![]() The dependence of the grooves height on the period is exponentially decreasing. Besides, we show how physical height of the grating grooves that allows cancelling zero-th diffraction order for a certain illumination wavelength depends on the metals used to manufacture the grating and its period. Beam-splitting is demonstrated for TE and TM polarization with slightly different dimensional parameters of the diffraction grating. After that, a more rigorous approach such as Rigorous Coupled Waves Analysis (TE and TM polarization) is used to evaluate the proposed diffraction gratings as reflective beam-splitters. Firstly, scalar approach is performed, showing an approximation to the parameters of the grating necessary to achieve beam-splitting. The main idea under the design is as simple as obligating the zero-th diffraction order to be null. This kind of beam-splitter could have potential applications in photonics and optical technologies in which robustness is necessary since it may be manufactured over malleable metallic substrates. The small sources of sound producing these wavelets are known as Huygens' sources Huygens' Principle: tiny pieces of PZT create V-shaped waves that interfere constructively (to form hourglass shape) and destructively (sound beam is cancelled) to create an hourglass-shaped beam.In this work, a reflective beam-splitter based on a metallic Ronchi diffraction grating normally illuminated is designed and analysed.AKA diffraction patterns, or Huygens' wavelets.V-shaped wave is created when the source is about the size of the sound' s wavelength.Definition is imprecise 1 Shallow Focus Deep Focus Smaller diameter PZT Larger diameter PZT Lower frequency Higher frequency Spherical Waves: sound waves produced by very small sources (tiny pieces of PZT) diverge in the shape of a 'V'.Half the focal zone is located in the near zone, and half in the far field.Region around the focus where the beam is relatively narrow.At the beginning of the far zone, beam is only ½ as wide as it is at the transducer at 2 near zone lengths it is same size as transducer at more than 2 near zone lengths it is larger than the diameter of the transducer 5.Region that starts at the focus and extends deeper.Fixed focus transducer- depth is determined by: ○ Transducer diameter ○ Frequency of the sound 4.Phased array- modern, adjustable focus systems.Distance from the transducer to the focus.(Focus is located at end of near zone) 3. Width as it leaves the transducer is the same as the diameter of the active element, it narrows to ½ at the focus.Width is ½ the width of the beam as it leaves the transducer 2.AKA 'focal point', 'end of near zone', 'beginning of far zone', 'middle of focal zone'.2 More divergence Less divergence Smaller diameter Larger diameter Lower frequency Higher frequencyĬhapter 9: Sound Beams Anatomy of a Sound Beam: 1. The small sources of sound producing these wavelets are known as Huygens' sources Huygens' Principle: tiny pieces of PZT create V-shaped waves that interfere constructively (to form hourglass shape) and destructively (sound beam is cancelled) to create an hourglass-shaped beam. ![]() ![]() Chapter 9: Sound Beams Anatomy of a Sound Beam: 1. ![]()
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