Optical resonators that are enhanced with photoluminescent phosphors and are designed and configured to output light at one or more wavelengths based on input/pump light, and systems and devices made with such resonators. In some embodiments, the resonators contain multiple optical resonator cavities in combination with one or more photoluminescent phosphor layers or other structures. In other embodiments, the resonators are designed to simultaneously resonate at the input/pump and output wavelengths. The photoluminescent phosphors can be any suitable photoluminescent material, including semiconductor and other materials in quantum-confining structures, such as quantum wells and quantum dots, among others.