T. Kavetskyy, O. Shpotyuk, V. Balitska, G. Dovbeshko, I. Blonskyy, I. Kaban, W. Hoyer, M. Iovu, A. Andriesh
Vibrational and structural properties of GexSb40 xS60 (x = 25, 27, 35) chalcogeide glasses are studied in unmodified and γ-radiation-modified states by using infrared spectroscopy, high-energy synchrotron x-ray diffraction and extended x-ray absorption fine structure spectroscopy. An agreement between radiation-induced structural changes and vibrational properties measured is established. It is suggested that the atomic pairs with wrong coordination created in the framework of coordination topological defect formation concept play a key role in the formation of radiation-modified state of the investigated glasses. Advantages and disadvantages of post-technological radiation-modification of chalcogenide glasses are considered within configuration coordinate model for description of unmodified and radiationmodified states.
{"title":"Vibrational and structural properties of unmodified and radiation-modified chalcogenide glasses for advanced optical applications","authors":"T. Kavetskyy, O. Shpotyuk, V. Balitska, G. Dovbeshko, I. Blonskyy, I. Kaban, W. Hoyer, M. Iovu, A. Andriesh","doi":"10.1117/12.815947","DOIUrl":"https://doi.org/10.1117/12.815947","url":null,"abstract":"Vibrational and structural properties of GexSb40 xS60 (x = 25, 27, 35) chalcogeide glasses are studied in unmodified and γ-radiation-modified states by using infrared spectroscopy, high-energy synchrotron x-ray diffraction and extended x-ray absorption fine structure spectroscopy. An agreement between radiation-induced structural changes and vibrational properties measured is established. It is suggested that the atomic pairs with wrong coordination created in the framework of coordination topological defect formation concept play a key role in the formation of radiation-modified state of the investigated glasses. Advantages and disadvantages of post-technological radiation-modification of chalcogenide glasses are considered within configuration coordinate model for description of unmodified and radiationmodified states.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"7142 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129462056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. G. Chufyrev, N. Sidorov, M. Palatnikov, K. Bormanis
Raman studies of ostensibly pure congruent, close to stoichiometric and stoichiometric lithium niobate single crystals and single crystals of lithium niobate containing admixture of Gd3+, Y+, and Mg2+ are reported. The authors have revealed weak Raman bands anomalously narrowing at changes of crystal composition disordering the cation sublattice and discuss the results with regard to evidence of anomalous ordering of structural units of the cation sublattice occurring at disordering of the cation sublattice as a whole.
{"title":"Manifestation of structural features in Raman spectra of LiNbO3 single crystals","authors":"P. G. Chufyrev, N. Sidorov, M. Palatnikov, K. Bormanis","doi":"10.1117/12.816512","DOIUrl":"https://doi.org/10.1117/12.816512","url":null,"abstract":"Raman studies of ostensibly pure congruent, close to stoichiometric and stoichiometric lithium niobate single crystals and single crystals of lithium niobate containing admixture of Gd3+, Y+, and Mg2+ are reported. The authors have revealed weak Raman bands anomalously narrowing at changes of crystal composition disordering the cation sublattice and discuss the results with regard to evidence of anomalous ordering of structural units of the cation sublattice occurring at disordering of the cation sublattice as a whole.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133429349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Paeglis, Irina Gorshanova, Kristine Bagucka, I. Lācis
Research of eye movements in reading textbooks suggests that reading the Cyrillic-based Russian language differs from reading the extended Latin-based Latvian texts. Ten bilingual students were asked to start reading a book passage in Latvian and to continue reading the text in Russian. Key parameters in information processing have been analyzed. Even though the difference in duration of fixations does not reach statistical significance, saccade size and regression rate are smaller in Russian.
