Tailoring ultrasonic beams with optoacoustic holography
| Autor: | Monika Ritsch-Marte, Alex Meyer, Stefan Bernet, Stefan Gspan |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Diffraction
Photoacoustic effect Liquid-crystal display Materials science business.industry Physics::Medical Physics Ultrasound Holography Physics::Optics Laser Computer Science::Other law.invention Computer Science::Graphics Optics law Optoelectronics Ultrasonic sensor business Absorption (electromagnetic radiation) |
| Zdroj: | Laser Resonators and Beam Control VI. |
| ISSN: | 0277-786X |
| DOI: | 10.1117/12.483648 |
| Popis: | A combination of laser-induced ultrasound generation and ultrasonic holography for spatial control of the generated ultrasonic pulse is presented. Ultrasound is produced by absorption of laser pulses at an absorbing layer in a water tank via the optoacoustic effect. In order to produce a defined ultrasonic frequency in the MHz range, the laser pulses are harmonically time-modulated using an acousto-optic modulator (AOM). Additionally, the laser intensity is spatially controlled. This is realized with a high resolution liquid crystal spatial light modulator (LCD). A computer generated pattern is displayed at the LCD and projected by the expanded laser beam to an absorptive layer in the water tank. As a result, the emitted ultrasonic wave emerges in a predetermined way, which is an acoustical analogue to the effect of a "diffractive optical element" in laser optics. The flexible method of optical ultrasound generation and diffractive steering promises new applications in medical and technical ultrasound diagnostics. |
| Databáze: | OpenAIRE |
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