Interferometric interpretation for the degree of polarization of classical optical beams

Leppänen, Lasse-Petteri; Saastamoinen, Kimmo; Friberg, Ari T.; Setälä, Tero

doi:10.1088/1367-2630/16/11/113059

Cited by 41 publications

(25 citation statements)

References 25 publications

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“…More precisely, the intensity-normalized Stokes parameters, s n =S n (α)/S 0 (α), with n ä {1, 2, 3}, are constant and only the intensity exhibits beating. We remark that electromagnetic interference laws analogous to equation (7), but in the context of random light, have been considered earlier [9,10,34,35].…”

Section: Temporal Electromagnetic Interferencementioning

confidence: 99%

Geometric phase in beating of light waves

et al. 2019

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Beating is a simple physical phenomenon known for long in the context of sound waves but remained surprisingly unexplored for light waves. When two monochromatic optical beams of different frequencies and states of polarization interfere, the polarization state of the superposition field exhibits temporal periodic variation-polarization beating. In this work, we reveal a foundational and elegant phase structure underlying such polarization beating. We show that the phase difference over a single beating period decomposes into the Pancharatnam-Berry geometric phase and a dynamical phase of which the former depends exclusively on the intensities and polarization states of the interfering beams whereas the sum of the phases is determined solely by the beam frequencies. Varying the intensity and polarization characteristics of the beams, the relative contributions of the geometric and dynamical phases can be adjusted. The geometric phase inherent in polarization beating is governed by a compact expression containing only the Stokes parameters of the interfering waves and can alternatively be obtained from the individual beam intensities and the amplitude of the intensity beats. We demonstrate both approaches experimentally by using an interferometer with a fast detector and a specific polarimetric arrangement. Polarization beating has a unique character that the geometric and dynamical phases are entangled, i.e. variation in one unavoidably leads to a change in the other. Our work expands geometric phases into a new domain and offers important novel insight into the role of polarization in interference of electromagnetic waves.

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Section: Temporal Electromagnetic Interferencementioning

confidence: 99%

Geometric phase in beating of light waves

et al. 2019

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“…We remark that alternative definitions for the degree of coherence of electromagnetic beam fields have been put forward (see, for instance, [9,15]). Besides the mutual coherence matrix, the coherence properties of an electromagnetic field can be described in terms of the coherence Stokes parameters introduced as [6][7][8]16] S 0 τ Γ xx τ Γ yy τ;…”

Section: Michelson's Interferometer and Temporal Stokes-parameter Modmentioning

confidence: 99%

“…However, in the case of random electromagnetic beams, which may have an arbitrary degree of polarization and for which a scalar-wave treatment is generally not sufficient, not only the intensity, but also, or only, the polarization characteristics (state and degree) can be modulated in interference [4]. This has been shown for spatial coherence in Young's interferometer [5,6], where the coherence (twopoint) Stokes parameters [7,8] at the pinholes specify the conventional polarization (one-point) Stokes-parameter variations on the observation screen [9].…”

Section: Introductionmentioning

confidence: 99%

Measurement of the degree of temporal coherence of unpolarized light beams

et al. 2017

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We measure the electromagnetic degree of temporal coherence and the associated coherence time for quasi-monochromatic unpolarized light beams emitted by an LED, a filtered halogen lamp, and a multimode He-Ne laser. The method is based on observing at the output of a Michelson interferometer the visibilities (contrasts) of the intensity and polarization-state modulations expressed in terms of the Stokes parameters. The results are in good agreement with those deduced directly from the source spectra. The measurements are repeated after passing the beams through a linear polarizer so as to elucidate the role of polarization in electromagnetic coherence. While the polarizer varies the equal-time degree of coherence consistently with the theoretical predictions and alters the inner structure of the coherence matrix, the coherence time remains almost unchanged when the light varies from unpolarized to polarized. The results are important in the areas of applications dealing with physical optics and electromagnetic interference.

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“…This result is obtained when the intensities at the two openings are equal. The polarization-state modulations given by jη n r 1 ; r 2 ; ωj, with n ∈ 1; 2; 3, can be measured experimentally by transforming the polarization changes into the intensity modulation, as has been shown recently in [18]. The aim of this work is to demonstrate the detection of the electromagnetic degree of coherence in Eq.…”

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confidence: 83%

“…(3) by probing the field with nanoscatterers at r 1 and r 2 instead of the pinholes as in Young's experiment. In the latter case, the measurement of the electromagnetic coherence has been considered by placing waveplates and polarizers in front of the apertures [3,4,15,18]. However, from a practical point of view, insertion of optical elements just before the nanoscatterers may be difficult, and hence we adopt a different approach.…”

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confidence: 99%

Detection of electromagnetic degree of coherence with nanoscatterers: comparison with Young’s interferometer

et al. 2015

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We show theoretically that the (spectral) electromagnetic degree of spatial coherence of a random, stationary light beam can be measured by using two dipolar nanoscatterers instead of aperture diffraction as in traditional Young's interferometer. The method is based on considering individually the correlation functions associated with the six polarization states that make up the coherence (two-point) Stokes parameters and observing separately the visibilities and the locations of the intensity fringes created by the interfering dipole fields, leading to a complete characterization of the beam's second-order spatial coherence. The novel technique, although introduced in this work for beams, paves the way toward the detection of spatial coherence in nonparaxial optical near-fields for which the use of nanoscatterers is necessary.

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Interferometric interpretation for the degree of polarization of classical optical beams

Cited by 41 publications

References 25 publications

Geometric phase in beating of light waves

Geometric phase in beating of light waves

Measurement of the degree of temporal coherence of unpolarized light beams

Detection of electromagnetic degree of coherence with nanoscatterers: comparison with Young’s interferometer

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