{"title":"Latvian and Russian textbooks: eye movements in reading text formatted in two columns","authors":"R. Paeglis, Irina Gorshanova, Kristine Bagucka, I. Lācis","doi":"10.1117/12.815344","DOIUrl":"https://doi.org/10.1117/12.815344","url":null,"abstract":"Research of eye movements in reading textbooks suggests that reading the Cyrillic-based Russian language differs from reading the extended Latin-based Latvian texts. Ten bilingual students were asked to start reading a book passage in Latvian and to continue reading the text in Russian. Key parameters in information processing have been analyzed. Even though the difference in duration of fixations does not reach statistical significance, saccade size and regression rate are smaller in Russian.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125051142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Multipurpose unified Monte Carlo (MC) based model is developed for adequate simulation of various aspects of optical/ laser radiation propagation within biological tissues. The modeling is aimed to provide predictive information to optimize clinical/biomedical optical diagnostic systems and improve interpretation of the experimental results in biomedical diagnostics. Complex structure of biological tissues in terms of scattering and absorption is presented on the example of human skin. Validation and verification are performed against the tabulated data, theoretical predictions, and experiments. We demonstrate the use of the model to imitate 2-D polarization-sensitive OCT images with non-planar boundaries of layers in the medium like a human skin. The performances of the model are demonstrated both for conventional and polarization-sensitive OCT modalities.
{"title":"The concept of a unified modeling of optical radiation propagation in complex turbid media","authors":"I. Meglinski, M. Kirillin","doi":"10.1117/12.816618","DOIUrl":"https://doi.org/10.1117/12.816618","url":null,"abstract":"Multipurpose unified Monte Carlo (MC) based model is developed for adequate simulation of various aspects of optical/ laser radiation propagation within biological tissues. The modeling is aimed to provide predictive information to optimize clinical/biomedical optical diagnostic systems and improve interpretation of the experimental results in biomedical diagnostics. Complex structure of biological tissues in terms of scattering and absorption is presented on the example of human skin. Validation and verification are performed against the tabulated data, theoretical predictions, and experiments. We demonstrate the use of the model to imitate 2-D polarization-sensitive OCT images with non-planar boundaries of layers in the medium like a human skin. The performances of the model are demonstrated both for conventional and polarization-sensitive OCT modalities.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124333143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The minimum average optical signal power, Pmin., in optical communications is limited by the photodetector quantum efficiency and by noise. In this paper, the effect of thermal photons irradiated by all materials at absolute temperatures T>0 on optical information detection in communication lines is quantitatively considered. Usually, only the thermal current fluctuations in the photodetector are taken into account. Basing on the negentropy principle of information, assuming the Planck's blackbody radiation spectral distribution of photons, and describing the optical communication channel as non-symmetric noisy binary channel we have calculated the minimum energy required for the detection of one bit of information, ε= 6.5kT/bit, k =1.38×10-23 J/K being the Boltzmann constant. This ε value corresponds to the large error probability q = 0.20. At T = 20°C ε=4.05×10-21 J/bit and for the bit rate of R = 1010 bits/s one finds Pmin = Rε2.63×10-7 mW. In the case of more realistic value of q=10-9 ε=26kT/bit=1.05×10-19 J/bit, Pmin = 1.05×10-6 mW. This is only about 10 times lower than the quantum photodetection limit of conventional photodetectors. For more sensitive photodetectors the thermal photon noise can become important. It is shown that the minimum signal energy estimate ε≈10-19 J/bit is applicable also in a wider error probability range of q=10-3-10-15.
{"title":"The energetical threshold of optical information detection due to thermal noise","authors":"A. Ozols, J. Porins, G. Ivanovs","doi":"10.1117/12.815191","DOIUrl":"https://doi.org/10.1117/12.815191","url":null,"abstract":"The minimum average optical signal power, Pmin., in optical communications is limited by the photodetector quantum efficiency and by noise. In this paper, the effect of thermal photons irradiated by all materials at absolute temperatures T>0 on optical information detection in communication lines is quantitatively considered. Usually, only the thermal current fluctuations in the photodetector are taken into account. Basing on the negentropy principle of information, assuming the Planck's blackbody radiation spectral distribution of photons, and describing the optical communication channel as non-symmetric noisy binary channel we have calculated the minimum energy required for the detection of one bit of information, ε= 6.5kT/bit, k =1.38×10-23 J/K being the Boltzmann constant. This ε value corresponds to the large error probability q = 0.20. At T = 20°C ε=4.05×10-21 J/bit and for the bit rate of R = 1010 bits/s one finds Pmin = Rε2.63×10-7 mW. In the case of more realistic value of q=10-9 ε=26kT/bit=1.05×10-19 J/bit, Pmin = 1.05×10-6 mW. This is only about 10 times lower than the quantum photodetection limit of conventional photodetectors. For more sensitive photodetectors the thermal photon noise can become important. It is shown that the minimum signal energy estimate ε≈10-19 J/bit is applicable also in a wider error probability range of q=10-3-10-15.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122596452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Two important features make a holographic system more substantial than an ordinary optical system: ability of phase information transmission (on a level with amplitude one) and ability of the separable overlapping of wavefronts from different objects. However, holographic signal is more complicated than that transmitted by ordinary optical devices. Due to this the statements of information theory require some modifications in a higher degree for holographic systems than for optical ones in order to provide the information transmission description.
