A high-flux and high-efficiency setup for magneto-infrared spectroscopy

Area of Science:

• Condensed Matter Physics
• Spectroscopy
• Materials Science

Background:

• High magnetic fields are crucial for studying quantum phenomena in materials.
• Magneto-infrared spectroscopy requires high signal-to-noise ratios for detailed analysis.
• Previous systems faced limitations in optical throughput and efficiency.

Purpose of the Study:

• To design and implement a high-flux, high-efficiency magneto-infrared spectroscopy system.
• To optimize the system for broadband measurements in high magnetic fields.
• To achieve a high signal-to-noise ratio for sensitive detection of weak spectral features.

Main Methods:

• Integration of a Fourier transform infrared spectrometer with a 12 T cryogen-free superconducting magnet.
• Optimization of optical throughput using polished, gold-plated light tubes and reflective focusing modules.
• Implementation of a motorized sample stage and automated control for high-throughput measurements.

Main Results:

• Reduced light tube loss from 65.5% to 22.0% m-1.
• Increased collection efficiency by nearly an order of magnitude with a single-on-axis parabolic-mirror Faraday module.
• Achieved a root-mean-square noise level of 0.0061% (signal-to-noise ratio > 1.6 × 10^4) for a 40% reflectivity sample.
• Successfully resolved weak replica bands in EuCd2As2 and high-index Landau level transitions in LaAlSi (amplitudes as low as 0.06%).

Conclusions:

• The developed magneto-infrared spectroscopy system significantly enhances measurement capabilities in high magnetic fields.
• The system's high efficiency and signal-to-noise ratio enable the study of subtle electronic and vibrational properties.
• This technology opens new avenues for exploring quantum materials and their responses to extreme conditions.