Pub Date : 1998-05-01DOI: 10.1088/0963-9659/7/3/015
H. Rigneault, S. Maure, C. Amra
Two rigorous theories are presented and compared to describe the interaction with the electromagnetic field of localized sources confined within microcavities. Both the light which can escape the structure and the embedded radiation are taken into account by these formalisms. The modal theory describes the field in terms of modal functions and is limited to lossless structures. On the other hand, the Green approach can naturally cope with lossy cavities and considers the coupling of the sources with a continuum of waves with spatial frequencies ranging from zero to infinity. The two theories are compared and the consequences of losses are investigated in the case of a current source located in the spacer of a resonant multilayer structure. It is shown that the modal theory gives correct predictions when the imaginary part of the refractive index is as large as , whereas the Green approach becomes necessary to describe the emission in lossy structures. In this last case, we show that the spontaneous emission factor is not strongly affected by losses, although the emitted power is decreased due to absorption.
{"title":"Spontaneous emission in multilayer microcavities: modal theory extended with Fourier-Green analysis for dissipative structures","authors":"H. Rigneault, S. Maure, C. Amra","doi":"10.1088/0963-9659/7/3/015","DOIUrl":"https://doi.org/10.1088/0963-9659/7/3/015","url":null,"abstract":"Two rigorous theories are presented and compared to describe the interaction with the electromagnetic field of localized sources confined within microcavities. Both the light which can escape the structure and the embedded radiation are taken into account by these formalisms. The modal theory describes the field in terms of modal functions and is limited to lossless structures. On the other hand, the Green approach can naturally cope with lossy cavities and considers the coupling of the sources with a continuum of waves with spatial frequencies ranging from zero to infinity. The two theories are compared and the consequences of losses are investigated in the case of a current source located in the spacer of a resonant multilayer structure. It is shown that the modal theory gives correct predictions when the imaginary part of the refractive index is as large as , whereas the Green approach becomes necessary to describe the emission in lossy structures. In this last case, we show that the spontaneous emission factor is not strongly affected by losses, although the emitted power is decreased due to absorption.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76171716","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}
Pub Date : 1998-05-01DOI: 10.1088/0963-9659/7/3/018
J. Stamnes, D. Jiang
We study the focusing of two-dimensional (2D) electromagnetic waves through a plane interface. Starting from the exact solution for the transmitted field due to an arbitrary three-dimensional (3D) incident wave, we derive solutions for focused 3D waves in the Kirchhoff approximation. Then we construct corresponding solutions for focused 2D electromagnetic waves and study in detail the focusing properties of a TM field numerically and analytically.
{"title":"Focusing of two-dimensional electromagnetic waves through a plane interface","authors":"J. Stamnes, D. Jiang","doi":"10.1088/0963-9659/7/3/018","DOIUrl":"https://doi.org/10.1088/0963-9659/7/3/018","url":null,"abstract":"We study the focusing of two-dimensional (2D) electromagnetic waves through a plane interface. Starting from the exact solution for the transmitted field due to an arbitrary three-dimensional (3D) incident wave, we derive solutions for focused 3D waves in the Kirchhoff approximation. Then we construct corresponding solutions for focused 2D electromagnetic waves and study in detail the focusing properties of a TM field numerically and analytically.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88516745","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}
Pub Date : 1998-05-01DOI: 10.1088/0963-9659/7/3/005
G. Artzner
We consider an application of the original Hartmann method to bundles of rays generated by a Shack-Hartmann analyser. Absolute Shack-Hartmann measurements of converging wavefronts with the nominal method of collimating optics, used to locate the real image of a pupil on a microlens array, are not applicable when the wavefront asphericity is so strong that real subimages produced by individual lenslets of the array are no longer simultaneously focused at a common plane. As examples of strongly aspherical wavefronts we consider reflected beams obtained when testing large aspherical mirrors at their centre of curvature. Analytic formulae are applied to several instances and a ray-tracing program for a large-diameter strongly paraboloidal liquid mirror suggests that the Shack-Hartmann method could, however, be used by combining several cross sections of interlaced rays located downstream from the microlens array. In order to estimate how precisely subbundles of rays may be reconstructed from several cross sections we performed a small-scale experiment to measure an aspherical wavefront departing by more than from a best-fit sphere. A microlens array samples 2000 subareas per pupil. Eleven cross sections, corresponding to as many real and virtual subbundles of rays, are obtained upstream and downstream from an array using a relay optics to give enlarged real images on photographic film. We measured 57 subbundles and verified the straight line propagation of light to within a precision on negatives corresponding to a local 45 nm wavefront uncertainty. The uncertainty value for calibration using additional cross sections upstream and downstream from the microlens array amounts to 8 nm. We conclude from these numerical and practical experiments that the Shack-Hartmann method may be modified in order to measure strongly aspherical wavefronts, including reflected wavefronts obtained from centre-of-curvature testing for large aspheric mirrors.
