Ebbesengeisler0404

Laser written waveguides in crystalline materials can be used to make highly efficient, high gain lasers. The bi-directional emission from such lasers however is typically broadband with poor spectral control. Hybridizing a tapered, mode matched laser written Bragg grating with a broadband YbYAG crystalline waveguide laser, we demonstrate single longitudinal mode output from one end of the device. Careful control of the grating characteristics led to laser thresholds below 90 mW, slope efficiencies greater than 42% and output powers greater than 20 mW.The tunable Stokes laser characteristics based on the stimulated polariton scattering in KTiOPO4 (KTP) crystal and the intracavity frequency doubling properties for the Stokes laser are investigated for the first time. When the pumping laser wavelength is 1064.2 nm, and the angle between the pumping and Stokes beams outside the KTP crystal changes from 1.875° to 6.750°, the obtained tunable Stokes laser wavelength varies discontinuously from 1076.5 nm to 1091.4 nm with four gaps. When the pumping pulse energy is 120.0 mJ, the maximum Stokes pulse energy is 46.5 mJ obtained at the wavelength of 1086.6 nm. By inserting a LiB3O5 (LBO) crystal into the cavity, the obtained frequency-doubled laser wavelength is inconsecutive tunable from 538.5 nm to 543.8 nm. The maximum frequency-doubled laser pulse energy is 15.9 mJ at the wavelength of 543.5 nm.Employing different output couplers and Cr4+YAG saturable absorbers with different initial transmittances in a Q-switched mode-locked (QML) NdLu0.15Y0.85VO4 laser, the symmetry of the Q-switched envelope was optimized and the envelope duration was shortened. By applying the above mentioned optimization into an EO/Cr4+YAG dual-loss-modulated QML NdLu0.15Y0.85VO4 laser, the Q-switched envelope can be further compressed until only containing one mode-locking pulse. Mode-locking pulse energy and peak power up to 1.15 mJ and 3.15 MW, respectively, were achieved. The rate equation theory was utilized to analyze the experimental results, and the theoretical simulation was basically in accordance with the experimental data.We apply an adaptive forward error correction (FEC) allocation strategy to an Elastic Optical Network (EON) operated with shared backup path protection (SBPP). buy T0901317 To maximize the protected network capacity that can be carried, an Integer Linear Programing (ILP) model and a spectrum window plane (SWP)-based heuristic algorithm are developed. Simulation results show that the FEC coding overhead required by the adaptive FEC scheme is significantly lower than that needed by a fixed FEC allocation strategy resulting in higher network capacity for the adaptive strategy. The adaptive FEC allocation strategy can also significantly outperform the fixed FEC allocation strategy both in terms of the spare capacity redundancy and the average FEC coding overhead needed per optical channel. The proposed heuristic algorithm is efficient and not only performs closer to the ILP model but also does much better than the shortest-path algorithm.We present a computational study of the internal optical forces arising in plasmonic gap antennas, dolmen structures and split rings. We find that very strong internal forces perpendicular to the propagation direction appear in these systems. These internal forces show a rich behaviour with varying wavelength, incident polarisation and geometrical parameters, which we explain in terms of the polarisation charges induced on the structures. Various interesting and anomalous features arise such as lateral force reversal, optical pulling force, and circular polarisation-induced forces and torques along directions symmetry-forbidden for orthogonal linear polarisations. Understanding these effects and mastering internal forces in plasmonic nanostructures will be instrumental in implementing new functionalities in these nanophotonic systems.A lab-on-fiber (LOF) optofluidic platform that provides physiologically relevant microenvironment was developed by integrating a long period grating (LPG) coupled with high order cladding mode to achieve high index sensitivity and a liquid-tight capillary tube assembly as a microfluidic chamber for LPG to mimic physiologically relevant microenvironment. We demonstrate the utility of LOF for in situ monitoring the construction of the [chitosan (CHI)/poly (acrylic acid) (PAA)/gentamicin sulfate (GS)/PAA]n multilayers at monolayer resolution as well as evaluating the rate of GS release at a flow rate of 0.127 mL/min at 37 °C in real time. We reveal that GS is released at a faster rate under the dynamic flow condition than in a static medium. Our findings underscore the importance of conducting drug release studies in physiologically relevant conditions.We report a metallic planar lens based on the coupled nanoslits with variable widths for superfocusing. The influence of the interaction between two adjacent nanoslits on the phase delay is systematically investigated using the finite-difference time-domain (FDTD) method. Based on the geometrical optics and the wavefront reconstruction theory, an array of nanoslits perforated in a gold film is optimally designed to achieve the desired phase modulation for light beaming. The simulation result verifies our design in excellent agreement and the realized metallic lens reveals the superfocusing capability of 0.38λ in resolution, well beyond the diffraction limit.A bendable ultra-black material consisting of graphite nanocones and nanowires is fabricated through a simple plasma etching process. The optical properties of the absorber are characterized in the wavelength