Laser Physics Dept. (Research Institute for Solid State Physics and Optics Hung. Acad. Sci.)
Starting date
2008-04-01
Closing date
2011-03-31
Funding (in million HUF)
12.400
FTE (full time equivalent)
0.63
state
closed project
Summary in Hungarian
Feluleti plazmonok alatt azon elektromagneses hullamokat erjuk, amelyek a feluleti toltes fluktuacioja reven jonnek letre, fem-vakuum hatarfeluleten. A feluleti plazmonok egyadulallo terjedesi tulajdonsagai lehetove teszik a fotonikai eszkozok miniaturizaciojat, uj lehetosegeket nyitva ezzel szamos alkalmazasi teruleten, mint pl. a nano-optikaban, ill. a napelemek vagy a bioszenzorok fejleszteseben. Ugyan a nanotechnologiaban legujabban elert eredmenyek modot adnak plazmonikai eszkozok nanometer pontossagu sorozatgyartasara, ezen eszkozok merestechnikaja a mai napig a kihivasok korebe tartozik. E projekt celja egy egyedulallo diagnosztikai eszkoz kifejlesztese, amley az alagutmikroszkopia (STM) es femtoszekundumos ultrarovid lezerimpulzusok elonyos tulajdonsagait hasznalja fel. A fejlesztes magaban foglalja egy STM mikroszkop kiboviteset fotoelektron-emisszio ultranagy vakuumban torteno tanulmanyozasara, illetve egy femtoszekundumos oszcillator kiboviteset kulso impulzuskompresszorral es fazisstabilizacioval. A projekt tovabbi celja a kifejlesztett eszkoz felhasznalasa feluleti fizikai alapkutatasra. Az eredmenyek uj bepillantast nyujtanak az ultragyors plazmonika kulonfele teruleteire, nevezetesen fennyel gerjesztett plazmonok terjedesi tulajdonsagaira, idoben felbontott dinamikajukra, lokalizaciojukra, es elektronemisszios tulajdonsagaira kulonfele fem nanostrukturakon. A kiserletek eredmenyei az alkalmazott fizika teruleten is felhasznalhatoak, elsosorban a szenzorikaban es egyeb nano-optikai alkalmazasokban.
Summary
Surface plasmons (SPs) are electromagnetic waves resulting from fluctuations of surface charges at metal-dielectric interfaces. The unique subwavelength properties of SPs allow the miniaturization of photonic devices and open up new opportunities in a wide range of applications including nano-optics, solar cells and biosensing. Although recent advances in nanotechnology allow reproducible fabrication of plasmonic devices on the nanometre scale, their characterization remains a challenging task. This project aims to develop a state-of-the-art diagnostic tool combining advanced Scanning Tunneling Microscopy (STM) and few-cycle laser pulses. This includes the development of an STM microscope by extending its capabilities for laser-assisted photoelectron emission measurements under Ultrahigh Vacuum (UHV) conditions, as well as extension of a femtosecond Chirped Pulse Oscillator (CPO) with an external pulse compressor unit and carrier-envelope (CE) phase stabilization. Further aim is to carry out fundamental research experiments with the developed surface science tool. Outcomes include new insights into ultrafast Plasmonics, such as propagation effects, time-resolved dynamics, localization and electron emission properties of SPs on different metal nanostructures upon photoexcitation. On the applied physics side, the experimental results will shed light in optimized geometries for sensing and nano-optical applications.
Final report
Results in Hungarian
Kutatasaim soran feluleti plazmonokat vizsgaltam meg egy pasztazo alagutmikroszkop (STM) alagut-atmeneteben. A feluleti plazmonokat arany vekonyreteg feluleten gerjesztettuk, amelyeknek lokalis kozelteret STM-tu segitsegevel tapogattuk le. Az alagutaram idobeli lefolyasabol kovetkezteteseket vonhattunk le azon fizikai mechanizmusokrol, amelyek a kolcsonhatasban reszt vevo elektromos erotereket befolyasoljak. Kihasznalva az alagut-atmenet nemlinearitasat, nagysagrendileg megbecsultuk a lokalis tererosseg-novekedes merteket a feluleti nanostrukturakon. A plazmonok terbeli elhelyezkedesenek a lekepezesevel, illetve ezek feluleti topografiaval torteno oszzehasonlitasaval kiserletileg igazoltuk a feluleti plazmonok lokalizalodasat nehany nanometer szelessegu uregekben illetve szemcsehatarok menten. Az elert eredmenyek kozvetlenul felhasznalhatoak pl. a nagy energiaju elektronforrasok feluleti geometriajanak fejleszteseben, ahol az elektronok a feluleti plazmonok tereben kerülnek gyorsitasra.
Results in English
We investigated surface plasmon (SP) waves in the junction of a scanning tunneling microscope (STM). The
SP waves were generated on a thin Au film and their near-field was locally probed by the tip of the STM. The temporal structure of the observed tunneling current signal revealed information on the physical mechanisms which regulate the interaction of the electric fields in play. We estimated the magnitude of the local electric field enhancement on surface nanostructures by taking advantage of the nonlinearity of the tunneling junction. The mapping of the plasmon field to the surface topography delivers experimental evidence for the localization of SP waves in narrow gaps of a few nanometers width and/or at grain boundaries. The results gained can directly be utilized e.g., in the development of nanoscale geometries for high-energy electron sources where electrons are accelerated in the electric field of surface plasmons.
P. Dombi, S.E. Irvine, P. Rácz, M. Lenner, N. Kroó, G. Farkas, A. Mitrofanov, A. Baltuska, T. Fuji, F. Krausz, A. Y. Elezzabi: Observation of few-cycle, strong-field phenomena in surface plasmon fields, Optics Express, 2010
M. Lenner, P. Dombi, P. Rácz, N. Kroó: Nonlinear STM plasmonics, Photon 10, 2010
P. Rácz, S.E. Irvine, M. Lenner, A. Mitrofanov, A. Baltuska, A.Y. Elezzabi, P. Dombi: Strong-field plasmonic electron acceleration with few-cycle, phase-stabilized laser pulses, Applied Physics Letters, 2011
M. Lenner, P. Rácz, P. Dombi, Gy. Farkas, N. Kroó: Field enhancement and rectification of surface plasmons detected by scanning tunneling microscopy, Physical Review B, 2011
