The Nanophotonics Group of the Laser Zentrum Hannover e.V. (LZH) has developed a method to print nanoparticles made of different materials with controlled, reproducible sizes and to precisely deposit these particles on a receiver substrate.
As a result, for the first time, the scientists succeeded in generating and positioning perfectly round silicon nanoparticles with a diameter of 165 nm. This method was presented in the March 4th issue of Nature Communications.
Molten silicon forms nanoparticles which, due to the surface tension, fly onto a receiver substrate.
For the first time, scientists at the LZH were able to fabricate perfectly round silicon nanoparticles with a diameter of 165 nm and to arrange them in ordered structures. This was achieved with their newly developed method that was published in the March 4th issue of Nature Communications.
This novel method uses ultrashort laser pulses to print nanoparticles with sizes in the two to three digit nanometer range made of different materials, such as metals, semiconductors and dielectrics. Afterwards, these nanoparticles can be precisely deposited on a receiver substrate.
Nanoparticles exhibit the unique optical property to scatter only light of a particular wavelength. Irradiated with white light and de-pending on their size, shape and on the interaction with their environment, they appear in a certain color. Therefore, they can be used for various applications in medicine and sensor technology.
Particle formation through surface tension
The starting point for the fabrication process is a thin layer of the material of which the nanoparticles shall be made. This layer is irradiated and molten using a single ultrashort laser pulse. Owing to the surface tension of the molten material, a nanosphere is formed which moves up and is finally captured by the receiver substrate. The position of the particles on the receiver material can be controlled very precisely.
Accurate and controllable
„This novel method is the first that allows for both fabricating and precisely depositing nanoparticles of a certain size”, explains Prof. Dr. Boris Chichkov, head of the Nanotechnology Department. “In this respect, our method is far superior to chemical processes which can produce large quantities of nanoparticles but not place them at the desired position.” With this method, two- or three-dimensionally arranged particle structures, such as nanoantennas, nanolasers and metamaterials, can be generated.
From the amorphous to the crystalline phase with the second pulse
The fabrication of silicon nanoparticles of a certain size is particu-larly interesting because of their special optical properties: They mainly scatter the visible light strongly, and besides the electrical field they also react to the magnetic field component. Other mate-rials, however, almost exclusively interact with the electrical field only. According to the Mie theory, the magnetic light is scattered here, too. After printing, the fabricated silicon particles are in amorphous phase and can be transformed into the crystalline phase with a second laser pulse.
„The results have already lead to the emergence of silicon nano-photonics as a new research field of worldwide interest”, says Chichkov. "Therefore, the new method will certainly find many new applications.
The investigations were carried out within the scope of the SPP 1391 “Ultrafast Nanooptics” priority program and the collaborative research center “Transregio 123 – Planar Optronic Systems” (PlanOS). Both programs are funded by the German Research Foundation (DFG).
The article was published in Nature Communications | 5:3402 | DOI: 10.1038/ncomms4402
Lena Bennefeld | Laser Zentrum Hannover e.V.
Structured light and nanomaterials open new ways to tailor light at the nanoscale
23.04.2018 | Academy of Finland
On the shape of the 'petal' for the dissipation curve
23.04.2018 | Lobachevsky University
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
23.04.2018 | Physics and Astronomy
23.04.2018 | Physics and Astronomy
23.04.2018 | Trade Fair News