A fiber-optic acoustic pressure sensor based on a large-area nanolayer silver diaphragm is demonstrated with a high dynamic pressure sensitivity of 160  nm/Pa at 4 kHz frequency. The sensor exhibits a noise limited detectable pressure level of 14.5  μPa/Hz(1/2). Its high dynamic pressure sensitivity and simple fabrication process make it an attractive tool for acoustic sensing and photo-acousti...

Measurement of stress transients generated by a 400ns pulsed HF laser in an infrared fluoride glass fiber has been made using fast time – response piezoelectric film transducer. Acoustic signals up to 12 mV with frequencies ranging in megahertz generated by 21 mJ laser pulse when passed through the fiber axis in the linear region. It is shown that useful information such as onset of non - linea...

The work presented in this paper addresses the problem of creating a low-cost, intrinsically safe, low-level gas sensor for mining and transportation applications. The system is to have no electrical connection to the remote sensor head, and as such relies on optical transmission via fibre. An integral component is the acoustically resonant chamber, which is excited by an appropriate laser exci...

On the basis of photo acoustic effect, photo acoustic spectroscopy is an unusual form of spectroscopy which uses both light and sound and is based on the absorption of electromagnetic radiation by analyte molecule. Photo acoustic effect offers a minimal or no sample preparation, the ability to look at opaque and scattering sample and the capability to perform depth profiling experiment. These f...

underwater acoustic wireless sensor network (uawsn) use acoustic signalsto transmit data. acoustic signals in underwater environment have high bit errorrate, long propagation delay and limited bandwidth. another constraint in uwasnis energy. due to these constraints, design of energy and bandwidth efficient andpropagation delay aware mac protocol is a great challenge in uwasn.underwater sensor ...

Long-term photo-acoustic stimulation leads to changes in the composition of saliva, which may have a key contribution to the effectivity of this technique in easing mucosal symptoms of psychosomatic patients. In the present study a significant (P <or= 0.01) increase in salivary 70 kDa heat shock protein, Hsp70 was demonstrated in human whole saliva after repeated photo-acoustic stimulation. Inc...

In the present work, the photo-acoustic emission from nanostructured copper/porous silicon hybrid systems was studied. Copper nanoparticles were grown by photo-assisted electroless deposition on crystalline silicon and nanostructured porous silicon (nanoPS). Both the optical and photo-acoustic responses from these systems were determined. The experimental results show a remarkable increase in t...