Applied Optics
High-resolution ex vacuo objective for cold atom experiments
Xiao Min Li, Feng Zhou, Ke Min, Peng Xu, Xiaodong He, Jin Wang, Mingsheng Zhan
Abstract
We present a versatile and cost-efficient objective with a five-lens configuration, which consists completely of commercial singlets. The home-built objective has a numerical aperture (NA) of 0.44 and a long working distance of 35.9 mm, making it suitable for ex vacuo utilization. A diffraction-limited resolution of 1.08 μm and a field of view of about 210 μm are achieved when a 780 nm light passes through a 5 mm thick vacuum window. Moreover, such a design can be well adapted to a broad range of laser wavelengths (560-1000 nm) and vacuum window thicknesses (0-6 mm) by simply modifying one lens spacing, while maintaining a NA of above 0.43. The characteristics of the objective are evaluated experimentally, which are in good agreement with the simulations. Also, the objective has been successfully used for single-atom trapping and detecting in experiments. We believe that it will find more applications in various cold atom experiments.