Polarisation-dependent single-pulse ultrafast optical switching of an elementary ferromagnet

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Hanan Hamamera ◽  
Filipe Souza Mendes Guimarães ◽  
Manuel dos Santos Dias ◽  
Samir Lounis
Keyword(s):  
Laser Pulse ◽  
Optical Switching ◽  
Atomic Orbital ◽  
Single Pulse ◽  
Laser Pulses ◽  
Pulse Parameter ◽  
Paradigm Shifts ◽  
Ultrafast Laser Pulses ◽  
Spintronic Devices ◽  
Ultrafast Optical

AbstractThe ultimate control of magnetic states of matter at femtosecond (or even faster) timescales defines one of the most pursued paradigm shifts for future information technology. In this context, ultrafast laser pulses developed into extremely valuable stimuli for the all-optical magnetization reversal in ferrimagnetic and ferromagnetic alloys and multilayers, while this remains elusive in elementary ferromagnets. Here we demonstrate that a single laser pulse with sub-picosecond duration can lead to the reversal of the magnetization of bulk nickel, in tandem with the expected demagnetization. As revealed by realistic time-dependent electronic structure simulations, the central mechanism involves ultrafast light-induced torques that act on the magnetization. They are only effective if the laser pulse is circularly polarized on a plane that contains the initial orientation of the magnetization. We map the laser pulse parameter space enabling the magnetization switching and unveil rich intra-atomic orbital-dependent magnetization dynamics featuring transient inter-orbital non-collinear states. Our findings open further perspectives for the efficient implementation of optically-based spintronic devices.

scholarly journals Polarisation-dependent single-pulse ultrafast optical switching of an elementary ferromagnet

2021 ◽  
Author(s):  
Hanan Hamamera ◽  
Filipe Souza Mendes Guimarães ◽  
Manuel dos Santos Dias ◽  
Samir Lounis
Keyword(s):  
Laser Pulse ◽  
Optical Switching ◽  
Atomic Orbital ◽  
Single Pulse ◽  
Laser Pulses ◽  
Pulse Parameter ◽  
Paradigm Shifts ◽  
Ultrafast Laser Pulses ◽  
Spintronic Devices ◽  
Ultrafast Optical

Abstract The ultimate control of magnetic states of matter at femtosecond (or even faster) timescales defines one of the most pursued paradigm shifts for future information technology. In this context, ultrafast laser pulses developed into extremely valuable stimuli for the all-optical magnetisation reversal in ferrimagnetic and ferromagnetic alloys and multilayers, while this remains elusive in elementary ferromagnets. Here we demonstrate that a single laser pulse with sub-picosecond duration can lead to the reversal of the magnetisation of bulk nickel, in tandem with the expected demagnetisation. As revealed by realistic time-dependent electronic structure simulations, the central mechanism is ultrafast light-induced torques acting on the magnetisation, which are only effective if the laser pulse is circularly polarised on a plane that contains the initial orientation of the magnetisation. We map the laser pulse parameter space enabling the magnetisation switching and unveil rich intra-atomic orbital-dependent magnetisation dynamics featuring transient inter-orbital non-collinear states. Our findings open further perspectives for the efficient implementation of optically-based spintronic devices.

scholarly journals Understanding all-optical spin switching: Comparison between experiment and theory

2018 ◽  
Vol 32 (28) ◽  
pp. 1830003 ◽  
Author(s):  
G. P. Zhang ◽  
M. Murakami ◽  
M. S. Si ◽  
Y. H. Bai ◽  
Thomas F. George
Keyword(s):  
Optical Switching ◽  
Magnetic Domain ◽  
Laser Pulses ◽  
Underlying Mechanism ◽  
Modern Technology ◽  
Single Shot ◽  
Ultrafast Laser Pulses ◽  
All Optical ◽  
Multiple Pulses ◽  
All Optical Switching

Information technology depends on how one can control and manipulate signals accurately and quickly. Transistors are at the core of modern technology and are based on electron charges. But as the device dimension shrinks, heating becomes a major problem. The spintronics explores the spin degree of electrons and thus bypasses the heat, at least in principle. For this reason, spin-based technology offers a possible solution. In this review, we survey some of the latest developments in all-optical switching (AOS), where ultrafast laser pulses are able to reverse spins from one direction to the other deterministically. But AOS only occurs in a special group of magnetic samples and within a narrow window of laser parameters. Some samples need multiple pulses to switch spins, while others need a single-shot pulse. To this end, there are several models available, but the underlying mechanism is still under debate. This review is different from other prior reviews in two aspects. First, we sacrifice the completeness of reviewing existing studies, while focusing on a limited set of experimental results that are highly reproducible in different labs and provide actual switched magnetic domain images. Second, we extract the common features from existing experiments that are critical to AOS, without favoring a particular switching mechanism. We emphasize that given the limited experimental data, it is really premature to identify a unified mechanism. We compare these features with our own model prediction, without resorting to a phenomenological scheme. We hope that this review serves the broad readership well.