{"title":"Aspherical wavefront measurements: Shack-Hartmann numerical and practical experiments","authors":"G. Artzner","doi":"10.1088/0963-9659/7/3/005","DOIUrl":"https://doi.org/10.1088/0963-9659/7/3/005","url":null,"abstract":"We consider an application of the original Hartmann method to bundles of rays generated by a Shack-Hartmann analyser. Absolute Shack-Hartmann measurements of converging wavefronts with the nominal method of collimating optics, used to locate the real image of a pupil on a microlens array, are not applicable when the wavefront asphericity is so strong that real subimages produced by individual lenslets of the array are no longer simultaneously focused at a common plane. As examples of strongly aspherical wavefronts we consider reflected beams obtained when testing large aspherical mirrors at their centre of curvature. Analytic formulae are applied to several instances and a ray-tracing program for a large-diameter strongly paraboloidal liquid mirror suggests that the Shack-Hartmann method could, however, be used by combining several cross sections of interlaced rays located downstream from the microlens array. In order to estimate how precisely subbundles of rays may be reconstructed from several cross sections we performed a small-scale experiment to measure an aspherical wavefront departing by more than from a best-fit sphere. A microlens array samples 2000 subareas per pupil. Eleven cross sections, corresponding to as many real and virtual subbundles of rays, are obtained upstream and downstream from an array using a relay optics to give enlarged real images on photographic film. We measured 57 subbundles and verified the straight line propagation of light to within a precision on negatives corresponding to a local 45 nm wavefront uncertainty. The uncertainty value for calibration using additional cross sections upstream and downstream from the microlens array amounts to 8 nm. We conclude from these numerical and practical experiments that the Shack-Hartmann method may be modified in order to measure strongly aspherical wavefronts, including reflected wavefronts obtained from centre-of-curvature testing for large aspheric mirrors.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77213159","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}
Pub Date : 1998-05-01DOI: 10.1088/0963-9659/7/3/009
V. Mushinski, M. Caraman, G. Lazăr, I. Lazar
Polarized absorption and wavelength modulation spectra of a complete series of single crystals near the excitonic bands have been studied in the temperature range 80-300 K. The large dichroism of absorption was observed, which depends on the composition of the crystals and the wavelength of the radiation. A qualitative explanation is given for the observed optical absorption critical points of the layered crystals.
