N. Mekhileri, L. Andrique, G. Recher, P. Nassoy, A. Badon
Optical sectioning is instrumental for the observation of extended biological samples. It allows the observation of only a slice of the sample while rejecting contributions from out of focus depths. The acquisition of the whole volume then requires an axial displacement of the sample or the focus. To satisfy Nyquist sampling, this axial displacement has to be equal to half the axial resolution. As lateral and axial resolutions are coupled by the numerical aperture of the microscope objective in most imaging techniques, high-resolution imaging of a volume is a time-consuming task, especially caused by the slow axial scanning. Here, we propose to adapt the axial resolution, or axial extent of the coherence volume, by filtering the spectrum of the illumination of an interferometric imaging technique. We applied our approach on full-field optical coherence tomography and show a tuning of this axial extent from 1.5 to 15 μm, allowing to adapt both the acquisition time and the amount of data. We finally demonstrate that the method is especially suited to image large biological samples such as millimetric engineered tissues.
{"title":"Adaptive coherence volume in full-field opticalcoherence tomography","authors":"N. Mekhileri, L. Andrique, G. Recher, P. Nassoy, A. Badon","doi":"10.1364/osac.442310","DOIUrl":"https://doi.org/10.1364/osac.442310","url":null,"abstract":"Optical sectioning is instrumental for the observation of extended biological samples. It allows the observation of only a slice of the sample while rejecting contributions from out of focus depths. The acquisition of the whole volume then requires an axial displacement of the sample or the focus. To satisfy Nyquist sampling, this axial displacement has to be equal to half the axial resolution. As lateral and axial resolutions are coupled by the numerical aperture of the microscope objective in most imaging techniques, high-resolution imaging of a volume is a time-consuming task, especially caused by the slow axial scanning. Here, we propose to adapt the axial resolution, or axial extent of the coherence volume, by filtering the spectrum of the illumination of an interferometric imaging technique. We applied our approach on full-field optical coherence tomography and show a tuning of this axial extent from 1.5 to 15 μm, allowing to adapt both the acquisition time and the amount of data. We finally demonstrate that the method is especially suited to image large biological samples such as millimetric engineered tissues.","PeriodicalId":19750,"journal":{"name":"OSA Continuum","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2021-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41927644","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}
Nourah F. Almuhawish, Shuying Chen, L. Downes, M. Jamieson, Andrew R. MacKellar, K. Weatherill
We investigate polarization spectroscopy of an excited state transition in room-temperature rubidium vapor. By applying a circularly polarized coupling beam, resonant with the 52S1/2 → 52P3/2 transition, we induce anisotropy in the atomic medium that is then probed by scanning a probe beam across the 52P3/2 → 62S1/2 transition. By performing polarimetry on the probe beam, a dispersive spectral feature is observed. We characterize the excited-state polarization spectrum as a function of coupling intensity for both isotopes and find that at high intensities, Autler-Townes splitting results in a sub-feature, which theoretical modelling shows is enhanced by Doppler averaging. This spectroscopic technique produces a narrow dispersive signal which is ideal for laser frequency stabilization to excited-state transitions.
{"title":"Polarization spectroscopy of an excited state transition in Rubidium","authors":"Nourah F. Almuhawish, Shuying Chen, L. Downes, M. Jamieson, Andrew R. MacKellar, K. Weatherill","doi":"10.1364/osac.439037","DOIUrl":"https://doi.org/10.1364/osac.439037","url":null,"abstract":"We investigate polarization spectroscopy of an excited state transition in room-temperature rubidium vapor. By applying a circularly polarized coupling beam, resonant with the 52S1/2 → 52P3/2 transition, we induce anisotropy in the atomic medium that is then probed by scanning a probe beam across the 52P3/2 → 62S1/2 transition. By performing polarimetry on the probe beam, a dispersive spectral feature is observed. We characterize the excited-state polarization spectrum as a function of coupling intensity for both isotopes and find that at high intensities, Autler-Townes splitting results in a sub-feature, which theoretical modelling shows is enhanced by Doppler averaging. This spectroscopic technique produces a narrow dispersive signal which is ideal for laser frequency stabilization to excited-state transitions.","PeriodicalId":19750,"journal":{"name":"OSA Continuum","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47848141","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}
Using high power quasi-cw pulse pumping, we show that energy transfer upconversion (ETU) processes in highly doped Dy3+ double clad ZBLAN fibers creates a pathway for significant excitation loss that clamps the gain. For a 4 mol.% Dy3+-doped fiber, we establish that the pump absorption is non-saturable up to a maximum launched (peak) pump power of 100 W. We propose that this arises from a co-operative three-ion ETU process. Additionally, the high power pulsed pumping of Tm3+, Dy3+-co-doped fiber produces laser relaxation spikes that appear after the pump pulse, suggesting that ETU dominates all other process during pumping.
