Amplitude Of Light Research Articles

Single-Atom Trapping in a Metasurface-Lens Optical Tweezer

Optical metasurfaces of subwavelength pillars have provided new capabilities for the versatile definition of the amplitude, phase, and polarization of light. In this work, we demonstrate that an efficient dielectric metasurface lens can be used to trap and image single neutral atoms with a long working distance from the lens of 3 mm. We characterize the high-numerical-aperture optical tweezers using the trapped atoms and compare with numerical computations of the metasurface lens performance. We predict that future metasurfaces for atom trapping will be able to leverage multiple ongoing developments in metasurface design and enable multifunctional control in complex quantum information experiments with neutral-atoms arrays.

Multibit NOT logic gate enabled by a function programmable optical waveguide.

Multibit logic gates are of great importance in optical switching and photonic computing. A 4-bit parallel optical NOT logic gate is demonstrated by an optical switching/computing engine based on a multimode waveguide. The multimode interference (MMI) patterns can be altered by thermal electrodes because the number of guided modes, their profiles, and propagation constants can all be altered via the thermo-optic effect. Instead of conventional forward design based on time-consuming simulations, the proposed engine can update the thermal electrodes automatically and monitor the change of the interference in a synchronized and rapid way until the desired function is reached, all experimentally. We name the system "function programmable waveguide engine" (FPWE). As opposed to solutions where the phase or amplitude of light is taken as the signal, the input stays in the electronic domain, and the output is converted into optical intensity variations, calculated from a truth table. This simple, low-cost yet powerful engine may lead to the development of a new set of devices for on-chip photonic computing and signal switching.

All dielectric metasurfaces for spin-dependent terahertz wavefront control

Metasurfaces consisting of artificial subwavelength structure arrays have shown unprecedented ability to manipulate the phase, amplitude, and polarization of light. Separate and complete control over different spin states, namely the orthogonal circular polarizations, has proven more challenging as compared to the control over orthogonal linear polarizations. Here, we present and experimentally demonstrate several spin-dependent wavefront control metasurfaces in the terahertz regime using all-silicon dielectric structures. Such spin-dependent all-silicon metasurfaces are easy to fabricate and have potential applications in spin-involved ultracompact and miniaturized terahertz optical systems as well as terahertz communication systems.

Daytime Lipid Metabolism Modulated by CLOCK Gene Is Linked to Retinal Ganglion Cells Damage in Glaucoma

Lipid metabolism is intimately linked to circadian mechanisms and light signaling. Deteriorated photic transduction because of retinal ganglion cell (RGC) loss occurring with glaucoma progression reduces perceived light amplitude, causing circadian disruption. To investigate associations with RGCs, total cholesterol (TC), its low-density (LDL-C) and high-density (HDL-C) fractions, and triglycerides (TG) were measured, under a controlled meal regimen, during daytime hours in 114 patients diagnosed with primary open-angle glaucoma (POAG). RGC damage was assessed by high-definition optical coherence tomography (HD-OCT). Analysis of eight clock, clock-related, and melatonin receptor gene polymorphisms was performed on 19 patients. RGC loss was associated with changes in lipid metabolism in a time-dependent manner. Morning (08:00) values of HDL-C (r = 0.613, p < 0.0001) and TG (r = 0.568, p < 0.0001) correlated positively with RGC global loss, while LDL-C at 08:00 had a weak correlation (r = 0.235; p = 0.012) but showed a strong correlation in the evening (20:00) (r = 0.533, p < 0.0001). The morning–evening gradients (MEGs, changes at 20:00 versus 08:00) in TC and LDL-C changed sign from a negative to a positive association in patients exceeding the 15% two-eye mean GLV threshold. MEG (LDL-C higher in the evening than in the morning) was positive only in POAG patients with the CLOCK_3111 TT genotype.

Correction to “Broadband Light Amplitude Tuning Characteristics of SnSe2 Coated Microfiber” [Nov 20 6089-6096

This correspondence corrects an error in the Acknowledgment section.

