Acousto-electromagnetic investigation of physical properties of an object
First Claim
1. A method of investigating physical properties of an object, comprising:
- applying to the object acoustic vibration localised in two or three dimensions in a region in the object, the acoustic vibration comprising a carrier wave that is amplitude modulated by an AM waveform, the carrier wave being selected to provide the localization of the acoustic vibration and the AM waveform including a frequency component selected to provide a vibration of the object of greater magnitude than the carrier wave;
simultaneously illuminating the object with an illuminating electromagnetic wave that has an EM frequency in a range extending up to 30 THz, the vibration direction of the acoustic vibration having a component parallel to the propagation direction of the illuminating electromagnetic wave so that the acoustic vibration of the object in the region generates a scattered electromagnetic wave including a set of Doppler components shifted from the frequency of the illuminating electromagnetic wave by frequencies of the vibration of the object caused by the acoustic vibration and multiples thereof; and
receiving the scattered electromagnetic wave generated in the region,detecting, from the received, scattered electromagnetic wave, a Doppler component shifted from the frequency of the illuminating electromagnetic wave by the frequency of said frequency component of the AM waveform; and
outputting a signal representing at least one characteristic of the detected Doppler component.
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Accused Products
Abstract
An imaging system for an object such as human or animal tissue applies acoustic vibrations localized in two or three dimensions and simultaneously illuminates the object with an illuminating electromagnetic wave. The acoustic vibration comprises a carrier wave that is amplitude modulated by an AM waveform. The carrier wave is selected to provide the localization of the acoustic vibration, whereas the AM waveform includes a frequency component selected to provide a vibration of the object of greater magnitude than the carrier wave. To detect a Doppler component shifted by the frequency of said frequency component of the AM waveform, a signal processing apparatus comprises a phase locked-loop locked to the EM frequency, producing a frequency-demodulated signal comprising the set of the Doppler components, and a lock-in amplifier configured to extract a signal at a reference frequency equal to the frequency of a frequency component of the AM waveform.
40 Citations
36 Claims
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1. A method of investigating physical properties of an object, comprising:
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applying to the object acoustic vibration localised in two or three dimensions in a region in the object, the acoustic vibration comprising a carrier wave that is amplitude modulated by an AM waveform, the carrier wave being selected to provide the localization of the acoustic vibration and the AM waveform including a frequency component selected to provide a vibration of the object of greater magnitude than the carrier wave; simultaneously illuminating the object with an illuminating electromagnetic wave that has an EM frequency in a range extending up to 30 THz, the vibration direction of the acoustic vibration having a component parallel to the propagation direction of the illuminating electromagnetic wave so that the acoustic vibration of the object in the region generates a scattered electromagnetic wave including a set of Doppler components shifted from the frequency of the illuminating electromagnetic wave by frequencies of the vibration of the object caused by the acoustic vibration and multiples thereof; and receiving the scattered electromagnetic wave generated in the region, detecting, from the received, scattered electromagnetic wave, a Doppler component shifted from the frequency of the illuminating electromagnetic wave by the frequency of said frequency component of the AM waveform; and outputting a signal representing at least one characteristic of the detected Doppler component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A system for investigating physical properties of an object, the system comprising:
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an acoustic transducer apparatus arranged to apply to the object acoustic vibration localised in two or three dimensions in a region in the object, the acoustic vibration comprising a carrier wave that is amplitude modulated by an AM waveform; a transmitter arrangement arranged to illuminate the object with an illuminating electromagnetic wave having a frequency in a range extending down from 30 THz simultaneously with the application of acoustic vibration, the vibration direction of the acoustic vibration having a component parallel to the propagation direction of the illuminating electromagnetic wave so that so that the vibration of the object caused by the acoustic vibration in the region generates a scattered electromagnetic wave including a set of Doppler components shifted from the frequency of the illuminating electromagnetic wave by frequencies of the vibration of the object caused by the acoustic vibration and multiples thereof; and a receiver arrangement arranged to receive the scattered electromagnetic wave generated in the region; and a signal processing apparatus arranged to detect, from the received, scattered electromagnetic wave, a Doppler component shifted from the frequency of the illuminating electromagnetic wave by the frequency of a frequency component of the AM waveform, and to output a signal representing at least one characteristic of the detected Doppler component. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification