High power acoustic resonator with integrated optical interfacial elements

Abstract

An optical element, which may be part of a system for optical analysis of a material in contact with it, is kept clean by means of the vibrations of a high power acoustic resonator. More specifically, but not by way of limitation, in certain embodiments of the present invention, one or more optical interfacial elements may be integrated with a high power acoustic resonator to provide a robust sensing device that may provide for acoustic cleaning of the optical interfacial elements and/or combining optical and acoustic measurements made by the integrated system for analysis purposes. In certain aspects, the high power acoustic resonator may include an acoustic horn for focusing acoustic energy and the optical interfacial elements may be integrated with the acoustic horn.

1 . A method for acoustically cleaning an optical interfacial element integrated with a high power acoustic resonator, comprising the steps of:
 vibrating the high power acoustic resonator, wherein the high power acoustic resonator is coupled with the optical interfacial element; and   transmitting the vibrations of the high power acoustic resonator onto the optical interfacial element to provide for acoustic cleaning of the optical element.   
     
     
         2 . The method of  claim 1 , wherein amplification of vibrations from the high power acoustic resonator is achieved by shaping an acoustic horn and integrating an optical conduit to the optical interfacial element within the acoustic horn. 
     
     
         3 . The method of  claim 1  wherein the acoustic resonator comprises:
 an acoustic body having a first end and a second end, wherein the first end comprises a base of the acoustic body and the second end defines a surface with an opening disposed in the defined surface configured to provide access to an interior of the acoustic body; and   a transducer coupled with the first end and configured to vibrate the acoustic body.   
     
     
         4 . The method of  claim 3  wherein the optical interfacial element is disposed at or proximal to the said opening of the acoustic body, is configured to provide for the transmission of electromagnetic radiation into and out of the optical interfacial elements, and is also configured to seal the interior of the acoustic body from an external environment. 
     
     
         5 . The method of  claim 1 , wherein the second end of the acoustic body defines a plane surface. 
     
     
         6 . The method of  claim 1  wherein the second end of the acoustic body is positioned to experience an antinode during vibration of the acoustic resonator. 
     
     
         7 . The system of  claim 1 , wherein the optical interfacial element comprises one of natural diamond, synthetic diamond, sapphire, silica, silicon, germanium, zinc selenide, zinc sulphide, barium fluoride, calcium fluoride and yttrium oxide. 
     
     
         8 . The system of  claim 1 , wherein the acoustic body comprises titanium. 
     
     
         9 . The system of  claim 1 , wherein the acoustic body comprises stainless steel. 
     
     
         10 . The system of  claim 1 , wherein the transducer comprises a piezoelectric element. 
     
     
         11 . The system of  claim 1 , wherein the optical element is disposed at a distance less than or equal to λ/5 from the surface defined by the second end of the acoustic body, and wherein λ, is the wavelength of an acoustic wave generated by the high power acoustic resonator in the acoustic horn. 
     
     
         12 . The method of  claim 1  wherein an optical system is configured to provide an optical path or paths between the first end of the acoustic body and the optical interfacial element located in the opening in the second end of the acoustic body
 the said optical system passing from the first end to the second end of the acoustic body entirely within a volume defined by an outer surface of the acoustic body.   
     
     
         13 . The system of  claim 1 , wherein the optical interfacial element integrated with the high power acoustic resonator is configured to function at temperatures in excess of 200 degrees Centigrade. 
     
     
         14 . The system of  claim 1 , wherein the optical interfacial element integrated with the high power acoustic resonator is configured to function in fluid pressures exceeding 700 bar. 
     
     
         15 . The method of  claim 1  wherein the optical interfacial element is configured to contact a material to be optically analyzed and to transmit electromagnetic radiation from an electromagnetic radiation source or to the electromagnetic radiation detector. 
     
     
         16 . A method for acousto-optically determining physical properties of a substance located at a sensing surface of a high power acoustic resonator, the sensing surface comprising a surface of an optical interfacial element that is optically coupled with an optical conduit passing through the high power acoustic resonator, comprising the steps of:
 oscillating the high power acoustic resonator in a resonance mode;   monitoring a frequency of the resonance mode of the high power acoustic resonator;   transmitting a beam of electromagnetic radiation down the optical conduit, through the optical element and onto the substance;   reflecting a portion of the beam of electromagnetic radiation from the substance or transmitting the beam through the substance;   measuring one or more spectral properties of the portion of the electromagnetic beam reflected from, or transmitted through, the substance; and   processing the frequency of the resonance mode and the one or more spectral properties to determine the physical properties of the substance.   
     
     
         17 . The method of  claim 16 , wherein reflecting a portion of the beam of electromagnetic radiation comprises creating an internal reflection surface from which a portion of the electromagnetic beam is reflected. 
     
     
         18 . The method of  claim 16 , wherein the step of oscillating the high power acoustic resonator in a resonance mode comprises longitudinally oscillating the high power acoustic resonator.