{"title":"Some optical absorption critical points in layered ? crystals","authors":"V. Mushinski, M. Caraman, G. Lazăr, I. Lazar","doi":"10.1088/0963-9659/7/3/009","DOIUrl":"https://doi.org/10.1088/0963-9659/7/3/009","url":null,"abstract":"Polarized absorption and wavelength modulation spectra of a complete series of single crystals near the excitonic bands have been studied in the temperature range 80-300 K. The large dichroism of absorption was observed, which depends on the composition of the crystals and the wavelength of the radiation. A qualitative explanation is given for the observed optical absorption critical points of the layered crystals.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86938298","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}
Pub Date : 1998-05-01DOI: 10.1088/0963-9659/7/3/013
A. Podoleanu, S. Taplin, D. Webb, D. Jackson
We report on a theoretical study of an interferometric system in which half of a collimated beam from a broadband optical source is intercepted by a glass slide, the whole beam subsequently being incident on a diffraction grating and the resulting spectrum being viewed using a linear CCD array. Using Fourier theory, we derive the expression of the intensity distribution across the CCD array. This expression is then examined for non-cavity and cavity sources for different cases determined by the direction from which the slide is inserted into the beam and the source bandwidth. The theoretical model shows that the narrower the source linewidth, the higher the deviation of the Talbot bands' visibility (as it is dependent on the path imbalance) from the previously known triangular shape. When the source is a laser diode below threshold, the structure of the CCD signal spectrum is very complex. The number of components present simultaneously increases with the number of grating lines and decreases with the laser cavity length. The model also predicts the appearance of bands in situations not usually associated with Talbot bands.
{"title":"Theoretical study of Talbot-like bands observed using a laser diode below threshold","authors":"A. Podoleanu, S. Taplin, D. Webb, D. Jackson","doi":"10.1088/0963-9659/7/3/013","DOIUrl":"https://doi.org/10.1088/0963-9659/7/3/013","url":null,"abstract":"We report on a theoretical study of an interferometric system in which half of a collimated beam from a broadband optical source is intercepted by a glass slide, the whole beam subsequently being incident on a diffraction grating and the resulting spectrum being viewed using a linear CCD array. Using Fourier theory, we derive the expression of the intensity distribution across the CCD array. This expression is then examined for non-cavity and cavity sources for different cases determined by the direction from which the slide is inserted into the beam and the source bandwidth. The theoretical model shows that the narrower the source linewidth, the higher the deviation of the Talbot bands' visibility (as it is dependent on the path imbalance) from the previously known triangular shape. When the source is a laser diode below threshold, the structure of the CCD signal spectrum is very complex. The number of components present simultaneously increases with the number of grating lines and decreases with the laser cavity length. The model also predicts the appearance of bands in situations not usually associated with Talbot bands.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79762072","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}
Pub Date : 1998-05-01DOI: 10.1088/0963-9659/7/3/016
A. Schilling, P. Blattner, H. Herzig
Rigorous diffraction theory is applied to analyse the direct-sampling (DS) encoding method, which is based on scalar diffraction theory. For given fabrication constraints and constant sampling width of the lens function, the quantized phase profiles obtained with scalar DS are close to the optimum solutions, even for grating period to wavelength ratios as small as about 3. For smaller ratios, the phase profiles obtained by DS can be improved by up to 25%, using a straightforward rigorous steepest-gradient optimization. Applied to cylindrical lenses with NA = 0.5 and 0.63, coding with DS and with rigorously improved DS gives quite similar results for the total diffraction efficiency.
