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1
Content available remote Locally-induced permanent birefringence by polymer-stabilization of liquid crystal in cells and photonic crystal fibers
Chychłowski M. S., Ertman S., Rutkowska K., Strzeżysz O., Dąbrowski R., Woliński T. R.
Opto-Electronics Review
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2018
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Vol. 26, No. 3
242--246
EN
The aim of this work was to induce permanent birefringence both in typical liquid crystal cells and photonic crystal fibers (PCFs) by photo-polymerization. For this purpose three different liquid crystalline materials, namely E7, 5CB, and 6CHBT were combined with a mixture of RM257 monomer and a UV sensitive initiator with the percentage weight less than 10%. Due to the photo-polymerization process it was possible to achieve polymer-stabilized liquid crystal orientation inside LC cells and micro-sizedcylindrical glass tubes. In particular, periodic change in spatial molecular orientation was achieved by selective photo-polymerization. Successful results obtained in these simple geometries allowed for the experimental procedure to be repeated in PCFs leading to locally-induced permanent birefringence in PCFs.
2
Content available remote Influence of the core size on light propagation in photonic liquid crystal fibers
Sala-Tefalska M. M., Ertman S., Woliński T. R., Mergo P.
Opto-Electronics Review
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2017
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Vol. 25, No. 3
198--204
EN
In this paper analyses of mode distribution, confinement and experimental losses of the photonic crystal fibers with different core sizes infiltrated with liquid crystal are presented. Four types of fibers are com-pared: with single-, seven-, nineteen-and thirty seven solid rods forming the core in the same hexagonal lattice of seven “rings” of unit cells (rods or capillaries). The experimental results confirming the influence of the core diameter on light propagation are also included. The diameter of cores determines not only the number of modes in the photonic liquid crystal fiber but also is correlated with experimentally observed attenuation. For fibers with larger cores confinement losses are expected to be higher, but the measured attenuation is smaller because the impact of liquid crystal material losses and scattering is smaller.
3
Content available remote Electrically tunable long-period fiber gratings with low-birefringence liquid crystal near the turn-around point
Czapla A., Bock W. J., Woliński T. R., Mikulic P., Dąbrowski R., Nowinowski-Kruszelnicki E.
Opto-Electronics Review
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2017
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Vol. 25, No. 4
290--295
EN
In this work, an electrically tunable long-period fiber grating (LPFG) coated with liquid crystal layer (LC) is presented. As a LC layer, a prototype low-birefringence 1550A LC mixture was chosen. As a LPFG host, two types of gratings were studied: the LPFGs based on a standard telecommunication fiber, produced by an electric arc technique with a period of 222 µm, and the LPFGs based on a boron co-doped fiber written by a UV technique with a period of 226.8 µm. The relatively short period of these gratings allowed exploiting unique sensing properties of the attenuation bands associated with modes close to the turn-around point. Experiments carried out showed that for the UV-induced LPFG with a LC layer, on the powered state the attenuation band could be offset from the attenuation band measured in the unpowered state by almost130 nm. When the arc-induced LPFG was coated with the LC, the depth of the attenuation band could be efficiently controlled by applying an external E-field. Additionally, all experimental results obtained in this work were supported by the theoretical analysis based on a model developed with Optigrating v.4.2 software.
4
Content available remote Light propagation mechanism switching in a liquid crystal infiltrated microstructured polymer optical fibre
Rutkowska K. A., Milenko K., Chojnowska O., Dąbrowski R., Woliński T. R.
Opto-Electronics Review
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2015
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Vol. 23, No. 4
252-258
EN
In this work studies on propagation properties of a microstructured polymer optical fibre infiltrated with a nematic liquid crystal are presented. Specifically, the influence of an infiltration method on the LC molecular alignment inside fibre air-channels and, thus, on light guidance is discussed. Switching between propagation mechanisms, namely the transition from modified total internal reflection (mTIR) to the photonic bandgap effect obtained by varying external temperature is also demonstrated.
5
Content available remote Photo-alignment of liquid crystals in micro capillaries with point-by-point irradiation
Siarkowska A., Jóźwik M., Ertman S., Woliński T. R., Chigrinov V. G.
Opto-Electronics Review
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2014
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Vol. 22, No. 3
178-182
EN
A photo-alignment method for micro capillaries based on the SD-1 azo-dye is demonstrated. In this work a liquid-crystal molecules aligning layer is created by point-by-point irradiation of the azo-dye film by using an UV laser light. The method opens up new possibilities for an improved molecules’ orientation control in both glass- and polymer-based photonic liquid crystal fibres.
6
Content available Długookresowe siatki światłowodowe jako czujniki drgań w materiałach kompozytowych
Domański A. W., Czapla A., Prokopczuk K., Poczęsny T., Bock W., Woliński T. R.
