Broad-band high-efficiency optoacoustic generation using a novel photonic crystal-metallic structure

Various optical structures have been investigated for high-frequency optoacoustic generation via thermoelastic effect, including metal films, mixture of polydimethylsiloxane (PDMS) and carbon black, two-dimensional (2-D) gold nanostructure with PDMS film, etc. However, they suffer from either low light absorption efficiency which affects the amplitude of generated ultrasound, or thick films that attenuate the amplitude and restrict its spectra bandwidth. Here we propose a novel one-dimensional photonic crystal-metallic (PCM) structure, which can be designed to absorb 100% optical energy of specific wavelengths in a total-internal-reflection geometry. The unique configuration enables us to choose suitable polymer films on top of the metallic structure, which can act as an ideal ultrasound transmitter to generate broad-band ultrasound with high conversion efficiency. Experimental results show that the PCM structure generated several times stronger ultrasound pressure than our previously demonstrated 2-D gold nanostructures [Appl. Phys. Lett. 89, 093901 (2006)]. Moreover, the generated ultrasound exhibited almost the same frequency spectrum as the input laser pulse (duration width 6 ns). This shows that the PCM structure has great potential to generate broad-band ultrasound signal. It is also important to mention that the simple PCM structure with the polymer film forms a Fabry-Pérot resonator and can play a role of an ultrasound receiver, which provides a convenient method to construct a broad-band and all-optical ultrasound transducer.

[1]  Matthew O'Donnell,et al.  Broadband all-optical ultrasound transducers , 2007 .

[2]  P. Wells,et al.  Ultrasound imaging , 2006, Physics in medicine and biology.

[3]  F. S. Foster,et al.  Beyond 30 MHz [applications of high-frequency ultrasound imaging] , 1996 .

[4]  M. Skorobogatiy,et al.  Plasmon excitation by the Gaussian-like core mode of a photonic crystal waveguide. , 2006, Optics express.

[5]  Yunbo Guo,et al.  Sensitive molecular binding assay using a photonic crystal structure in total internal reflection. , 2008, Optics express.

[6]  F. Lizzi.  Ultrasound Imaging , 1991, Proceedings Technology Requirements for Biomedical Imaging.

[7]  Matthew O'Donnell,et al.  Optical generation of high frequency ultrasound using two-dimensional gold nanostructure , 2006 .

[8]  D. A. Christopher,et al.  Advances in ultrasound biomicroscopy. , 2000, Ultrasound in medicine & biology.

[9]  Sheng-Wen Huang,et al.  Improvements in optical generation of high-frequency ultrasound , 2007, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[10]  Lihong V. Wang.  Photoacoustic imaging and spectroscopy , 2009 .

[11]  Tao Ling,et al.  Carbon nanotube composite optoacoustic transmitters for strong and high frequency ultrasound generation. , 2010, Applied physics letters.

[12]  Matthew O'Donnell,et al.  High-frequency ultrasound array element using thermoelastic expansion in an elastomeric film , 2001 .

[13]  Brian Culshaw,et al.  Optical generation and detection of ultrasound , 2003 .

[14]  Sheng-Wen Huang,et al.  Low-noise wideband ultrasound detection using polymer microring resonators. , 2008, Applied physics letters.