We experimentally investigate the acoustic characteristic of micro plasma shock wave obtained by femtosecond laser ablation of silicon wafer surface using F-P optical fiber acoustic sensor with anti electromagnetic interference. The experimental results show that each of the femtosecond laser pulse can only produce a plasma shock wave. Under the different femtosecond laser energy, the acoustic ...

We present a new concept for waveguide acousto-optical devices based on coupled Mach–Zehnder interferometers driven by acoustic waves. These acousto-optical multiple interference devices use the periodic refractive index modulation induced by the acoustic wave to realize functionalities such as ON/OFF switching for an arbitrary time interval, as well as for efficient light modulation at high ha...

optical interferometry is being used as an efficient tool to analyse smooth surfaces for more than a century. although, due to introduction of novel computer assisted analyzing techniques and array detectors, like ccd, the speed and the precision of processing have been increased tremendously, but the main equation involved is not changed. the main equation is the intensity distribution in the ...

Optical fiber based Extrinsic Fabry-Perot Interferometric (EFPI) sensor significantly emerged as an advanced optical sensor for the health monitoring of civil, mechanical and aeronautical structures. This sensor responds its well capability also towards the measurement of acoustic/shock wave pressure. This paper presents an approach for high blast (acoustic/shock wave) pressure measurement usin...

Information on the distance to the target is very important to achieve the practical use of hands-free speech interfaces and nursing-care robots. Many distance measurement methods, which use the time-of-flight (TOF) of a reflected wave measured with reference to the transmitted wave, have been proposed. However, these methods cannot measure short distances because the transmitted wave, which ha...

This paper did a radial compression fatigue test on glass fiber winding composite tubes, collects acoustic emission signals on different fatigue damages stages, used time frequency analysis techniques of modern wavelet transform, and analyzed the wave form and frequency characteristics of fatigue damaged acoustic emission signals. Three main frequency bands of acoustic emission signal had been ...

Extensive applications of carbon dioxide (CO2) in various fields, such as food industry, agricultural production, medical and pharmacological industries, have caused a great demand for high-performance CO2 sensors. However, most existing sensors suffer from poor performance wet environment often cannot work accurately high humidity condition. In this study, quartz crystal resonator (QCR) coated...