Pomiary Automatyka Kontrola
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2010
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R. 56, nr 7
809-811
PL
Użycie czujników opartych na siatkach LPFG otwiera nowe możliwości diagnostyczno-pomiarowe, takie jak na przykład monitorowanie w czasie rzeczywistym stanu zużycia materiałów kompozytowych. Dzięki zatopieniu włókna w takim materiale możliwe jest monitorowanie drgań i naprężeń nie powodując przy tym znaczących zmian parametrów eksploatacyjnych i wytrzymałościowych kompozytu. W prezentowanej pracy przedstawiono zastosowanie siatek LPFG do detekcji deformacji geometrycznych oraz przeprowadzono badania porównawcze czujników światłowodowych z siatkami LPFG zatopionych w materiale kompozytowym z tego samego typu czujnikami pracującymi w swobodnej przestrzeni.
EN
Vigorously growing fiber-optic technology allows constructing sophisticated sensors to monitor vibrations and stress. Application of long period fiber gratings (LPFG) enables making an optical fiber sensitive to various external parameters caused by longitudinal or transverse stress changes in material. An additional advantage of sensors based on LPFG is the measuring part insensitivity to electromagnetic disturbance and lack of electric noise and interference emission. The manufacturing of optical fiber with LPFG is based on precise heating or exposition a part of the fiber to ultraviolet radiation thereby inducing a periodic change of the refraction index along the fiber core. As a result, the transmission spectrum of LPFG is characterized by a number of attenuation bands induced by coupling between the elementary mode propagating in the core and cladding modes. Location of the attenuation bands in the LPFGs transmission spectrum is dependent on external physical factors. This paper presents application of LPFG to geometric deformation detection. The use of sensors based on LPFG opens new diagnostic and measuring possibilities like real-time monitoring of composite material wear. Due to sinking the LPFGs in this material, it is possible to monitor the vibrations and stresses without causing significant changes in operational performance and durability of the composite. The paper also presents a comparative study on LPFGs sunk in composite material with the same type of LPFGs operating in free space.
7
Tensometryczny czujnik światłowodowy do badania rozkładu naprężeń w materiale kompozytowym
Woliński T. R., Lesiak P., Szeląg M., Mileńko K., Domański A., Jędrzejewski K., Lewandowski L., Boczkowska A., Kurzydłowski K
Elektronika : konstrukcje, technologie, zastosowania
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2010
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Vol. 51, nr 6
148-150
PL
Jedną z metod, która daje możliwości oceny stopnia degradacji nowoczesnych materiałów kompozytowych jest metoda wykorzystująca czujniki światłowodowe najnowszej generacji. Czujniki światłowodowe można stosować do oceny stopnia zniszczenia konstrukcji w sposób nieniszczący, jednocześnie znacznie ograniczając czas samego pomiaru; zarówno do badań on-line struktur kompozytowych, w trakcie ich eksploatacji, a nawet w procesie ich wytwarzania [1, 2]. W pracy przedstawiono możliwości zastosowania światłowodów do pomiaru odkształceń w materiale kompozytowym.
EN
One of the methods that gives a possibility to estimate degree of degradation of new composite materials is the method that uses optical fiber sensors of the newest generation. We can use them to investigate on-line composite structures during either their exploitation or their manufacturing process. In this paper we present possible applications of the optical fibers to measure deformations in composite materials. In particular, we have analyzed the composite structure due to the bend-induced deformation of the sensor and we have demonstrated that the changes in the Bragg wavelength linearly depend on strain. As predicted, the fiber located closer to the neutral surface is less sensitive to bending.
8
Tensometryczny czujnik światłowodowy do badania rozkładu naprężeń w materiale kompozytowym
Woliński T. R., Lesiak R., Szeląg M., Mileńko K., Domański A., Jędrzejewski K., Lewandowski L., Boczkowska A., Kurzydłowski K
Elektronika : konstrukcje, technologie, zastosowania
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2010
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Vol. 51, nr 5
115-117
PL
Jedną z metod, która daje możliwości oceny stopnia degradacji nowoczesnych materiałów kompozytowych jest metoda wykorzystująca czujniki światłowodowe najnowszej generacji. Czujniki światłowodowe można stosować do oceny stopnia zniszczenia konstrukcji w sposób nieniszczący, jednocześnie znacznie ograniczając czas samego pomiaru; zarówno do badań on-line struktur kompozytowych, w trakcie ich eksploatacji, a nawet w procesie ich wytwarzania [1, 2]. W pracy przedstawiono możliwości zastosowania światłowodów do pomiaru odkształceń w materiale kompozytowym.
