Parallel Polarization State Generation.

Alan She,Federico Capasso

doi:10.1038/srep26019

Abstract

The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security.

Highlights

The control of polarization, an essential property of light, is of wide scientific and technological interest
The polarization of an input beam, Ein, may be linearly transformed into any arbitrary output polarization, Eout, through a product of Jones matrices Mn corresponding to variable optical iemlepmleemntesn, teaatciohnosfowf sheircihalhPaSsGasduesgeroepetoicfaflreeleedmoemn,tsρtnh: aEtoiuntt=rodMucNe(ρsuNi)t...ablMe p2h(ρas2e)Msh1i(fρts1)oErinb.irCeofrminmgeonncley, found which are represented by a product of at least two Jones matrices
We propose polarization state generation (PSG) by combining a limited set of prepared states of polarization (SOP), which we refer to here for convenience as the “Stokes Basis Vectors” (SBVs), and are not necessarily linearly independent in the conventional sense

Summary

Discussion

The main concern with the parallel architecture, yet, is insertion loss. In our demonstration, the most significant contributions to insertion loss were light diffracted and deflected by the DMD as well as reflection losses by the multiple beam splitters used for beam combining. Numerical calculations show that loss due to coherent beam combining is at a level that may be acceptable for applications in which the features of parallel polarization state generation are desirable. We have introduced and experimentally implemented a parallel architecture for PSG, based on intensity modulation of separate polarization components. In addition to foreseeing new applications in science and technology, analogous interference phenomena exist in quantum mechanics (as can be seen by the mathematical relationship of the Pauli matricies[28] and the coherency matrix[3] with the Stokes parameters, as well as the Bloch sphere with the Poincaré sphere), which may provide the potential to generalize this method to two-level quantum systems, such as coherent electronic and magnetic systems

Methods

Additional Information