- 标题
- 摘要
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- 实验方案
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Handbook of Exoplanets || Multi-Pixel Imaging of Exoplanets with a Hypertelescope in Space
摘要： Resolved images of habitable exoplanets, within tens of parsecs, are of interest for searching biosignatures such as the “Indian-summer” signal. SETI applications are also considered. Forming multi-pixel images of such exoplanets is in principle possible with hypertelescopes, resembling a giant telescope but in dilute form with a large flotilla of small mirrors in space. Simulations show that the proposed Exo-Earth Imager flotilla (EEI), with its 100 mirrors of 3 m forming a 100 km meta-aperture, can produce a direct image of an exo-Earth at 3 parsecs, containing 30×30 resolved elements. This requires accurate control of the meta-mirror’s shape, preferably parabolic for directly co-phasing the beams co-focused toward a focal spaceship. According to the principle of hypertelescope imaging, a pupil densifier element is also needed in the focal optics for concentrating the planet’s light, otherwise spread within a broad diffractive halo. And exoplanet imaging also requires coronagraphic optics for attenuating the contaminating light from the parent star.
关键词： exoplanet imaging,SETI,coronagraphic optics,biosignatures,hypertelescope
更新于2025-09-23 15:21:01
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[IEEE 2019 4th Scientific International Conference Najaf (SICN) - Al-Najef, Iraq (2019.4.29-2019.4.30)] 2019 4th Scientific International Conference Najaf (SICN) - Study Evanescent-field Penetration Depth in Tapered Nano-fiber Optics
摘要： the use of etching in the fabrication of nanofiber optic (NFO) can enable the creation of thinner, longer, bundled, and strong wires. The aim of this etching methodology is to control the reduction of the core diameter and to demonstrate two different reducing methods applied to fabricate NFO. A large penetration depth of an evanescent field (EF) is the explanation of achievement for increasing a fiber-optic evanescent-field sensor (FOEFS). In general, the penetration depth (dp) of an optical fiber, stripped of its cladding, was a relation to the wavelength of the incident light, the refractive index (RI) of the surrounding medium and the incident angle on the basis of the ray-tracing model. Ray tracing analysis of tapered nano fiber optics segments and of combination taper probes make evident that the increases along the length of the taper, creating a segmented sensor with increased excitation light available at the surface for stimulating of ray transmitting. In this work, to study an NFO based on a tapered sensing probe by using the numerical analysis. The light power transmission and ultimate sensitivity of the element sensor are influenced by the incident angle, the numerical aperture (NA), core diameter, and taper ratio (TR). The TR of 0.1 and 0.7 are yield higher dp in certain regions. Then, the optimal result and the maximum dp were obtained with dp =1140 nm in TR=0.1 and a tapering length (L) of position tapering Z=40 mm.
关键词： fabricated nanofiber optics,ray tracing,tapered fiber optics,nanofiber optic sensors
更新于2025-09-23 15:19:57
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Multi-octave spanning, Watt-level ultrafast mid-infrared source
摘要： We present a source of brilliant mid-infrared radiation, seamlessly covering the wavelength range between 1.33 and 18 μm (7500–555 cm?1) with three channels, employing broadband nonlinear conversion processes driven by the output of a thulium-fiber laser system. The high-average-power femtosecond frontend delivers a 50 MHz train of 250 fs pulses spectrally centered at 1.96 μm. The three parallel channels employ soliton self-compression in a fused-silica fiber, supercontinuum generation in a ZBLAN fiber, and difference-frequency generation in GaSe driven by soliton self-compressed pulses. The total output enables spectral coverage from 1.33 to 2.4 μm, from 2.4 to 5.2 μm, and from 5.2 to 18 μm with 4.5 W, 0.22 W and 0.5 W, respectively. This spatially coherent source with a footprint of less than 4 m2 exceeds the brilliance of 3rd-generation synchrotrons by more than three orders of magnitude over 90% of the bandwidth.
