Loading Atomic Systems Using Light Induced Atomic Desorption

The path to using quantum systems for more applications means improving aspects of current experimental platforms, such as atom sources for ion and neutral atom traps. Improvements include reducing experimental complexity, size, and cost; extending source lifetimes; and providing colder atoms. Previous works used light induced atomic desorption (LIAD) to desorb calcium from a polymer surface [1] and strontium from both bulk metal and oxide [2]. In the latter case the resulting atoms were loaded into a MOT. Instead of using ovens and ablation lasers to load atoms, LIAD uses non-resonant light to desorb material from a surface at room temperature. We study LIAD using a platform we constructed for testing how non-resonant 405, 450, and 808 nm laser light desorbs calcium off several surfaces, including fused silica, borosilicate glass, gold, and other ultra-high vacuum compatible materials. The desorbed calcium is detected by driving fluorescence with 423 nm laser light while a high numerical aperture imaging system directs fluorescence photons onto a photomultiplier tube. We found substrate material, intensity of light, and thickness of calcium all play a role in determining if desorption events are sustained or repeatable. One combination allows for several repeated sustained desorption events lasting several hours while other combinations only allow for the desorption of calcium for fractions of a second. To ascertain if we are observing LIAD or simply thermal desorption, we are setting up experiments that will determine the temperature of desorbed atoms.

[1] Mango, F., Maccioni, E. Light-induced ejection of calcium atoms from polymer surfaces. Eur. Phys. J. D 50, 253 (2008).

[2] Kock, O. et al. Laser controlled atom source for optical clocks. Sci Rep 6, 37321 (2016).