摘要:
A system and method of detecting acousto-photonic emissions in optically turbid media that provide increased levels of detection sensitivity. The detection system includes an ultrasonic transducer, a laser, a photo-detector for detecting ultrasound-modulated laser light, and circuitry for processing the detected signals for subsequent analysis. The ultrasonic transducer generates an ultrasonic wave that propagates within an optically turbid medium. The laser generates a coherent light beam, which is split to form signal and reference beams. The signal beam is sent through the turbid medium, where it is phase modulated by the ultrasound. The ultrasound-modulated signal beam is provided to a photo-refractive crystal for subsequent interference with the reference beam to convert the phase modulation to intensity modulation. The DC offset of the signal beam intensity provides a measure of the magnitude of the mean phase shift induced by the ultrasound on the multiply scattered optical field within the turbid medium.
摘要:
A system and method of detecting acousto-photonic emissions in optically turbid media that provide increased levels of detection sensitivity. The detection system includes an ultrasonic transducer, a laser, a photo-detector for detecting ultrasound-modulated laser light, and circuitry for processing the detected signals for subsequent analysis. The ultrasonic transducer generates an ultrasonic wave that propagates within an optically turbid medium. The laser generates a coherent light beam, which is split to form signal and reference beams. The signal beam is sent through the turbid medium, where it is phase modulated by the ultrasound. The ultrasound-modulated signal beam is provided to a photo-refractive crystal for subsequent interference with the reference beam to convert the phase modulation to intensity modulation. The DC offset of the signal beam intensity provides a measure of the magnitude of the mean phase shift induced by the ultrasound on the multiply scattered optical field within the turbid medium.
摘要:
A microscopy apparatus includes a heating source to provide a pulse of heating energy focused on a target to heat a localized region of the target, such as human tissue, to generate motion. A measuring source provides a measuring light beam focused on the target. A coherent confocal microscopy assembly focuses the measuring light beam on the target and returns a reflected signal from the target. A detection assembly receives the reflected signal from the target and detects a Doppler shift of the reflected signal. A scanning assembly scans pulses from the heating source over the target and scans the measuring light beam from the measuring source over the target to build up an image of a plane of the target.