Plasmonic Nanostructures

Transcription

1 Psoc Nosucus Dk Mch Dc 7 8 Iouco Wh c vcs phoocs w hv cy vs ous of foo coss ocs wh xcpo cy. Ths hs poss y h vop of ws co of spcfc cc cos o ock h pssg of c of wvghs. Th hop o of hs ccopsh ws h opcs wou o y pc coc ccus. Th ssu h ws h cus of ffco coss h wh of h u wv psss hough us s hf h gh s wvgh. Fo f gh wh wvghs ou 5 os hs wou qu vcs of s 75 os wh. Ths s o sgfc sp up fo so of ou cu ccus so of whch hv copos s h os. css ow schg fo souo o hs po psocs. Bckgou Phoocs c spy sc s uzg scos of ocoucv wh g cc coss o c gp of fqucs h copy jc. Ths c us cojuco wh scos h ow h spcf wvghs o c wvgus. Psocs o h oh h s o -cc fc o cpu o fc c wvghs of gh. Noy s poo choc fo opcs s h f uc h cs wh f cos p h whch co wh oh f cos upg h oscos cusg h f o ssp. By pcg ocoucv cc o op of h w c ow h f o x o h cc wh h o f cos wh s cg wh h sufc cos h. Ths poucs sco whch wv of cos og wh s f c h cc c pogss og ph f y h p w h wo s. Ths wv s c pso. Ths pocss sus h pogsso of wv wvgh uc y h uco h vg sp of h wv. Noy gh wvs ccu h sp of gh whch focs y uco wvgh o qu s cs fqucy. I hs cs howv h so fo gh wv o osco of cos sows h wv pogsso owg popoo cs wvgh. Ths wou ow fo h co of s wvgus o jucos h copss h c gh jc h of h gu. Ths s ky sp ows cg s sc gh-s ccuy. Fo h sp cs of cc wh h f

2 h wvghs fqucs of h psos c jus y choosg ff hcksss of h f cou cy s f s fw cs fo yg ou. ucus of hs yp cou pu o pc coc vcs u h cc fs pouc wou oo g o covy sgs h osc v. To sov hs ssu fw osucus hv xpo h hv pouc sg sus. Nosh Psos Rh h pc h cc ou h sucus hv fc h coss of cc co wh sh pos ou. Ths oshs c sc s of h ou. Ths yp of sucu povs wo fcs o psos h c o c soc fqucs s o h sh sz. Ths fqucs s fuco of h uk pso fqucy whch s sc s: B Wh s h co chg s h ufo co gs sy s h ss of co. Th so fqucs of h vu psos c fou y vug h gg of chg copss oo fu : η η I hs fuco h foo of h fu s sc s of h sc fuco η : η ( ) ( ) Wh sc h ou us of h sh h fucos sc h pu of h cvy sph psos spcvy. Th vus c h upo x zuh g. Th sufc chg s so sc s h g of o vv of hs foo fuco : η ˆ Th foo fuco s xpss s o vv oh hs cs h gg so wou hp o f h: η η η ( ) ( ) ˆ W c ow xpss s g of hs fuco ov. To o so w w k h ssupo h h fucos of h fo: N M Ths ows us o xpss s: η ( ) ( ) ( ) ˆ

3 W c ow ccu h kc of h gg: [ ] 3 η η H w shou o h h sphc hoc fucos sv o y s h hv uqu upo xs o zuh gs ( o ) y s of h foowg quy: s δ δ φ θ θ φ θ φ θ Ths ows us o ou suo s pop fo. Th po of h gg s o ffcu. Fo h vu sph cvy psos w o o o cos coupg w h wo. Ths ows us o xpss h foowg poo hs fo: Th xp fo fo oh gs pps s such: I o o g hs fucos w o poy upo xpso. W c choos spf fo s h chg sy s p of h zuh g φ. Ths ows us o ssu h h fuco s su of oy. Th xpso occus h foowg fo: > < Wh s < h u vu of ( ) > s h xu. Ths cospos o o o fo h cvy xo o fo h sph. Appyg h xpso sus :

4 W c ow w ou h gg fo h who ucoup sys. Nx w us h Eu-gg quos o vop x scg ou sys. W c sp hs o cs M K fo ch p of h quo: M K / / Th cs c ow suc w c vu h fo h fqucy. K M Af susug fo h uk fqucy vg ou h ous coss cs o zo w v h foowg poyo xpsso:

