Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userA few-emitter solid-state multi-exciton laser
60
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We report a combined experimental and theoretical study of non-conventional lasing from higher multi-exciton states of a few quantum dot-photonic crystal nanocavity. We show that the photon output is fed from saturable quantum emitters rather than a non-saturable background despite being rather insensitive to the spectral position of the mode. Although the exciton transitions of each quantum dot are detuned by up to $160$ cavity linewidths, we observe that strong excitation populates a multitude of closely spaced multi-exciton states, which partly overlap spectrally with the mode. The limited number of emitters is confirmed by a complete saturation of the mode intensity at strong pumping, providing sufficient gain to reach stimulated emission, whilst being accompanied by a distinct lasing threshold. Detailed second-order photon-correlation measurements unambiguously identify the transition to lasing for strong pumping and, most remarkably, reveal super-thermal photon bunching with $g^{(2)}(0)>2$ below lasing threshold. Based on our microscopic theory, a pump-rate dependent $beta$-factor $beta(P)$ is needed to describe the nanolaser and account for the interplay of multi-exciton transitions in the few-emitter gain medium. Moreover, we theoretically predict that the super-thermal bunching is related to dipole-anticorrelated multi-exciton recombination channels via sub- and super-radiant coupling below and above lasing threshold, respectively. Our results provide new insights into the microscopic light-matter-coupling of spatially separated emitters coupled to a common cavity mode and, thus, provides a complete understanding of stimulated emission in nanolasers with discrete emitters.
rate research
Read More
We report a 2mu m ultrafast solid-state Tm:Lu2O3 laser, mode-locked by single-layer graphene, generating transform-limited~410fs pulses, with a spectral width~11.1nm at 2067nm. The maximum average output power is 270mW, at a pulse repetition frequency of 110MHz. This is a convenient high-power transform-limited laser at 2mu m for various applications, such as laser surgery and material processing.
We use multi-pulse dynamical decoupling to increase the coherence lifetime (T2) of large numbers of nitrogen-vacancy (NV) electronic spins in room temperature diamond, thus enabling scalable applications of multi-spin quantum information processing and metrology. We realize an order-of-magnitude extension of the NV multi-spin T2 for diamond samples with widely differing spin environments. For samples with nitrogen impurity concentration <~1 ppm, we find T2 > 2 ms, comparable to the longest coherence time reported for single NV centers, and demonstrate a ten-fold enhancement in NV multi-spin sensing of AC magnetic fields.
We propose a state of excitonic solid for double layer two dimensional electron hole systems in transition metal dicalcogenides stacked on opposite sides of thin layers of BN. Properties of the exciton lattice such as its Lindemann ratio and possible supersolid behaviour are studied. We found that the solid can be stabilized relative to the fluid by the potential due to the BN.
The quantum coherence of electronic quasiparticles underpins many of the emerging transport properties of conductors at small scales. Novel electronic implementations of quantum optics devices are now available with perspectives such as flying qubit manipulations. However, electronic quantum interferences in conductors remained up to now limited to propagation paths shorter than $30,mu$m, independently of the material. Here we demonstrate strong electronic quantum interferences after a propagation along two $0.1,$mm long pathways in a circuit. Interferences of visibility as high as $80%$ and $40%$ are observed on electronic analogues of the Mach-Zehnder interferometer of, respectively, $24,mu$m and $0.1,$mm arm length, consistently corresponding to a $0.25,$mm electronic phase coherence length. While such devices perform best in the integer quantum Hall regime at filling factor 2, the electronic interferences are restricted by the Coulomb interaction between copropagating edge channels. We overcome this limitation by closing the inner channel in micron-scale loops of frozen internal degrees of freedom, combined with a loop-closing strategy providing an essential isolation from the environment.
We analyze the dynamics of a continuously observed, damped, microwave driven solid state charge qubit. The qubit consists of a single electron in a double well potential, coupled to an oscillating electric field, and which is continuously observed by a nearby point contact electrometer. The microwave field induces transitions between the qubit eigenstates, which have a profound effect on the detector output current. We show that useful information about the qubit dynamics, such as dephasing and relaxation rates, and the Rabi frequency, can be extracted from the DC detector conductance and the detector output noise power spectrum. We also demonstrate that these phenomena can be used for single shot electron emph{spin} readout, for spin based quantum information processing.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