{"title":"Role of energy transfer in concentrated Dy3+-doped fibers","authors":"S. Jackson, M. Majewski","doi":"10.1364/osac.435526","DOIUrl":"https://doi.org/10.1364/osac.435526","url":null,"abstract":"Using high power quasi-cw pulse pumping, we show that energy transfer upconversion (ETU) processes in highly doped Dy3+ double clad ZBLAN fibers creates a pathway for significant excitation loss that clamps the gain. For a 4 mol.% Dy3+-doped fiber, we establish that the pump absorption is non-saturable up to a maximum launched (peak) pump power of 100 W. We propose that this arises from a co-operative three-ion ETU process. Additionally, the high power pulsed pumping of Tm3+, Dy3+-co-doped fiber produces laser relaxation spikes that appear after the pump pulse, suggesting that ETU dominates all other process during pumping.","PeriodicalId":19750,"journal":{"name":"OSA Continuum","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47393720","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}
{"title":"Refractive index of phosphate-buffered salinein the telecom infrared C+L bands","authors":"Ricardo Janeiro, R. Flores, Jaime Viegas","doi":"10.1364/osac.434864","DOIUrl":"https://doi.org/10.1364/osac.434864","url":null,"abstract":"","PeriodicalId":19750,"journal":{"name":"OSA Continuum","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2021-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42413114","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}
Yang Huang, Wei Zhou, Baoteng Xu, Jialin Liu, D. Xiong, Xi-bin Yang
{"title":"Resolution improvement in real-time and video mosaicing for fiber bundle imaging","authors":"Yang Huang, Wei Zhou, Baoteng Xu, Jialin Liu, D. Xiong, Xi-bin Yang","doi":"10.1364/osac.435313","DOIUrl":"https://doi.org/10.1364/osac.435313","url":null,"abstract":"","PeriodicalId":19750,"journal":{"name":"OSA Continuum","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2021-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46713598","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 study, we demonstrate an asymmetric counter-propagating beam system with engineered optical forces allowing for long-range particle trapping and manipulation. We achieved this by breaking the symmetry of the well-known counter-propagating optical trapping beams. By doing so, we extend the range of optical forces for particle confinement and transportation to significantly larger foci separations, creating an optical tunnel. These tunnels are capable of moving matter forward and back with controllable speeds for more than a millimeter length with the ability to bring them to a full stop at any point, creating a stable 3D trap. Our trap stiffness measurements for the asymmetric trapping system demonstrate at least one order of magnitude larger values with respect to the symmetric counter-propagating beams so far reported. Our system is quite versatile as it allows for single or multi trapping with flexible positioning of any size particle ranging from tens of nanometers to tens of microns with powers as low as a few milliwatts.
{"title":"Optical tunnels: long-range optical trapping and manipulation in aqueous media","authors":"Laurynas Lialys, Justinas Lialys, S. Fardad","doi":"10.1364/osac.436245","DOIUrl":"https://doi.org/10.1364/osac.436245","url":null,"abstract":"In this study, we demonstrate an asymmetric counter-propagating beam system with engineered optical forces allowing for long-range particle trapping and manipulation. We achieved this by breaking the symmetry of the well-known counter-propagating optical trapping beams. By doing so, we extend the range of optical forces for particle confinement and transportation to significantly larger foci separations, creating an optical tunnel. These tunnels are capable of moving matter forward and back with controllable speeds for more than a millimeter length with the ability to bring them to a full stop at any point, creating a stable 3D trap. Our trap stiffness measurements for the asymmetric trapping system demonstrate at least one order of magnitude larger values with respect to the symmetric counter-propagating beams so far reported. Our system is quite versatile as it allows for single or multi trapping with flexible positioning of any size particle ranging from tens of nanometers to tens of microns with powers as low as a few milliwatts.","PeriodicalId":19750,"journal":{"name":"OSA Continuum","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2021-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46389539","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}
{"title":"Investigation of ablation efficiency during the pulsed laser ablation of a zinc metal target in a distilled water environment","authors":"Mohammadmahdi Khodaverdi, E. Irani","doi":"10.1364/osac.438834","DOIUrl":"https://doi.org/10.1364/osac.438834","url":null,"abstract":"","PeriodicalId":19750,"journal":{"name":"OSA Continuum","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2021-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42620359","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}
{"title":"Performance study of a highly sensitive plasmonic sensor based on microstructure photonics using an outside detecting method","authors":"Nazmus Sakib, Walid Hassan, Thouhidur Rahman","doi":"10.1364/osac.433758","DOIUrl":"https://doi.org/10.1364/osac.433758","url":null,"abstract":"","PeriodicalId":19750,"journal":{"name":"OSA Continuum","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2021-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46894202","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}
Large aperture beam steering in a transmissive and compact device has been an important design objective for various technologies including LIDAR and 3D displays. We propose a new aperture variable beam steering method using an electrowetting prism array. By individually controlling the voltage of electrode, 3-dimensional beam steering is possible because it can manipulate beam steering and forming simultaneously. The total aperture of the prism array can be varied depending on the number of arrays. The operating speed was 25ms and the steering range was ±9.5° in the transverse and longitudinal directions, and ±13.2° in the diagonal direction. The range of optical power was −47.6D to 47.6D. Measurement of optical properties such as the RMS wavefront error as the sum of all aberrations of the prism and the radius of curvature, which is the flatness of the interface, and a demonstration of a 3-dimensional beam steering is also presented.
{"title":"Beam steering and forming in compact electrowetting prism array with separate electrode control","authors":"Joo-ho Lee, Junsik Lee, Y. Won","doi":"10.1364/osac.430925","DOIUrl":"https://doi.org/10.1364/osac.430925","url":null,"abstract":"Large aperture beam steering in a transmissive and compact device has been an important design objective for various technologies including LIDAR and 3D displays. We propose a new aperture variable beam steering method using an electrowetting prism array. By individually controlling the voltage of electrode, 3-dimensional beam steering is possible because it can manipulate beam steering and forming simultaneously. The total aperture of the prism array can be varied depending on the number of arrays. The operating speed was 25ms and the steering range was ±9.5° in the transverse and longitudinal directions, and ±13.2° in the diagonal direction. The range of optical power was −47.6D to 47.6D. Measurement of optical properties such as the RMS wavefront error as the sum of all aberrations of the prism and the radius of curvature, which is the flatness of the interface, and a demonstration of a 3-dimensional beam steering is also presented.","PeriodicalId":19750,"journal":{"name":"OSA Continuum","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41618654","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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