Orthogonal HL states and extrema method for the polarization evaluation

Abstract

Is it possible to quantitatively measure the polarization of light without a light meter? Since the Stokes parameters require four or six intensity measurements, the immediate reply would be negative. Surprisingly, the query can be answered in the affirmative. To this end, it is convenient to describe the polarization of light via orthogonal Heaviside Larmor (HL) elliptical polarization states. The parameters of an ellipse are in this way directly related to the wave coefficients. Thereafter, utilizing a modified null ellipsometry novel method, we show that it is possible to measure the Poincaré polarization sphere angles circumventing intensity measurements. The procedure involves setting a linear polarizer and a removable quarter waveplate at the intensity extrema, without requiring to take intensity readings unless the depolarized contribution needs to be assessed. To this end, only three simple steps need to be performed taking two angle readings from the rotation mount. It is also possible to use this extrema procedure recording four intensities in order to obtain the state of polarization of a source. In either case, the Stokes parameters are unneeded although they can be derived from the extrema measurements. This method could prove useful to measure space dependent polarizations in structured light. It may also provide a more economic measurement procedure in null ellipsometry.