Laser Technology for Advanced Acceleration: Accelerating Beyond TeV

2016 ◽  
Vol 09 ◽  
pp. 151-163 ◽  
Author(s):  
Jonathan Wheeler ◽  
Gérard Mourou ◽  
Toshiki Tajima
Keyword(s):  
Laser Pulse ◽  
Near Infrared ◽  
High Efficiency ◽  
Pulse Length ◽  
Laser Pulses ◽  
Single Cycle ◽  
X Ray ◽  
Ultrafast Laser Pulses ◽  
Laser Plasma Interaction ◽  
Laser Acceleration

The implementation of the suggestion of thin film compression (TFC) allows the newest class of high power, ultrafast laser pulses (typically 20[Formula: see text]fs at near-infrared wavelengths) to be compressed to the limit of a single-cycle laser pulse (2[Formula: see text]fs). Its simplicity and high efficiency, as well as its accessibility to a single-cycle laser pulse, introduce a new regime of laser–plasma interaction that enhances laser acceleration. Single-cycle laser acceleration of ions is a far more efficient and coherent process than the known laser-ion acceleration mechanisms. The TFC-derived single-cycle optical pulse is capable of inducing a single-cycle X-ray laser pulse (with a far shorter pulse length and thus an extremely high intensity) through relativistic compression. The application of such an X-ray pulse leads to the novel regime of laser wakefield acceleration of electrons in the X-ray regime, yielding a prospect of “TeV on a chip.” This possibility of single-cycle X-ray pulses heralds zeptosecond and EW lasers (and zeptoscience). The additional invention of the coherent amplification network (CAN) fiber laser pushes the frontier of high repetition, high efficiency lasers, which are the hallmark of needed applications such as laser-driven LWFA colliders and other, societal applications. CAN addresses the crucial aspect of intense lasers that have traditionally lacked the above properties.

scholarly journals Large ultrafast-modulated Voigt effect in noncollinear antiferromagnet Mn3Sn

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
H. C. Zhao ◽  
H. Xia ◽  
S. Hu ◽  
Y. Y. Lv ◽  
Z. R. Zhao ◽  
...  
Keyword(s):  
High Speed ◽  
Linear Dichroism ◽  
Laser Pulses ◽  
Time Resolved ◽  
Spin Configuration ◽  
Ultrafast Laser Pulses ◽  
Spintronic Devices ◽  
Wide Range ◽  
Kerr Angle ◽  
Increasing Temperature

AbstractThe time-resolved magneto-optical (MO) Voigt effect can be utilized to study the Néel order dynamics in antiferromagnetic (AFM) materials, but it has been limited for collinear AFM spin configuration. Here, we have demonstrated that in Mn3Sn with an inverse triangular spin structure, the quench of AFM order by ultrafast laser pulses can result in a large Voigt effect modulation. The modulated Voigt angle is significantly larger than the polarization rotation due to the crystal-structure related linear dichroism effect and the modulated MO Kerr angle arising from the ferroic ordering of cluster magnetic octupole. The AFM order quench time shows negligible change with increasing temperature approaching the Néel temperature (TN), in markedly contrast with the pronounced slowing-down demagnetization typically observed in conventional magnetic materials. This atypical behavior can be explained by the influence of weakened Dzyaloshinskii–Moriya interaction rather than the smaller exchange splitting on the diminished AFM order near TN. The temperature-insensitive ultrafast spin manipulation can pave the way for high-speed spintronic devices either working at a wide range of temperature or demanding spin switching near TN.

scholarly journals All-optical spin switching probability in [Tb/Co] multilayers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
L. Avilés-Félix ◽  
L. Farcis ◽  
Z. Jin ◽  
L. Álvaro-Gómez ◽  
G. Li ◽  
...  
Keyword(s):  
Optical Switching ◽  
Laser Pulses ◽  
Multilayered Structures ◽  
Magnetization Switching ◽  
Thermally Induced ◽  
Spintronic Devices ◽  
Single Laser ◽  
All Optical ◽  
Reversal Mechanism ◽  
All Optical Switching

AbstractSince the first experimental observation of all-optical switching phenomena, intensive research has been focused on finding suitable magnetic systems that can be integrated as storage elements within spintronic devices and whose magnetization can be controlled through ultra-short single laser pulses. We report here atomistic spin simulations of all-optical switching in multilayered structures alternating n monolayers of Tb and m monolayers of Co. By using a two temperature model, we numerically calculate the thermal variation of the magnetization of each sublattice as well as the magnetization dynamics of [$$\text {Tb}_n$$ Tb n /$$\text {Co}_m$$ Co m ] multilayers upon incidence of a single laser pulse. In particular, the condition to observe thermally-induced magnetization switching is investigated upon varying systematically both the composition of the sample (n,m) and the laser fluence. The samples with one monolayer of Tb as [$$\text {Tb}_1$$ Tb 1 /$$\text {Co}_2$$ Co 2 ] and [$$\text {Tb}_1$$ Tb 1 /$$\text {Co}_3$$ Co 3 ] are showing thermally induced magnetization switching above a fluence threshold. The reversal mechanism is mediated by the residual magnetization of the Tb lattice while the Co is fully demagnetized in agreement with the models developed for ferrimagnetic alloys. The switching is however not fully deterministic but the error rate can be tuned by the damping parameter. Increasing the number of monolayers the switching becomes completely stochastic. The intermixing at the Tb/Co interfaces appears to be a promising way to reduce the stochasticity. These results predict for the first time the possibility of TIMS in [Tb/Co] multilayers and suggest the occurrence of sub-picosecond magnetization reversal using single laser pulses.

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

2004 ◽  
Vol 22 (1) ◽  
pp. 19-24 ◽  
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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