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.

Femtosecond Laser-Induced Nanowelding: Fundamentals and Applications

“…It is important to mention that if nanoparticles are tiny clusters with limited atoms they may display suddenly global melting without surface melting. If we consider the heat dissipation into the surrounding, the recent simulation displays that the maximum penetration depth of heat is about 40 nm after the femtosecond laser irradiation [33]. This supports that the femtosecond laser irradiation can induce the surface melting of large nanoparticles.…”

Molecular plasmonics: light meets molecules at the nanoscale

“…Therefore, we studied the laser light effect on metal nanoparticles, also in combination with DNA. The laser effect could be visualized by immobilization of particles onto polymer-coated substrates [62]. Poly(methyl methacrylate) (PMMA) was chosen as polymer material, owing to its established layer fabrication technique (using spin coating).…”

Active Shape-Morphing Elastomeric Colloids in Short-Pitch Cholesteric Liquid Crystals

“…1) [32][33][34][35]. LCE microcylinders bend toward the beam scanning direction typically chosen to be orthogonal or tilted with respect to the cylinder axis (Figs.…”