range of 400-2000 nm with average specular reflectance 0.05 ± 0.03% at normal incidence and the material thickness is only around 5 μm. The reflectance of the absorber remains low at large incident angles and is relatively independent of polarization. Simulations confirm the cooperative effect of the nanowires and nanocones leading to an ultra-black thin carbon material.A calculation based on surface plasmon coupling condition and Maxwell-Garnett equation was performed for predicting the coupling angle shift and thin film thickness in scanning surface plasmon microscopy (SSPM). The refractive index sensitivity and lateral resolution of an SSPM system was also investigated. The limit of detection of angle shift was 0.01°, the limit of quantification of angle shift was 0.03°, and the sensitivity was around 0.12° shift per nm ZnO film when the film thickness was less than 22.6 nm. Two partially connected Au nano-discs with a center-to-center distance of 1.1 μm could be identified as two peaks. The system was applied to image nanostructure defects and a virus-probe functionalized nanoarray. We expect the potential application in nanobiosensors with further optimization in the future.A novel design of decorating microsphere surface with concentric rings to modulate the photonic nanojet (PNJ) is investigated. By introducing the concentric ring structures into the illumination side of the microspheres, a reduction of the full width at half maximum (FWHM) intensity of the PNJ by 29.1%, compared to that without the decoration, can be achieved numerically. Key design parameters, such as ring number and depth, are analyzed. Engineered microsphere with four uniformly distributed rings etched at a depth of 1.2 μm and width of 0.25 μm can generate PNJ at a FWHM of 0.485 λ (λ = 400nm). Experiments were carried out by direct observation of the PNJ with an optical microscope under 405 nm laser illumination. As a result, shrinking of PNJ beam size of 28.0% compared to the case without the rings has been achieved experimentally. Sharp FWHM of this design can be beneficial to micro/nanoscale fabrication, optical super-resolution imaging, and sensing.We report the first experimental study of the effects of coupling phase dispersion on the spectral response of a two-dimensionally coupled quadrupole micro-racetrack resonator. Negative coupling in the system is observed to manifest itself in the sharp stop band transition and deep extinction in the pseudo-elliptic filter response of the quadrupole. The results demonstrate the feasibility of realizing advanced silicon microring devices based on the 2D coupling topology with general complex coupling coefficients.Large-scale integrated silicon photonic circuits suffer from two inevitable issues that boost the overall power consumption. First, fabrication imperfections even on sub-nm scale result in spectral device non-uniformity that require fine-tuning during device operation. Second, the photonic devices need to be actively corrected to compensate thermal drifts. As a result significant amount of power is wasted if no athermal and wavelength-trimmable solutions are utilized. Consequently, in order to minimize the total power requirement of photonic circuits in a passive way, trimming methods are required to correct the device inhomogeneities from manufacturing and athermal solutions are essential to oppose temperature fluctuations of the passive/active components during run-time. We present an approach to fabricate CMOS backend-compatible and athermal passive photonic filters that can be corrected for fabrication inhomogeneities by UV-trimming based on low-loss amorphous-SOI waveguides with TiO2 cladding. The trimming of highly confined 10 μm ring resonators is proven over a free spectral range retaining athermal operation. The athermal functionality of 2nd-order 5 μm add/drop microrings is demonstrated over 40°C covering a broad wavelength interval of 60 nm.Conventional X-ray micro-computed tomography (μCT) is unable to meet the need for real-time, high-resolution, time-resolved imaging of multi-phase fluid flow. High signal-to-noise-ratio (SNR) data acquisition is too slow and results in motion artefacts in the images, while fast acquisition is too noisy and results in poor image contrast. We present a Bayesian framework for time-resolved tomography that uses priors to drastically reduce the required amount of experiment data. This enables high-quality time-resolved imaging through a data acquisition protocol that is both rapid and high SNR. Here we show that the framework (i) encompasses our previous, algorithms for imaging two-phase flow as limiting cases; (ii) produces more accurate results from imperfect (i.e. real) data, where it can be compared to our previous work; and (iii) is generalisable to previously intractable systems, such as three-phase flow.We fabricate a free-standing molybdenum diselenide (MoSe2) saturable absorber by embedding liquid-phase exfoliated few-layer MoSe2 flakes into a polymer film. The MoSe2-polymer composite is used to Q-switch fiber lasers based on ytterbium (Yb), erbium (Er) and thulium (Tm) gain fiber, producing trains of microsecond-duration pulses with kilohertz repetition rates at 1060 nm, 1566 nm and 1924 nm, respectively. Such operating wavelengths correspond to sub-bandgap saturable absorption in MoSe2, which is explained in the context of edge-states, building upon studies of other semiconducting transition metal dichalcogenide (TMD)-based saturable absorbers. Our work adds few-layer MoSe2 to the growing catalog of TMDs with remarkable optical properties, which offer new opportunities for photonic devices.