New achromatic quarter-wave combination of birefringent plates
01 Jan 2012-Optical Engineering (International Society for Optics and Photonics)-Vol. 51, Iss: 1, pp 013001
TL;DR: In this article, the design and characteristics of an achromatic cascaded system of birefringent plates were studied, and the authors used the succinct and relatively simple Jones matrix formalism to derive a general expression for the equivalent retardation of this combination.
Abstract: Phase retarders usually exhibit strong wavelength dependence. For this paper, the design and characteristics of an achromatic cascaded system of birefringent plates were studied. The combination of three retarders in a series had been previously proposed by Pancharatnam, and he discussed the possibility of fabricating reasonably good achromatic quarter-wave plates with a suitable level of retardance. This combination, however, still shows substantial variation in terms of retardance within 500 to 700 nm. Here, the combination of four plates for the construction of an almost achromatic quarter-wave plate, which has a variation of only ± 1 degree over the wavelength spectrum of 500 to 700 nm, is proposed. Moreover, spherical trigonometric considerations have been used by Pancharatnam for obtaining the transmission characteristics of a cascaded system. We, however, used the succinct and relatively simple Jones matrix formalism to derive a general expression for the equivalent retardation of this combination. The proposed arrangement of four birefringent plates promises better achromatic combinations.
Citations
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TL;DR: A novel achromatic waveplate based on two nematic liquid crystal retarders is designed and demonstrated tunable over a wide spectral range using different voltages applied to the two retarders.
Abstract: The wavelength dependence of phase retarders is considered as a challenge in different applications such as polarimetric systems. A novel achromatic waveplate based on two nematic liquid crystal retarders is designed and demonstrated tunable over a wide spectral range using different voltages applied to the two retarders. The achromatic behavior is achieved based on the fact that the dispersion of the retardation of liquid crystals is voltage dependent. Achromatic quarter and half-waveplates are demonstrated using the same device as well as the tunability of the achromatic operation range.
24 citations
TL;DR: This approach has a simple geometric interpretation and simplifies the problem of designing an achromatic elliptical polarizer to find overlapping arcs on the Poincaré sphere.
Abstract: A method of designing achromatic elliptical polarizers using a combination of multiple birefringent waveplates is demonstrated. This approach has a simple geometric interpretation and simplifies the problem of designing an achromatic elliptical polarizer to find overlapping arcs on the Poincare sphere. The technique is applied to the design of achromatic elliptical polarizers for a broadband division-of-focal-plane full-Stokes imaging polarimeter for visible wavelength band (λ = 450nm to 650nm). An achromatic elliptical polarizer sample with a two-layer retarder is fabricated using liquid crystal polymer. The performance of the polarizer sample is measured and compared with the theoretical calculation. For comparison, a superachromatic polarizer design (λ = 400nm to 1μm) is also presented by using three-layer and four-layer retarder configurations.
13 citations
TL;DR: In this paper, the design and characteristics of an achromatic half-wave plate, formed by a cascaded system of birefringent plates, have been studied.
4 citations
TL;DR: In this article , a polymer-based patterned elliptical polarizer for short-wave infrared (SWIR) imaging polarimetry has been proposed, which can be used in telecommunication, medical imaging, surveillance, remote sensing, and industrial metrology.
Abstract: Short-wave infrared (SWIR) imaging polarimetry has widespread applications in telecommunication, medical imaging, surveillance, remote-sensing, and industrial metrology. In this work, we design, fabricate, and test an achromatic SWIR elliptical polarizer, which is a key component of SWIR imaging polarimetry. The elliptical polarizer is made of a patterned linear polarizer and a patterned optical elliptical retarder. The linear polarizer is a wire grid polarizer. The elliptical retarder is constructed with three layers of nematic phase A-plate liquid crystal polymer (LCP) films with different fast axis orientations and physical film thicknesses. For each LCP layer, four arrays of hexagonal patterns with individual fast-axis orientations are realized utilizing selective linearly polarized ultraviolet (UV) irradiation on a photo-alignment polymer film. The Mueller matrices of the optical filters were measured in the wavelength range 1000 nm to 1600 nm and compared with theory. Our results demonstrate the functionality and quality of the patterned retarders with normalized analyzer vector parameter deviation below 7% over this wavelength range. To the best of our knowledge, this work represents the first polymer-based patterned elliptical polarizer for SWIR polarimetry imaging applications.
