Double resonance experiments in the Tm I - spectrum

Quankui K. Yang, Rebekka Eberle, Lara Ruppert +3 more

Entangled photon pairs with orthogonal polarizations, namely the fundamental transverse-electric (TE) and the transverse-magnetic (TM), have important applications in quantum communication and quantum information processing. We report on the simultaneous generation of photons in TE and TM modes from diamond micro-ring resonators (radius: 2.25 µm) doped with nitrogen-vacancy centers and fabricated using Faraday-cage angled etching. Double peaks are observed in the photoluminescence spectra of the ring resonators. These double peaks are investigated in detail and are attributed to the simultaneous excitation of the fundamental TE and TM modes. Polarization-resolved measurements are performed to verify this interpretation.

Noriaki Tsukada, T. Koyama, Toru Ogawa

P. Thornton Greenland

A simple analytic expression for the double optical resonance spectrum obtained when a two-level atom is excited by a noisy pump laser is derived for two different models of laser noise, the phase diffusion model, and a model in which the laser bandwidth arises from a random telegraph signal in the laser phase. The double optical resonance spectrum is identical for both models and therefore double optical resonance experiments cannot distinguish between them. The importance of transients in cases where the laser bandwidth is comparable with or less than the atomic linewidth is stressed. Experiments which can distinguish between the two sources of bandwidth are identified.

J. I. Steinfeld, Paul L. Houston

D P O'Brien, S. Swain

The authors examine the theory of optical double resonance using two lasers whose finite linewidths are produced by the process of phase-diffusion. Their lineshapes, which are nonLorentzian, are characterised by a bandwidth B and a cut off C. The authors are concerned with obtaining an analytic theory; they achieve this by assuming the ratio B/C to be small and work to first order in B/C (although the method can be extended to higher order in B/C). They obtain analytic expressions for the optical double resonance spectrum and discuss the results of recent experiments by Hogan et al. (1978) and Nitz et al. (1981) in which it was found that the asymmetry of the peaks in the optical double resonance spectrum changed with detuning. It is found that a qualitative understanding can be achieved but that a full quantitative comparison is not yet possible.

Alan Corney