Dynamics of Silicon Nanostructures Under Laser Irradiation Studied Quantum Mechanically

MRS Proceedings ◽

10.1557/proc-850-mm3.4 ◽

2004 ◽

Vol 850 ◽

Author(s):

A.M. Mazzone ◽

M. Bianconi

Keyword(s):

Electronic Devices ◽

Finite Size ◽

Laser Pulses ◽

Real Space ◽

Atomic Scale ◽

Silicon Nanostructures ◽

Hartree Fock ◽

Nuclear Subsystem ◽

Short Laser Pulses ◽

Small Clusters

ABSTRACTThis study is motivated by recent applications of ultra-short laser pulses to the manipulation of structures on the atomic scale. It describes the energies and the time-scale needed to induce and to observe such changes. The structures adopted to this purpose are taken from the field of silicon nanotechnology and consist on monotaomic wires and small clusters of a columnar shape. These last ones are covered on both sides with an aluminum overlayer and can be regarded as the finite-size analogous of macroscopic electronic devices. The effect of laser is simply described as an increase of the kinetic energy in the nuclear subsystem. The calculations are based on real-time, real-space implementation of the semiempirical Hartree-Fock theory. The results show the occurrence of phenomena similar to recristallization and melting in the bulk and illustrate the dependence of these effects on the energy input and on the cluster size and composition.

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Real-space observation of surface structuring induced by ultra-fast-laser illumination far below the melting threshold

Scientific Reports ◽

10.1038/s41598-021-91894-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ch. Zaum ◽

N. Osterloh ◽

R. Darkins ◽

D. M. Duffy ◽

K. Morgenstern

Keyword(s):

Morphological Changes ◽

Laser Pulses ◽

Real Space ◽

Atomic Scale ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Laser Illumination ◽

Surface Structuring ◽

Structure Changes ◽

Melting Threshold

AbstractIntense short laser pulses are an intriguing tool for tailoring surface properties via ultra-fast melting of the surface layer of an irradiated target. Despite extensive studies on the interaction of femto-second laser interaction with matter, the initial steps of the morphological changes are not yet fully understood. Here, we reveal that substantial surface structure changes occur at energy densities far below the melting threshold. By using low-temperature scanning tunneling microscopy we resolve atomic-scale changes, i.e. the creation of nanosized adatom and vacancy clusters. The two cluster types have distinct non-linear fluence-dependencies. A theoretical analysis reveals their creation and motion to be non-thermal in nature. The formation of these atomistic changes, individually resolved here for the first time, recast our understanding of how surfaces respond to low-intensity ultra-short laser illumination. A visualization and control of the initial morphological changes upon laser illumination are not only of fundamental interest, but pave the way for the designing material properties through surface structuring.

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Probing vacancies and structural distortions at individual defects in ceramics using EELS

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100165859 ◽

1996 ◽

Vol 54 ◽

pp. 678-679

Author(s):

D. J. Wallis ◽

N. D. Browning

Keyword(s):

Structural Information ◽

Core Loss ◽

Nearest Neighbors ◽

Ceramic Materials ◽

Scanning Transmission Electron Microscope ◽

Real Space ◽

Atomic Scale ◽

Structure Property ◽

Scanning Transmission ◽

Key Issues

In electron energy loss spectroscopy (EELS), the near-edge region of a core-loss edge contains information on high-order atomic correlations. These correlations give details of the 3-D atomic structure which can be elucidated using multiple-scattering (MS) theory. MS calculations use real space clusters making them ideal for use in low-symmetry systems such as defects and interfaces. When coupled with the atomic spatial resolution capabilities of the scanning transmission electron microscope (STEM), there therefore exists the ability to obtain 3-D structural information from individual atomic scale structures. For ceramic materials where the structure-property relationships are dominated by defects and interfaces, this methodology can provide unique information on key issues such as like-ion repulsion and the presence of vacancies, impurities and structural distortion.An example of the use of MS-theory is shown in fig 1, where an experimental oxygen K-edge from SrTiO3 is compared to full MS-calculations for successive shells (a shell consists of neighboring atoms, so that 1 shell includes only nearest neighbors, 2 shells includes first and second-nearest neighbors, and so on).

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Development of the UHV-STM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100180367 ◽

1990 ◽

Vol 48 (1) ◽

pp. 322-323

Author(s):

M. Iwatsuki ◽

S. Kitamura ◽

A. Mogami

Keyword(s):

Surface Science ◽

Real Space ◽

Atomic Scale ◽

Scanning Tunneling ◽

Great Promise ◽

Force Microscopy ◽

Atomic Force ◽

Stm Image ◽

Surface Construction ◽

Very High

Since Binnig, Rohrer and associates observed real-space topographic images of Si(111)-7×7 and invented the scanning tunneling microscope (STM),1) the STM has been accepted as a powerful surface science instrument.Recently, many application areas for the STM have been opened up, such as atomic force microscopy (AFM), magnetic force microscopy (MFM) and others. So, the STM technology holds a great promise for the future.The great advantages of the STM are its high spatial resolution in the lateral and vertical directions on the atomic scale. However, the STM has difficulty in identifying atomic images in a desired area because it uses piezoelectric (PZT) elements as a scanner.On the other hand, the demand to observe specimens under UHV condition has grown, along with the advent of the STM technology. The requirment of UHV-STM is especially very high in to study of surface construction of semiconductors and superconducting materials on the atomic scale. In order to improve the STM image quality by keeping the specimen and tip surfaces clean, we have built a new UHV-STM (JSTM-4000XV) system which is provided with other surface analysis capability.