3 citations
References
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TL;DR: This achromatic wave plate demonstrates a huge frequency bandwidth (upsilonmax/upsilonmin approximately 7), and therefore can be applied to terahertz time domain spectroscopy and polarimetry.
Abstract: Phase retarders usually present a strong frequency dependence. We discuss the design and characterization of a terahertz achromatic quarter-wave plate. This wave plate is made from six birefringent quartz plates precisely designed and stacked together. Phase retardation has been measured over the whole terahertz range by terahertz polarimetry. This achromatic wave plate demonstrates a huge frequency bandwidth (upsilonmax/upsilonmin approximately 7), and therefore can be applied to terahertz time domain spectroscopy and polarimetry.
268 citations
01 Apr 1955
TL;DR: In this paper, an achromatic quarter-wave plate is obtained by superposing three birefringent plates of the same material; the first and last should have the same retardation 2δ1 their fast vibration directions being parallel to one another but inclined at a specific angle c to that of the central plate-of retardation π.
Abstract: An achromatic quarter-wave plate is obtained by superposing three birefringent plates of the same material; the first and last should have the same retardation 2δ1 their fast vibration directions being parallel to one another but inclined at a specific angle c to that of the central plate-of retardation π. The desired range of achromatism determines the optimum values of 2δ1 and c (which, in turn, will determine the orientation of the effective principal planes of the combination). As an example, using mica retardation plates prepared for Hg 5461, the range from 4100 A to 6800 A is covered with 2δ1 = 115° 42' and c = 69° 54'. Further, for a particular wave-length, a birefringent compensator of variable retardation (0 to 2π) is obtained by interposing a half-wave plate that can be rotated in its own plane, between two quarter-wave plates that have their fast vibration directions parallel. The results follow from the Poincare sphere by geometrically compounding successive rotations.
230 citations
01 Apr 1955
TL;DR: In this article, two half-wave plates and one quarter-wave plate are superposed on the same material, such that the fast vibration-directions of the successive plates make specific angles with the azimuth of the linear vibration incident on the first plate.
Abstract: Circularly polarised light is obtained by superposing two half-wave plates and one quarter-wave plate, all of the same material, such that the fast vibration-directions of the successive plates make specific angles θ1, θ2, θ3 with the azimuth of the linear vibration incident on the first plate The required range of achromatism determines the optimum values of the angles Thus, using mica retardation plates prepared for Na 5890, the range from 4000 A to 7800 A is covered with θ1
= 6° 52′, θ2
= 34° 32′, θ3
= 100° 20′; while the range 4400 A to 7400 A can be covered with superior achromatism by taking θ1 = 6° 30′, θ2
= 34° 34′, θ3 = 101° 8′
200 citations
TL;DR: A achromatic quarter-wave plate whose retardation errors are smaller than 3 degrees for a +/-10% change in wavelength is proposed, and the wave plates designed were evaluated by numerical calculation with a rigorous electromagnetic grating theory.
Abstract: We propose achromatic quarter-wave plates of a subwavelength grating structure. When the period of the grating structure is smaller than the wavelengths of the incident light, the structure is considered to be an optically anisotropic medium. The effective refractive indices strongly depend on the wavelengths, especially when the period is close to the wavelength. Using this feature, we can design a grating quarter-wave plate whose phase retardation is maintained at pi/2 for a wide wavelength range. A design method using the effective medium theory is described, and the wave plates designed were evaluated by numerical calculation with a rigorous electromagnetic grating theory. The calculation results led to the possibility of an achromatic quarter-wave plate whose retardation errors are smaller than 3 degrees for a +/-10% change in wavelength.
178 citations