Jianbao Zhao1
Canadian Light Source1
The study of materials under extreme conditions, such as high-pressure or low-temperature, is essential in understanding a broad range of problems in physics, chemistry, geology, and materials science. Extreme conditions can cause significant changes in the physical and chemical properties of matter, such as structural phase transitions, alterations in chemical bonding, and the emergence of new properties. Consequently, there is considerable research interest in studying materials under such conditions.<br/>A synchrotron radiation-based infrared source is an ideal tool for investigating microscopic samples under extreme conditions due to its high brightness. The Far-infrared beamline at the Canadian Light Source (CLS) is a state-of-the-art synchrotron facility that offers significantly more brightness than conventional sources. The high brightness of the synchrotron radiation allows for the acquisition of Far-infrared reflectivity or transmission spectrum on small samples with greater throughput than with conventional sources. This capability is ideal for high-pressure studies using the Diamond Anvil Cell (DAC).<br/>A synchrotron radiation-based Far-infrared spectroscopic experiment is particularly crucial for studying the lattice modes of materials as they typically appear in the Far-infrared region. Additionally, Far-infrared spectroscopy provides detailed information on the electrical transport properties of metallic materials, the bandgap of semiconductors, and the chemical bonding properties of materials.<br/>This presentation will provide a brief overview of the capabilities of the Far-infrared beamline at the CLS. It will also highlight the Far-infrared equipment used for solid-state experiments, especially for Far-infrared transmission and reflectivity measurements under high-pressure using the DAC. The CLS provides a custom-made horizontal microscope for Far-infrared microscopy during high-pressure studies. The optical set-up allows for transmission and reflectivity measurements, and two infinity-corrected long working distance Schwarzschild objectives (working distance-47 mm; numerical aperture-0.5) are suitable for high-pressure infrared studies using the DAC. The CLS records synchrotron radiation-based Far-infrared Fourier transform spectrum in the low-frequency region (30-600 cm<sup>-1</sup>) and the high-frequency region (300-1300 cm<sup>-1</sup>) using the liquid helium free detector system manufactured by QMC Instruments Inc. Moreover, the homemade ruby fluorescence spectrometer is available on-site at the CLS to measure the sample pressure inside the DAC. The Far-infrared beamline of the CLS is open to users through peer review, with calls for proposals issued twice per year for experimental beam time.