Edo Waks

Loyola University Maryland, Baltimore, Maryland, United States

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Publications (130)

  • [Show abstract] [Hide abstract] ABSTRACT: Interactions between solid-state quantum emitters and cavities are important for a broad range of applications in quantum communication, linear optical quantum computing, nonlinear photonics, and photonic quantum simulation. These applications often require combining many devices on a single chip with identical emission wavelengths in order to generate two-photon interference, the primary mechanism for achieving effective photon-photon interactions. Such integration remains extremely challenging due to inhomogeneous broadening and fabrication errors that randomize the resonant frequencies of both the emitters and cavities. In this letter we demonstrate two-photon interference from independent cavity-coupled emitters on the same chip, providing a potential solution to this long-standing problem. We overcome spectral mismatch between different cavities due to fabrication errors by depositing and locally evaporating a thin layer of condensed nitrogen. We integrate optical heaters to tune individual dots within each cavity to the same resonance with better than 3 {\mu}eV of precision. Combining these tuning methods, we demonstrate two-photon interference between two devices spaced by less than 15 {\mu}m on the same chip with a post-selected visibility of 33%. These results pave the way to integrate multiple quantum light sources on the same chip to develop quantum photonic devices.
    Article · Aug 2016
  • Shuo Sun · Edo Waks
    [Show abstract] [Hide abstract] ABSTRACT: We show that a quantum network can protect the identity of a sender and receiver from wiretapping without using entanglement. This new quantum communication protocol, which we call secure quantum routing, requires only single photons routed by linear optical elements and photon counters, and does not require active feedforward. We prove that secure quantum routing protects both the contents of the message and the identity of the sender and receiver, and creates only a negligible reduction in the network channel capacity.
    Article · Jul 2016
  • [Show abstract] [Hide abstract] ABSTRACT: Long-distance quantum communication relies on the ability to efficiently generate and prepare single photons at telecom wavelengths. In many applications these photons must also be indistinguishable such that they exhibit interference on a beam splitter, which implements effective photon–photon interactions. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem. We demonstrate two-photon interference at telecom wavelengths using an InAs/InP quantum dot in a nanophotonic cavity. The cavity enhances the quantum dot emission, resulting in a nearly Gaussian transverse mode profile with high outcoupling efficiency exceeding 36% after multiphoton correction. We also observe a Purcell enhanced spontaneous emission rate of up to 4. Using this source, we generate linearly polarized, high purity single photons at 1.3 μm wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement, which exhibits indistinguishable visibilities of 18% without postselection and 67% with postselection. Our results provide a promising approach to generate bright, deterministic single photons at telecom wavelength for applications in quantum networking and quantum communication.
    Article · Jun 2016 · Optica
  • Kangmook Lim · Chad Ropp · John T Fourkas · [...] · Edo Waks
    [Show abstract] [Hide abstract] ABSTRACT: Single-emitter microscopy has emerged as a promising method of imaging nanostructures with nanoscale resolution. This technique uses the centroid position of an emitters far-field radiation pattern to infer its position to a precision that is far below the diffraction limit. However, nanostructures composed of high-dielectric materials such as noble metals can distort the far-field radiation pattern. Nanoparticles also exhibit a more complex range of distortions, because in addition to introducing a high dielectric surface, they also act as efficient scatterers. Thus, the distortion effects of nanoparticles in single-emitter microscopy remains poorly understood. Here we demonstrate that metallic nanoparticles can significantly distort the accuracy of single-emitter imaging at distances exceeding 300 nm. We use a single quantum dot to probe both the magnitude and the direction of the metallic nanoparticle-induced imaging distortion and show that the diffraction spot of the quantum dot can shift by more than 35 nm. The centroid position of the emitter generally shifts away from the nanoparticle position, in contradiction to the conventional wisdom that the nanoparticle is a scattering object that will pull in the diffraction spot of the emitter towards its center. These results suggest that dielectric distortion of the emission pattern dominates over scattering. We also show that by monitoring the distortion of the quantum dot diffraction spot we can obtain high-resolution spatial images of the nanoparticle, providing a new method for performing highly precise, sub-diffraction spatial imaging. These results provide a better understanding of the complex near-field coupling between emitters and nanostructures, and open up new opportunities to perform super-resolution microscopy with higher accuracy.
    Article · May 2016 · Nano Letters
  • Shuo Sun · Edo Waks
    [Show abstract] [Hide abstract] ABSTRACT: We propose a method to perform single-shot optical readout of a quantum bit (qubit) using cavity quantum electrodynamics. We selectively couple the optical transitions associated with different qubit basis states to the cavity, and utilize the change in cavity transmissivity to generate a qubit readout signal composed of many photons. We show that this approach enables single-shot optical readout even when the qubit does not have a good cycling transition required for standard resonance fluorescence measurements. We calculate the probability that the measurement detects the correct spin state using the example of a quantum dot spin under various experimental conditions and demonstrate that it can exceed 0.99.
