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Photonic delay-based reservoir computing (RC) has gained considerable attention lately, as it allows for simple technological implementations of the RC concept that can operate at high speed. In this paper, we discuss a practical, compact and robust implementation of photonic delay-based RC, by integrating a laser and a 5.4 cm delay line on an InP photonic integrated circuit. We demonstrate the operation of this chip with 23 nodes at a speed of 0.87 GSa/s, showing performances that is similar to previous non-integrated delay-based setups. We also investigate two other post-processing methods to obtain more nodes in the output layer. We show that these methods improve the performance drastically, without compromising the computation speed.The scattering and resonant properties of optical scatterers/resonators are determined by the relative ratios among the associated multipole components, the calculation of which usually is analytically tedious and numerically complicated for complex structures. Here we identify the constraints as well as the relative relations among electromagnetic multipoles for the eigenmodes of symmetric scatterers/resonators. By reducing the symmetry properties of the vector spherical harmonic waves to those of the modified generating functions, we systematically study the required conditions for electromagnetic multipoles under several fundamental symmetry operations, i.e., 2D rotation and reflection operations and 3D proper and improper rotations. Taking a 2D scatterer with C4v as an example, we show that each irreducible representation of C4v can be assigned to corresponding electromagnetic multipoles, and consequently the constraints of the electromagnetic multipoles can be easily extracted. Such group approach can easily be extended to more complex 3D scatterers with higher symmetry group. Subsequently, we use the same procedure to map out the complete relation and constraint on the electromagnetic multipoles of a 3D scatterer imposed by D3h symmetry. Our theoretical analyses are in perfect agreements with the fullwave finite element calculations of the eigenmodes of the symmetric scatters.The singlet plenoptic camera, which consists of a single lens, microlens array (MLA) and image sensor, possesses the superiority that the imaging system is compact and lightweight, which is beneficial to miniaturization. However, such plenoptic cameras suffer from severe optical aberrations and their imaging quality is inferior for post-capture processing. Therefore, this paper proposes an optical-aberrations-corrected light field re-projection method to obtain high-quality singlet plenoptic imaging. First, optical aberrations are modeled by Seidel polynomials and included into point spread function (PSF) modeling. The modeled PSF is subsequently used to reconstruct imaging object information. Finally, the reconstructed imaging object information is re-projected back to the plenoptic imaging plane to obtain high-quality plenoptic images without optical aberrations. PSF modeling is validated by a self-built singlet plenoptic camera and the utility of the proposed optical-aberrations-corrected light field re-projection method is verified by numerical simulations and real imaging experiments.For scanning systems the resolution, distortion as well as the telecentricity are important performance criteria. For two-dimensional scanning systems, scan mirrors deflecting in only one transverse direction are not allowing for telecentricity in x and y simultaneously in case of an axisymmetric system. It is possible to achieve two-dimensional telecentricity by splitting the pupils in x- and y-direction and shifting the principal planes in one dimension by changing the focal power using an anamorphic setup. However, for higher specifications concerning a large aperture and wide scanning angle, using cylindrical lenses are not enough to achieve a good system quality. It has been proved in many researches that freeform surfaces are effective to improve the resolution of systems without rotational symmetry. In this work, a systematic case study is presented to investigate the potential of freeform surfaces to improve the resolution, telecentricity, and distortion simultaneously. It is shown as a result that freeform surfaces offer large correction ability in all the three aspects concerning high specifications of 2D-telecentric anamorphic scan systems. This contribution provides the insight into the application of freeform surfaces in non-rotationally symmetric optical systems with refractive components.Simultaneous multi-point multi-parameter flow measurement using Interferometric Rayleigh scattering (IRS) at 100-kHz repetition rate is demonstrated. Using a burst-mode laser and an un-intensified high-speed camera, interferograms are obtained that contain spatial, temporal and scattered light frequency information. The method of analysis of these interferograms to obtain simultaneous multi-point flow velocity and temperature measurements is described. SH-4-54 mouse These methods are demonstrated in a 100-kHz-rate study of a choked, under-expanded jet flow discharged by a convergent nozzle. Measurement results and uncertainties are discussed. The 100-kHz IRS technique with un-intensified imaging is applicable in large-scale wind tunnels for the study of unsteady and turbulent flows.We report laser operation of PrYAlO3 pumped by a frequency-doubled optically pumped semiconductor laser. Continuous-wave laser oscillations at around 622 nm, 662 nm, and 747 nm were demonstrated in plano-concave or/and plano-plano cavities. The maximum slope efficiencies were found to be 37%, 35%, and 59%, respectively, which are record-high values for PrYAlO3 lasers. Furthermore, lasing at 622 nm was demonstrated at room temperature for the first time to the best of our knowledge.We reveal the potential of bound states in the continuum (BIC) to enhance the nonlinear response in specialty optical resonators in the presence of gain and loss. We demonstrate this phenomenon in a square core-shell AlGaAs nanowire having a proper engineered spatial variation of gain and loss to sustain quasi-BICs. The presence of these high-quality modes at both fundamental and second-harmonic wavelengths leads to an extremely high enhancement in second harmonic generation, thus preluding a framework to fabricate composite media with high effective nonlinearity.