Related Experiment Video
Updated: Aug 2, 2025
08:01
Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures
Published on: November 21, 2019
7.2K
Ultrafast light-driven magneto-optical nonlinearity in ferromagnetic heterostructures
Optics Letters
|April 14, 2023
Summary
Ultrafast laser pulses dynamically control magnetization in metallic heterostructures. This study reveals terahertz radiation generation mechanisms, highlighting spin-to-charge conversion and demagnetization as key factors.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Optoelectronics
Background:
- Dynamic control of magnetization using short laser pulses is a growing research area.
- Previous studies explored transient magnetization via second-harmonic generation and time-resolved magneto-optical effects.
- The ultrafast light-driven magneto-optical nonlinearity in ferromagnetic heterostructures for terahertz (THz) radiation requires further clarification.
Purpose of the Study:
- To investigate THz generation from a metallic heterostructure (Pt/CoFeB/Ta).
- To elucidate the underlying physical mechanisms contributing to THz emission.
- To establish THz-emission spectroscopy as a tool for studying picosecond-timescale nonlinear magneto-optical effects.
Main Methods:
- Fabrication of a Pt/CoFeB/Ta metallic heterostructure.
- Utilizing THz-emission spectroscopy to probe ultrafast dynamics.
- Analyzing contributions from magnetization-induced optical rectification, spin-to-charge current conversion, and ultrafast demagnetization.
Main Results:
- Observed THz generation from the Pt/CoFeB/Ta heterostructure.
- Quantified the contributions to THz generation: ~6-8% from magnetization-induced optical rectification.
- ~94-92% from spin-to-charge current conversion and ultrafast demagnetization.
Conclusions:
- Spin-to-charge current conversion and ultrafast demagnetization are dominant mechanisms for THz generation in this heterostructure.
- THz-emission spectroscopy is demonstrated as an effective technique for probing picosecond-timescale nonlinear magneto-optical phenomena.
- The findings advance understanding of light-matter interactions in magnetic heterostructures for THz applications.
Related Concept Videos
01:31Ferromagnetism
2.4K
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
2.4K
01:05Atomic Nuclei: Magnetic Resonance
709
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...
709
03:02Colors and Magnetism
12.0K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
12.0K
01:17Force On A Current Loop In A Magnetic Field
3.3K
Magnetic forces on wires carrying current are most frequently applied in motors. A DC motor is a device that converts electrical energy into mechanical work. In motors, wire loops are enclosed in a magnetic field. When current flows through the loops, the magnetic field applies torque, which causes the shaft to rotate. The direction of the current is reversed once the loop's surface area is lined up with the magnetic field, causing a constant torque on the loop. During the process,...
3.3K