Atmospheric pressure plasma jets are effective for generating optical freeform surfaces and correcting figure errors. They can also reduce high spatial frequency surface roughness, potentially replacing mechanical-abrasive polishing. Plasma jet polishing involves thermally driven material redistribution. Current research aims to predict surface topography and roughness by analyzing initial surface topography and the local effect of the plasma jet tool. The tool interaction function was mathematically described by evaluating a microstructure pattern before and after plasma jet polishing, revealing a 2D Gaussian convolution function. This function can be applied to areal topography measurements of lapped and mechanically ground surfaces to predict the polishing performance with respect to reduction of tool marks originating from pre-machining processes. Additionally, the convolution function can be used to predict the dimensions of an initial surface structure in order to produce a defined smooth microstructure using plasma jet polishing. Evaluating the smoothing capability of plasma jet polishing helps identify suitable pre-machining conditions in optics manufacturing, such as grinding or laser micromachining, enabling a more efficient process chain for freeform optics fabrication.
{"title":"Surface morphology in plasma jet polishing: theoretical description and application","authors":"H. Müller","doi":"10.1051/jeos/2023034","DOIUrl":"https://doi.org/10.1051/jeos/2023034","url":null,"abstract":"Atmospheric pressure plasma jets are effective for generating optical freeform surfaces and correcting figure errors. They can also reduce high spatial frequency surface roughness, potentially replacing mechanical-abrasive polishing. Plasma jet polishing involves thermally driven material redistribution. Current research aims to predict surface topography and roughness by analyzing initial surface topography and the local effect of the plasma jet tool. The tool interaction function was mathematically described by evaluating a microstructure pattern before and after plasma jet polishing, revealing a 2D Gaussian convolution function. This function can be applied to areal topography measurements of lapped and mechanically ground surfaces to predict the polishing performance with respect to reduction of tool marks originating from pre-machining processes. Additionally, the convolution function can be used to predict the dimensions of an initial surface structure in order to produce a defined smooth microstructure using plasma jet polishing. Evaluating the smoothing capability of plasma jet polishing helps identify suitable pre-machining conditions in optics manufacturing, such as grinding or laser micromachining, enabling a more efficient process chain for freeform optics fabrication.","PeriodicalId":674,"journal":{"name":"Journal of the European Optical Society-Rapid Publications","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41281757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Medical femtosecond laser devices are used in dermatology for non-linear high-resolution imaging to obtain non-invasive and label-free optical skin biopsies (multiphoton tomography) as well as in ophthalmology for refractive surgery.
{"title":"Medical Femtosecond Laser","authors":"Karsten Koenig","doi":"10.1051/jeos/2023032","DOIUrl":"https://doi.org/10.1051/jeos/2023032","url":null,"abstract":"Medical femtosecond laser devices are used in dermatology for non-linear high-resolution imaging to obtain non-invasive and label-free optical skin biopsies (multiphoton tomography) as well as in ophthalmology for refractive surgery.","PeriodicalId":674,"journal":{"name":"Journal of the European Optical Society-Rapid Publications","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46493717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents optical solitons with the concatenation model having spatio-temporal and chromatic dispersions. This model can advantageously curtail the Internet bottleneck effect. Two integration schemes yield these solitons. By utilizing the multipliers approach, the conservation laws are also derived.
{"title":"OPTICAL SOLITONS AND CONSERVATION LAWS FOR THE CONCATENATION MODEL WITH SPATIO–TEMPORAL DISPERSION (INTERNET TRAFFIC REGULATION)","authors":"L. Moraru","doi":"10.1051/jeos/2023031","DOIUrl":"https://doi.org/10.1051/jeos/2023031","url":null,"abstract":"This paper presents optical solitons with the concatenation model having spatio-temporal and chromatic\u0000dispersions. This model can advantageously curtail the Internet bottleneck effect. Two integration schemes\u0000yield these solitons. By utilizing the multipliers approach, the conservation laws are also derived.","PeriodicalId":674,"journal":{"name":"Journal of the European Optical Society-Rapid Publications","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44893710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Infrared spectroscopy is often used to spot differences between benign and malignant tissue. Due to the proliferation of tumorous cells, the composition of tissue changes drastically. In the consequence shifts occur in its optical properties that are indicated by spectral biomarkers in the so-called fingerprint region. In this work, we propose a new concept for a sparsified multi-spectral measurement of the most important and informative biomarker signals. The results of a data-driven feature selection approach show that a reliable discrimination of the tissue is still possible, even though utilizing only a small fraction of the measured data. A selected arrangement of only a few narrow-band quantum cascade lasers could provide proficient signal-to-noise ratios and can noticeably reduce the data acquisition time. Consequentially, real-time applications will be possible in short-term and in-vivo diagnostics in the long-term. First measurements of silicone phantoms validate the imaging capability of the sensor concept.