关键词： intra-pulse difference frequency generation (DFG),ultrafast optics,supercontinuum generation,mid-infrared generation,ZBLAN optical fibre,nonlinear optics
更新于2025-09-23 15:19:57
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5-Channel Polymer/Silica Hybrid Arrayed Waveguide Grating
摘要： A 5-channel polymer/silica hybrid arrayed waveguide grating (AWG), fabricated through a simple and low-cost microfabrication process is proposed, which covers the entire O-band (1260–1360 nm) of the optical communication wavelength system. According to the simulation results, the insertion loss is lower than 4.7 dB and the crosstalk within 3-dB bandwidth is lower than ~?28 dB. The actual fiber–fiber insertion loss is lower than 14.0 dB, and the crosstalk of the 5 channels is less than ?13.0 dB. The demonstrated AWG is ideally suitable for optical communications, but also has potential in the multi-channel sensors.
关键词： integrated optics,polymer optical waveguides,planar lightwave circuit,optical communication systems
更新于2025-09-23 15:19:57
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A Miniature Fibre-Optic Raman Probe Fabricated by Ultrafast Laser-Assisted Etching
摘要： Optical biopsy describes a range of medical procedures in which light is used to investigate disease in the body, often in hard-to-reach regions via optical fibres. Optical biopsies can reveal a multitude of diagnostic information to aid therapeutic diagnosis and treatment with higher specificity and shorter delay than traditional surgical techniques. One specific type of optical biopsy relies on Raman spectroscopy to differentiate tissue types at the molecular level and has been used successfully to stage cancer. However, complex micro-optical systems are usually needed at the distal end to optimise the signal-to-noise properties of the Raman signal collected. Manufacturing these devices, particularly in a way suitable for large scale adoption, remains a critical challenge. In this paper, we describe a novel fibre-fed micro-optic system designed for efficient signal delivery and collection during a Raman spectroscopy-based optical biopsy. Crucially, we fabricate the device using a direct-laser-writing technique known as ultrafast laser-assisted etching which is scalable and allows components to be aligned passively. The Raman probe has a sub-millimetre diameter and offers confocal signal collection with 71.3% ± 1.5% collection efficiency over a 0.8 numerical aperture. Proof of concept spectral measurements were performed on mouse intestinal tissue and compared with results obtained using a commercial Raman microscope.
关键词： Raman spectroscopy,ultrafast laser-assisted etching,micro-optics,optical biopsy
更新于2025-09-23 15:19:57
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2D Layered Graphene Oxide Films Integrated with Microa??Ring Resonators for Enhanced Nonlinear Optics
摘要： Layered 2D graphene oxide (GO) films are integrated with micro-ring resonators (MRRs) to experimentally demonstrate enhanced nonlinear optics. Both uniformly coated (1?5 layers) and patterned (10?50 layers) GO films are integrated on complementary-metal-oxide-semiconductor (CMOS)-compatible doped silica MRRs using a large-area, transfer-free, layer-by-layer GO coating method with precise control of the film thickness. The patterned devices further employ photolithography and lift-off processes to enable precise control of the film placement and coating length. Four-wave-mixing (FWM) measurements for different pump powers and resonant wavelengths show a significant improvement in efficiency of ≈7.6 dB for a uniformly coated device with 1 GO layer and ≈10.3 dB for a patterned device with 50 GO layers. The measurements agree well with theory, with the enhancement in FWM efficiency resulting from the high Kerr nonlinearity and low loss of the GO films combined with the strong light–matter interaction within the MRRs. The dependence of GO’s third-order nonlinearity on layer number and pump power is also extracted from the FWM measurements, revealing interesting physical insights about the evolution of the GO films from 2D monolayers to quasi bulk-like behavior. These results confirm the high nonlinear optical performance of integrated photonic resonators incorporated with 2D layered GO films.
关键词： four-wave mixing,graphene oxide,micro-ring resonators,integrated optics,Kerr nonlinearity,2D materials
更新于2025-09-23 15:19:57
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Cuprous Sulfide for Different Laser Pulse Generation: Q-Switching and Mode-Locking
摘要： As a new type of copper-based chalcogenide two-dimensional nanomaterial, cuprous sulfide (Cu2S) has attracted much attention due to its unique band structure and optical properties. In this paper, all-fiber ring laser at the 1.53 μm regime with two kinds of Cu2S saturable absorber devices is demonstrated. The self-started Q-switched pulse with a central wavelength of 1530 nm was obtained for the first time by using Cu2S deposited on the fiber jumper as SA. When the tapered fibers deposited with Cu2S are used to replace the jumpers in the cavity, it can be found that the loss is significantly reduced and a mode-locked pulse with a pulse width of 896 fs has been achieved via evanescent field interaction. This experiment further enriches the application of Cu2S nanosheets in pulsed lasers and promotes the development and application of metal sulfides in nonlinear optics and ultrafast photonics.
