Automated polarization rotation for multi-axis rotational-anisotropy second harmonic generation experiments.

Area of Science:

• Nonlinear Optics
• Condensed Matter Physics
• Materials Science

Background:

• Rotational anisotropy second harmonic generation (RA-SHG) is a key nonlinear optical technique for investigating condensed matter symmetries.
• Probing complex quantum material phases requires measuring SHG susceptibility dependence on external parameters like strain or temperature.
• Manual polarization rotation in multi-axis RA-SHG experiments is labor-intensive and prone to noise.

Purpose of the Study:

• To design and implement a cost-effective, high-fidelity automated polarization rotator system for multi-axis RA-SHG.
• To overcome geometrical constraints in automated polarization control for complex optical setups.
• To enhance the efficiency and scope of RA-SHG experiments for quantum material characterization.

Main Methods:

• Developed automated polarization rotators using miniature stepper motors and electrical slip rings.
• Integrated the rotators into a multi-axis RA-SHG experimental setup.
• Demonstrated the system's performance using time-resolved RA-SHG measurements on GaAs.

Main Results:

• The automated system significantly reduces manual labor and uncertainty from low-frequency noise.
• Data collection is vastly expedited, allowing for longer averaging periods.
• The system expands measurement capabilities for multi-axis RA-SHG experiments.

Conclusions:

• The developed automated polarization rotators provide a low-cost, high-fidelity solution for multi-axis RA-SHG.
• This automation facilitates more efficient and comprehensive probing of quantum materials.
• The system opens new avenues for exploring quantum materials under multiple tunable external parameters.