EN
One of the methods that gives a possibility to estimate degree of degradation of new composite materials is the method that uses optical fiber sensors of the newest generation. Optical fiber sensors can be applied to evaluate degradation of structures in non-destructive way while reducing measurements time. We can use them to investigate on-line composite structures during either their exploitation or their manufacturing process. As predicted, the fiber located closer to the neutral surface is less sensitive to bending.
9
Content available remote Light propagation in highly birefringent photonic liquid crystal fibers
Ertman S., Czapla A., Woliński T. R., Nasiłowski T., Thienpont H., Nowinowski-Kruszelnicki E., Dąbrowski R.
Opto-Electronics Review
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2009
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Vol. 17, No. 2
150-155
EN
Photonic liquid crystal fibers have already been demonstrated as a promising perspective for creation of new classes of dynamically tunable optical fiber devices. By combining different geometries of photonic crystal fibers with a variety of different liquid crystals it is possible to obtain a new generation of fibers with dynamically tunable properties, e.g., transmission spectra, attenuation or dispersion. In this paper, tunable birefringence in a commercially available highly birefringent Blazephotonics PM-1550-01 photonic crystal fiber selectively filled with a low birefringence liquid crystal has been experimentally demonstrated. Theses experimental results have been compared with simulations based on the multipole method.
10
Content available remote Depolarization of light in microstructured fibers filled with liquid crystals
Budaszewski D., Domański A. W., Czapla A., Ertman S., Woliński T. R., Nasilowski T., Thienpont H.
Opto-Electronics Review
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2009
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Vol. 17, No. 2
156-160
EN
In the paper we analyze microstructured optical fibers filled with typical nematic liquid crystals, i.e., 5CB and 6CHBT under influence of external electric field or temperature. We use the modified Mueller matrix method with an additional depolarization matrix to calculate degree of polarization changes of the light propagating in the liquid-crystal infiltrated microstructured optical fibers. Preliminary experimental results of light depolarization measurements during propagation in these microstructured fibers are also presented.
11
Content available remote Powstało Polskie Stowarzyszenie Fotoniczne
Woliński T. R., Romaniuk R. S.
Pomiary Automatyka Robotyka
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2008
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R. 12, nr 7-8
56-57
PL
Obecnie w kraju występuje bardzo wyraźna konieczność silnej konsolidacji i przebudowy środowisk naukowo-technicznych. Muszą one dostosowywać się do potrzeb zmieniającego się społeczeństwa wiedzy. Wyraźnym odzwierciedleniem tych dynamicznych procesów jest powstanie Polskiego Stowarzyszenia Fotonicznego (PSP - Photonics Society of Poland).
12
Czujniki światłowodowe w materiałach kompozytowych
Domański A. W., Boczkowska A., Jędrzejewski K., Lesiak P., Lewandowski L., Woliński T. R.
Pomiary, Automatyka, Komputery w Gospodarce i Ochronie Środowiska
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2008
|
nr 1
8-11
PL
W pracy przedstawiono dwa typy czujników światłowodowych mogących mierzyć naprężenia mechaniczne i temperaturę po wbudowaniu ich w strukturę materiału kompozytowego. Jednym z typów czujników był czujnik polarymetryczny wykorzystujący standardowy światłowód o dużej dwójłomności. Drugim typem był czujnik z siatka Bragga wykonana we własnym zakresie na standardowym światłowodzie telekomunikacyjnym. Przeprowadzone pomiary wykazały, że następuje zmiana parametrów metrologicznych obu typów czujników ale nadal można wykorzystywać je w procesie tworzenia materiału kompozytowego jak i w czasie jego eksploatacji do kontroli wewnętrznych naprężeń i zmian temperatury.
EN
In the paper two types of optical fiber sensors for monitoring of strain and temperature in composite structures are described. One of the sensor was polarimetric fiber-optic sensor which utilized standard highly birefringent fiber. The second one was Bragg grating sensor produced in laboratory with help typical telecommunication fiber. Results of tests showed that both types of sensors changed the measuring parameters but both allowed to measure strains and temperature changes during creation of the composite material as well as during work the composite under different kind of mechanical stresses.
13
Content available remote Photonics Society of Poland established
Woliński T. R., Romaniuk R. S.
Metrology and Measurement Systems
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2008
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Vol. 15, nr 2
241-244
14
Content available remote Polarimetric optical fiber sensors of a new generation for industrial applications
Woliński T.R., Lesiak P., Domański A.W.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2008
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Vol. 56, nr 2
125-132
EN
Polarimetric optical fiber sensors based on highly birefringent (HB) polarization-maintaining libel's have focused great interest for last decades. The paper presents a novel modular fiber optic sensing system of potential industrial applications to measure temperature, hydrostatic pressure, and strain that is based on classical HB and photonic crystal fibers and can operate at visible and infrared wavelengths. The main idea of the system is a novel and replaceable fiber-optic head, which allows adjusting the measuring system both to the required range and type (strain, pressure or temperature) of the external measurand. We propose also a new configuration of the fiber optic strain gauge with a free cylinder and an all-fiber built-in analyzer based on the photonic crystal fiber filled with a liquid crystal. Additionally, strain sensitivities of various HB fibers operating at visible and infrared wavelengths range have been measured.