关键词： saturable absorber,cuprous sulfide,mode-locking,Q-switching,ultrafast photonics,Cu2S,nonlinear optics
更新于2025-09-23 15:19:57
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Glymphatic clearance of simulated silicon dispersion in mouse brain analyzed by laser induced breakdown spectroscopy
摘要： Silicon-based devices, such as neural probes, are increasingly used as electrodes for receiving electrical signals from neural tissue. Neural probes used chronically have been known to induce inflammation and elicit an immune response. The current study detects and evaluates silicon dispersion from a concentrated source in the mouse brain using laser induced breakdown spectroscopy. Element lines for Si (I) were found at the injection site at approximately 288 nm at 3hr post-implantation, even with tissue perfusion, indicating possible infusion into neural tissue. At 24hr and 1-week post-implantation, no silicon lines were found, indicating clearance. An isolated immune response was found by CD68 macrophage response at 24hr post injection. Future studies should measure chronic silicon exposure to determine if the inflammatory response is proportional to silicon administration. The present type of protocol, coupling laser induced breakdown spectroscopy, neuroimaging, histology, immunohistochemistry, and determination of clearance could be used to investigate the glymphatic system and different tissue states such as in disease (e.g. Alzheimer's).
关键词： Inflammation,Silicon,Neuroscience,Biophysics,Physics methods,Probe,Toxicology,Physics,Optics,Immune response,Electrode
更新于2025-09-23 15:19:57
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Time-energy filtering of single electrons in ballistic waveguides
摘要： Characterizing distinct electron wave packets is a basic task for solid-state electron quantum optics with applications in quantum metrology and sensing. A important circuit element for this task is a non-stationary potential barrier that enables backscattering of chiral particles depending on their energy and time of arrival. Here we solve the quantum mechanical problem of single-particle scattering by a ballistic constriction in an fully depleted quantum Hall system under spatially uniform but time-dependent electrostatic potential modulation. The result describes electrons distributed in time-energy space according to a modi?ed Wigner quasiprobability distribution and scattered with an energy-dependent transmission probability that characterizes constriction in the absence of modulation. Modi?cation of the incoming Wigner distribution due to external time-dependent potential simpli?es in case of linear time-dependence and admits semiclassical interpretation. Our results support a recently proposed and implemented method for measuring time and energy distribution of solitary electrons as a quantum tomography technique, and offer new paths for experimental exploration of on-demand sources of coherent electrons.
关键词： single-electron devices,electron quantum optics,quantum state tomography,time-dependent scattering
更新于2025-09-23 15:19:57
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Entanglement teleportation with photons from quantum dots: towards a solid-state based quantum network
摘要： Semiconductor quantum dots are currently emerging as one of the most promising sources of non-classical light on which to base future quantum networks. They can generate single photons as well as pairs of entangled photons with unprecedented brightness, indistinguishability, and degree of entanglement. These features have very recently opened up the possibility to perform advanced quantum optics protocols that were previously inaccessible to single quantum emitters. In this work, we report on two experiments that use the non-local properties of entanglement to teleport quantum states: three-photon state teleportation and four-photon entanglement teleportation. We discuss all the experimental results in light of a theoretical model that we develop to account for the non-idealities of the quantum source. The excellent agreement between theory and experiment enables a deep understanding of how each parameter of the source affects the teleportation fidelities and it pinpoints the requirements needed to overcome the classical limits. Finally, our model suggests how to further improve quantum-dot entangled-photon sources for practical quantum networks.
关键词： quantum teleportation,entanglement swapping,quantum optics,semiconductor physics,quantum entanglement,quantum dot
更新于2025-09-23 15:19:57