{"title":"Direct sampling for diffractive microlens encoding from a rigorous point of view","authors":"A. Schilling, P. Blattner, H. Herzig","doi":"10.1088/0963-9659/7/3/016","DOIUrl":"https://doi.org/10.1088/0963-9659/7/3/016","url":null,"abstract":"Rigorous diffraction theory is applied to analyse the direct-sampling (DS) encoding method, which is based on scalar diffraction theory. For given fabrication constraints and constant sampling width of the lens function, the quantized phase profiles obtained with scalar DS are close to the optimum solutions, even for grating period to wavelength ratios as small as about 3. For smaller ratios, the phase profiles obtained by DS can be improved by up to 25%, using a straightforward rigorous steepest-gradient optimization. Applied to cylindrical lenses with NA = 0.5 and 0.63, coding with DS and with rigorously improved DS gives quite similar results for the total diffraction efficiency.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75076284","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}
Pub Date : 1998-05-01DOI: 10.1088/0963-9659/7/3/017
J. Solhaug, K. Oughstun, J. Stamnes, P. Smith
It is well known that the dynamical evolution of the Brillouin precursor field in a single-resonance Lorentz model dielectric can be fully explained in terms of a pair of saddle points that evolve in a region of the complex -plane near the origin such that , where is the undamped resonance frequency of the dispersive medium. As time increases at a fixed propagation distance, these two near first-order saddle points first approach each other along the imaginary frequency axis, then coalesce into a second-order saddle point at the time , and finally separate from each other in the lower half-plane, one with an increasing real part and the other with a decreasing real part. The uniform asymptotic description of the Brillouin precursor provides an accurate description of the field evolution about the observation time , at which the saddle-point order changes discontinuously. However, previous approximate expressions for the phase behaviour in the region of the near saddle points have resulted in an inaccurate field evolution around . This inaccuracy is corrected in this paper. Numerical illustrations of the complete precursor evolution for the delta function pulse and the step function modulated signal are provided.
{"title":"UNIFORM ASYMPTOTIC DESCRIPTION OF THE BRILLOUIN PRECURSOR IN A SINGLE-RESONANCE LORENTZ MODEL DIELECTRIC","authors":"J. Solhaug, K. Oughstun, J. Stamnes, P. Smith","doi":"10.1088/0963-9659/7/3/017","DOIUrl":"https://doi.org/10.1088/0963-9659/7/3/017","url":null,"abstract":"It is well known that the dynamical evolution of the Brillouin precursor field in a single-resonance Lorentz model dielectric can be fully explained in terms of a pair of saddle points that evolve in a region of the complex -plane near the origin such that , where is the undamped resonance frequency of the dispersive medium. As time increases at a fixed propagation distance, these two near first-order saddle points first approach each other along the imaginary frequency axis, then coalesce into a second-order saddle point at the time , and finally separate from each other in the lower half-plane, one with an increasing real part and the other with a decreasing real part. The uniform asymptotic description of the Brillouin precursor provides an accurate description of the field evolution about the observation time , at which the saddle-point order changes discontinuously. However, previous approximate expressions for the phase behaviour in the region of the near saddle points have resulted in an inaccurate field evolution around . This inaccuracy is corrected in this paper. Numerical illustrations of the complete precursor evolution for the delta function pulse and the step function modulated signal are provided.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85556490","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}
Pub Date : 1998-05-01DOI: 10.1088/0963-9659/7/3/014
S. Popov, A. Friberg
The effects of apodization of a generalized holographic axicon that produces a uniform axial line intensity distribution are considered. It is shown, both by simulations and experimentally, that the apodization considerably improves the image line quality within the extended focal region, especially near the image end points. A simple method of implementing the apodization by a binary-amplitude encoding of the generalized axicon is assessed in detail. Fabrication of the axicon by photoreduction and experimental results on the intensity variations of the line image, which are in substantial agreement with the theoretical considerations, are presented and analysed. On apodization the axial intensity becomes nearly uniform, while transversely the line image retains its high definition.