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Compact Energy Measuring System for Short Pulse Lasers

Metrology and Measurement Systems ◽

10.2478/mms-2013-0016 ◽

2013 ◽

Vol 20 (2) ◽

pp. 183-190 ◽

Cited By ~ 3

Author(s):

A. Barna ◽

I. B. Földes ◽

Z. Gingl ◽

R. Mingesz

Keyword(s):

Short Pulse ◽

Electronic Devices ◽

Laser Pulses ◽

Measuring System ◽

Electric Response ◽

Usb Interface ◽

Radiated Noise ◽

Fiber Optical ◽

Measurement Control ◽

Short Pulse Lasers

Abstract In experiments with short-pulse lasers the measurement control of the energy of the laser pulse is of crucial importance. Generally it is difficult to measure the amplitude of the pulses of short-pulse lasers using electronic devices, their response time being longer than the duration of the laser pulses. The electric response of the detector is still too fast to be directly digitized therefore a peak-hold unit can be used to allow data processing for the computer. In this paper we present a device which measures the energy of UV short (fs) pulses shot-byshot, digitizes and sends the data to the PC across an USB interface. The circuit is based on an analog peak detect and hold unit and the use of fiber optical coupling between the PC and the device provides a significant improvement to eliminate potential ground loops and to reduce conductive and radiated noise as well. The full development is open source and has been made available to download from our web page (http://www.noise.inf.u-szeged.hu/Instruments/PeakHold/).

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UN-CHIRPED SHORT LASER PULSES AMPLIFICATION AND COMPRESSION IN A COMPACT EDFA BASED ON A 3 WT.% ER-DOPED COMPOSITE FIBER

Proceedings of the IX International Conference ”Science and Society - Methods and Problems of Practical Application" ◽

10.29013/ix-conf-canada-9-22-28 ◽

2020 ◽

Author(s):

B. I. Galagan ◽

I. V. Zhluktova ◽

V. A. Kamynin ◽

A. A. Ponosova ◽

S. E. Sverchkov ◽

...

Keyword(s):

Laser Pulses ◽

Composite Fiber ◽

Short Laser Pulses ◽

Er Doped

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Production of ion beams in high-power laser–plasma interactions and their applications

Laser and Particle Beams ◽

10.1017/s0263034604221048 ◽

2004 ◽

Vol 22 (1) ◽

pp. 19-24 ◽

Cited By ~ 21

Author(s):

F. PEGORARO ◽

S. ATZENI ◽

M. BORGHESI ◽

S. BULANOV ◽

T. ESIRKEPOV ◽

...

Keyword(s):

Laser Pulse ◽

Medical Physics ◽

Ion Beam ◽

Laser Pulses ◽

Ion Beams ◽

Laser Plasma Interactions ◽

Physical Mechanisms ◽

Short Laser Pulses ◽

Laser Pulse Intensity ◽

Target Design

Energetic ion beams are produced during the interaction of ultrahigh-intensity, short laser pulses with plasmas. These laser-produced ion beams have important applications ranging from the fast ignition of thermonuclear targets to proton imaging, deep proton lithography, medical physics, and injectors for conventional accelerators. Although the basic physical mechanisms of ion beam generation in the plasma produced by the laser pulse interaction with the target are common to all these applications, each application requires a specific optimization of the ion beam properties, that is, an appropriate choice of the target design and of the laser pulse intensity, shape, and duration.

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Probing resonating valence bond states in artificial quantum magnets

Nature Communications ◽

10.1038/s41467-021-21274-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Kai Yang ◽

Soo-Hyon Phark ◽

Yujeong Bae ◽

Taner Esat ◽

Philip Willke ◽

...

Keyword(s):

Quantum Information Processing ◽

Energy Levels ◽

Finite Size ◽

Valence Bond ◽

Exchange Interactions ◽

Atomic Scale ◽

Scanning Tunneling ◽

Many Body ◽

Quantum Magnets ◽

Resonating Valence Bond

AbstractDesigning and characterizing the many-body behaviors of quantum materials represents a prominent challenge for understanding strongly correlated physics and quantum information processing. We constructed artificial quantum magnets on a surface by using spin-1/2 atoms in a scanning tunneling microscope (STM). These coupled spins feature strong quantum fluctuations due to antiferromagnetic exchange interactions between neighboring atoms. To characterize the resulting collective magnetic states and their energy levels, we performed electron spin resonance on individual atoms within each quantum magnet. This gives atomic-scale access to properties of the exotic quantum many-body states, such as a finite-size realization of a resonating valence bond state. The tunable atomic-scale magnetic field from the STM tip allows us to further characterize and engineer the quantum states. These results open a new avenue to designing and exploring quantum magnets at the atomic scale for applications in spintronics and quantum simulations.

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