5 B B Fcog hs w y h vo fqucs of h cvy sph psos. B B I h s w cou coupg o h gg wou v h hyzo fqucs of h osph. ± ± / B Ths fqucy quos fc h syc syc coupg w h wo pso os. Th syc o cs wky wh h cg opc f wh h syc o h ow gy of h wo cs sogy. Fgu. Egy v g of so os 5 ucus of hs yp hv succssfuy fc o h sc of 5 o o h os hv spo s xpc fo h ccuos. O ho fo vopg oshs cosss of uco of choouc c wh suf os whch sus Au co wh go sh y. Oh hos ow fo h gowh of h co sp fo h sh whch ows uch o coo pcso h sg of oshs. Ths yp of sucu howv hs cy o pk shpy c wvgh whch os ow uch fo sgg s of spog foo. Aoh opc h ogg c pov us wh oh g of jusy o ou sys. Nogg I sphc osh h soc w os occus oy wh hos of h s upo x. I ogg h c of h cc co s offs y sc D. Ths offs ows os of h sph sh psos o hyz o c g. Ths cuss h y shp pks o sp shf o hgh

6 fqucs. Th su s w upk spos h css copxy wh csg D. Fgu. (A) chc of pso hyzo osh (f) ogg (Rgh). (B) cu -5 pso gs s fuco of co offs fo p pozo (f) ppcu pozo (). (Rgh) Thoc spc s fuco of h offs D fo (398) Au osh wh vcuu cos Ths oggs c pouc y posg Au o y fc oshs. I hs h hs poo s c y h sh hckss y h offs c h jus y h ou of Au pos o o s of h osh. Noyushks Aoh ho of g coo o h fqucy spos hs oyushk. A oyushk s cocc osh copos of cc co wh g ys of cc o op. Ths sucu o oy ows jus of h spos of vu oshs y s of h ( ) u so jus of h coupg y s of h hckss of h cc spc -.

7 Fgu 3. Noyushk sucu spos 5 Ig A o h f scs h sc sucu of h oyushk. B ow shows h gy sucu of h sys s o pso syy. Th gs o h gh show xp of ffg szs of oyushk. Th s show hoc xco spc wh h u s show xp spc. Th s sh shows scy coup pks wh h oyushk wh g ou shs xh ow o os o coupg. Th sos fo hs sucus : A ( / / / ) (8/7/35/57) B (77///5) (396/8/65/693) wh vus os. Po Uss As s fo h w of psocs s h y o squz hgh fqucy gh o osc wvgus h wou ow fo fs ssso of g ous of. Th hop s h opcs w o y pc coc ccus scy cs pocssg po. Th hv fw s og hs s s w s fw ohs h hv spug ou of h u cous of xpo. O of h o sg uss ss fo h osucu s y o so gh s h s w s h ocopy of go. Rschs hv fou h h go p oshs c jc o h oy whou vs ffc. Fo sg puposs hy hv jc o h oos of c wh ccous uos. Th shs w fou o hv pos o o ccous ssu h hhy os u o h hvy fow o h py gowg uos. Ths shs w h g wh f o wvgh h psss hough ssu. Th so

8 sopo s h pu of h cs fo ou 37 gs sus o ou 5 gs kg h cc cs wh vg hhy ssu uh. I h c hs wy sgs of cc spp wh ys wh uos of h c h coo goup cou o gow py. Aoh popos us vovs psocs scov h 98s. I hs fou h y hcg h f h cc h sso of usc ys h s sufc c cs. Ths cou poy ow h fco of EDs h sh jus s ghy s o gh soucs. yss hv c h coup sv o go osucus wh quu o ys h oos sso y ou s. Th hop s h vuy psocs w h co of gh EDs ou of chp s such s sco. Aoh h hs c o of o s h po us of osucus o c vsy cok. I hs show h y xcg pso wh o fqucy cos o s so fqucy ks h sucu s fcv x quv o h of. I wou poss o c ojc h fo c of wvghs wou pp o vs. Ths howv wou o ppy o yhg s h ojc. Th x sp wou o c ho of vg h gh ou h cos of h vsy co ou h ck h s co sy s gh c o h co. Though ffcu so scss v poss. ocuso Psocs pps o pvg h wy ows opc ccuy. By povg ho of shkg h wvgh of ou foo u w c ow us s o copx sucus o pocss v h foo. Ev wh h gh o c y f sspo psocs hs fou y uss s jucos wvgus so uss f ous hos y cos. Th posss v u h v of psocs gvs pos f xcg h of phoocs.

9 Rfcs: [] H. Wg D. W. B P. No N. J. Hs "Psoc Nosucus: Afc Mocus" Acc. h. Rs (7). [] H. Wg. Wu B. ss. Nh J.H. Hf P. No N. J. Hs yy-kg vu psoc opcs. Poc. N. Ac. c. U..A [3] Aw Hy A. (7). "Th Pos of Psocs". cfc Ac 96 (): [] Mk W Kgh No J Hs Noshs o oggs o ocups: opc pops of uc syy co sh opcs yo h qussc. 8 Nw J. Phys. 56 (pp) [5] Po E Roff Hs N J No P A hyzo o fo h pso spos of copx osucus. cc 3 3 9