Mccarthynorton6221

Optically variable devices (OVDs) are well received for anti-counterfeiting and decorative applications. In this study, new strategies to develop highly decoupled OVDs were proposed and demonstrated based on the fast patterning of blazed gratings by vibration-assisted diamond texturing. A unique surface generation mechanism was revealed as a combined cutting and forming process. One facet of blazed grating is generated by the cutting motion defined by the tool tip trajectory. The other facet is formed by the tool flank face, which establishes the blaze angle. This process is able to generate high-resolution, structurally colored graphics by modulating cutting velocity to control the grating distribution. Due to the unique surface generation mechanism, the orientation of the created blazed gratings is intrinsically perpendicular to the cutting direction. Thus, it enables the flexible control of concentration directions of diffracted light by tuning the orientation of blazed gratings. We designed and demonstrated two types of highly decoupled OVDs based on vibration-induced blazed gratings. The orthogonal-type OVD utilizes the azimuth angle dependence of blazed gratings to encode two images in orthogonal cutting directions. The in-plane-type OVD utilizes the optimized diffraction efficiency of blazed gratings in a given diffraction order to encode two images in opposite cutting directions. The fabricated OVDs are presented and compared with optical simulation results based on an extended scalar diffraction theory.Laser cooled ions trapped in a linear Paul trap are long-standing ideal candidates for realizing quantum simulation, especially of many-body systems. The properties that contribute to this also provide the opportunity to demonstrate unexpected quantum phenomena in few-body systems. A pair of ions interacting in such traps exchange vibrational quanta through the Coulomb interaction. This linear interaction can be anharmonically modulated by an elementary coupling to the internal two-level structure of one of the ions. Driven by thermal energy in the passively coupled oscillators, which are themselves coupled to the internal ground states of the ions, the nonlinear interaction autonomously and unconditionally generates entanglement between the mechanical modes of the ions. We examine this counter-intuitive thermally induced entanglement for several experimentally feasible model systems and propose parameter regimes where state-of-the-art trapped ion systems can produce such phenomena. In addition, we demonstrate a multiqubit enhancement of such thermally induced entanglements.We investigate a fast and accurate technique for mode decomposition in multimode optical fibers. Initial decomposition task of near-field beam patterns is reformulated in terms of a system of linear equations, requires neither machine learning nor iterative routines. We apply the method to step and graded-index fibers and compare the decomposition performance. We determine corresponding application boundaries, propose an efficient algorithm for phase retrieval and carry out a specific preselective procedure that increases the number of decomposable modes and makes it possible to handle up to fifteen modes in presence of realistic noise levels.Terahertz radiation as an upcoming carrier frequency for next-generation wireless communication systems has great potential to enable ultra-high-capacity transmissions with several tens of gigahertz bandwidths. Nevertheless, dispersion is one of the main impairments in achieving a higher bit rate. Here, we experimentally demonstrate a compact terahertz dispersion compensator based on subwavelength gratings. The gratings are fabricated from the low-loss cyclic olefin copolymer exploiting micro-machining fabrication techniques. With the strong index modulation introduced in the subwavelength grating, the high negative group velocity dispersion of -188 (-88) ps/mm/THz is achieved at 0.15 THz for x-polarization (y-polarization), i.e., 7.5 times increase compared to the state-of-the-art reported to date for terahertz. Such high negative dispersion is realized in a grating of 43 mm length. The asymmetric cross-section and periodic-structural modulation along propagation direction lead to considerable birefringence that maintains and filters two orthogonal polarization states, respectively. These polymer-based birefringent gratings can be integrated into terahertz communication systems for dispersion compensation of both long-haul wireless links and waveguide-based interconnect links.The measurement of hotspot electron temperature is a paramount technique of implosion physics research in inertial confinement fusion. This study proposes a novel quasi-coaxis dual-energy flat spectral response high-resolution X-ray imaging instrument comprising a dual-channel total-reflection Kirkpatrick-Baez microscope and two flat non-periodic multilayer mirrors, which can image at 6.4 ± 0.5 and 9.67 ± 0.5 keV simultaneously. Various theoretical simulations were performed to verify the performance and feasibility of the imaging instrument, which was assembled and characterized in a laboratory. Experimental results show that the imaging instrument could achieve a high spatial resolution of 5 µm in a ± 150 µm field of view (FOV), the root mean square(RMS) deviation values of the measured reflection efficiency are 1.71% and 1.82% for the 6.4 keV and 9.67 keV imaging channels, respectively, in the ± 150 µm FOV.Realizing a high solar light conversion magnitude in Cr,Nd YAG transparent ceramic is crucial to its applications in solar pumped solid state lasers. In this study, high quality Cr,NdYAG transparent laser ceramics with homogeneous microstructure and theoretical transmittance were fabricated, and an efficient laser oscillation of watt-level was realized by pumping ceramic at 808 nm. There were no any characteristic absorptions corresponding to Cr2+ or Cr4+ ions detected, even when the Cr3+ ion doping concentration reached 0.6 at.