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Analysis of aberrations and performance evaluation of adaptive optics in two-photon light-sheet microscopy
摘要： Two-photon light-sheet microscopy (TP-LSM) system performance is greatly degraded by specimen-induced aberrations in illumination path, which limit the field of view, axial resolution and excitation efficiency of the system. Adaptive optics (AO) is an effective method for attenuating these effects. For the design and evaluation of an AO system, a comprehensive analysis of the effects of aberrations is needed. In this paper, a TP-LSM system is simulated, and new indexes based on integral intensity are introduced for the evaluation of an aberrated light-sheet. Then, the influences of each Zernike mode and random aberrations on the illumination path of the TP-LSM system are investigated with a numerical simulation method. Results show that high-order aberrations have little effect on the axial resolution and excitation efficiency of the system and only low-order components require correction. The random aberrations varied in strength with the depth of the specimens, so the number of corrected Zernike modes is variable. A general formula is generated for the estimation of the number of modes that should be detected and corrected under different aberrations and different numerical aperture of the objective. The results can provide important guidance in the design and evaluation of AO units for TP-LSM systems.
关键词： Two-photon Light-sheet Microscopy,Aberration correction,Adaptive optics
更新于2025-09-23 15:21:01
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Sub-nanosecond multiple-wavelength harmonic mode-locked Tm-Ho co-doped fiber laser
摘要： We demonstrate an all-fiber sub-nanosecond passively mode-locked Tm-Ho co-doped fiber laser. With 1.1-km single-mode fiber (SMF) inserted into the cavity, the laser system can generate 183.4-kHz and 720-ps pulses based on a GaAs saturable absorber (SA). The output spectrum is presented with three wavelengths, which are at 1858.5, 1861.3, and 1864.2 nm, respectively. In addition, with the adjustment of the polarization controller and pump power, the multiple-pulse operation, such as the harmonic mode-locking operation, can also be observed. Higher order of harmonic mode locking is promising but limited by the damage threshold of the SA.
关键词： Mode-locked lasers,Ultrafast optics,Optical fiber lasers
更新于2025-09-23 15:21:01
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Near-field observation of guided-mode resonances on a metasurface via dielectric nanosphere excitation
摘要： We study laser-induced guided-mode resonances on an ultra-thin anisotropic metallic metasurface using direct near-field mapping. Coupling of the incident light to the surface waves is provided by a resonant laser-printed silicon nanosphere placed on the metasurface using nano-manipulation under electron-beam supervision. To visualize the propagation of the guided modes, we employ scattering-type scanning near-field optical microscopy in the near-infrared region (850 nm). The guided-mode resonances excited by the nanosphere demonstrate vanishing anisotropy due to weak confinement at the metasurface/air interface. We also extract the wavenumber of the observed modes through Fourier transformation of the measured near-field maps and find it to be in good agreement with numerical calculations.
关键词： Metasurface,Surface waves,Anisotropy,s-SNOM,Guided-mode resonance,Nano-Optics
更新于2025-09-23 15:21:01
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Impact of Contrasted Weather Conditions on CDOM Absorption/Fluorescence and Biogeochemistry in the Eastern Lagoon of New Caledonia
摘要： New Caledonia (Southwest Pacific), like all tropical Pacific Island countries, is impacted by weather events, climate change, and local anthropogenic forcing. Strong erosion of particles and dissolved organic matter (DOM) from ultramafic rocks, associated with trace metals dissemination (i.e., nickel, manganese and cobalt), potentially affects lagoon waters and coral reefs surrounding the main island. The CALIOPE (CALedonian Inherent Optical PropErties) cruises were performed along the Eastern Lagoon of New Caledonia (ELNC) (400 km, 13 transects from Bay to open ocean, 51 stations) during contrasted meteorological conditions: a dry period (October 2011), a windy situation (March 2014), and a strong rainy event (March 2016). CDOM absorption and fluorescence (FDOM), particulate absorption, backscattering, suspended particulate matter (SPM), total chlorophyll a (TChla), nutrients (NOx), pigment and phytoplankton composition were measured. Among the four CDOM fluorophores, the humic-like component (λEx/λEm: 235/460 nm), assimilated to a photoproduct of terrestrial organic matter, had relatively low fluorescence compared to protein-like fluorophores. As CDOM absorption, particulate absorption, backscattering, SPM, total chlorophyll a (TChla) and nutrient (NOx) concentrations, this humic-like material generally showed the highest values during rainfall events, the latter inducing an increase in riverine terrigeneous inputs and change toward higher phytoplankton size classes. The tyrosine 1-like (λEx/λEm: 220, 275/304 nm) and tryptophan-like fluorophores (λEx/λEm: 230, 300/352 nm) were strongly influenced by wind displaying a 7-fold and 3-fold increase, respectively in windy situation compared to calm conditions. These increases could be related to enhancements of autochthonous biological activities (highest mean concentrations of Synechococcus spp., phycoerythrin, pico- and nano-eukaryotes, heterotrophic bacteria and nanoplankton observed in wind condition) through the inputs of organic and mineral materials issued from the wind-induced sediment resuspension, atmospheric deposition and water mass mixing. By contrast, the tyrosine 2-like fluorophore (λEx/λEm: 245, 275/304 nm) substantially increased during rain events and presented the lowest values in wind conditions. These strong increases may be linked to the stimulation of planktonic activities due to riverine inputs. Therefore, this study emphasizes the significant differential influence of weather conditions (calm/wind/rain) on biogeochemistry and CDOM/FDOM distributions in the ELNC.
