The world's highest field optical microscopy probe compatible with 42 T steady magnetic field and down to 1.8 K

Imaging technologies under high magnetic fields and at low temperatures are uniquely valuable to materials science and life science due to their capability to visually capture microstructural features and dynamic evolution of both material and biological systems. In this work, we design and fabricate an optical microscopy probe compatible with an ultra-high magnetic field up to 42 T and down to 1.8 K. To the best of our knowledge, this is the first optical microscopy probe compatible with such extreme steady-field conditions. The probe supports steady long-range imaging with a working distance of more than 1500 mm and offers a 1 mm field of view with resolution better than 10 μm. With a diameter of 28 mm, it can fit in standard laboratory magnets, cryostats, and water-cooled high-field magnets. Moreover, it is equipped with transmission, reflection, and polarization imaging functions all together to enable real-time observation of structural variations and behavioral changes of micro-organisms and the dynamic evolution of microstructures of materials under combined low temperature and high magnetic field conditions.