Hodgesvelez4643

Results show that in clear water (no-algae scenario), the water-pump-induced movement effect over the mean and variance of the received optical power can be neglected, while when microalgae are present, the average optical power value decreases and the variance increases with all measured wavelengths. Finally, the SNR penalty due to the movement of microalgae is statistically evaluated.Oblique incidence is the general working state for multilayer diffractive optical elements (MLDOEs) in an imaging optical system. The polychromatic integral diffraction efficiency (PIDE) is very sensitive to the incident angle. Therefore, it is necessary to analyze the effect of tilt error on diffraction efficiency/PIDE with oblique incidence. The theoretical model of the relationship between the diffraction efficiency and tilt error with oblique incidence is presented, and the effect of tilt error on diffraction efficiency/PIDE is analyzed. The analysis model of comprehensive PIDE for a certain range of incident angles and the tilt error for MLDOEs is established. The simulation results showed that the comprehensive PIDE is sensitive to tilt angle with oblique incidence, and the tolerance of the tilt error angle can be determined by the comprehensive PIDE. The tilt error tolerance is furthermore investigated with decenter error based on the maximum of comprehensive PIDE. The method and results can be used to guide the tolerance formulation of tilt error for MLDOEs in hybrid optical systems.Efficient measurement of a line laser sensor can be achieved by combining it with a multi-axis platform. However, the measuring results are significantly affected by the precision of the platform. To provide a criterion for verifying and compensating for the geometric errors of a platform, a measuring method based on a line laser sensor for angular motion errors is proposed for the first time to the best of our knowledge in this work. The principles of separating and simultaneously detecting the yaw, roll, and pitch errors are elaborated. Based on this, the detection model is built for a three-dimensional platform. Under such an experimental condition, the stability and accuracy of the line laser sensor is tested, and the experimental results revealed small deviations of 3 µm and 10 µm in z axis and x axis, respectively. Ultimately, a series of experiments is performed to verify the feasibility and repeatability of the method. The yaw experimental results indicate that the trend and rule of error conform to the measured value by a laser interferometer, and the maximum variation value is 0.0075 mrad.In this research, we present a novel device that solves the reduced visual acuity caused by involuntary movements of the retina in nystagmus. The proposed solution comprises a contact lens that moves together with the eyeball and an ophthalmic lens (spectacles). Our work has three parts numerical simulation of the proposed solution, an experimental optical bench procedure, and a clinical experiment, with nonnystagmus subjects, in which we mimicked the uncontrolled eye movements in nystagmus. In the numerical and experimental bench sections of this study, we show that the proposed optics produces a clear and stable image on a screen. In the clinical study, subjects with the device felt only small movements of the image when they moved their eyes across the field of view. They described a magnification resulting in narrowing the field of view, and therefore had to move their heads to see the space of the room. This follows the theoretical expectation for the proposed concept. Thus, the proposed device may help nystagmus subjects fixate the image on the center of the retina and thus enable improved visual acuity. The device may be used in young children suffering from nystagmus to prevent amblyopia.The motivation behind time-resolved Raman spectroscopy for planetary surface exploration is (1) to provide comprehensive identification of minerals (nearly all rock-forming minerals and weathering products) and many organics of prime importance including fossilized carbonaceous materials; (2) to do so ensuring that it is possible to characterize even the most sensitive materials that would be altered by current state-of-the-art pulsed lasers (e.g., dark minerals, organics). These goals are accomplished here using a lightweight, high-speed (MHz) pulsed ( less then 100ps) Raman spectrometer based on a high-speed microchip laser combined with a single photon avalanche diode detector array. Using a Mars analog sample set and an automated grid sampling technique, we demonstrate consistent identification of major minerals and kerogen detection at ∼≥1% by volume, without losses typically associated with the two biggest problems fluorescence interference and sample damage. Despite improvements, we find that time-resolved Raman spectroscopy is still limited by the availability of a suitable laser and detector. As technology advances and such devices become available, we expect that this technique will hold an important place in Raman spectroscopy for both commercial and planetary science applications. MLN0128 mw We also discuss the utility of Raman point mapping for planetary science (e.g., in comparison with other common techniques like infrared reflectance spectroscopy) and conclude that the choice of technique must be planetary mission-specific; one must consider whether incurring the time to map single microscopic points is worthwhile, and how many points would be sufficient to gain the required information to characterize the surface.We present a continuously tunable silicon photonics assisted radio frequency (RF) phase shifter using a coupled microring resonator. Using the coupled cavity, we demonstrate a sub-1 dB power penalty for a RF bandwidth of 34.5 GHz (9-43.5 GHz) and a phase shift of π over the reported frequency range. Rigorous optimization of the cavity design using the coupled-mode theory is carried out to realize ultranarrow resonance peaks with a low-extinction ratio and large phase shift. Thermal tuning of the cavity is used to tune the phase while all-optical tuning is exploited to achieve broadband operation. We present a detailed simulation and experimental study of the proposed configuration. The proposed device configuration exhibits a configurable resonance linewidth and extinction ratio that allows for a broad bandwidth and an extremely low power penalty microwave phase shifter. We believe the demonstration would allow better integration of the on-chip functional elements of integrated microwave photonics.