The optical design of a hybrid heliostat-parabolic mirror for collecting sunlight at a solarpowered laser head is proposed. The simulated results expressed that the concentrated power at the focal spot of the parabolic mirror is 1,078W.
In recent years, Fresnel lens has significantly improved solar energy consumption. The scientific community considers the imaging and non-imaging Fresnel lens as a solar concentrator. Compared to imaging, non-imaging concentrators usually have a larger acceptance angle, higher optical efficiency, and higher concentration ratios with less volume and shorter focal length. This paper summarizes the saga of the Fresnel lens for solar energy concentration technology. The optical design, fabrication methods, and challenges associated with the Fresnel lens are described in the context of numerous applications including daylighting, photovoltaic (PV), solar-powered lasers, space-concentrated PV, and hydrogen generation.
Three different fiber-coupled laser diode system of size 500 μm are designed and simulated using Zemax optical design software. The performance of each designed system is compared in terms of output power and coupling efficiency. At the wavelength of 808 nm, the output of a 10-watt single emitter laser diode is coupled into the multimode fiber. Since the laser diode beam is highly divergent, in order to reduce the divergence angle and collimate the beam, the ball, cylindrical, and toroidal lenses are used as a collimator. The focused beams are coupled into a 200 μm core diameter multimode fiber, which has a numerical aperture of 0.22. Beam parameter product is calculated as the product of half waist width and half far-field divergence angle to evaluate the beam quality. The ray simulation results revealed that the output power with the ball lens is 9 watts, corresponding to a total coupling efficiency of 90%. Similarly, the calculated output power is 9.2 watt from the cylindrical lens, resulting to a total coupling efficiency of 92%. The calculated output power with the toroidal lens is greater than 9.5 watts, corresponding to a total coupling efficiency of more than 95%. The comparative analysis of newly designed system shows that with a toroidal profile, fiber-coupled laser diode attained the highest coupling efficiency with minimum aberrations.
Silicon is widely used in IR optics, X-Ray optics and electronics applications. These applications require Silicon of
optical quality surface as well as good form accuracy. To get the desired finish and dimensional accuracy, diamond
turning is preferable. Taylor-Hobson Nanoform-250 diamond turning equipment is used to machine flat Silicon mirror.
Negative rake diamond tool is used with a tool nose radius of 1.5 mm. A series of SPDT machining operations are
performed in the sequential combinations of tool feed rate, Spindle Speed and depth of cut. In order to find out the effect
of machining parameters on the Surface Roughness during turning, Response Surface Methodology (RSM) is used and a
prediction model is developed related to average Surface Roughness (Ra) using experimental data. The surface quality is
analyzed in terms of arithmetic roughness (Ra) and Power Spectral Density for uniform evaluation. In addition, a good
agreement between the predicted and measured Surface Roughness is observed.
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