光学学报, 2005, 25 (1): 40, 网络出版: 2006-05-22
超声换能器带宽对光声成像的影响
Influence of Bandwidth of Ultrasonic Transducer on Photoacoustic Imaging
信息光学 光声成像 超声换能器 带宽 脉冲响应 information optics photoacoustic imaging ultrasonic transducer bandwidth impulse response
摘要
研究了不同尺寸吸收体产生的光声压的频谱特性
Abstract
Photoacoustic signals induced by a short pulse laser cover a wide spectral range. The spectral characteristics of absorbers with different sizes and the influence of photoacoustic signals with different spectral components on photoacoustic imaging are explored. The main frequency ranges of photoacoustic pressures of absorbers with diameters of ~cm, ~mm and hundreds of μm are about 20~300 kHz, 70 kHz~2.5 MHz and 400 kHz~20 MHz, respectively. The low spectral components of photoacoustic signals contributed to the non-boundary region of absorbers, and the high spectral components contributed to the small structure, especially, to the boundary. It is demonstrated that the ultrasonic transducers used to detect photoacoustic pressures should be designed and selected according to the frequency ranges of absorbers. When the frequency response range of transducers accords to that of absorbers, almost the whole frequency components of photoacoustic pressure can be detected. That produces good reconstructed images. A Q-switched Nd∶YAG laser operating at 532 nm was used as light source. The laser had a pulse width of 7 ns and a repetition frequency of 30 Hz, and a needle PVDF hydrophone with diameter of 1 mm was used to detect photoacoustic signals.
谭毅, 邢达, 王毅, 曾亚光, 尹邦政. 超声换能器带宽对光声成像的影响[J]. 光学学报, 2005, 25(1): 40. 谭毅, 邢达, 王毅, 曾亚光, 尹邦政. Influence of Bandwidth of Ultrasonic Transducer on Photoacoustic Imaging[J]. Acta Optica Sinica, 2005, 25(1): 40.