Ultrafast manipulation of electron spin coherence

Area of Science:

• Semiconductor physics
• Quantum optics
• Spintronics

Background:

• Electron spin manipulation is crucial for developing advanced electronic devices.
• Achieving precise, ultrafast control over electron spins remains a significant challenge.

Purpose of the Study:

• To develop a technique for coherent all-optical control of electron spins in semiconductors.
• To demonstrate ultrafast manipulation of electron spin states on femtosecond timescales.

Main Methods:

• Utilizing optical "tipping" pulses to induce electron spin rotations.
• Employing the optical Stark effect as the underlying mechanism for spin manipulation.
• Measuring spin precession amplitude changes in a transverse magnetic field after optical excitation.

Main Results:

• Demonstrated substantial rotations of electron spins, approaching pi/2 radians.
• Confirmed the reversible nature of the spin rotation using a two-pulse sequence.
• Established the coherent nature of the optical tipping process.

Conclusions:

• The developed technique enables coherent all-optical control of electron spins in semiconductors.
• Femtosecond optical pulses can precisely manipulate electron spin states via the optical Stark effect.
• This work lays the foundation for ultrafast semiconductor spintronics.