Pikekelley7052

Breath sensing is an effective tool for health monitoring. Previously, high-mesa waveguide structures have been proposed by our group for realizing a compact breath-sensing photonic circuit. By using the doped SiO2 as the waveguide core, 50% concentration CO2 has been detected. One issue of preventing parts per million (ppm)-order detection is the low portion of evanescent light (Γair=2.2%) in the doped SiO2 waveguides. In order to realize low propagation loss α and high Γair simultaneously, thin silicon (Si) waveguides with a Γair as high as 37.6% have been proposed and fabricated in this work. A thermal oxidation technique was applied to further reduce α, so that α was decreased from 1.45 to 0.84 and 0.29 to 0.2 dB/cm for the 0.5 and 3-µm-wide waveguide, respectively. According to our analysis, the significantly decreased α is attributed to recovering the damaged Si core and smoothing the waveguide sidewalls. The high Γair and effective loss reduction show a promising potential of applying Si high-mesa waveguides to realize ppm-order sensing.The shortest path is an extensive algorithm problem in graph theory. When faced with a huge amount of data in the shortest path problem, the problem with using traditional algorithms is the slow operation speed and high power consumption. To address these problems, this paper proposes a fully parallel matrix (FPM) algorithm. It uses the matrix multiplication principle and one-step modified signed-digit (MSD) adder, which can effectively implement parallel computing in ternary optical computers (TOCs). Finally, we compare clock cycles, and the results show that the TOC-based FPM algorithm can efficiently reduce the calculation time when solving the shortest path problem.The Lyot coronagraph is a widely known astronomical instrument used to realize direct imaging of exoplanets, and designing transmittance of an apodizer and Lyot stop is the key to obtaining high-contrast imaging. In this paper a new (to the best of our knowledge) optimization procedure used to design the apodizer and Lyot stop in the Lyot coronagraph is proposed. A two-step optimization program is established to obtain the optimum transmittance of an apodizer and Lyot stop in a sequential way. By using the optimized apodizer and Lyot stop obtained through the proposed optimization procedure, both the stellar light and its diffraction light could be strongly suppressed. Numerical results indicate that such an optimized Lyot coronagraph can produce a 1e-10 extinction of the stellar light near the diffraction limit (1.59λ/D), and a high contrast imaging of 1e-07 could still be obtained even with the influence of light intensity of planets themselves. In addition, the two-step optimization procedure brings in two benefits. First, the two-step optimization is approximately 1000 times faster than the joint optimization method [J. Astron. Telesc. WZB117 inhibitor Instrum. Syst.2, 011012 (2016)2329-412410.1117/1.JATIS.2.1.011012]. Second, the optimum transmittance of the Lyot stop is binary, and therefore, the requirements of the production process are reduced, resulting in a greatly reduced cost. At the same time, the performance of the optimized Lyot coronagraph is also analyzed in the case of a monochromatic light incident and bandwidth light incident, and the effect of the diameter of the Lyot stop on the results is also discussed in this paper, which makes sense when designing a coronagraph.A coupler is a device that allows interconversion of angular momentum of the optical beam among spin and orbital parts, without absorbing any angular momentum. In this paper, we demonstrate that a q-plate with q=1 can act as a coupler for any of the polarization distribution that can be represented by a point on a Poincare sphere (PS), or on a higher-order PS, or on a hybrid-order PS. A q-plate with any q-value can act as a coupler for polarization distribution that can be represented by an equatorial point on any of these spheres. It is also possible to find a q-plate with an appropriate q-value that can act as a creation or annihilation operator that raises or lowers the polarization singularity index. The q-plate being a coupler and made of half-wave plate segments, the singularity index change is concomitant with the helicity inversion of C-points. Interconversion of bright and dark C-points is possible by using a q-plate.In this work, laser-induced breakdown spectroscopy (LIBS) has been used for the quantitative and qualitative analysis of the sage sample using the calibration-free LIBS (CF-LIBS) technique. The sage plasma is generated by focusing the second harmonics (532 nm) of a Q-switched NdYAG laser with a repetition rate of 10 Hz and pulse duration of 5 ns. The emission spectra are recorded using a LIBS 2000 detection system spectrometer consisting of five high-resolution spectrometers covering a wavelength range from 200 to 720 nm. The optical emission spectra of the sage sample reveal the spectral lines of Fe, Ca, Ti, Co, Mn, Ni, and Cr. The plasma temperature and electron number density of the neutral spectral lines of the pertinent elements have been deduced using the Boltzmann plot and Stark-broadening line profile method, with average values 8855±885K and 3.89×1016cm-3, respectively. The average values of the plasma parameters were used for the quantification of the detected elements in the sample. Based on the calibration-free method, the measured results demonstrate that Fe is the major constituent in the sample, having a percentage concentration of 48.1%, while the remaining elements are Ca, Ti, Co, Mn, Ni, and Cr, with percentage concentrations 0.7%, 5.3%, 8%, 11%, 12.3%, and 14.6%, respectively. This study demonstrates the feasibility of LIBS for the compositional analysis of major and trace elements present in the plant samples and its further applications in medicine.We present the design and characterization of a zinc-indiffused periodically poled lithium-niobate ridge waveguide for second-harmonic generation of ∼390nm light from 780 nm. We use a newly developed, broadband near-infrared vertical external-cavity surface-emitting laser (VECSEL) to investigate the potential for lower-footprint nonlinear optical pump sources as an alternative to larger commercial laser systems. We demonstrate a VECSEL with an output power of 500 mW, containing an intracavity birefringent filter for spectral narrowing and wavelength selection. In this first demonstration of using a VECSEL to pump a nonlinear waveguide, we present the ability to generate 1 mW of ∼390nm light with further potential for increased efficiency and size reduction.