Broadband optoacoustic characterization of cMUT and PZT transducer directivity in receive mode.
    
    
        
    
    
        
        Proc. SPIE 10139:101391K (2017)
    
    
    
      
      
	
	    Optoacoustic imaging is a rapidly developing area of biomedical imaging due its combination of rich optical contrast and ultrasound depth penetration. Just like conventional pulse-echo ultrasound imaging, optoacoustic tomography relies on the use of ultrasound detector arrays with a large number of elements. The precise knowledge of the transducer's sensitivity is crucial for the prediction of its performance for a given imaging task. Sensitivity characteristics such as the central frequency and bandwidth are routinely characterized. However, this characterization is typically performed solely under normal incidence since the measurement of the angle and frequency depended sensitivity (directivity) is difficult and time consuming with existing ultrasound characterization methods. We present a simple and fast characterization method for broadband directivity measurements of the angular transducer sensitivity based on the optoacoustic effect. The method utilizes a thin absorbing suture in order to generate omnidirectional and broadband optoacoustic signals, which are calibrated using a needle hydrophone. We applied this method to characterize and compare the directivity of a conventional piezoelectric (PZT) transducer to the directivity of a capacitive micromachined ultrasonic (cMUT) transducer. Both technologies showed a similar broadband response at normal incidence and the PZT transducer displayed a more than two times larger signal to noise ratio at normal incidence. However, the cMUT transducer's sensitivity was significantly less angle-depended and outperformed the PZT's sensitivity for angles larger than 20°.
	
	
	    
	
       
      
	
	    
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        Publication type
        Article: Journal article
    
 
    
        Document type
        Scientific Article
    
 
    
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        Keywords
        Angle Of Incidence ; Bandwidth ; Directivity ; Photoacoustic ; Spectrum ; Ultrasound
    
 
    
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        Publication Year
        2017
    
 
    
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        HGF-reported in Year
        2017
    
 
    
    
        ISSN (print) / ISBN
        0277-786X
    
 
    
        e-ISSN
        1996-756X
    
 
    
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        Conference Title
        Ultrasonic Imaging and Tomography
    
 
	
        Conference Date
        11 - 16 February 2017
    
     
	
        Conference Location
        Orlando, Florida, USA
    
 
	
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        Quellenangaben
        
	    Volume: 10139,  
	    Issue: ,  
	    Pages: ,  
	    Article Number: 101391K  
	    Supplement: ,  
	
    
 
    
        
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            SPIE
        
 
        
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        Reviewing status
        Peer reviewed
    
 
     
    
        POF-Topic(s)
        30205 - Bioengineering and Digital Health
    
 
    
        Research field(s)
        Enabling and Novel Technologies
    
 
    
        PSP Element(s)
        G-505590-001
    
 
    
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        Erfassungsdatum
        2017-07-14