%. Increasing Cr3+ and Nd3+ doping concentrations significantly enhanced the emission intensity of ceramics at 1.06 µm, and energy transfer efficiency of the 0.3 at.% Cr,Nd YAG ceramics was increased from 14.9% to 36.9% when increasing Nd3+ ion concentration from 0.3 at.% to 1.0 at.%, with an increasing magnitude of 247.6%. The results indicated that Cr,Nd YAG transparent ceramic is a promising gain medium for solar pumped solid state lasers.A micro-newton strain force and temperature synchronous fiber sensor with a high Q-factor is proposed. The sensor is based on a commercial quartz microbubble (QMB, the diameter is less than 80 µm) that is attached to the end surface of the suspending taper integrated in the hollow core fiber. The multi-beam interference and long-active-length make the sensor show both high sensitivity (0.150 nm/mN) and Q-factor (1470 based on the 3dB-bandwidth). The actual detection limit of the strain force reaches about 50 µN. The UV-cured polymer between the QMB and taper improves the temperature sensitivity. The strain force and temperature can be demodulated synchronously by using band-pass filtering and sensing matrix. The sensor can have actual application in micro-newton strain force detection as its low cost and flexible structure.We demonstrate the lateral monolithic integration of a tunable first-order surface-grating loaded vertical-cavity surface-emitting laser (VCSEL) and slow-light waveguide with fan-beam steering and amplifier function. Shallow Bragg-grating formed on the surface of a VCSEL section enables the selection of a single slow-light mode, which can be coupled into the integrated long waveguide and amplified through pumping the amplifier above threshold. We obtained over 3W amplified slow-light power with single-mode operation and over 4W amplified quasi-single-mode power under pulsed current injection. To the best of our knowledge, this is the highest output power for single-mode VCSELs. Solid-state beam steering of the device is also demonstrated with 9° fan-beam steering range and 200 resolution points.We demonstrated sub-10 fs pulse generation by the post-compression of a 100 TW TiSapphire laser to enhance the peak-power. In the post-compression, the laser spectrum was widely broadened by self-phase modulation in thin fused silica plate(s), and the induced spectral phase was compensated with a set of chirped mirrors. A spatial filter stage, consisting of two cylindrical lenses and a spherical lens, was employed to reduce the intensity modulation existing in the laser beam, which effectively suppressed intensity spikes induced by self-focusing. The laser beam was post-compressed from 23 fs to 9.7 fs after propagating through a 1.5 mm fused silica plate, resulting in the peak-power enhancement by a factor of 2.1.We study a polymer-based hyperbolic metamaterial (HMM) structure composed of three Au-polymer bilayers with a hyperbolic dispersion relation. Using an effective refractive index retrieval algorithm, we obtain the effective permittivity of the experimentally fabricated polymer-based structure. In particular, the unique polymer-based HMM shows the existence of high-k modes that propagate in the metal-dielectric multilayered structure due to the excitation of bulk plasmon-polaritonic modes. Moreover, we compare the experimental luminescence and fluorescence lifetime results of the multilayered Au and a dye-doped polymer (PMMA) to investigate the dynamics of three different emitters, each incorporated within the unique polymer-based HMM structure. With emitters closer to the epsilon-near-zero region of the HMM, we observed a relatively high shortening of the average lifetime as compared to other emitters either close or far from the epsilon-near-zero region. This served as evidence of coupling between the emitters and the HMM as well as confirmed the increase in the non-radiative recombination rate of the different emitters. We also show that the metallic losses of a passive polymer-based HMM can be greatly compensated by a gain material with an emission wavelength close to the epsilon-near-zero region of the HMM. These results demonstrate the unique potential of an active polymer-based hyperbolic metamaterial in loss compensation, quantum applications, and sub-wavelength imaging techniques.Skin-elasticity measurements can assist in the clinical diagnosis of skin diseases, which has important clinical significance. Accurately determining the depth-resolved elasticity of superficial biological tissue is an important research direction. This paper presents an optical coherence elastography technique that combines surface acoustic waves and shear waves to obtain the elasticity of multilayer tissue. First, the phase velocity of the high-frequency surface acoustic wave is calculated at the surface of the sample to obtain the Young's modulus of the top layer. Then, the shear wave velocities in the other layers are calculated to obtain their respective Young's moduli. In the bilayer phantom experiment, the maximum error in the elastic estimation of each layer was 2.2%. Selleck AT7867 The results show that the proposed method can accurately evaluate the depth-resolved elasticity of layered tissue-mimicking phantoms, which can potentially expand the clinical applications of elastic wave elastography.