{"title":"Data-driven Development of Sparse Multi-spectral Sensors for Urological Tissue Differentiation","authors":"Felix Fischer","doi":"10.1051/jeos/2023030","DOIUrl":"https://doi.org/10.1051/jeos/2023030","url":null,"abstract":"Infrared spectroscopy is often used to spot differences between benign and malignant tissue. Due to the proliferation of tumorous cells, the composition of tissue changes drastically. In the consequence shifts occur in its optical properties that are indicated by spectral biomarkers in the so-called fingerprint region. In this work, we propose a new concept for a sparsified multi-spectral measurement of the most important and informative biomarker signals. The results of a data-driven feature selection approach show that a reliable discrimination of the tissue is still possible, even though utilizing only a small fraction of the measured data. A selected arrangement of only a few narrow-band quantum cascade lasers could provide proficient signal-to-noise ratios and can noticeably reduce the data acquisition time. Consequentially, real-time applications will be possible in short-term and in-vivo diagnostics in the long-term. First measurements of silicone phantoms validate the imaging capability of the sensor concept.","PeriodicalId":674,"journal":{"name":"Journal of the European Optical Society-Rapid Publications","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46764252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Enhancing the lateral resolution in optical microscopy and interferometry is of great interest in recent research. In order to laterally resolve structures including feature dimensions below the Abbe resolution limit, microspheres in the optical near-field of the specimen are shown to locally improve the resolution of the imaging system. Experimental and simulated results following this approach are obtained by a high NA Linnik interferometer and analyzed in this contribution. They show the reconstructed surface of a 1D phase grating below the resolution limit. For further understanding of the transfer characteristics, measured interference data are compared with FEM (finite element method) based simulations with respect to the polarization dependency of the relevant image information for 1D phase gratings. Therefore, the implemented Koehler illumination as well as the experimental setup utilize polarized light.
{"title":"Experimental and numerical polarization analysis of the 3D transfer behavior in microsphere-assisted interferometry for 1D phase gratings","authors":"Lucie Hüser","doi":"10.1051/jeos/2023029","DOIUrl":"https://doi.org/10.1051/jeos/2023029","url":null,"abstract":"Enhancing the lateral resolution in optical microscopy and interferometry is of great interest in recent research. In order to laterally resolve structures including feature dimensions below the Abbe resolution limit, microspheres in the optical near-field of the specimen are shown to locally improve the resolution of the imaging system. Experimental and simulated results following this approach are obtained by a high NA Linnik interferometer and analyzed in this contribution. They show the reconstructed surface of a 1D phase grating below the resolution limit. For further understanding of the transfer characteristics, measured interference data are compared with FEM (finite element method) based simulations with respect to the polarization dependency of the relevant image information for 1D phase gratings. Therefore, the implemented Koehler illumination as well as the experimental setup utilize polarized light.","PeriodicalId":674,"journal":{"name":"Journal of the European Optical Society-Rapid Publications","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42972744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Al-Ghafri, M. Sankar, E. Krishnan, Salam Khan, A. Biswas
The objective of the present study is to examine the behaviors of chirped optical solitons in fiber Bragg gratings (BGs) with dispersive reflectivity. The form of nonlinear refractive index represents polynomial law nonlinearity. By virtue of phase-matching condition, the discussed model of coupled nonlinear Schrödinger equation is reduced to an integrable form. Consequently, chirped optical solitons having various profiles such as W-shaped, bright, dark, kink and anti-kink solitons are derived. Further to this, the chirp associated with these soliton structures are extracted. The impact of dispersive reflectivity, self-phase modulation and cross-phase modulation on the pulse propagation is investigated and it is induced that the changes of self-phase modulation and cross-phase modulation cause a marked rise in soliton amplitude which is subject to minor variations by dispersive reflectivity. The physical evolutions of chirped optical solitons are described along with the corresponding chirp to pave the way for possible applications in the field of fiber BGs.
