Design And Test Of High-resolution Imaging System For Ultracold Atoms

The rich and complex physical phenomena in the strongly correlated quantum many-body system attract a large number of physicists to explore them,such as hightemperature superconductivity,giant magnetoresistance and other effects,which are of great significance to future science and technology.While it is a challenge in understanding the strong correlations between particles.As a many-body strong correlation system that can be prepared in the laboratory,ultra-cold Fermi gas plays an important role in the study of quantum many-body phenomena.The high-resolution insitu imaging technology provides a more precise and intuitive method for ultra-cold atomic gas experiments.It can detect and manipulate atomic gases at a single lattice site,allowing direct observation of the spatial structure and magnetic ordering and dynamic correlation.They play an important role in the study of physical phenomena ranging from high-temperature superconductivity to quantum magnetism.The spatial resolution of high-resolution imaging systems generally reaches the sub-micron order close to the wavelength of the imaging laser light.However,commercial microscopy systems have short working distances and cannot compensate for the aberrations introduced by the vacuum window in the imaging system.It cannot be directly used to imaging the atoms with high resolution.In this dissertation,we specifically design a microscopic objective with correctable aberrations,large numerical aperture,and long working distance that meets the requirements of ultra-cold atom high-resolution in-situ imaging systems.The microscope objective is composed of five commercial lenses with a numerical aperture of 0.55 and a working distance of14mm.The modulation transfer function value at 600lp/mm in the full field of view of200?m×200?m is greater than 0.45.It corrects the aberration brought into the imaging system by the vacuum window and greatly improves the resolution of the ultracold atom in-situ imaging in the vacuum system.Meanwhile,we also analyzed the tolerance of the microscope objective,and successfully manufactured the microscope objective.Finally,we tested the actual resolution of the microscope objective using two methods of resolution target and pinhole point light source imaging.When the system was imaged through a 3.35mm thick window at the design wavelength of 671nm,it realized a sub-micron resolution in a 200?m×200?m field of view.