Time-resolved magneto-optical spectroscopy for micrometer-sized flakes of 2D materials
Our Magneto-Optical Lab (MO-Lab) hosts a table-top setup to perform ultrafast magneto-optical pump–probe measurements with the possibility to independently tune the photon-energy of both pump and probe beams in the 0.5 eV–3.5 eV range. Our apparatus relies on a commercial turn-key amplified laser system, able to generate light pulses with duration shorter than or comparable to 100 fs throughout the whole spectral range. The repetition rate of the source can be modified via the computer in the 1 kHz to 1 MHz range. A commercial balanced detector is connected to a high-frequency digitizer, allowing for a highly-sensitive detection scheme: rotations of the probe polarization as small as 70 μdeg can be measured. Additionally, a DC magnetic field as high as 9 T and voltages in the kV regime can be applied on the sample. A cryostat allows us to precisely set the temperature of the specimen in the 4 K–420 K interval.
In this publication we have studied the ultrafast coherent THz lattice dynamics in FePS3, a van der Waals antiferromagnetic flake:
Recently, we have upgraded the system by integrating a microscope objective. This allows to perform time-resolved experiments with a lateral resolution down to 3 µm, which is particularly helpful for the study of micrometer-sized flakes of 2D antiferromagnets.
The setup is described in the following publication:
F. Mertens, M. Terschanski, D. Mönkebüscher, S. Ponzoni, D. Bossini, and M. Cinchetti, Wide Spectral Range Ultrafast Pump–Probe Magneto-Optical Spectrometer at Low Temperature, High-Magnetic and Electric Fields, Review of Scientific Instruments 91, 113001 (2020); https://doi.org/10.1063/5.0024449