{"title":"Chirped optical solitons in fiber Bragg gratings with polynomial law of nonlinear refractive index","authors":"K. Al-Ghafri, M. Sankar, E. Krishnan, Salam Khan, A. Biswas","doi":"10.1051/jeos/2023025","DOIUrl":"https://doi.org/10.1051/jeos/2023025","url":null,"abstract":"The objective of the present study is to examine the behaviors of chirped optical solitons in fiber Bragg gratings (BGs) with dispersive reflectivity. The form of nonlinear refractive index represents polynomial law nonlinearity. By virtue of phase-matching condition, the discussed model of coupled nonlinear Schrödinger equation is reduced to an integrable form. Consequently, chirped optical solitons having various profiles such as W-shaped, bright, dark, kink and anti-kink solitons are derived. Further to this, the chirp associated with these soliton structures are extracted. The impact of dispersive reflectivity, self-phase modulation and cross-phase modulation on the pulse propagation is investigated and it is induced that the changes of self-phase modulation and cross-phase modulation cause a marked rise in soliton amplitude which is subject to minor variations by dispersive reflectivity. The physical evolutions of chirped optical solitons are described along with the corresponding chirp to pave the way for possible applications in the field of fiber BGs.","PeriodicalId":674,"journal":{"name":"Journal of the European Optical Society-Rapid Publications","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48941937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Brillouin Light Scattering (BLS) spectroscopy is a label-free method of measuring the GHz-frequency viscoelastic properties. The measured longitudinal modulus is acutely sensitive to the degree of hydration, crosslinking, and temperature, which can be indicative of tissue health. As such, performing in situ measurements on humans is particularly desirable for exploring potential clinical translation, however, is not possible with existing designs which are coupled to bench-top microscopes. Here we introduce a robust fiber coupled hand-held BLS probe and demonstrate its reliability for measuring excised human tissue. We verify its accuracy using confocal BLS microscopy and further show that it is possible to distinguish veins, arteries, nerves and muscles based on their BLS-measured viscoelasticity. This provides a necessary first step towards in situ clinical BLS viscoelasticity studies of human tissue.
{"title":"Brillouin Scattering Spectroscopy for studying human anatomy: Towards in situ mechanical characterization of soft tissue","authors":"K. Elsayad","doi":"10.1051/jeos/2023028","DOIUrl":"https://doi.org/10.1051/jeos/2023028","url":null,"abstract":"Brillouin Light Scattering (BLS) spectroscopy is a label-free method of measuring the GHz-frequency viscoelastic properties. The measured longitudinal modulus is acutely sensitive to the degree of hydration, crosslinking, and temperature, which can be indicative of tissue health. As such, performing in situ measurements on humans is particularly desirable for exploring potential clinical translation, however, is not possible with existing designs which are coupled to bench-top microscopes. Here we introduce a robust fiber coupled hand-held BLS probe and demonstrate its reliability for measuring excised human tissue. We verify its accuracy using confocal BLS microscopy and further show that it is possible to distinguish veins, arteries, nerves and muscles based on their BLS-measured viscoelasticity. This provides a necessary first step towards in situ clinical BLS viscoelasticity studies of human tissue.","PeriodicalId":674,"journal":{"name":"Journal of the European Optical Society-Rapid Publications","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48869212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Detecting the retro-reflected trap beam is a convenient way to measure forces applied by optical tweezers on biological systems, leaving free top access to the sample and making it easier to combine with fluorescence and phase contrast imaging. Doing so in the back focal plane of the microscope objective makes the calibration insensitive to the joint displacement of the trap and bead. Here, in addition, we take advantage of the very well contrasted interference rings observed in this specific plane to extract with good accuracy the height of the trapped bead. We thus map the viscous drag dependence close to the surface and reach an agreement between four calibration techniques, on an accurate value of the trap stiffness down to 2 micron distance to the surface and up to 600 mW of laser power. Combining this detection scheme with phase contrast microscopy, we show that the phase ring in the back focal plane of the objective overlaps with the interference rings and must be deported in a conjugate plane on the imaging path.
