Simsgould4253

This paper describes a fast, wide-angle, afocal, catadioptric optical assembly designed and used for the projection of coherent collimated beams in Fourier-sampling computational microscopy, which demands an unorthodox set of optical requirements unmet by traditional imaging designs. The system accepts a diverging set of collimated beams as an input and produces a converging set of collimated beams that overlap on the surface of a target at 5 m scale distances. We derive equations for the focal surfaces relevant for system alignment and report the results of simulations of the optical performance of the system for axially symmetric and asymmetric beam interferometry. We also describe a method to vary the microscope imaging distance by up to one meter through small positional shifts in the optical elements.We have developed an SI-traceable narrow-band tunable radiance source based on an optical parametric oscillator (OPO) and an integrating sphere for the calibration of spectroradiometers. The source is calibrated with a reference detector over the ultraviolet/visible spectral range with an uncertainty of less then 1%. As a case study, a CubeSat spectroradiometer has been calibrated for radiance over its operating range from 370 nm to 480 nm. To validate the results, the instrument has also been calibrated with a traditional setup based on a diffuser and an FEL lamp. Both routes show good agreement within the combined measurement uncertainty. The OPO-based approach could be an interesting alternative to the traditional method, not only because of reduced measurement uncertainty, but also because it directly allows for wavelength calibration and characterization of the instrumental spectral response function and stray light effects, which could reduce calibration time and cost.Using the wave vector surface, we have derived the analytical expressions for the group velocities of the extraordinary light and the ordinary light traveling in an optically uniaxial crystal. Our formulas are in terms of either the wavevector direction or the ray direction, and they use only the principal refractive indices and their frequency dispersions. The algebraic equation for the group velocity surface of the crystal is also derived. While the group velocity is in the same direction as the ray velocity, numerical calculation shows that in the visible region the group velocity is slower than the ray velocity, and the difference between them becomes significant at short wavelengths.Nanosecond dissipative soliton resonance pulse is a demonstration of an all polarization-maintaining (PM) thulium-doped fiber laser in a nonlinear amplifying loop mirror (NALM)-based figure-eight configuration. Each loop of the apparatus includes a controllable power amplifier. With increased amplifier power, pulse width broadens linearly from 3.6 to 13.5 ns, and maximum single pulse energy can reach 27.5 nJ. Interestingly, the output peak power presents two completely opposite proportional effects in terms of the variation of settings for two amplifiers, respectively. The experimental results show that the NALM loop plays an important role for tunable pulse duration, and the unidirectional ring part makes a significant contribution for power scaling.Deflectometry, with its noticeable advantages such as simple structure, large dynamic range, and high accuracy comparable to interferometry, has been one of the powerful metrological techniques for optical surfaces in recent years. In the "null" deflectometric transmitted wavefront testing of refractive optics, ray tracing of the test system model is required, in which both the miscalibration of system geometrical parameters and optical tolerances on tested optics could introduce significant geometrical aberrations in the testing results. In this paper, the geometrical aberration introduced by a system modeling error in the transmitted wavefront testing is discussed. Besides, a calibration method based on polynomial optimization of geometrical aberration is presented for the geometrical aberration calibration. Both simulation and experiment have been performed to validate the feasibility of the proposed calibration method. NSC 74859 The proposed method can calibrate the optical tolerances on tested optics effectively, and it is feasible even with a large geometric error, providing a viable way to address the uncertainty in system modeling in transmitted wavefront testing of freeform refractive optics with large dynamic range.A super-multiview light-field display with horizontal and vertical parallax is realized by time-division and color multiplexing to deliver full-color images to each viewpoint. In the conventional study, an image of a different color is delivered to each viewpoint to induce focal accommodation. In the proposed method, we deliver images of different colors sequentially to generate a full-color image by an after-image effect. Though the number of time-divisions increases in the proposed method, perceived flicker is suppressed by showing different colors at different timings. We compare the observed images given by the proposed method with those given by the conventional method to find out that the former reproduces a natural blur effect when the image is defocused. We also confirm with a psychophysical experiment using a refractometer that the proposed method induces a stronger focal accommodation than other super-multiview methods with a smaller number of time-divisions or with a stronger flicker. The proposed optics is applicable to a near-eye display with a natural focal effect.With the availability of high-power (milliwatts) single-mode tunable laser sources that operate at room temperature across the infrared (IR) region, tunable laser spectrometers have seen an explosion of growth in applications that include commercial, Earth and planetary science, and medical and industrial sensing. While the laser sources themselves have shown steady improvement, the detection architecture of using a single-element detector at one end of a multipass cell has remained unchanged over the last few decades. We present here an innovative new approach using a detector array coupled to an IR-transmissive mirror to image all or part of the multipass spot pattern of the far mirror and record spectra for each pixel. This novel approach offers improved sensitivity, increased dynamic range, laser power normalization, contaminant subtraction, resilience to misalignment, and reduces the instrument power requirement by avoiding the need for "fringe-wash" heaters. With many tens of pixels representing each spot during the laser spectral scan, intensity and optical fringe amplitude and phase information are recorded.