{"title":"Apodization of generalized axicons to produce uniform axial line images","authors":"S. Popov, A. Friberg","doi":"10.1088/0963-9659/7/3/014","DOIUrl":"https://doi.org/10.1088/0963-9659/7/3/014","url":null,"abstract":"The effects of apodization of a generalized holographic axicon that produces a uniform axial line intensity distribution are considered. It is shown, both by simulations and experimentally, that the apodization considerably improves the image line quality within the extended focal region, especially near the image end points. A simple method of implementing the apodization by a binary-amplitude encoding of the generalized axicon is assessed in detail. Fabrication of the axicon by photoreduction and experimental results on the intensity variations of the line image, which are in substantial agreement with the theoretical considerations, are presented and analysed. On apodization the axial intensity becomes nearly uniform, while transversely the line image retains its high definition.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79114907","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}
Pub Date : 1998-05-01DOI: 10.1088/0963-9659/7/3/020
C. Yeo, I. Watson, D. Stewart-Tull, A. Wardlaw, G. Armstrong
The effect of laser radiation on Staphylococcus aureus 6571 (Oxford strain) was studied with high-power Nd:YAG laser radiation between 50 and 300 W. A range of laser pulse repetition frequencies (PRF) from 5 to 30 Hz, with a combination of pulse energies from 2 to 30 J were applied; this covered a range of energy densities from 800 to . The area of inactivation of S. aureus, lawned on nutrient agar plates, was quantified as a function of energy density and exposure time. The shortest exposure time which produced an area of inactivation equal to 50% of the beam area was achieved at a PRF of 30 Hz, pulse energy of 10 J, and with an exposure time of 10.75 s; this was equivalent to an applied energy density of . No bacterial inactivation was observed at relatively low-power settings for PRF, pulse energies and exposure time of: 20 Hz, 3 J and 34 s; 25 Hz, 2 J and 45 s and 30 Hz, 2 J and 35 s, respectively. These results shows that pulse energy, PRF and exposure time are important criteria when considering inactivation of micro-organisms by laser radiation.
{"title":"Bactericidal effects of high-power Nd:YAG laser radiation on Staphylococcus aureus","authors":"C. Yeo, I. Watson, D. Stewart-Tull, A. Wardlaw, G. Armstrong","doi":"10.1088/0963-9659/7/3/020","DOIUrl":"https://doi.org/10.1088/0963-9659/7/3/020","url":null,"abstract":"The effect of laser radiation on Staphylococcus aureus 6571 (Oxford strain) was studied with high-power Nd:YAG laser radiation between 50 and 300 W. A range of laser pulse repetition frequencies (PRF) from 5 to 30 Hz, with a combination of pulse energies from 2 to 30 J were applied; this covered a range of energy densities from 800 to . The area of inactivation of S. aureus, lawned on nutrient agar plates, was quantified as a function of energy density and exposure time. The shortest exposure time which produced an area of inactivation equal to 50% of the beam area was achieved at a PRF of 30 Hz, pulse energy of 10 J, and with an exposure time of 10.75 s; this was equivalent to an applied energy density of . No bacterial inactivation was observed at relatively low-power settings for PRF, pulse energies and exposure time of: 20 Hz, 3 J and 34 s; 25 Hz, 2 J and 45 s and 30 Hz, 2 J and 35 s, respectively. These results shows that pulse energy, PRF and exposure time are important criteria when considering inactivation of micro-organisms by laser radiation.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90660340","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}
Pub Date : 1998-05-01DOI: 10.1088/0963-9659/7/3/006
A. A. Hamza, A. Nasr
Multiple-beam interference of the Fizeau type is used to investigate multi-mode step-index optical fibres. Two different types of multi-mode step-index optical fibres are studied interferometrically. The first has a plastic cladding and silica core (the problems of studying this type of fibre and how to overcome these problems are outlined). The second fibre is a multi-mode multi-step-index (quadruple-layer) optical fibre. This sample is used to test the accuracy of the method used for calculating the refractive index profile of the fibres.
{"title":"Interferometric studies on multi-mode step-index optical fibres","authors":"A. A. Hamza, A. Nasr","doi":"10.1088/0963-9659/7/3/006","DOIUrl":"https://doi.org/10.1088/0963-9659/7/3/006","url":null,"abstract":"Multiple-beam interference of the Fizeau type is used to investigate multi-mode step-index optical fibres. Two different types of multi-mode step-index optical fibres are studied interferometrically. The first has a plastic cladding and silica core (the problems of studying this type of fibre and how to overcome these problems are outlined). The second fibre is a multi-mode multi-step-index (quadruple-layer) optical fibre. This sample is used to test the accuracy of the method used for calculating the refractive index profile of the fibres.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85905997","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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