{"title":"Some features of information theory application to holographic systems","authors":"B. Gurevich, S. Gurevich, K. Jumaliev","doi":"10.1117/12.815418","DOIUrl":"https://doi.org/10.1117/12.815418","url":null,"abstract":"Two important features make a holographic system more substantial than an ordinary optical system: ability of phase information transmission (on a level with amplitude one) and ability of the separable overlapping of wavefronts from different objects. However, holographic signal is more complicated than that transmitted by ordinary optical devices. Due to this the statements of information theory require some modifications in a higher degree for holographic systems than for optical ones in order to provide the information transmission description.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126860218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Vengalis, K. Sliuziene, I. Černiukė, R. Butkutė, V. Lisauskas, A. Maneikis
We report preparation and properties of hybrid bilayer structures composed of the organic semiconductor, 8-hydroxyquinoline aluminum (Alq3), p-type Si and two ferromagnetic oxides, namely, colossal magnetoresistance manganite, La2/3Sr1/3MnO3 (LSMO), and magnetite (Fe3O4). Thin Alq3 films were thermally evaporated in vacuum. The bottom LSMO films were grown in-situ at 750°C by dc magnetron sputtering on crystalline SrTiO3 while Fe3O4 films were magnetron sputtered at 400°C on glass. Current versus voltage in a case of vertical current flow has been investigated for the heterojunctions. The investigations revealed dominating role of thermoionic emission in a barrier of Schottky type for the Alq3/p-Si heterojunction while a mechanism based on carrier tunnelling through an interface and space charge limited current processes were considered to explain nonlinear electrical transport in the Alq3/LSMO, Alq3/ Fe3O4 heterojunctions. The Alq3/LSMO demonstrated magnetoresistance values up to 11 % (at T=240 K and B=1 T).
{"title":"Preparation and properties of hybrid bilayer structures based on organic Alq3, ferromagnetic La2/3Sr1/3MnO3 and Fe3O4","authors":"B. Vengalis, K. Sliuziene, I. Černiukė, R. Butkutė, V. Lisauskas, A. Maneikis","doi":"10.1117/12.815942","DOIUrl":"https://doi.org/10.1117/12.815942","url":null,"abstract":"We report preparation and properties of hybrid bilayer structures composed of the organic semiconductor, 8-hydroxyquinoline aluminum (Alq3), p-type Si and two ferromagnetic oxides, namely, colossal magnetoresistance manganite, La2/3Sr1/3MnO3 (LSMO), and magnetite (Fe3O4). Thin Alq3 films were thermally evaporated in vacuum. The bottom LSMO films were grown in-situ at 750°C by dc magnetron sputtering on crystalline SrTiO3 while Fe3O4 films were magnetron sputtered at 400°C on glass. Current versus voltage in a case of vertical current flow has been investigated for the heterojunctions. The investigations revealed dominating role of thermoionic emission in a barrier of Schottky type for the Alq3/p-Si heterojunction while a mechanism based on carrier tunnelling through an interface and space charge limited current processes were considered to explain nonlinear electrical transport in the Alq3/LSMO, Alq3/ Fe3O4 heterojunctions. The Alq3/LSMO demonstrated magnetoresistance values up to 11 % (at T=240 K and B=1 T).","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116886419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ē. Sļedevskis, V. Gerbreders, V. Kolbjonoks, J. Teteris, A. Gulbis
Results of second harmonic (SH) generation in amorphous and crystalline selenium films induced by titanium-sapphire femtosecond laser (wavelength λ - 800-1000 nm) are presented. It is found that the highest intensity of SH is provided by fundamental wave at wavelength 1000 nm and it reaches maximum in approximately 100 sec. The intensity of transmitted SH depends on film thickness while that of reflected does not.
