A Quarter-Wave Compensator with a Sensitive Half-Shadow Device

Jerrard, H.G.

doi:10.1364/josa.44.000289

Cited by 35 publications

(19 citation statements)

References 11 publications

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“…Then The light beam is linearly polarized by a polarizer P, making an angle 0 with the principal directions of the crystal (Fig. 1 c) [25] shows similar variations.…”

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confidence: 91%

Electro-optic measurement of the order parameter of NH4Cl

1978

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Résumé. 2014 Abstract. 2014 We present here measurements of the temperature variation of the electro-optic effect in the low temperature phase of NH4Cl and we show how they are related to the order parameter of the order-disorder transition. These measurements are made difficult by the presence of parasitic strain birefringence, and by the existence of domains which produce a change of sign of the electro-optic effect. The results are compared with previous measurements of the order parameter by the piezoelectric effect and second harmonic generation, and their interpretation, following the Landau theory or power law with critical exponents, is discussed in relation to the existence of a multicritical point under high pressure.An exponential tail of the order parameter, extending over several degrees in the high temperature phase is systematically found in all these experiments. The origin of this residual order is probably related to the stresses produces by crystalline defects.

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“…Then The light beam is linearly polarized by a polarizer P, making an angle 0 with the principal directions of the crystal (Fig. 1 c) [25] shows similar variations.…”

mentioning

confidence: 91%

Electro-optic measurement of the order parameter of NH4Cl

1978

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“…A variety of methods have been developed to track the polarization state as it propagates through successive optical elements and complex samples. These are the Poincaré sphere [42], the Müller calculus [43], and the Jones formalism [44]. For a detailed treatment of these tools, the reader is referred to [45].…”

Section: The Jones Formalismmentioning

confidence: 99%

Polarization-Modulation Techniques in Near-Field Optical Microscopy for Imaging of Polarization Anisotropy in Photonic Nanostructures

Gucciardi

Micheletto

Kawakami

et al. 2006

Applied Scanning Probe Methods II

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“…The operation of this system can be followed by means of the Poincaré sphere [7,8] (see gure 2). We consider a vertically polarized input represented by the point A 1 on the equator of the sphere.…”

Section: Optical Systemmentioning

confidence: 99%

“…LCSM: liquid-crystal spatial light modulator, Q: quarter-wave plate, H: half-wave plate. axis (represented by the point Q on the equator) at an angle of ¡608 to the axis of H. Note that the diå erence in longitude of these points corresponds to twice the diå erence in their azimuths [7]. The lines A 1 A 2 , HQ 0 and QH 0 obviously lie in the equatorial plane.…”

Section: Optical Systemmentioning

confidence: 99%

Broad-band polarization-insensitive optical-path-length modulator

Ciddor¹,

Hariharan²

2001

J. Mod. Optics

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We present an improved design for a polarization-insensitive liquid-crystal optical-path-length modulator that can be used with white light in an adaptive optics system. IntroductionLiquid-crystal spatial light modulators (LCSLMs) have been shown to be good candidates for use in adaptive optical systems as high-performance optical-pathlength modulating elements, even with unpolarized light [1,2].The problem with such devices, originally, was that they had to be used with polarized light, since only the extraordinary refractive index of a nematic liquid crystal (LC) could be varied by the application of an electric eld. This problem can be overcome by using the LCSLM in the re ection mode [3].If unpolarized light is incident on the LCSLM, two orthogonally polarized components emerge from each cell, which have experienced diå erent retardations, corresponding to the ordinary (n o ) and extraordinary (n e ) refractive indices of the LC. A combination of a quarter-wave plate (QWP) set at 45 8 and a mirror rotates the planes of polarization of both these components by 90 8 , so that the component that experienced the ordinary index on the outward pass experiences the extraordinary index on the return pass, and vice versa. Accordingly, at the design wavelength of the QWP, both orthogonal components of the incident unpolarized light experience the same change in the optical path length when a voltage is applied to the LCSLM.However, many applications, such as astronomical image sharpening, require an adaptive system that works with white light [4]. While the change in optical path length introduced by the LCSLM varies by only §5% over the range of wavelengths from 450 to 700 nm [4], a problem with a simple QWP is that, at wavelengths other than the design wavelength, light that is linearly polarized at 45 8 to the fast axis of the QWP is converted to elliptically polarized light, instead of circularly polarized light. The result is that each of the orthogonally polarized components (say V e and V o ) emerging from the LCSLM produces two orthogonally polarized output beams, so that we have four incoherent output beams (V eo , V oe , V ee , V oo ) contributing to the nal point-spread function. Two of these beams (V eo and V oe ) experience the required change in optical path length, but the optical path length of the third beam (V ee ) changes by twice the required amount, while that of the fourth beam (V oo ) undergoes no change. The presence of these

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A Quarter-Wave Compensator with a Sensitive Half-Shadow Device

Cited by 35 publications

References 11 publications

Electro-optic measurement of the order parameter of NH4Cl

Electro-optic measurement of the order parameter of NH4Cl

Polarization-Modulation Techniques in Near-Field Optical Microscopy for Imaging of Polarization Anisotropy in Photonic Nanostructures

Broad-band polarization-insensitive optical-path-length modulator

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