G. Battaglin, E. Borsella, G. De Marchi, F. Gonella, G. Mattei, P. Mazzoldi, A. Quaranta
Light waveguides were obtained by ion-exchange process in soda- lime glasses. Metal nanoclusters were subsequently formed in waveguides by either low-mass ion irradiation, at energies of 20 - 2000 keV, or by heating in hydrogen atmosphere at temperatures varying in the range 100 - 250 degree(s)C. Nanoclusters modification induced by pulsed laser irradiation were investigated. The materials were characterized by secondary ion mass spectrometry and nuclear techniques, such as Rutherford backscattering spectrometry, to determine concentration depth-profiles, and by transmission electron microscopy for the nanoclusters detection and size evaluation. Optical analyses were performed to evidence linear and nonlinear properties.
{"title":"Formation of nonlinear optical MQD (metal quantum dot) in waveguides and modification by high-power laser irradiation","authors":"G. Battaglin, E. Borsella, G. De Marchi, F. Gonella, G. Mattei, P. Mazzoldi, A. Quaranta","doi":"10.1117/12.312804","DOIUrl":"https://doi.org/10.1117/12.312804","url":null,"abstract":"Light waveguides were obtained by ion-exchange process in soda- lime glasses. Metal nanoclusters were subsequently formed in waveguides by either low-mass ion irradiation, at energies of 20 - 2000 keV, or by heating in hydrogen atmosphere at temperatures varying in the range 100 - 250 degree(s)C. Nanoclusters modification induced by pulsed laser irradiation were investigated. The materials were characterized by secondary ion mass spectrometry and nuclear techniques, such as Rutherford backscattering spectrometry, to determine concentration depth-profiles, and by transmission electron microscopy for the nanoclusters detection and size evaluation. Optical analyses were performed to evidence linear and nonlinear properties.","PeriodicalId":383583,"journal":{"name":"ROMOPTO International Conference on Micro- to Nano- Photonics III","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128197087","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 bistability that we are describing results from designing properly the cavity of a Distributed Bragg Reflector laser realized with an external fiber grating and is based on longitudinal mode competition. The analysis of the output power bistability is done with a simulation of the static behavior of the laser. An accurate and fast computing algorithm has been implemented to solve the steady state rate equations for photon and carrier density. The used model is based on multimode analysis and includes gain saturation.
{"title":"Optical bistability in short-external-cavity DBR semiconductor lasers","authors":"V. Guja, I. Montrosset, O. Iancu","doi":"10.1117/12.312788","DOIUrl":"https://doi.org/10.1117/12.312788","url":null,"abstract":"The bistability that we are describing results from designing properly the cavity of a Distributed Bragg Reflector laser realized with an external fiber grating and is based on longitudinal mode competition. The analysis of the output power bistability is done with a simulation of the static behavior of the laser. An accurate and fast computing algorithm has been implemented to solve the steady state rate equations for photon and carrier density. The used model is based on multimode analysis and includes gain saturation.","PeriodicalId":383583,"journal":{"name":"ROMOPTO International Conference on Micro- to Nano- Photonics III","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129922767","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}
C. Logofatu, B. Iliescu, I. Enculescu, C. Grigorescu, S. A. Manea
This paper reports on controlled electric and optical properties of single crystalline sapphire for substrates use. The crystals were grown by the Czochralski method from a graphite crucible by using an original non-conventional crystal growth assembly. We paid a special attention to the homogeneity of the crystal. A new model for the electric conduction mechanisms is considered, the validity of which was confirmed by experimental measurements.
{"title":"Al2O3 single-crystalline substrates for optoelectronic applications","authors":"C. Logofatu, B. Iliescu, I. Enculescu, C. Grigorescu, S. A. Manea","doi":"10.1117/12.312684","DOIUrl":"https://doi.org/10.1117/12.312684","url":null,"abstract":"This paper reports on controlled electric and optical properties of single crystalline sapphire for substrates use. The crystals were grown by the Czochralski method from a graphite crucible by using an original non-conventional crystal growth assembly. We paid a special attention to the homogeneity of the crystal. A new model for the electric conduction mechanisms is considered, the validity of which was confirmed by experimental measurements.","PeriodicalId":383583,"journal":{"name":"ROMOPTO International Conference on Micro- to Nano- Photonics III","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130137630","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}
C. Fenic, I. Chis, R. Dabu, A. Stratan, I. Apostol, R. Stoian, C. Luculescu, C. Ghica, L. Nistor
A Q-switched Nd:YAG laser beam and its second and fourth harmonics were focused onto the polished surface of dentine samples in order to compare the ablative effect for the three wavelengths. A photoacoustic technique is applied for the ablation threshold determination. The Scanning Electron Microscope images of the produced craters are investigated and the volume of ablated material is determined. The necessary optical constants for the ablation calculation are experimentally determined.
