Enhancement of terahertz pulse emission by optical nanoantenna.

Bridging the gap between ultrashort pulsed optical waves and terahertz (THz) waves, the THz photoconductive antenna (PCA) is a major constituent for the emission or detection of THz waves by diverse optical and electrical methods. However, THz PCA still lacks employment of advanced breakthrough technologies for high-power THz emission. Here, we report the enhancement of THz emission power by incorporating optical nanoantennas with a THz photoconductive antenna. The confinement and concentration of an optical pump beam on a photoconductive substrate can be efficiently achieved with optical nanoantennas over a high-index photoconductive substrate. Both numerical and experimental results clearly demonstrate the enhancement of THz wave emission due to high photocarrier generation at the plasmon resonance of nanoantennas. This work opens up many opportunities for diverse integrated photonic elements on a single PCA at THz and optical frequencies.

[1]  Harry A. Atwater,et al.  Plasmonic nanoparticle enhanced light absorption in GaAs solar cells , 2008 .

[2]  Willie J Padilla,et al.  Terahertz Magnetic Response from Artificial Materials , 2004, Science.

[3]  Fujikata Junichi,et al.  Si Nano-Photodiode with a Surface Plasmon Antenna , 2006 .

[4]  K. Kawase,et al.  Non-destructive terahertz imaging of illicit drugs using spectral fingerprints. , 2003, Optics express.

[5]  Andreas Tünnermann,et al.  Microlens coupled interdigital photoconductive switch , 2008 .

[6]  E. Linfield,et al.  Terahertz Pulsed Imaging of Skin Cancer in the Time and Frequency Domain , 2003, Journal of biological physics.

[7]  A. Polman.  Plasmonic Solar Cells , 2010 .

[8]  Takashi Mukai,et al.  Surface-plasmon-enhanced light emitters based on InGaN quantum wells , 2004, Nature materials.

[9]  Wenzel,et al.  Decay times of surface plasmon excitation in metal nanoparticles by persistent spectral hole burning , 2000, Physical review letters.

[10]  K Ueda,et al.  High-power terahertz radiation emitter with a diamond photoconductive switch array. , 2001, Applied optics.

[11]  Harry A Atwater,et al.  Large integrated absorption enhancement in plasmonic solar cells by combining metallic gratings and antireflection coatings. , 2011, Nano letters.

[12]  K. Nishi,et al.  Si Nano-Photodiode with a Surface Plasmon Antenna , 2005, LEOS 2007 - IEEE Lasers and Electro-Optics Society Annual Meeting Conference Proceedings.

[13]  E. Linfield,et al.  Terahertz pulse imaging in reflection geometry of human skin cancer and skin tissue. , 2002, Physics in medicine and biology.

[14]  J. V. Rudd,et al.  Influence of substrate-lens design in terahertz time-domain spectroscopy , 2002 .

[15]  Zhang Xi,et al.  Materials for terahertz science and technology , 2003 .

[16]  Xicheng Zhang,et al.  Materials for terahertz science and technology , 2002, Nature materials.

[17]  L. Novotný,et al.  Antennas for light , 2011 .

[18]  W. Cai,et al.  Plasmonics for extreme light concentration and manipulation. , 2010, Nature materials.

[19]  H. Atwater,et al.  Plasmonics for improved photovoltaic devices. , 2010, Nature materials.

[20]  M Pepper,et al.  Using Terahertz pulse spectroscopy to study the crystalline structure of a drug: a case study of the polymorphs of ranitidine hydrochloride. , 2003, Journal of Pharmacy and Science.

[21]  Thomas Dekorsy,et al.  High-intensity terahertz radiation from a microstructured large-area photoconductor , 2005 .

[22]  Willie J Padilla,et al.  Active terahertz metamaterial devices , 2006, Nature.

[23]  X. Zhang,et al.  Free‐space electro‐optic sampling of terahertz beams , 1995 .

[24]  Richard R. Grote,et al.  Integrated plasmonic lens photodetector , 2009 .

[25]  Edward S. Barnard,et al.  Design of Plasmonic Thin‐Film Solar Cells with Broadband Absorption Enhancements , 2009 .

[26]  Michael Herrmann,et al.  Generation and detection of terahertz pulsed radiation with photoconductive antennas and its application to imaging , 2002 .

[27]  K. Saraswat,et al.  Nanometre-scale germanium photodetector enhanced by a near-infrared dipole antenna , 2008 .

[28]  T. Ebbesen,et al.  Light in tiny holes , 2007, Nature.

[29]  A. Tünnermann,et al.  Terahertz line detection by a microlens array coupled photoconductive antenna array. , 2008, Optics express.

[30]  Carsten Rockstuhl,et al.  Plasmonic nanowire antennas: experiment, simulation, and theory. , 2010, Nano letters.

[31]  Daniel M. Mittleman,et al.  Metal wires for terahertz wave guiding , 2004, Nature.

[32]  Masayoshi Tonouchi,et al.  Cutting-edge terahertz technology , 2007 .

[33]  E. Yu,et al.  Enhanced semiconductor optical absorption via surface plasmon excitation in metal nanoparticles , 2005 .