Coherent and Incoherent Photons from a Single Solid State Emitter Ilja Gerhardt, PhD., University of British Columbia, Chemistry Department, Low Temperature Group, 2036 Main Mall, Vancouver, B.C., V6T 1Z1, Canada, ilja@quantumlah.org Spectroscopy on single emitters has become an indispensable tool for biologists and material scientists. Single molecules, nano crystals and also defect centers in diamond can be optically detected and utilized as labels and reporters to their specific nano-environment. The techniques were engineered towards highly efficient detection of small photon numbers and of localization accuracies down to a couple of nanometers. A variety of experiments rely on distinct techniques for efficient optical excitation and detection of single emitters. By decreasing the temperature and subsequently the coupling of a single emitter to its environment, it is possible to acquire spectra, showing lifetime limited linewidths. The highly coherent nature of the system allows for a variety of quantum optical experiments. In single photon counting experiments we are able to extract and detect coherent and incoherent photons. In this talk, I will review the properties of single emitters at cryogenic conditions, with a special focus on single molecules and defect centers in diamond. Their potential to compete with ions and atoms for quantum optical experiments will be discussed. As an experimentalist, I will introduce a number of strategies for the efficient excitation and detection of their coherent photons and properties. [1] I. Gerhardt, G. Wrigge et al., Strong Extinction of a Laser Beam by a Single Molecule, Physical Review Letters, 2007, 98, 4 [2] G. Wrigge, I. Gerhardt et al., Efficient coupling of photons to a single molecule and the observation of its resonance fluorescence, Nature Physics, 2008, 4, 60-66 [3] I. Gerhardt, G. Wrigge et al., Coherent state preparation and observation of Rabi oscillations in a single molecule, Physical Review A, 2009, 79, 4 [4] P. Siyushev, F. Kaiser, V. Jacques, I. Gerhardt, S. Bischof, H. Fedder, J. Dodson, M. Markhamand D. Twitchen, F. Jelezko, J. Wrachtrup, Monolithic diamond optics for single photon detection, Applied Physics Letters, 2010, 97, 241902 [5] I. Gerhardt, G. Wrigge, J. Hwang, G. Zumofen, V. Sandoghdar, Coherent Nonlinear Single Molecule Microscopy, Physical Review A, 2010, 82, 063823