Active longitudes and starspot evolution of the young rapidly rotating star USNO-B1.0 1388−0463685 discovered in the Yunnan–Hong Kong survey

ABSTRACT We have discovered a young, rapidly rotating active star USNO-B1.0 1388−0463685 with a rotational period of 0.508750 ± 0.000153 d in the Yunnan–Hong Kong wide-field photometric survey. Based on the chromospheric activity identified in the dedicated spectroscopic observations, the brightness variation of this star is attributed to cool spots on its photosphere. We derived the spot maps from 14 light curves, which demonstrate that the strong spot tends to appear in the same hemisphere, and the light curve amplitude varies with a period of about 2.4 yr. Low-resolution spectroscopic observations revealed the chromospheric activity of the star through the indicators Hα, Na i D1 and D2, He i D3, and Ca ii H & K lines. Moreover, there was a clear anticorrelation between the equivalent width variation of the Hα, Na i D1 and D2 lines and the simultaneous light curve, implying the photosphere and chromosphere connection. Using the spectral subtraction technique, the spectral type of the star was determined as K0–2V and its projected rotational velocity v sin i is 107.492 ± 7.388 km s−1. Both the lithium equivalent width of 254.0 ± 43.3 mÅ and its location on the Hertzsprung–Russell diagram indicate that this star should be in the stage from late pre-main sequence to zero-age main sequence.

Metasurface Holography Reaching the Highest Efficiency Limit in the Visible via One‐Step Nanoparticle‐Embedded‐Resin Printing

AbstractMetasurface holography, the reconstruction of holographic images by modulating the spatial amplitude and phase of light using metasurfaces, has emerged as a next‐generation display technology. However, conventional fabrication techniques used to realize metaholograms are limited by their small patterning areas, high manufacturing costs, and low throughput, which hinder their practical use. Herein, a high efficiency hologram using a one‐step nanomanufacturing method with a titanium dioxide nanoparticle‐embedded‐resin, allowing for high‐throughput and low‐cost fabrication is demonstrated. At a single wavelength, a record high theoretical efficiency of 96.9% is demonstrated with an experimentally measured conversion efficiency of 90.6% and zero‐order diffraction of 7.3% producing an ultrahigh‐efficiency, twin‐image free hologram that can even be directly observed under ambient light conditions. Moreover, a broadband meta‐atom with an average efficiency of 76.0% is designed, and a metahologram with an average efficiency of 62.4% at visible wavelengths from 450 to 650 nm is experimentally demonstrated.

Polarization-independent electro-optic phase modulator based on trilayer birefringent materials

ABSTRACT Manipulating the phase and amplitude of light led to many important breakthroughs in optics, and it is still considered one of the most critical technologies in emerging optical systems. However, conventional phase modulators generally suffer from the strong polarisation dependence that stems from the anisotropic optical property of the base material. Here, we report a phase modulator that is polarisation-independent and is based on the trilayer of birefringent materials which have their optical axes aligned at specific angles. The proposed structure effectively eliminates the polarisation dependence of the phase modulator without compromising its electro-optic properties. This technology provides a simple but significant method for developing a polarisation-independent phase modulator without fabrication complexity.

I/Q Demodulator Based Optical Camera Communications

Visible light communications achieve wireless communications using light sources such as lighting fixtures and electric signboards. The light sources need to blink at high speed to avoid flickering. However, the blinking frequency is much higher than the frame rate of the general-purpose cameras that are integrated into consumer devices such as smartphones. This paper proposes a method where the principle of the I/Q demodulator as employed in radio frequency communications is used to estimate the phase and amplitude of modulated light blinking at a sufficiently higher speed than the frame rate. This is achieved by using two cameras with slightly different exposure start timing and estimating the phase and amplitude from the pixel values of the light-emitting diode (LED) image in one frame for each camera. In contrast to the conventional method with a very short exposure time, the exposure time can be increased, resulting in higher efficiency of light capture. Additionally, we propose another configuration employing one camera and two LEDs. An experiment to verify that communication is possible with the proposed method, which achieved 200 bits/s with 60 frames per second cameras. We also confirmed the proposed methods have similar signal-to-noise ratio to bit error ratio performance.