    Article · Feb 2016
  • [Show abstract] [Hide abstract] ABSTRACT: Interactions between single spins and photons are essential for quantum networks and distributed quantum computation. Achieving spin-photon interactions in a solid-state device could enable compact chip-integrated quantum circuits operating at gigahertz bandwidths. Many theoretical works have suggested using spins embedded in nanophotonic structures to attain this high-speed interface. These proposals implement a quantum switch where the spin flips the state of the photon and a photon flips the spin state. However, such a switch has not yet been realized using a solid-state spin system. Here, we report an experimental realization of a spin-photon quantum switch using a single solid-state spin embedded in a nanophotonic cavity. We show that the spin state strongly modulates the polarization of a reflected photon, and a single reflected photon coherently rotates the spin state. These strong spin-photon interactions open up a promising direction for solid-state implementations of high-speed quantum networks and on-chip quantum information processors using nanophotonic devices.
    Article · Feb 2016 · Nature Nanotechnology
  • Shuo Sun · Hyochul Kim · Glenn Solomon · Edo Waks
    Conference Paper · Jan 2016
  • [Show abstract] [Hide abstract] ABSTRACT: Long-distance quantum communication relies on the ability to efficiently generate and prepare single photons at telecom wavelengths. In many applications these photons must also be indistinguishable such that they exhibit interference on a beamsplitter, which implements effective photon-photon interactions. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem. We demonstrate a telecom wavelength source of indistinguishable single photons using an InAs/InP quantum dot in a nanophotonic cavity. The cavity enhances the quantum dot emission, resulting in a nearly Gaussian transverse mode profile with high out-coupling efficiency exceeding 46%, leading to detected photon count rates that would exceed 1.5 million counts per second. We also observe Purcell enhanced spontaneous emission rate as large as 4. Using this source, we generate linearly polarized, high purity single photons at telecom-wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement. Our results provide a promising approach to generate on-demand indistinguishable single photons at telecom wavelength for applications in quantum networking and quantum communication.
    Article · Nov 2015
  • [Show abstract] [Hide abstract] ABSTRACT: Advances in single photon creation, transmission, and detection suggest that sending quantum information over optical fibers may have losses low enough to be correctable using a quantum error correcting code. Such error-corrected communication is equivalent to a novel quantum repeater scheme, but crucial questions regarding implementation and system requirements remain open. Here we show that long range entangled bit generation with rates approaching $10^8$ ebits/s may be possible using a completely serialized protocol, in which photons are generated, entangled, and error corrected via sequential, one-way interactions with a minimal number of matter qubits. Provided loss and error rates of the required elements are below the threshold for quantum error correction, this scheme demonstrates improved performance over transmission of single photons. We find improvement in ebit rates at large distances using this serial protocol and various quantum error correcting codes.
    Article · Aug 2015
  • [Show abstract] [Hide abstract] ABSTRACT: Strong interactions between single spins and photons are essential for quantum networks and distributed quantum computation. They provide the necessary interface for entanglement distribution, non-destructive quantum measurements, and strong photon-photon interactions. Achieving a spin-photon interface in a solid-state device could enable compact chip-integrated quantum circuits operating at gigahertz bandwidths. Many theoretical works have suggested using nanophotonic structures to attain this high-speed interface. These proposals exploit strong light-matter interactions to coherently switch a photon with a single spin embedded in a nanoscale cavity or waveguide. However, to date such an interface has not been experimentally realized using a solid-state spin system. Here, we report an experimental demonstration of a nanophotonic spin-photon quantum interface operating on picosecond timescales, where a single solid-state spin controls the quantum state of a photon and a single photon controls the state of the spin. We utilize an optical nano-cavity strongly coupled to a charged quantum dot containing a single trapped spin. We show that the spin-state strongly modulates the cavity reflection coefficient, which conditionally flips the polarization state of a reflected photon. We also demonstrate the complementary effect where a single photon applies a \pi\ phase shift on one of the spin-states, thereby coherently rotating the spin. These results demonstrate a spin-photon quantum phase gate that retains phase coherence, an essential requirement for quantum information applications. Our results open up a promising direction for solid-state implementations of quantum networks and quantum computers operating at gigahertz bandwidths.
    Article · Jun 2015
  • [Show abstract] [Hide abstract] ABSTRACT: We experimentally realize a solid-state spin-photon transistor using a quantum dot strongly coupled to a photonic crystal cavity. We are able to control the light polarization through manipulation of the quantum dot spin states.