{"title":"Accurate Calibration of Optical Tweezers close to a glass surface using interference rings in backscattered light","authors":"N. Westbrook","doi":"10.1051/jeos/2023026","DOIUrl":"https://doi.org/10.1051/jeos/2023026","url":null,"abstract":"Detecting the retro-reflected trap beam is a convenient way to measure forces applied by optical tweezers on biological systems, leaving free top access to the sample and making it easier to combine with fluorescence and phase contrast imaging. Doing so in the back focal plane of the microscope objective makes the calibration insensitive to the joint displacement of the trap and bead. Here, in addition, we take advantage of the very well contrasted interference rings observed in this specific plane to extract with good accuracy the height of the trapped bead. We thus map the viscous drag dependence close to the surface and reach an agreement between four calibration techniques, on an accurate value of the trap stiffness down to 2 micron distance to the surface and up to 600 mW of laser power. Combining this detection scheme with phase contrast microscopy, we show that the phase ring in the back focal plane of the objective overlaps with the interference rings and must be deported in a conjugate plane on the imaging path.","PeriodicalId":674,"journal":{"name":"Journal of the European Optical Society-Rapid Publications","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47908663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We propose a Time-Gated-Single-Pixel-Camera as a promising sensor for image-free object detection for automotive application in adverse weather conditions. By combining the well-known principles of time-gating and single-pixel detection with neural networks, we aim to ultimately detect objects within the scene rapidly and robustly with a low-cost sensor. Here, we evaluate the possible data reduction such a system can provide compared to a conventional time-gated camera.
{"title":"Evaluation of a Time-Gated-Single-Pixel-Camera as a Promising Sensor for Autonomous Vehicles in Harsh Weather Conditions","authors":"C. Bett","doi":"10.1051/jeos/2023023","DOIUrl":"https://doi.org/10.1051/jeos/2023023","url":null,"abstract":"We propose a Time-Gated-Single-Pixel-Camera as a promising sensor for image-free object detection for automotive application in adverse weather conditions. By combining the well-known principles of time-gating and single-pixel detection with neural networks, we aim to ultimately detect objects within the scene rapidly and robustly with a low-cost sensor. Here, we evaluate the possible data reduction such a system can provide compared to a conventional time-gated camera.","PeriodicalId":674,"journal":{"name":"Journal of the European Optical Society-Rapid Publications","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45616890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Interferometric detection enables the acquisition of the amplitude and phase of the optical field. By making use of the synthetic wavelength as a computational construct arising from digital processing of two off-axis digital holograms, it is possible to identify the shape of an object obscured by fog and further increase the imaging range due to the increased sensitivity in coherent detection. Experiments have been conducted inside a 27m long fog tube filled with ultrasonically generated fog. We show the improved capabilities of synthetic phase imaging through fog and compare this technique with conventional active laser illumination imaging.
{"title":"Two-Wavelength Digital Holography through Fog","authors":"F. Fischer","doi":"10.1051/jeos/2023024","DOIUrl":"https://doi.org/10.1051/jeos/2023024","url":null,"abstract":"Interferometric detection enables the acquisition of the amplitude and phase of the optical field. By making use of the synthetic wavelength as a computational construct arising from digital processing of two off-axis digital holograms, it is possible to identify the shape of an object obscured by fog and further increase the imaging range due to the increased sensitivity in coherent detection. Experiments have been conducted inside a 27m long fog tube filled with ultrasonically generated fog. We show the improved capabilities of synthetic phase imaging through fog and compare this technique with conventional active laser illumination imaging.","PeriodicalId":674,"journal":{"name":"Journal of the European Optical Society-Rapid Publications","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44064077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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