-
Keating Slot posted an update 20 hours, 18 minutes ago
We experimentally study the optical properties of Al-SiO2 hyperbolic metamaterials. The hyperbolic dispersion and ultrathin Al film ∼12nm make the Al-SiO2 multilayers possess transmission efficiency ∼0.3 for the spatial frequency ranging from k0 to 1.42 k0 at 363.8 nm illumination. The atomic concentration of 3% Cu-doping is experimentally demonstrated to obtain Al film ∼12nm with root-mean-square roughness ∼0.49nm. The fabricated Al-SiO2 multilayers combined with the optimized ZrO2 resonant grating with period 280 nm serves as a structured illumination device, which efficiently converts the P-polarized normal field to the spatial frequency 1.3 k0 structured field. The measured average transmission intensity of the ±1 order is ∼0.14, and the intensity ratio of the ±1 order and 0 order is ∼65. This Letter is promising for structured illumination, spontaneous emission enhancement, Cherenkov radiation, etc.Recent progress has enabled the reconstruction of the local (i.e., depth-resolved) optic axis (OAx) of biological tissue from measurements made with polarization-sensitive optical coherence tomography (PS-OCT). Here we demonstrate local OAx imaging in healthy human skin in vivo. The images reveal dense, weaving patterns that are imperceptible in OCT intensity tomograms or conventional PS-OCT metrics and that suggest a mesh-like tissue organization, consistent with the morphology of dermal collagen. Using co-registered polarization-sensitive optical coherence microscopy, we furthermore investigated the impact of spatial resolution on the recovered OAx patterns and confirmed their consistency. OAx orientation as a contrast mechanism merits further exploration for applications in dermatology.TE/TM-pass polarizers based on the lithium niobate-silicon nitride hybrid platform are numerically proposed for the first time, to the best of our knowledge. By utilizing the lateral leakage of a shallowly etched rib waveguide, 1-mm-long TE/TM-pass polarizers with high extinction ratios of 28.72/24.03 dB are obtained. Because of the anisotropy of the lithium niobate, the lateral leakage of TE/TM polarization modes can occur along crystallographic z/y directions, respectively. Such TE/TM-pass polarizers can be integrated in the same wafer.We demonstrated an ultra-low-noise polarization-maintaining (PM) single-frequency fiber laser at 2 µm. Both relative intensity noise (RIN) and frequency noise were improved by suppressing the pump source RIN using feedback control. After a two-stage Tm3+-doped PM fiber amplifier, the output power reached about 5 W, and the amplifier did not introduce any observable extra frequency noise. The frequency noise was less than 100Hz/Hz above 13 Hz, which is comparable to the frequency noise of a typical seed laser of the Advanced LIGO high-power laser. The central wavelength was measured to be 1990.25 nm, with a polarization extinction ratio above 24 dB.A high degree of chaos synchronization among transverse mode pairs with parity-symmetric polarizations was demonstrated in a laser-diode pumped thin-slice c-cut NdGdVO4 laser. The amplitude correlation coefficient greater than R>0.994 resulted from a non-reversing mirror symmetric-polarization-dependent structural change in the modal patterns, where chaotic dynamics of the whole system consisting of qualitatively different dynamics, which depend on the polarization crossing angle, resembled that of a chaotic single mode laser. A self-organized sender-receiver type of chaos synchronization of a single pair of modes among an infinite number of parity-symmetric polarizations, the associated chaotic camouflaging, and the extracting experiment of a self-mixing solid-state laser Doppler velocimetry signal were demonstrated.We report on the formation of novel turbulent coherent structures in a long cavity semiconductor laser near the lasing threshold. Experimentally, the laser emits a series of power dropouts within a roundtrip, and the number of dropouts per series depends on a set of parameters including the bias current. At fixed parameters, the drops remain dynamically stable, repeating over many roundtrips. By reconstructing the laser electric field in the case where the laser emits one dropout per roundtrip and simulating its dynamics using a time-delayed model, we discuss the reasons for long-term sustainability of these solutions. We suggest that the observed dropouts are closely related to the coherent structures of the cubic complex Ginzburg-Landau equation.In this Letter, we report the experimental observations of a tunable curved photonic nanojet (photonic hook) generated by a 5 µm polydimethylsiloxane microcylinder deposited on a silicon substrate and illuminated by 405 nm laser beam. A moveable opaque aluminum-mask is mounted in front of the microcylinder implementing partial illumination and imparting spatial curvature to the photonic nanojet. Experimental results of main parameters (tilt angle, width, and intensity) of emerging photonic hooks exhibit close agreement with numerical predictions of the near-field optical structures. The experimentally measured full widths at half-maximum of photonic hooks are 0.48λ, 0.56λ, and 0.76λ for tilt angles of θ=0∘, 5.7°, and 20.1°, respectively. Photonic hooks possess great potential in complex manipulation such as super-resolution imaging, surface fabrication, and optomechanical manipulation along curved trajectories.The wideband tuning of strong bands generated through polarization modulation instability (PMI) in microstructured optical fibers (MOFs) is reported. learn more Tunability is achieved by exploiting the dependence of the phase-matching condition on the fiber’s chromatic dispersion and birefringence, which is particularly sensitive when the fiber is pumped near the zero-dispersion wavelength. MOFs designed to accomplish PMI phase-matching when they are infiltrated with ethanol and pumped at 1064 nm were designed and fabricated. Taking advantage of the large thermo-optic coefficient of ethanol, both chromatic dispersion and birefringence were varied through temperature. Wavelength shifts from 937 nm to 863 nm (anti-Stokes) and from 1231 nm to 1387 nm (Stokes) are demonstrated. Such a tuning range corresponds to a frequency shift between the pump and a PMI sideband ranging from 1274cm-1 to 2189cm-1.