  We report on the trapping of single rubidium atoms in large arrays of optical
tweezers comprising up to 2088 sites in a cryogenic environment at 6 K. Our
approach relies on the use of microscope objectives that are in-vacuum but at
room temperature, in combination with windowless thermal shields into which the
objectives are protruding to ensure a cryogenic environment for the trapped
atoms. To achieve enough optical power for efficient trapping, we combine two
lasers at slightly different wavelengths. We discuss the performance and
limitations of our design. Finally, we demonstrate atom-by-atom rearrangement
of an 828-atom target array using moving optical tweezers controlled by a
field-programmable gate array.
