Cavity-funneled generation of indistinguishable single photons from strongly dissipative quantum emitters (original) (raw)

Coherent single-photon generation and trapping with practical cavity QED systems

2007 Quantum Electronics and Laser Science Conference, 2007

We study analytically the dynamics of cavity QED nodes in a practical quantum network. Given a single 3-level Λ-type atom or quantum dot coupled to a micro-cavity, we derive several necessary and sufficient criteria for the coherent trapping and generation of a single photon pulse with a given waveform to be realizable. We prove that these processes can be performed with practical hardware -such as cavity QED systems which are operating deep in the weak coupling regime -given a set of restrictions on the single-photon pulse envelope. We systematically study the effects of spontaneous emission and spurious cavity decay on the transfer efficiency, including the case where more than one excited state participates in the dynamics. This work should open the way to very efficient optimizations of the operation of quantum networks.

Pure emitter dephasing: A resource for advanced solid-state single-photon sources

Physical Review A, 2009

We have computed the spectrum emitted spontaneously by a quantum dot coupled to an arbitrarily detuned single mode cavity, taking into account pure dephasing processes. We show that if the emitter is incoherent, the cavity can efficiently emit photons with its own spectral characteristics. This effect opens unique opportunities for the development of devices exploiting both cavity quantum electrodynamics effects and pure dephasing, such as wavelength stabilized single photon sources robust against spectral diffusion.

On-chip generation of indistinguishable photons using cavity quantum-electrodynamics

2014

The on-chip generation of non-classical states of light is a key-requirement for future optical quantum hardware. In solid-state cavity quantum electrodynamics, such non-classical light can be generated from self-assembled quantum dots strongly coupled to photonic crystal cavities. Their anharmonic strong light-matter interaction results in large optical nonlinearities at the single photon level, where the admission of a single photon into the cavity may enhance (photon-tunnelling) or diminish (photon-blockade) the probability for a second photon to enter the cavity. Here, we demonstrate that detuning the cavity and QD resonances enables the generation of high-purity non-classical light from strongly coupled systems. For specific detunings we show that not only the purity but also the efficiency of single-photon generation increases significantly, making high-quality single-photon generation by photon-blockade possible with current state-of-the-art samples.

A versatile source of single photons for quantum information processing

Nature Communications, 2013

The quantum state of a single photon stands amongst the most fundamental and intriguing manifestations of quantum physics . At the same time single photons and pairs of single photons are important building blocks in the fields of linear optical based quantum computation and quantum repeater infrastructure . These fields possess enormous potential and much scientific and technological progress has been made in developing individual components, like quantum memories and photon sources using various physical implementations . However, further progress suffers from the lack of compatibility between these different components. Ultimately, one aims for a versatile source of single photons and photon pairs in order to overcome this hurdle of incompatibility. Such a photon source should allow for tuning of the spectral properties (wide wavelength range and narrow bandwidth) to address different implementations while retaining high efficiency. In addition, it should be able to bridge different wavelength regimes to make implementations compatible. Here we introduce and experimentally demonstrate such a versatile single photon and photon pair source based on the physics of whispering gallery resonators. A diskshaped, monolithic and intrinsically stable resonator is made of lithium niobate and supports a cavity-assisted triply-resonant spontaneous parametric down-conversion process. Measurements show that photon pairs are efficiently generated in two highly tunable resonator modes. We verify wavelength tuning over 100 nm between both modes with a controllable bandwidth between 7.2 and 13 MHz. Heralding of single photons yields anti-bunching with g (2) (0) < 0.2. This compact source provides unprecedented possibilities to couple to different physical quantum systems and makes it ideal for the implementation of quantum repeaters and optical quantum information processing.

Filtering multiphoton emission from state-of-the-art cavity quantum electrodynamics

Optica

Engineering multiphoton states is an outstanding challenge with applications in multiple fields, such as quantum metrology, quantum lithography or even biological systems. State-of-the-art methods to obtain them rely on post-selection, multi-level systems or Rydberg atomic ensembles. Recently, it was shown that a strongly driven two-level system interacting with a detuned cavity mode can be engineered to continuously emit n-photon states. In the present work, we show that spectral filtering of its emission relaxes considerably the requirements on the system parameters even to the more accessible bad-cavity situation, opening up the possibility of implementing this protocol in a much wider landscape of different platforms. This improvement is based on a key observation: in the imperfect case where only a certain fraction of emission is composed of n-photon states, these have a well defined energy separated from the rest of the signal, which allows to reveal and purify multiphoton emission just by frequency filtering. We demonstrate these results by obtaining analytical expressions for relevant figures of merit of multiphoton emission, such as the n-photon coupling rate between cavity and emitter, the fraction of light emitted as n-photon states, and n-photon emission rates. This allows us to make a systematic study of such figures of merit as a function of the system parameters and demonstrate the viability of the protocol in several relevant types of cavity QED setups, where we take into account the impact of their respective experimental limitations.

Coherent single-photon generation and trapping with imperfect cavity QED systems

Eprint Arxiv Quant Ph 0606204, 2006

We study analytically the dynamics of cavity QED nodes in a practical quantum network. Given a single 3-level Lambda\LambdaLambda-type atom or quantum dot coupled to a micro-cavity, we derive several necessary and sufficient criteria for the coherent trapping and generation of a single photon pulse with a given waveform to be realizable. We prove that these processes can be performed with practical hardware -- such as cavity QED systems which are operating deep in the weak coupling regime -- given a set of restrictions on the single-photon pulse envelope. We systematically study the effects of spontaneous emission and spurious cavity decay on the transfer efficiency, including the case where more than one excited state participates in the dynamics. This work should open the way to very efficient optimizations of the operation of quantum networks.

Continuous monitoring can improve indistinguishability of a single-photon source

Physical Review A, 2009

A new engineering technique using continuous quantum measurement in conjunction with feedforward is proposed to improve indistinguishability of a single-photon source. The technique involves continuous monitoring of the state of the emitter, processing the noisy output signal with a simple linear estimation algorithm, and feed forward to control a variable delay at the output. In the weak coupling regime, the information gained by monitoring the state of the emitter is used to reduce the time uncertainty inherent in photon emission from the source, which improves the indistinguishability of the emitted photons. 73.21.La, 03.65.Yz, 02.70.Ss Developing a scalable model to implement quantum computation on physical systems has generated consuming interest in the quantum computing community ever since Shor [1] and Grover showed that quantum computing can outperform any classical device for certain algorithms of practical interest. Knill et al.

Qubit-photon interactions in a cavity: Measurement-induced dephasing and number splitting

Physical Review A, 2006

We theoretically study measurement induced-dephasing of a superconducting qubit in the circuit QED architecture and compare the results to those obtained experimentally by Schuster et al., [Phys. Rev. Lett. 94, 123602 (2005)]. Strong coupling of the qubit to the resonator leads to a significant ac-Stark shift of the qubit transition frequency. As a result, quantum fluctuations in the photon number populating the resonator cause dephasing of the qubit. We find good agreement between the predicted line shape of the qubit spectrum and the experimental results. Furthermore, in the strong dispersive limit, where the Stark shift per photon is large compared to the cavity decay rate and the qubit linewidth, we predict that the qubit spectrum will be split into multiple peaks, with each peak corresponding to a different number of photons in the cavity.