TY  - JOUR
A1  - Kim, Seonghoon
A1  - Zhang, Bo
A1  - Wang, Zhaorong
A1  - Fischer, Julian
A1  - Brodbeck, Sebastian
A1  - Kamp, Martin
A1  - Schneider, Christian
A1  - Höfling, Sven
A1  - Deng, Hui
T1  - Coherent Polariton Laser
JF  - Physical Review X
N2  - The semiconductor polariton laser promises a new source of coherent light, which, compared to conventional semiconductor photon lasers, has input-energy threshold orders of magnitude lower. However, intensity stability, a defining feature of a coherent state, has remained poor. Intensity noise many times the shot noise of a coherent state has persisted, attributed to multiple mechanisms that are difficult to separate in conventional polariton systems. The large intensity noise, in turn, limits the phase coherence. Thus, the capability of the polariton laser as a source of coherence light is limited. Here, we demonstrate a polariton laser with shot-noise-limited intensity stability, as expected from a fully coherent state. This stability is achieved by using an optical cavity with high mode selectivity to enforce single-mode lasing, suppress condensate depletion, and establish gain saturation. Moreover, the absence of spurious intensity fluctuations enables the measurement of a transition from exponential to Gaussian decay of the phase coherence of the polariton laser. It suggests large self-interaction energies in the polariton condensate, exceeding the laser bandwidth. Such strong interactions are unique to matter-wave lasers and important for nonlinear polariton devices. The results will guide future development of polariton lasers and nonlinear polariton devices.
KW  - polariton laser
KW  - condensed matter physics
KW  - photonics
KW  - quantum physics
KW  - coherent light
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166597
VL  - 6
IS  - 011026
ER  - 
TY  - JOUR
A1  - Dietrich, Christof P.
A1  - Steude, Anja
A1  - Tropf, Laura
A1  - Schubert, Marcel
A1  - Kronenberg, Nils M.
A1  - Ostermann, Kai
A1  - Höfling, Sven
A1  - Gather, Malte C.
T1  - An exciton-polariton laser based on biologically produced fluorescent protein
JF  - Science Advances
N2  - Under adequate conditions, cavity polaritons form a macroscopic coherent quantum state, known as polariton condensate. Compared to Wannier-Mott excitons in inorganic semiconductors, the localized Frenkel excitons in organic emitter materials show weaker interaction with each other but stronger coupling to light, which recently enabled the first realization of a polariton condensate at room temperature. However, this required ultrafast optical pumping, which limits the applications of organic polariton condensates. We demonstrate room temperature polariton condensates of cavity polaritons in simple laminated microcavities filled with biologically produced enhanced green fluorescent protein (eGFP). The unique molecular structure of eGFP prevents exciton annihilation even at high excitation densities, thus facilitating polariton condensation under conventional nanosecond pumping. Condensation is clearly evidenced by a distinct threshold, an interaction-induced blueshift of the condensate, long-range coherence, and the presence of a second threshold at higher excitation density that is associated with the onset of photon lasing.
KW  - polarition condensate
KW  - enhanced green fluorescent protein
KW  - photon lasing
KW  - quantum physics
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171305
VL  - 2
IS  - 8
ER  - 
TY  - JOUR
A1  - Astakhov, Georgy V.
A1  - Kraus, Hannes
A1  - Soltamov, V. A.
A1  - Fuchs, Franziska
A1  - Simin, Dimitrij
A1  - Sperlich, Andreas
A1  - Baranov, P. G.
A1  - Dyakonov, Vladimir
T1  - Magnetic field and temperature sensing with atomic-scale spin defects in silicon carbide
N2  - Quantum systems can provide outstanding performance in various sensing applications, ranging from bioscience to nanotechnology. Atomic-scale defects in silicon carbide are very attractive in this respect because of the technological advantages of this material and favorable optical and radio frequency spectral ranges to control these defects. We identified several, separately addressable spin-3/2 centers in the same silicon carbide crystal, which are immune to nonaxial strain fluctuations. Some of them are characterized by nearly temperature independent axial crystal fields, making these centers very attractive for vector magnetometry. Contrarily, the zero-field splitting of another center exhibits a giant thermal shift of −1.1 MHz/K at room temperature, which can be used for thermometry applications. We also discuss a synchronized composite clock exploiting spin centers with different thermal response.
KW  - condensed-matter physics
KW  - quantum physics
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-113025
ER  -