{"title":"Dependence of the ablative effect of nanosecond laser pulses at the surface of dentine samples on the laser wavelength","authors":"C. Fenic, I. Chis, R. Dabu, A. Stratan, I. Apostol, R. Stoian, C. Luculescu, C. Ghica, L. Nistor","doi":"10.1117/12.312649","DOIUrl":"https://doi.org/10.1117/12.312649","url":null,"abstract":"A Q-switched Nd:YAG laser beam and its second and fourth harmonics were focused onto the polished surface of dentine samples in order to compare the ablative effect for the three wavelengths. A photoacoustic technique is applied for the ablation threshold determination. The Scanning Electron Microscope images of the produced craters are investigated and the volume of ablated material is determined. The necessary optical constants for the ablation calculation are experimentally determined.","PeriodicalId":383583,"journal":{"name":"ROMOPTO International Conference on Micro- to Nano- Photonics III","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130740528","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}
In this paper, one investigated the yield of some optical coatings with a nonquarterwave structure within the classical vacuum systems by modeling of the monitoring process. The correlation of the synthesis and modeling process, allows to set the optimum monitoring process for different types of coatings. The experimental results tested on antireflection coatings are according to the theoretical ones.
{"title":"Yield optimization of multilayer optical coating by modeling of the monitoring process","authors":"G. Muscalu","doi":"10.1117/12.312732","DOIUrl":"https://doi.org/10.1117/12.312732","url":null,"abstract":"In this paper, one investigated the yield of some optical coatings with a nonquarterwave structure within the classical vacuum systems by modeling of the monitoring process. The correlation of the synthesis and modeling process, allows to set the optimum monitoring process for different types of coatings. The experimental results tested on antireflection coatings are according to the theoretical ones.","PeriodicalId":383583,"journal":{"name":"ROMOPTO International Conference on Micro- to Nano- Photonics III","volume":"3405 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130901517","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}
Marius Nicola, E. Darvasi, Despina Gomoiescu, E. Cordos
The effect of the composition and of the grain size of Fe, Cu and Sn metallic powders on the reflectance spectra in VIS range have been studied. Calibration curves for determination of the percentage composition of Fe-Cu mixtures and for determination of the medium grain sizes for Fe, Cu and Sn powders were plotted.
{"title":"Estimation of some physical characteristics of metallic powders using VIS reflectance measurements","authors":"Marius Nicola, E. Darvasi, Despina Gomoiescu, E. Cordos","doi":"10.1117/12.312719","DOIUrl":"https://doi.org/10.1117/12.312719","url":null,"abstract":"The effect of the composition and of the grain size of Fe, Cu and Sn metallic powders on the reflectance spectra in VIS range have been studied. Calibration curves for determination of the percentage composition of Fe-Cu mixtures and for determination of the medium grain sizes for Fe, Cu and Sn powders were plotted.","PeriodicalId":383583,"journal":{"name":"ROMOPTO International Conference on Micro- to Nano- Photonics III","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114302506","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 hysteretical behavior of imaginary and real parts of the semiconductor susceptibility in the exciton range of spectrum taking into account the exciton-photon and elastic exciton- exciton interaction in the pump-probe regime depending on the intensity and frequency of the strong pump laser pulse and on the frequency of the test pulse is studied. The conditions of the emergence of the damping suppression and test pulse gain are determined. The abrupt red and blue shifts of the spectral position of the exciton absorption band depending on the intensity of the pump pulse are predicted.
{"title":"Nonlinear excitonic susceptibilities of semiconductors at high levels of excitation","authors":"P. I. Khadzhi, D. V. Tkachenko","doi":"10.1117/12.312782","DOIUrl":"https://doi.org/10.1117/12.312782","url":null,"abstract":"The hysteretical behavior of imaginary and real parts of the semiconductor susceptibility in the exciton range of spectrum taking into account the exciton-photon and elastic exciton- exciton interaction in the pump-probe regime depending on the intensity and frequency of the strong pump laser pulse and on the frequency of the test pulse is studied. The conditions of the emergence of the damping suppression and test pulse gain are determined. The abrupt red and blue shifts of the spectral position of the exciton absorption band depending on the intensity of the pump pulse are predicted.","PeriodicalId":383583,"journal":{"name":"ROMOPTO International Conference on Micro- to Nano- Photonics III","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115213300","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}
We present static light scattering measurements of size-shape distributions of biological particles in suspension. Results are compared to the Rayleigh-Debye-Gans theory predictions. They are inverted to retrieve the geometrical parameters of the suspended particles and their size-distribution function. The inversion of data is performed by a combined method using normalized cubic B spline functions and linear programming, which is firstly applied to different sets of simulated data, to study its efficiency and stability in the presence of experimental noise.
