Optically modulated magnetic resonance of erbium implanted silicon

Er implanted Si is a candidate for quantum and photonic applications; however, several different Er centres are generated, and their symmetry, energy level structure, magnetic and optical properties, and mutual interactions have been poorly understood, which has been a major barrier to the development of these applications. Optically modulated magnetic resonance (OMMR) gives a spectrum of the modulation of an electron paramagnetic resonance (EPR) signal by a tuneable optical field. Our OMMR spectrum of Er implanted Si agrees with three independent measurements, showing that we have made the first measurement of the crystal field splitting of the (4)I(13/2) manifold of Er implanted Si, and allows us to revise the crystal field splitting of the (4)I(15/2) manifold. This splitting originates from a photoluminescence (PL) active O coordinated Er centre with orthorhombic C(2v) symmetry, which neighbours an EPR active O coordinated Er centre with monoclinic C(1h) symmetry. This pair of centres could form the basis of a controlled NOT (CNOT) gate.