Applied optics
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Aspheric non-null testing, as an alternative to the traditional null testing, achieves more flexible measurements. However, figure-error reconstruction in non-null tests has always been difficult due to the presence of retrace error. A novel method with reverse optimization is proposed for aspheric figure-error reconstruction in a non-null interferometer. ⋯ Through the reverse optimization process with iterative ray tracing, the optimal solutions can be extracted and the desired figure error is reconstructed with a simple fitting procedure. Numerical simulations verifying the high accuracy of the proposed method are presented with error considerations. A set of experiments has also been carried out to demonstrate the validity and repeatability of this method.
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A general method for the calculation of paraxial design parameters of a double-sided telecentric zoom lens system with three components is given. Formulas that define the interval distances between components while zooming, the extremum of magnification, and the magnification of each component are derived. ⋯ As a result of the study, a classification of three-component double-sided telecentric zoom lenses is given, which is based on the magnification, signs of component optical power, and the position of stop while zooming. Some numerical examples are given in the third section of the paper.
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A systematic approach for the aberration correction of zoom systems is presented. It is assumed that the powers and movements of the components of the zoom systems are known. Each component is considered as a system of thin lenses in contact. ⋯ In most of the zoom lens systems it is important to achieve stability in the primary aberrations of the system over the zoom range. This is facilitated by proper formulation of the merit function for the optimization process. Investigations have been carried out on four-component zoom lenses, and an ab initio structure of a four-component zoom lens is presented.
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The performances of traditional laser-induced breakdown spectroscopy (LIBS) and laser ablation-LIBS (LA-LIBS) were compared by quantifying the total elemental concentration of potassium in highly heterogeneous solid samples, namely soils. Calibration curves for a set of fifteen samples with a wide range of potassium concentrations were generated. The LA-LIBS approach produced a superior linear response different than the traditional LIBS scheme. ⋯ Results showed an acceptable linear response for Ca, Fe, Mg, and K while poor signal responses were found for Na and Mn. Signs of remaining matrix effects for the LA-LIBS approach in the case of soil analysis were found and discussed. Finally, some improvements and possibilities for future studies toward quantitative soil analysis with the LA-LIBS technique are suggested.
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A method is presented for the calculation of paraxial design parameters of a double-sided telecentric zoom lens with easy variation of the magnification range. The telecentric lens consists of a zoom lens with a fixed distance between focal points and a lens with a fixed focal length. The third-order aberration analysis is also performed, and spot diagrams are calculated for two f-number values.