The two rare earth doping methods that we employ are ion implantation and sol-gel.
Ion implantation allows for highly controlled placement of Erbium in the silica. In collaboration with Prof. Albert Polman at FOM, we have fabricated planar arrays of low threshold microlasers out of both microtoroids and microdisks.
We have also used Erbium (Er+) doped sol-gel for microlaser fabrication. Sol-gel is significantly less expensive than ion implantation. This allows for Erbium to be distributed over much larger areas of the wafer, via spinning or dip-coating. Using Er+ doped sol-gel, we have both coated UHQ silica microtoroids and fabricated Er+ sol-gel microtoroids.
In collaboration with Prof. Harry Atwater and co-workers, chemically synthesized nanocrystal, CdSe/ZnS core/shell, quantum dots are coated on the surface of an ultrahigh-Q toroidal microcavity. The coverage of the quantum dots on the surface of the cavity can be accurately controlled using this technique. The minumum threshold energy achieved was 9.9 fJ.
rare earth rare-earth sol-gel doped erbium ion implantation near-IR visible laser nanocrystal quantum dot chip on-a-chip high Q quality factor ultra high Q