关键词： rivers,phytoplankton,New Caledonia,fluorescence,chromophoric dissolved organic matter,bio-optics,lagoons,Tropical Pacific
更新于2025-09-23 15:21:01
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Observation the Multi-Soliton Patterns From the Er-Doped Mode-Locked Fiber Laser Modulated by PtSe2
摘要： The passively mode-locked ?ber laser modulated by low-dimensional materials can provide an ideal platform to investigate the soliton dynamics. Here, we experimentally explored the soliton formation and evolution from an erbium-doped ?ber laser mode-locked by mechanically exfoliated PtSe2 saturable absorber via evanescent ?eld interaction. With the increasing pump power, different soliton patterns, such as single soliton, two solitons, and bound soliton, can be observed experimentally. The experimental results can identify the non-linear optical response of the PtSe2 and may make avenue toward unveiling the nature of the soliton dynamics in the ?ber laser system.
关键词： non-linear optics,soliton dynamics,?ber laser,mode-locking,saturable absorber
更新于2025-09-23 15:21:01
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Sensing coherent phonons with two-photon interference
摘要： Detecting coherent phonons pose different challenges compared to coherent photons due to the much stronger interaction between phonons and matter. This is especially true for high frequency heat carrying phonons, which are intrinsic lattice vibrations experiencing many decoherence events with the environment, and are thus generally assumed to be incoherent. Two photon interference techniques, especially coherent population trapping (CPT) and electromagnetically induced transparency (EIT), have led to extremely sensitive detection, spectroscopy and metrology. Here, we propose the use of two photon interference in a three-level system to sense coherent phonons. Unlike prior works which have treated phonon coupling as damping, we account for coherent phonon coupling using a full quantum–mechanical treatment. We observe strong asymmetry in absorption spectrum in CPT and negative dispersion in EIT susceptibility in the presence of coherent phonon coupling which cannot be accounted for if only pure phonon damping is considered. Our proposal has application in sensing heat carrying coherent phonons effects and understanding coherent bosonic multi-pathway interference effects in three coupled oscillator systems.
关键词： phonons,coherence,interference,optics
更新于2025-09-23 15:21:01
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Effective many-body Hamiltonians of qubit-photon bound states
摘要： Quantum emitters (QEs) coupled to structured baths can localize multiple photons around them and form qubit-photon bound states. In the Markovian or weak coupling regime, the interaction of QEs through these single-photon bound states is known to lead to effective many-body QE Hamiltonians with tuneable but yet perturbative interactions. In this work we study the emergence of such models in the non-Markovian or strong coupling regime in different excitation subspaces. The effective models for the non-Markovian regime with up to three excitations are characterized using analytical methods, uncovering the existence of doublons or triplon states. Furthermore, we provide numerical results for systems with multiple excitations and demonstrate the emergence of polariton models with optically tuneable interactions, whose many-body ground state exhibits a super?uid-Mott insulator transition.
关键词： long-range interactions,quantum simulation,quantum optics
更新于2025-09-23 15:21:01
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Wehrl entropy based quantification of nonclassicality for single mode quantum optical states
摘要： Nonclassical states of a quantized light are described in terms of Glauber-Sudarshan P distribution which is not a genuine classical probability distribution. Despite several attempts, defining a uniform measure of nonclassicality (NC) for the single mode quantum states of light is yet an open task. In our previous work [Phys. Rev. A 95, 012330 (2017)] we have shown that the existing well-known measures fail to quantify the NC of single mode states that are generated under multiple NC-inducing operations. In this paper, we propose a new quantification of NC for the single mode quantum states as the difference between the total Wehrl entropy of the state and the maximum Wehrl entropy arising due to its classical characteristics. The classical reference state is chosen at the same randomness, given by the von-Neumann entropy, as the state itself. We further suggest operational interpretation of the proposed measure in terms of phase-space sampling entropy as well as potential to generate entanglement, in the case of pure states. We obtain analytic expressions of NC for pure states and Gaussian mixed states. We show that, along with the states generated under single NC-inducing operations, also for the broader class of states that are generated under multiple NC-inducing operations, our quantification enumerates the NC consistently. However, the evaluation of NC for the non-Gaussian mixed states is subject to extensive numerical computation that lies beyond the scope of the current work. We finally conclude with certain open questions.
关键词： Wehrl Entropy,Quantumness,Phase Space Distributions,Quantum Optics,Nonclassicality
更新于2025-09-23 15:21:01
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Linear and nonlinear optical effects in biophotonic structures using classical and nonclassical light
摘要： In this perspective article, we review the optical study of different biophotonic geometries and biological structures using classical and nonlinear regime, especially highlighting the link between these morphologies and modern biomedical research. Additionally, the importance of nonlinear optical study in biological research, beyond traditional cell imaging is also highlighted and described. Finally, we present a short introduction regarding nonclassical light and describe the new future perspective of quantum optical study in biology, revealing the link between quantum realm and biological research.
关键词： linear and nonlinear spectroscopy,nonclassical light,squeezed light,optics,ghost imaging,biophotonics,fluorescence spectroscopy
更新于2025-09-23 15:21:01
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functions
摘要： We propose a quantum optical device to experimentally realize quantum processes, which perform the regularization of the—in general highly singular—Glauber–Sudarshan P functions of arbitrary quantum states before their application and/or measurement. This allows us to produce a broad class of nonclassical states with regular P functions, also called nonclassicality quasiprobabilities. For this purpose, the input states are combined on highly transmissive beam splitters with specific Gaussian or non-Gaussian classical states. We study both balanced and unbalanced homodyne detections for the direct sampling of the output states of the implemented processes, which requires no further regularization or state-reconstruction. By numerical simulations we demonstrate the feasibility of our approach and we outline the generalization to multimode light.
关键词： quantum processes,Glauber–Sudarshan P functions,homodyne detection,nonclassical states,quantum optics
更新于2025-09-23 15:21:01