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Optics Letters

Optics Letters


  • Editor: Anthony J. Campillo
  • Vol. 30, Iss. 24 — Dec. 15, 2005
  • pp: 3341–3343

Photoacoustic flow measurements by use of laser-induced shape transitions of gold nanorods

Pai-Chi Li, Sheng-Wen Huang, Chen-Wei Wei, Ya-Chin Chiou, Cheng-Dah Chen, and Churng-Ren Chris Wang  »View Author Affiliations

Optics Letters, Vol. 30, Issue 24, pp. 3341-3343 (2005)

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A quantitative technique for flow measurements based on a wash-in analysis is proposed. The technique makes use of the shape dependence of the optical absorption of gold nanorods and the transitions in their shape induced by pulsed laser irradiation. The photon-induced shape transition of gold nanorods involves mainly a rod-to-sphere conversion and a shift in the peak optical absorption wavelength. The application of a series of laser pulses will induce shape changes in gold nanorods as they flow through a region of interest, with quantitative flow information being derived from the photoacoustic signals from the irradiated gold nanorods measured as a function of time. To demonstrate the feasibility of the technique, a Nd:YAG laser operating at 1064 nm was used for irradiation and a 1 MHz ultrasonic transducer was used for acoustic detection. The flow velocity ranged from 0.35 to 2.83 mm/s. Excellent agreement between the measured velocities and the actual velocities was demonstrated, with a linear regression correlation coefficient of 0.93. This study is a pioneer work on wash-in flow estimation in photoacoustic imaging.

© 2005 Optical Society of America

OCIS Codes
(110.0110) Imaging systems : Imaging systems
(170.5120) Medical optics and biotechnology : Photoacoustic imaging

ToC Category:
Medical Optics and Biotechnology

Virtual Issues
Vol. 1, Iss. 1 Virtual Journal for Biomedical Optics

Pai-Chi Li, Sheng-Wen Huang, Chen-Wei Wei, Ya-Chin Chiou, Cheng-Dah Chen, and Churng-Ren Chris Wang, "Photoacoustic flow measurements by use of laser-induced shape transitions of gold nanorods," Opt. Lett. 30, 3341-3343 (2005)

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