Thermomechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near‐infrared pump‐probe diffraction experiments and finite element simulations

2008 ◽  
Vol 123 (5) ◽  
pp. 3555-3555
Author(s):  
Claudio Giannetti ◽  
Francesco Banfi ◽  
Damiano Nardi ◽  
Bernard Revaz ◽  
Gabriele Ferrini ◽  
...  
Keyword(s):  
Finite Element ◽  
Acoustic Waves ◽  
Near Infrared ◽  
Surface Acoustic Waves ◽  
Thermomechanical Behavior ◽  
Finite Element Simulations ◽  
Pump Probe ◽  
Ordered Arrays

Ladder Type of Leaky Surface Acoustic Waves Filters on Substrate of Lithium Niobate

2021 ◽  
Vol 23 (3) ◽  
pp. 139-147
Author(s):  
A.S. Koigerov ◽  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Acoustic Waves ◽  
Communication Systems ◽  
Surface Acoustic Waves ◽  
Bandpass Filters ◽  
The Finite Element Method ◽  
Frequency Responses ◽  
Method Of Extraction ◽  
Element Method

High requirements on the electrical parameters of the filters are made in wireless radio communication systems. A number of tasks require bandpass filters with relative bandwidths of 8-12 %. In this case, the filter must have insertion losses of not more than 10 dB, have a rejection is not worse than 40 dB, unevenness in the bandwidth of not more than 1 dB. In addition, the amplitude frequency responses of the filter must have steep slopes due to the closely spaced frequency bands of neighboring communication systems. Due to its small size and other advantages, ladder resonator filters on surface acoustic waves are widely used in communication systems. To realize the high requirements of this type of filters, it is necessary not only to select all the topology parameters of the individual resonators included in the filter very accurately, but also to have a good computational theory and the necessary material parameters for the selected model at the design stage. Purpose: to show on the example of comparison of calculated and experimental frequency responses of ladder filters the validity of the method of extraction of the necessary parameters obtained for an infinite periodic structure by the finite element method for calculating of finite structures of real inter digital transducer and reflective gratings. Results: the method of extraction of parameters necessary for calculation by the method of connected modes on the basis of P-matrices is offered. The technique is based on the analysis of infinite periodic electrodes by the finite element method. Bandpass filters with a relative bandwidth 8-12 % on a piezosubstrate 49° YX LiNbO3 were designed and manufactured based on the proposed theory. It is shown that for this material, the calculation must take into account the direct radiation of bulk acoustic waves, since the design of ladder type filters, the radiation falls into the projected bandwidth of the filters. These calculations are confirmed by the results of experiments.

scholarly journals Liquid Droplet Microresonators

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 473 ◽  
Author(s):  
Antonio Giorgini ◽  
Saverio Avino ◽  
Pietro Malara ◽  
Paolo De Natale ◽  
Gianluca Gagliardi
Keyword(s):  
Acoustic Waves ◽  
Near Infrared ◽  
Liquid Droplet ◽  
Scattered Light ◽  
Surface Acoustic Waves ◽  
Optical Quality ◽  
Whispering Gallery Modes ◽  
New Paradigm ◽  
Frequency Locking ◽  
Whispering Gallery

We provide here an overview of passive optical micro-cavities made of droplets in the liquid phase. We focus on resonators that are naturally created and suspended under gravity thanks to interfacial forces, illustrating simple ways to excite whispering-gallery modes in various slow-evaporation liquids using free-space optics. Similar to solid resonators, frequency locking of near-infrared and visible lasers to resonant modes is performed exploiting either phase-sensitive detection of the leakage cavity field or multiple interference between whispering-gallery modes in the scattered light. As opposed to conventional micro-cavity sensors, each droplet acts simultaneously as the sensor and the sample, whereby the internal light can detect dissolved compounds and particles. Optical quality factors up to 107–108 are observed in liquid-polymer droplets through photon lifetime measurements. First attempts in using single water droplets are also reported. These achievements point out their huge potential for direct spectroscopy and bio-chemical sensing in liquid environments. Finally, the first experiments of cavity optomechanics with surface acoustic waves in nanolitre droplets are presented. The possibility to perform studies of viscous-elastic properties points to a new paradigm: a droplet device as an opto-fluid-mechanics laboratory on table-top scale under controlled environmental conditions.

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