Digital Stokes polarimetry and its application to structured light: tutorial

Abstract

Stokes polarimetry is a mature topic in optics, most commonly performed to extract the polarization structure of optical fields for a range of diverse applications. For historical reasons, most Stokes polarimetry approaches are based on static optical polarization components that must be manually adjusted, prohibiting automated, real-time analysis of fast changing fields. Here we provide a tutorial on performing Stokes polarimetry in an all-digital approach, exploiting a modern optical toolkit based on liquid-crystal-on-silicon spatial light modulators and digital micromirror devices. We explain in a tutorial fashion how to implement two digital approaches, based on these two devices, for extracting Stokes parameters in a fast, cheap, and dynamic manner. After outlining the core concepts, we demonstrate their applicability to the modern topic of structured light, and highlight some common experimental issues. In particular, we illustrate how digital Stokes polarimetry can be used to measure key optical parameters such as the state of polarization, degree of vectorness, and intra-modal phase of complex light fields.

Laser spectroscopy of hot atomic vapours: from ’scope to theoretical fit

“…For the absorption spectrum a single detector after the cell is used to measure the transmission spectrum (see details in part II of this tutorial); it is possible to add a second detector, and a polarising beamsplitter (PSB). The polarisation state of the transmitted light can be characterised by pairs of measurements of the intensity in different sets of orthogonal polarisation bases; these are processed to calculate the Stokes parameters [183][184][185]. Of most importance to this tutorial is the Stokes parameter S 0 , which is equal to T , see section 1.1.2.…”

Theory and Practice of Orbital Angular Momentum and Beyond

“…3) Toward the Use of Complete Modal Bases: Using the full Laguerre Gaussian mode basis has been found to be efficient in communication [67]. More than 100 LG modes over 3 wavelengths were successfully multiplexed and de-multiplexed using CGHs, demonstrating the feasibility to encode information using the full LG basis [67]. The use of 4 LG modes with different radial and azimuthal indices enabled an FSO transmission of 400 Gbps [68].…”

“…As such, if they are to be used to create vector modes, then the output beams must somehow be separated and passed through wave plates (phase retarders) to impose different polarizations on each mode before coherently recombining them into a vector mode. High resolution digital micro-mirror devices are becoming popular as they can also be used as digital holograms, albeit with lower light efficiency, but for arbitrary polarization [100]. Another benefit of DMDs is their high speed compared to liquid crystal spatial light modulators [19], [24], [101].…”

Thermal aberrations and structured light II: experimental simulation with DMDs

“…By doing so, we are able to fully characterise the impact of thermal aberrations on structured light, demonstrating our prior predictions and outlining a robust toolkit for future studies. Although we consider only thermal aberrations here and not polarization distortions due to thermally induced stresses, it is possible to extend the DMD demonstration to cover this too by exploiting its ability to modulate polarization states independently and in real time [70][71][72].…”