Research on photoacoustic microscopy imaging based on photoacoustic transmission matrix with a digital micromirror device

Due to the high penetrability of ultrasonic signals in scattering media, photoacoustic imaging based on photoacoustic effect is of great significance in the research of non-destructive testing and imaging of biological tissues. However, multiple light scattering will occur after the laser is incident on the scattering medium, resulting in poor imaging quality or inability to image. In this paper, we propose a novel method for wavefront shaping and photoacoustic imaging based on a photoacoustic transmission matrix. We use the photoacoustic transmission matrix method as the algorithm for wavefront shaping, and combine the superpixel method with a digital micromirror device (DMD) to modulate the amplitude and phase of the incident light, resulting in an enhancement factor of 10.75 for the photoacoustic signal. Then, we realize photoacoustic scanning imaging by moving the two-dimensional translation stage to drive the absorber above. Compared with the inability to image the initial photoacoustic signal before shaping, the shaped photoacoustic signal can obtain a clear photoacoustic image with a contrast ratio of 16.85. The wavefront shaping and photoacoustic imaging of photoacoustic signals based on photoacoustic transmission matrix method have a good prospect in the imaging of weaker photoacoustic signals.

Longitudinal conductivity in ABC-stacked trilayer graphene under irradiating of linearly polarized light

We study the effect of linearly polarized light on the band structure and longitudinal conductivity in ABC-stacked trilayer graphene. The linearly polarized light can induce a pair of additional points in ABC-stacked trilayer graphene, where conduct and valence bands touch. The locations of these points are determined by the amplitude of the light. Furthermore, the layer pseudospin polarization can be controlled by the light. When the Fermi energy locates at Dirac points, i.e., E f = 0, the longitudinal conductivity shows resonance phenomena when the light is present. Away from the Dirac points, the longitudinal conductivity is unchanged as varying E f for weak light field at larger Fermi energy, and the amplitude of longitudinal conductivity can be controlled by tuning the light field amplitude. Moreover, the effect of linearly polarized light on resonance phenomena in k-cubic Rashba–Dresselhaus system under the irradiating of linearly polarized light is discussed.

Ultraspectral Imaging Based on Metasurfaces with Freeform Shaped Meta‐Atoms

AbstractMetasurfaces have an exceptional capacity to manipulate the phase, amplitude, polarization, or spectrum of light. However, unit cells, or meta‐atoms, of metasurfaces are conventionally designed using regular shapes, limiting performance improvement. The utilization of metasurfaces with freeform shaped meta‐atoms for on‐chip ultraspectral imaging is proposed, where the freeform shaped patterns are generated with controllable feature sizes and boundary curvatures for feasible fabrication. These patterns broaden design diversity and enrich metasurface‐unit spectral response with complicated Bloch modes, thus improving spectral imaging performance with enhanced spectrum recovery precision for broadband spectra and smaller center‐wavelength deviation for narrowband spectra. A snapshot on‐chip ultraspectral imaging, with 356 × 436 spectral pixels is experimentally demonstrated. Spectral resolution is state‐of‐the‐art, at 0.5 nm, and mean fidelity of spectral reconstruction for a standard color board reaches 98.78%. These results support future applications in the field of precise intelligent perception. Moreover, the generating method for freeform shaped patterns also benefits for the forward and inverse designs for high‐performance metasurfaces.

Association of PCSK9 with inflammation and platelet activation markers and recurrent cardiovascular risks in STEMI patients undergoing primary PCI with or without diabetes