15
Content available remote Temperature tuning of polarization mode dispersion in single-core and two-core photonic liquid crystal fibers
Lesiak P., Woliński T. R., Brzdąkiewicz K., Nowecka K., Ertman S., Karpierz M., Domański A. W., Dąbrowski R.
Opto-Electronics Review
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2007
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Vol. 15, No. 1
27-31
EN
In this paper we present numerical and experimental results of propagation and polarization properties of the photonic liquid crystal fibers (PLCFs) in which only selected micro holes were filled with nematic liquid crystal (LC) guest materials. As a host photonic crystal fiber (PFC) structure, we used a commercially available highly birefringent PCF (Blazephotonic, UK). A tunable laser operated at infrared has powered the PLCFs under investigation infiltrated by the 1550 nematic LC synthesized at the Military University of Technology. Temperature induced changes of the polarization mode dispersion (PMD) as well switching between fundamental and higher order modes and also single-core and two-core propagation were successfully demonstrated.
16
Content available remote Tunable properties of light propagation in photonic liquid crystal fibers
Szaniawska K., Nasilowski T., Woliński T. R., Thienpont H.
Opto-Electronics Review
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2006
|
Vol. 14, No. 4
339-343
EN
Tunable properties of light propagation in photonic crystal fibers filled with liquid crystals, called photonic liquid crystal fibers (PLCFs) are presented. The propagation properties of PLCFs strongly depend on contrast between refractive indices of the solid core (pure silica glass) and liquid crystals (LCs) filing the holes of the fiber. Due to relatively strong thermo-optical effect, we can change the refractive index of the LC by changing its temperature. Numerical analysis of light propagation in PLCF, based on two simulation methods, such as finite difference (FD) and multipole method (MM) is presented. The numerical results obtained are in good agreement with our earlier experimental results presented elsewhere [1].
17
Content available remote Photonic liquid crystal fibers : a new challenge for fiber optics and liquid crystals photonics
Woliński T. R., Ertman S., Lesiak P., Domański A. W., Czapla A., Dąbrowski R., Nowinowski-Kruszelnicki E., Wójcik J.
Opto-Electronics Review
|
2006
|
Vol. 14, No. 4
329-334
EN
The paper reviews and discusses the latest developments in the field of the photonic liquid crystal fibers that have occurred for the last three years in view of new challenges for both fiber optics and liquid crystal photonics. In particular, we present the latest experimental results on electrically induced birefringence in photonic liquid crystal fibers and discuss possibilities and directions of future developments.
18
Content available remote Linear and nonlinear properties of photonic crystal fibers filled with nematic liquid crystals
Brzdąkiewicz K. A., Laudyn U. A., Karpierz M. A., Woliński T. R., Wójcik J.
Opto-Electronics Review
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2006
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Vol. 14, No. 4
287-292
EN
We investigate linear and nonlinear light propagation in the photonic crystal fibers infiltrated with nematic liquid crystals. Such a photonic structure, with periodic modulation of refractive index, which could be additionally controlled by the temperature and by the optical power, allows for the study of discrete optical phenomena. Our theoretical investigations, carried out with the near infrared wavelength of 830 nm, for both focusing and defocusing Kerr-type nonlinearity, show the possibility of the transverse light localization, which can result in the discrete soliton generation. In addition, we present the preliminary experimental results on the linear light propagation in the photonic crystal fiber with the glycerin-water solution and 6CHBT nematics, as the guest materials.
19
Content available remote Depolarization of partially coherent light in liquid crystals
Domański A. W., Budaszewski D., Sierakowski M., Woliński T. R.
Opto-Electronics Review
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2006
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Vol. 14, No. 4
305-310
EN
In the paper we present results of analysis of partially coherent light depolarization in two types of liquid crystals possessing linear birefringence controlled by temperature and external electric field changes. Some experimental results of degree of polarization measurements for different light sources as a superluminescent diode and a laser diode are also presented.
20
Content available remote Simultaneous twist and longitudinal strain effects on polarization mode dispersion in highly birefringent fibers
Lesiak P., Woliński T. R.
Opto-Electronics Review
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2005
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Vol. 13, No. 2
183-186
EN
Simultaneous twist and longitudinal strain effects on polarization mode dispersion (PMD) in highly birefringent (HB) bow-tie and photonic crystal fibers have been investigated. External twist has been found to modify both modal birefringence and differential group delay (DGD) in HB fibers, and in particular to influence the range of DGD changes under longitudinal strain.
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