{"title":"Determination of size-shape distribution of biological particles from light-scattering measurements","authors":"N. Mincu, M. Popovici, M. Dobre","doi":"10.1117/12.312653","DOIUrl":"https://doi.org/10.1117/12.312653","url":null,"abstract":"We present static light scattering measurements of size-shape distributions of biological particles in suspension. Results are compared to the Rayleigh-Debye-Gans theory predictions. They are inverted to retrieve the geometrical parameters of the suspended particles and their size-distribution function. The inversion of data is performed by a combined method using normalized cubic B spline functions and linear programming, which is firstly applied to different sets of simulated data, to study its efficiency and stability in the presence of experimental noise.","PeriodicalId":383583,"journal":{"name":"ROMOPTO International Conference on Micro- to Nano- Photonics III","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131406180","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}
M. Jurbă, V. Babin, N. Bǎlţǎţeanu, Ion Gherghina, V. Jipa, E. Popescu, L. Coşereanu, Marinica Mirzu
Spiking behavior can be analytically described using laser rate equations. Control or suppress of spiking behavior can be obtained by placing suitable absorbers in the laser cavity. LiF:F2- saturable absorbers obtained by electron irradiation of LiF crystals were employed in control of laser spiking of pulsed Nd:YAG lasers. Experimental results are in good concordance with theoretical values.
{"title":"Control of laser spiking in Nd:YAG lasers with saturable absorbers","authors":"M. Jurbă, V. Babin, N. Bǎlţǎţeanu, Ion Gherghina, V. Jipa, E. Popescu, L. Coşereanu, Marinica Mirzu","doi":"10.1117/12.312691","DOIUrl":"https://doi.org/10.1117/12.312691","url":null,"abstract":"Spiking behavior can be analytically described using laser rate equations. Control or suppress of spiking behavior can be obtained by placing suitable absorbers in the laser cavity. LiF:F2- saturable absorbers obtained by electron irradiation of LiF crystals were employed in control of laser spiking of pulsed Nd:YAG lasers. Experimental results are in good concordance with theoretical values.","PeriodicalId":383583,"journal":{"name":"ROMOPTO International Conference on Micro- to Nano- Photonics III","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115153766","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}
M. Pascu, B. Carstocea, G. Popescu, O. Gafencu, S. Apostol, N. Moise, M. Roman, C. Ticoș
This paper reports a laser method for corneal structure investigation which allows to obtain images of corneal layers as well as information about dimensions of the endothelium and basal epithelium cells. The method's principle is based on the laser radiation reflection at the interface between ocular media having different refractive indices. So, the laser incident beam on the cornea is multiply reflected and refracted within it, since the cornea is a superposition of several transparent layers with different refractive indices. If observed on a screen, the radiation reflected by a certain corneal layer forms on it the image of corneal cell structure. Because of cornea curvature, the reflected beam which contains information about corneal structure--becomes strongly divergent; therefore the experimental set-up forms the cell images big enough to be seen directly by eye.
{"title":"Laser method for corneal structure investigation","authors":"M. Pascu, B. Carstocea, G. Popescu, O. Gafencu, S. Apostol, N. Moise, M. Roman, C. Ticoș","doi":"10.1117/12.312825","DOIUrl":"https://doi.org/10.1117/12.312825","url":null,"abstract":"This paper reports a laser method for corneal structure investigation which allows to obtain images of corneal layers as well as information about dimensions of the endothelium and basal epithelium cells. The method's principle is based on the laser radiation reflection at the interface between ocular media having different refractive indices. So, the laser incident beam on the cornea is multiply reflected and refracted within it, since the cornea is a superposition of several transparent layers with different refractive indices. If observed on a screen, the radiation reflected by a certain corneal layer forms on it the image of corneal cell structure. Because of cornea curvature, the reflected beam which contains information about corneal structure--becomes strongly divergent; therefore the experimental set-up forms the cell images big enough to be seen directly by eye.","PeriodicalId":383583,"journal":{"name":"ROMOPTO International Conference on Micro- to Nano- Photonics III","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133349052","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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