Figure 1: Atomic cladding waveguide illustration and photograph.
From: Nanoscale light–matter interactions in atomic cladding waveguides

(a) Illustration of the ACWG. (b) Cross section of the SiN waveguide in the interaction area with the simulated fundamental TE mode superimposed. A Rb atom is illustrated as reflecting the surface, leaving the surface at a quenched state. (c) Photograph of the device showing the bonding of the vapour cell to the chip.