title: Optically controlled thermal management on the nanometer length scale.
abstract: The manipulation of polymers and biological molecules or the control of chemical reactions on a nanometer scale by means of laser pulses shows great promise for applications in modern nanotechnology, biotechnology, molecular medicine or chemistry. A controllable, parallel, highly efficient and very local heat conversion of the incident laser light into metal nanoparticles without ablation or fragmentation provides the means for a tool like a 'nanoreactor', a 'nanowelder', a 'nanocrystallizer' or a 'nanodesorber'. In this paper we explain theoretically and show experimentally the interaction of laser radiation with gold nanoparticles on a polymethylmethacrylate (PMMA) layer (one-photon excitation) by means of different laser pulse lengths, wavelengths and pulse repetition rates. To the best of our knowledge this is the first report showing the possibility of highly local (in a 40 nm range) regulated heat insertion into the nanoparticle and its surroundings without ablation of the gold nanoparticles. In an earlier paper we showed that near-infrared femtosecond irradiation can cut labeled DNA sequences in metaphase chromosomes below the diffraction-limited spot size. Now, we use gold as well as silver-enhanced gold nanoparticles on DNA (also within chromosomes) as energy coupling objects for femtosecond laser irradiation with single-and two-photon excitation. We show the results of highly localized destruction effects on DNA that occur only nearby the nanoparticles.
authors.affiliation: Institute of Photonic Technology (IPHT) Jena, PO Box 100239, D-07745 Jena, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Garwe
authors.forename: U
authors.initials: U
authors.lastname: Bauerschäfer
authors.forename: A
authors.initials: A
authors.lastname: Csaki
authors.forename: A
authors.initials: A
authors.lastname: Steinbrück
authors.forename: K
authors.initials: K
authors.lastname: Ritter
authors.forename: A
authors.initials: A
authors.lastname: Bochmann
authors.forename: J
authors.initials: J
authors.lastname: Bergmann
authors.forename: A
authors.initials: A
authors.lastname: Weise
authors.forename: D
authors.initials: D
authors.lastname: Akimov
authors.forename: G
authors.initials: G
authors.lastname: Maubach
authors.forename: K
authors.initials: K
authors.lastname: König
authors.forename: G
authors.initials: G
authors.lastname: Hüttmann
authors.forename: W
authors.initials: W
authors.lastname: Paa
authors.forename: J
authors.initials: J
authors.lastname: Popp
authors.forename: W
authors.initials: W
authors.lastname: Fritzsche