degree of wavelength diversity. We developed a new way of designing polarization modulators that operate over a wide wavelength range with near optimal polarimetric efficiency. They are directly applicable to the next generation of multi-line Stokes polarimeters. These modulators are not achromatic in the usual sense because their polarimetric properties vary with wavelength, but they do so in an optimal way. We refer to these modulators as polychromatic. In this paper, we presented the theory behind polychromatic modulators, illustrated the concept with design examples, and presented the performance properties of a prototype polychromatic modulator.