The goal of the proposed research is to develop a new class of devices based on Er-doped microcavities that function as efficient light emitters, as photonic switches and as terahertz signal oscillators. The devices will exploit the basic physics of the strong photon-atom interaction to determine the feasibility of the using of Er-doped media in a high Q microcavity as a basic unit of photonic device design. The fabrication of these devices will involve the design of the structures and the process metrics, such as stress relief, planarity and uniformity of the layers and the phase stability of the materials systems. If successful, this research creates a new class of devices for the generation, detection and manipulation of photons that could be critical to the evolution of all optical networking for the movement and management of information. Our preliminary results obtained with an Er 2 O 3 microcavity medium clad by Si/SiO 2 dielectric stack mirrors showed direct evidence of photon-atom coupling, an enhancement of the light emitted from the microcavity by orders of magnitude at room temperature, and the capability of optical switching. The Si/SiO 2 microcavity structure of this potential new class of devices provides a very important route to CMOS compatible processing and integration. In addition, the high dielectric contrast of the Si/SiO 2 materials system (D nr=2) means that only four layer pairs are required for cavity Qs of 1000. Rare earth elements as quantum dot analogs offer the ultimate in size monodispersity and electronic localization. Erbium is an ideal rare earth optical dopant because of its emission spectrum in the telecommunications standard, l=1.55 micron wavelength region. The main obstacle to the development of a Si:Er platform is the small optical cross section, long radiative lifetime and difficulty of tuning of the atomic resonances of the rare earth elements. We propose to use monolithic planar microcavities to enhance the Er-photon coupling, and hence, add a mechanism for tuning of the oscillator strength. An Er2 O3 cavity medium provides a high density of atoms that can experience coherent interactions with light. These interacting Er atoms are weakly coupled to their host matrix with sharp emission lines. This property yields a device that responds to light as a set of Er-photon coupled oscillators. By tuning the microcavity resonance the emission, transmission and reflection properties of the structure may be controlled at speeds equivalent to the frequency difference between the Er and cavity resonances. We propose a three-year effort to design, fabricate and characterize room temperature operating devices for emission and switching of light in the l=1.55 micron wavelength region. The proposed study explores a new device platform of photon coupling to optically active ions and its application to the generation and control of light. If the promised performance can be achieved, then this Er:Si/SiO2 system will provide a highly manufacturable, silicon compatible photonic device platform.
