  We study the field-angle resolved electronic Raman scattering in
2-dimensional d-wave superconducting vortex states theoretically by
quasi-classical approximation, the so-called Doppler-shift method. An analytic
expression is obtained for the field angle dependence of the Raman scattering
amplitude at zero temperature. After numerical integration, we obtain the
scattering intensity for various field angles by changing the Raman shift
energy. Field-angle resolved electronic Raman scattering turns out to be an
effective method for probing unconventional superconducting gap structures. It
shows a novel phenomenon: reversal of extrema as a function of frequency
without changing temperature or field magnitude.