BackgroundProprotein convertase subtilisin/kexin type 9 (PCSK9) has been shown to be predictive of cardiovascular outcomes in stable coronary artery disease with diabetes. We aimed to assess the relationship between PCSK9 and major adverse cardiovascular events (MACEs) in ST-segment elevation myocardial infarction (STEMI) patients with or without diabetes, as well as the relationships between PCSK9 and metabolism, inflammation and platelet activation markers.MethodsA total of 1027 patients with STEMI undergoing primary percutaneous coronary intervention (PCI) and without prior lipid-lowering therapy were consecutively enrolled and the baseline plasma PCSK9 levels were determined by ELISA. Patients were divided into high and low PCSK9 groups according to PCSK9 median. All patients were followed up for the occurrence of MACEs. The associations of PCSK9 with metabolism, inflammation and platelet activation markers and MACEs were evaluated.ResultsPCSK9 levels were positively correlated with triglycerides, high-sensitivity C reactive protein, soluble CD40 ligand and soluble P-selectin levels, and the correlations were stronger in diabetic patients than in non-diabetic patients. In diabetic patients receiving ticagrelor, PCSK9 levels were positively correlated with maximal platelet aggregation measured by light transmittance aggregometry and maximum amplitude of adenosine diphosphate-induced platelet-fibrin clots measured by thrombelastography in the maintenance phase of treatment, whereas no correlations were found in non-diabetic patients. During a median follow-up of 2.0 years, 155 (15.1%) MACEs occurred. The Kaplan–Meier analysis displayed that the patients with high PCSK9 levels had lower event-free survival rate than those with low PCSK9 levels (P = 0.030). When participants were categorized into 4 subgroups according to PCSK9 levels and diabetes status, high PCSK9 levels plus diabetes subgroup had the lowest cumulative event-free survival rate (P = 0.043). Multivariable Cox regression analysis revealed that high PCSK9 levels were independently associated with MACEs in diabetic patients (hazard ratio 2.283, 95% confidence interval: 1.094–4.764, P = 0.028), but not in the whole cohort or non-diabetic patients.ConclusionsThe study showed that high PCSK9 levels were independently associated with MACEs in STEMI patients with diabetes undergoing primary PCI, and the association may be due to stronger correlations of PCSK9 with inflammation and platelet activation markers in diabetic patients.

Controllable Optical Vortex Array for Image Encoding

Optical cryptosystems mostly use spatial distributions of amplitude, phase, and polarization of light to encrypt two-dimensional data/image. In this letter, we demonstrate the use of light carrying an array of optical vortices for image encryption. Spatially concatenated orthogonal states of optical vortices allow high-dimensional encoding and minimize the quality degradation during practical implementation. These features offer an efficient way to design an optical cryptosystem.

Magnetic Activity on Four Short-period Contact Binaries: V0576 Peg, KW Psc, V0873 Per, and FY Boo

We presented new photometry for four short-period late-type binaries, observed by three small telescopes in China from 2020 September to 2021 December. Seven sets of light curves (including the TESS data for FY Boo) were analyzed by using the W-D method. Three binaries (V0576 Peg, V0873 Per, and FY Boo) are W-type binaries with q ≃ 2.5, while KW Psc is an A-type binary with q ≃ 0.43. Max.I−Max.II is up to 10% of variable light amplitude for the asymmetric light curves, which are modeled by a dark spot on the surface of the more massive component. Photometric results imply the existence of movement and evolution of the cool spot. From the temperature−luminosity and mass–luminosity diagrams, the more massive components are a bit evolved main-sequence stars, while the less massive ones are oversized and overluminous owing to energy exchange. Orbital period analyses indicate that the cyclic oscillations occur in the (O − C) curves. Their modulated periods approach 11 yr, which may preferably result from the magnetic activity cycle for four late-type contact binaries. With angular momentum loss through magnetic braking, these short-period contact binaries may evolve into deep-contact configurations.

Rotation periods and shape asphericity in asteroid families based on TESS S1-S13 observations

Here we present the analysis of the distribution of rotation periods and light curve amplitudes based on 2859 family asteroids in 16 Main Belt families based on 9912 TESS asteroid light curves in the TSSYS-DR1 asteroid light curve database. We found that the distribution of the light curve properties follow a family-specific character in some asteroid families, including the Hungaria, Maria, Juno, Eos, Eucharis, and Alauda families. While in other large families, these distributions are in general very similar to each other. We confirm that older families tend to contain a larger fraction of more spheroidal, low-amplitude asteroids. We found that rotation period distributions are different in the cores and outskirts of the Flora and Maria families, while the Vesta, Eos, and Eunomia families lack this feature. We also confirm that very fast spinning asteroids are close to spherical (or spinning top shapes), and minor planets rotating slower than ≈11 h are also more spherical than asteroids in the 4–8 h period range and this group is expected to contain the most elongated bodies.