{"title":"Second harmonic generation in selenium thin films","authors":"Ē. Sļedevskis, V. Gerbreders, V. Kolbjonoks, J. Teteris, A. Gulbis","doi":"10.1117/12.815490","DOIUrl":"https://doi.org/10.1117/12.815490","url":null,"abstract":"Results of second harmonic (SH) generation in amorphous and crystalline selenium films induced by titanium-sapphire femtosecond laser (wavelength λ - 800-1000 nm) are presented. It is found that the highest intensity of SH is provided by fundamental wave at wavelength 1000 nm and it reaches maximum in approximately 100 sec. The intensity of transmitted SH depends on film thickness while that of reflected does not.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122645731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The holographic recording efficiency in doped LiNbO3 crystals has been studied both experimentally and theoretically depending on the type of dope, on the recording geometry and on the polarizations of the recording and readout light.. The studied crystals can be arranged in the following order by their efficiency: LiNbO3:Cu, LiNbO3:Fe (yet having a smaller thickness and donor concentration than LiNbO3:Cu), LiNbO3:Fe+Cu, LiNbO3:Fe+Ti, LiNbO3:Ti. It was found that the recording geometry with the holographic grating vector along the optical axis is much more efficient than in the perpendicular configuration.This fact is in accordance with the photorefraction theory based on photogalvanic and linear electro-optic effects (PGE-LEO theory). Other recording mechanisms are active, too, but much less eficient. The recording efficiency polarization dependence is mainly determined by dopes.It is different in the cases of Fe and Cu impurities. It also follows from our studies that photoconductivity along the optical axis is much larger than in the perpendicular direction.
{"title":"Effects of light polarization and crystal orientation on the holographic recording efficiency in doped LiNbO3 crystals","authors":"A. Ozols, M. Reinfelde","doi":"10.1117/12.814971","DOIUrl":"https://doi.org/10.1117/12.814971","url":null,"abstract":"The holographic recording efficiency in doped LiNbO3 crystals has been studied both experimentally and theoretically depending on the type of dope, on the recording geometry and on the polarizations of the recording and readout light.. The studied crystals can be arranged in the following order by their efficiency: LiNbO3:Cu, LiNbO3:Fe (yet having a smaller thickness and donor concentration than LiNbO3:Cu), LiNbO3:Fe+Cu, LiNbO3:Fe+Ti, LiNbO3:Ti. It was found that the recording geometry with the holographic grating vector along the optical axis is much more efficient than in the perpendicular configuration.This fact is in accordance with the photorefraction theory based on photogalvanic and linear electro-optic effects (PGE-LEO theory). Other recording mechanisms are active, too, but much less eficient. The recording efficiency polarization dependence is mainly determined by dopes.It is different in the cases of Fe and Cu impurities. It also follows from our studies that photoconductivity along the optical axis is much larger than in the perpendicular direction.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"124 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123304740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Millimeter wave bridge technique for non-destructive material homogeneity characterization is described. The idea of this technique is the local excitation of the millimeter waves in the testing material and the measurement of the transmitted (reflected) wave amplitude and phase in different places of it, i.e. the material plate is scanned by the beam of the millimeter waves. Same results of the homogeneity measurements for dielectric wafers according to dielectric constant anisotropy are presented. The measurement technique sensitivity is discussed.
{"title":"Study of optical material anisotropy using scanning millimeter wave beam","authors":"A. Laurinavičius, V. Derkach, Tomas Anbinderis","doi":"10.1117/12.815946","DOIUrl":"https://doi.org/10.1117/12.815946","url":null,"abstract":"Millimeter wave bridge technique for non-destructive material homogeneity characterization is described. The idea of this technique is the local excitation of the millimeter waves in the testing material and the measurement of the transmitted (reflected) wave amplitude and phase in different places of it, i.e. the material plate is scanned by the beam of the millimeter waves. Same results of the homogeneity measurements for dielectric wafers according to dielectric constant anisotropy are presented. The measurement technique sensitivity is discussed.","PeriodicalId":273853,"journal":{"name":"International Conference on Advanced Optical Materials and Devices","volume":"52 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128392405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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