Aging test of an atomic vapor cell with Al₂O₃ wall coating on cubic glass

We conducted a long-term aging test at high temperature on cubic glass rubidium vapor cells. The inner surface of the cubic glass cell was coated with <i>A</i><i>l</i>₂<i>O</i>₃ using electron beam deposition, resulting in a thickness of 26.9 nm on the side walls and 63.8 nm on the bottom surface. The rubidium number density was monitored by measuring the absorption spectrum of the <i>D</i>₁ line. The measured spectrum was compared with a simulated profile based on the Beer-Lambert law. The rubidium number density in the <i>A</i><i>l</i>₂<i>O</i>₃-coated rubidium vapor cell remained constant for nearly four times longer and then decreased 4.6 times more slowly than in the uncoated rubidium vapor cell.