D(s) to light tensor meson form factors and semileptonic decays via LCSR in HQEFT

In this paper, the form factors of D(s) to light tensor mesons a2(1320), [Formula: see text], [Formula: see text], [Formula: see text] and corresponding semileptonic decays are investigated through the method of light cone sum rules (LCSR) in the framework of heavy quark effective field theory (HQEFT). Considering the light cone distribution amplitudes (DAs) of tensor mesons to twist-3, we give numerical results of form factors systematically, which are necessary inputs for the analysis of relevant D(s) decays. Based on the form factor results, the relevant semileptonic decays induced by charged current (CC) as well as flavor changing neutral current (FCNC) are studied. Our predictions for the branching ratios, longitudinal polarization fractions and forward–backward asymmetries can be tested by more precise experiments such as LHCb, BESIII and BelleII in the future.

Zwicky Transient Facility and Globular Clusters: The RR Lyrae gri-band Period–Luminosity–Metallicity and Period–Wesenheit–Metallicity Relations

Based on time-series observations collected from the Zwicky Transient Facility (ZTF), we derived period–luminosity–metallicity (PLZ) and period–Wesenheit–metallicity (PWZ) relations for RR Lyrae located in globular clusters. We have applied various selection criteria to exclude RR Lyrae with problematic or spurious light curves. These selection criteria utilized information on the number of data points per light curve, amplitudes, colors, and residuals on the period–luminosity and/or period–Wesenheit relations. Due to blending, a number of RR Lyrae in globular clusters were found to be anomalously bright and have small amplitudes of their ZTF light curves. We used our final sample of ∼750 RR Lyrae in 46 globular clusters covering a wide metallicity range (−2.36 dex < [Fe/H] < −0.54 dex) to derive PLZ and PWZ relations in the gri bands. In addition, we have also derived the period–color–metallicity and, for the first time, the period-Q-index-metallicity relations, where the Q-index is extinction-free by construction. We have compared our various relations to empirical and theoretical relations available in the literature and found a good agreement with most studies. Finally, we applied our derived PLZ relation to a dwarf galaxy, Crater II, and found that its true distance modulus should be larger than the most recent determination.

All-dielectric metasurface designs for spin-tunable beam splitting via simultaneous manipulation of propagation and geometric phases.

Metasurfaces offer diverse wavefront control by manipulating amplitude, phase, and polarization of light which is beneficial to design subwavelength scaled integrated photonic devices. Metasurfaces based tunable circular polarization (CP) beam splitting is one functionality of interest in polarization control. Here, we propose and numerically realize metasurface based spin tunable beam splitter which splits the incoming CP beam into two different directions and tune the splitting angles by switching the handedness of incident light polarization. The proposed design approach has potential in applications such as optical communication, multiplexing, and imaging.

Mid-infrared biomimetic moth-eye-shaped polarization-maintaining and angle-insensitive metalens.

Metalenses can potentially reduce the size and complexity of existing cameras, displays, and other optical devices, owing to their capability of flexible manipulation of the polarization, amplitude, and phase of light. However, metalenses capable of maintaining polarization and broadband wavefront shaping under arbitrarily polarized excitation have not been studied. In this study, we present the first demonstration of a biomimetic moth-eye-shaped metalens for polarization-maintaining, broadband and angle-insensitive focusing under an arbitrarily polarized excitation in the mid-infrared waveband (3.1-8.0 µm). Modulation and focusing efficiencies of 92% and 90%, respectively, were achieved. Moreover, a bifocal moth-eye-shaped metalens operating at normal and oblique incidences was realized. Compared to previously reported metalenses, the one proposed in this study exhibited a better focusing under oblique incidence, ensuring light transmission as effectively as a traditional lens. This study paves the way for the development of polarization-maintaining, broadband, and angle-insensitive microscale optical devices and imaging systems.