Liquid crystal retarder spectral retardance characterization based on a Cauchy dispersion relation and a voltage transfer function

Vargas, Asticio; Donoso, Ramiro; Ramírez, Manuel; Carrión, J.V.; Sánchez-López, Marı́a del Mar; Moreno, Ignacio

doi:10.1007/s10043-013-0068-4

Cited by 23 publications

(31 citation statements)

References 22 publications

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“…Para la generación de las imá-genes con las que se desea generar espectros, se estudiaron tres métodos distintos de caracte- rizar la respuesta óptica del modulador frente a la longitud de onda. El primer método consiste en tener un conocimiento del desfase en cada longitud de onda realizando una serie de medidas, paraasí obtener el desfase en todas las longitudes de ondas utilizando un ajuste de Cauchy [14], [15].…”

Section: Métodos Y Calibraciónunclassified

Desarrollo de un sistema basado en un LCOS-SLM para la generación de espectros sintonizables

Henríquez¹

2017

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Cómo citar este trabajo How to cite this paperA. Cofré Hernríqez, "Desarrollo de un sistema basado en un LCOS-SLM para la generación de espectros sintonizables" Revista Doctorado UMH, vol. 2, no 2, p.2, 2016. [Online].Desarrollo de un sistema basado en un LCOS-SLM para la generación de espectros sintonizablesDevelopment based on a LCoS-SLM for generatingtunable spectra system RESUMENEmpleando un modulador espacial de luz de cristal líquido sobre silicio (LCoS-SLM) como un retardador pixelado programable, se ha logrado desarrollar un sistema óptico que permite controlar el espectro de una fuente de luz láser de supercontínuo. El haz polarizado pasa por una red de difracción que descompone sus componentes espectrales, que se proyectansobre el LCoS-SLM, al cual aplicamos desde un ordenador diferentes máscaras de nivel de gris, logrando modificar la fase de cada longitud de onda. Al recombinarse el haz completo y atravesar por un analizador permite el paso de la intensidad de la luz de cada longitud de onda de acuerdo a la nueva fase que ésta adquirió en el modulador. Para la creación de las máscaras se analizaron tres métodos, el primero basado en un ajuste de Cauchy, el segundo en una interpolación de los valores obtenidos por un muestreo rápido y la última propuesta en la creación de una tabla con todos los valores.Finalmente presentamos los diferentes resultados que se obtuvieron como la elección de ciertas longitudes de onda y la creación de un filtro paso banda variable.Palabras clave: Dispositivo cristal líquido, modulador, espectro, polarización. ABSTRACTWe used a liquid crystal on silicon spatial light modulator (LCoS-SLM) as a programmable pixelated retarder. We have developed an optical system that allows to control the spectrum of a supercontinuum laser light source. The polarized beam passes through a diffraction grating which splits the spectral components. Then is projected onto the LCoS-SLM where we apply from a computer different masks gray level, in order to modify the phase of each wavelength.After recombination and passage through an analyzer,the different wavelengths pass or not according to the new phase acquired in the modulator. Three methods were analyzed for creating masks, the first based on aCauchy relation fit, the second in an interpolation of the values obtained by rapid sampling and the latest proposal on creating a table with all values. Finally, we present the different results obtained as the choice of certain wavelengths and creating a variable pass band filter.

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Section: Métodos Y Calibraciónunclassified

Desarrollo de un sistema basado en un LCOS-SLM para la generación de espectros sintonizables

Henríquez¹

2017

DOCTUMH

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“…However, characterization of their spectral retardance properties can be very valuable for several reasons: 1) the retarder can be used at wavelengths different to the original design; 2) the retarder can be applied to build spectral birefringent filters, which are based on the wavelength variation of the retardance [4], 3) it allows the simple identification of the ordinary and extraordinary neutral axes of the retarder [5], and 4) the retardance modulation of tunable LC retarders can be characterized [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…A usual technique consists in inserting the retarder in between two linear polarizers, which are oriented at ±45°with respect to the retarder neutral axes. The system is illuminated with a light source with broadband spectrum, and the transmission is analyzed with a spectrometer [6][7][8][9][10]. The transmitted spectrum typically shows an oscillatory dependence with wavelength from which the spectral retardance function can be retrieved.…”

Section: Introductionmentioning

confidence: 99%

“…Here we apply the above mentioned technique of measuring the transmittance spectra between crossed or parallel polarizers to determine the spectral retardance function [6][7][8][9][10][11][12], but we use an optical calibration system developed for extending the measurement range to wavelengths from 450 nm to 1600 nm. The system incorporates a thermal broadband light source or a super-continuum laser, two broadband beam-splitter polarizers, and two spectrometers that operate in the VIS and in the NIR band regions respectively.…”

Section: Introductionmentioning

confidence: 99%

“…As a result, we can determine the spectral retardance function of different retarders in a very wide spectral range by fitting the measured and the simulated transmission curves. In some cases, a Cauchy-like dispersion relation can be applied, which has been proved to give good approximations far from the absorption bands of anisotropic materials [6,7,10,12].…”

Section: Introductionmentioning

confidence: 99%

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Optical system for measuring the spectral retardance function in an extended range

Messaadi

Sánchez-López

García‐Martínez

et al. 2016

J. Eur. Opt. Soc.-Rapid Publ.

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Background: Optical retarders are key elements for the control of the state of polarization of light, and their wavelength dependance is of great importance in a number of applications. Methods: We apply a well-known technique for determinig the spectral retardance by measuring the transmission spectra between crossed or parallel polarizers. But we we develop an optical system to perform this measurement in a wide spectral range covering the visible (VIS) and near infrared (NIR) spectrum in the range from 400 to 1600 nm. Results: As a result we can measure the spectral retardance of different retarders and easily identify the kind of reterder (multiple order, zero-order, achromatic). We show results with tunable liquid-crystal retarders as well, where the technique is applied to determine the spectral retardance as a function of the applied voltage. Finally, the accuracy of the technique is verified by the generation of a birefringent spectral filter. Conclusions: A technique to measure the spectral retardance of a linear retarder in a wide spectral range is applied to identify different types of retarders, and provide an accurate description of the spectral polarization conversion properties of these elements.

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Simple spectral technique to identify the ordinary and extraordinary axes of a liquid crystal retarder

Sánchez-López

Vargas

Cofré

et al. 2015

Optics Communications

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Liquid crystal retarder spectral retardance characterization based on a Cauchy dispersion relation and a voltage transfer function

Cited by 23 publications

References 22 publications

Desarrollo de un sistema basado en un LCOS-SLM para la generación de espectros sintonizables

Desarrollo de un sistema basado en un LCOS-SLM para la generación de espectros sintonizables

Optical system for measuring the spectral retardance function in an extended range

Simple spectral technique to identify the ordinary and extraordinary axes of a liquid crystal retarder

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