0000000000181774
AUTHOR
Vasily V. Temnov
Terahertz spectroscopy for all-optical spintronic characterization of the spin-Hall-effect metals Pt, W and Cu80Ir20
Identifying materials with an efficient spin-to-charge conversion is crucial for future spintronic applications. In this respect, the spin Hall effect is a central mechanism as it allows for the interconversion of spin and charge currents. Spintronic material research aims at maximizing its efficiency, quantified by the spin Hall angle and the spin-current relaxation length . We develop an all-optical contact-free method with large sample throughput that allows us to extract and . Employing terahertz spectroscopy and an analytical model, magnetic metallic heterostructures involving Pt, W and Cu80Ir20 are characterized in terms of their optical and spintronic properties. The validity of our …
Gain Dynamics after Ultrashort Pulse Trains in Quantum Dot based Semiconductor Optical Amplifiers
We study the gain dynamics in QD-based SOAs after excitation with fs-pulse trains of up to THz repetition rates. A complete ground-state gain recovery is found for 200 GHz repetition rates and injection currents around 90 mA.
Ultrafast Gain Recovery in Quantum Dot based Semiconductor Optical Amplifiers
Summary form only given. The limiting factor in ultrahigh bit rate amplification is the ultrafast population recovery in the resonant level, which is mainly limited by carrier capture and relaxation processes in the QD. We use pump-probe measurements resonant to the QDs confined states energies (ground and excited state) to investigate the response to a four fs-pulse train of 1 THz repetition rate. A deep insight about the capture process implied is then obtained, and direct capture from the wetting layer is identified as the dominant mechanism in the high current regime.