    Article · May 2015
  • Source
    Chad Ropp · Zachary Cummins · Sanghee Nah · [...] · Edo Waks
    [Show abstract] [Hide abstract] ABSTRACT: An emitter near a surface induces an image dipole that can modify the observed emission intensity and radiation pattern. These image-dipole effects are generally not taken into account in single-emitter tracking and super-resolved imaging applications. Here we show that the interference between an emitter and its image dipole induces a strong polarization anisotropy and a large spatial displacement of the observed emission pattern. We demonstrate these effects by tracking the emission of a single quantum dot along two orthogonal polarizations as it is deterministically positioned near a silver nanowire. The two orthogonally polarized diffraction spots can be displaced by up to 50 nm, which arises from a Young's interference effect between the quantum dot and its induced image dipole. We show that the observed spatially varying interference fringe provides a useful measure for correcting image-dipole-induced distortions. These results provide a pathway towards probing and correcting image-dipole effects in near-field imaging applications.
    Full-text Article · Mar 2015 · Nature Communications
  • [Show abstract] [Hide abstract] ABSTRACT: We demonstrate localized magnetometry using a single nitrogen vacancy (NV) center in the microfluidic devices. Our approach enables three dimensional manipulation of a magnetic object in solution with nanoscale spatial accuracy, and also enables us to orient its dipole moment. A diamond nanocrystal is integrated into the microfluidic device and serves as a local magnetic field probe. We vary the position of a magnetic object in liquid and map out its magnetic field distribution by perform continuous electron spin resonance (ESR) measurement on the NV center. These results open up the possibility for using NV centers as nanosized magnetometers with high sensitivity in microfluidic device for applications in chemical sensing, biological sensing and microscopy.
    Article · Mar 2015
  • [Show abstract] [Hide abstract] ABSTRACT: We experimentally realize a solid-state spin-photon transistor using a quantum dot strongly coupled to a photonic crystal cavity. We are able to control the light polarization through manipulation of the quantum dot spin states. The spinphoton transistor is crucial for realizing a quantum logic gate or generating hybrid entanglement between a quantum dot spin and a photon. Our results represent an important step towards semiconductor based quantum logic devices and onchip quantum networks.
    Article · Mar 2015 · Proceedings of SPIE - The International Society for Optical Engineering
  • Tao Cai · Ranojoy Bose · Kaushik R. Choudhury · [...] · Edo Waks
    [Show abstract] [Hide abstract] ABSTRACT: Vacuum Rabi oscillation is a damped oscillation in which energy can transfer between an atomic excitation and a photon when an atom is strongly coupled to a photonic cavity. This process is challenging to be coherently controlled due to the fact that interaction between the atom and the electromagnetic resonator needs to be modulated in a quick manner compared to vacuum Rabi frequency. This control has been achieved at microwave frequencies, but has remained challenging to be implemented in the optical domain. Here we demonstrated coherent control of energy transfer in a semiconductor quantum dot strongly coupled to a photonic crystal molecule by manipulating the vacuum Rabi oscillation of the system. Instead of using a single photonic crystal cavity, we utilized a photonic crystal molecule consisting two coupled photonic crystal defect cavities to obtain both strong quantum dot-cavity coupling and cavityenhanced AC stark shift. In our system the AC stark shift modulates the coupling interaction between the quantum dot and the cavity by shifting the quantum dot resonance, on timescales (picosecond) shorter than the vacuum Rabi period. We demonstrated the ability to transfer excitation between a quantum dot and cavity, and performed coherent control of light-matter states. Our results provides an ultra-fast approach for probing and controlling light-matter interactions in an integrated nanophotonic device, and could pave the way for gigahertz rate synthesis of arbitrary quantum states of light at optical frequencies.
    Article · Mar 2015 · Proceedings of SPIE - The International Society for Optical Engineering
  • Kangmook Lim · Chad Ropp · Ben Shapiro · [...] · Edo Waks
    [Show abstract] [Hide abstract] ABSTRACT: Nitrogen vacancy (NV) color centers in diamond enable local magnetic field sensing with high sensitivity by optical detection of electron spin resonance (ESR). The integration of this capability with microfluidic technology has a broad range of applications in chemical and biological sensing. We demonstrate a method to perform localized magnetometry in a microfluidic device with a 48 nm spatial precision. The device manipulates individual magnetic particles in three dimensions using a combination of flow control and magnetic actuation. We map out the local field distribution of the magnetic particle by manipulating it in the vicinity of a single NV center and optically detecting the induced Zeeman shift with a magnetic field sensitivity of 17.5 microTesla/Hz^1/2. Our results enable accurate nanoscale mapping of the magnetic field distribution of a broad range of target objects in a microfluidic device.
    Article · Feb 2015 · Nano Letters
  • Edo Waks · Chad Ropp · Roland Probst · [...] · Benjamin Shapiro
    Conference Paper · Jan 2015
  • Source
    Full-text Chapter · Dec 2014
  • Edo Waks · Hyochul Kim · Ranojoy Bose · [...] · Glenn S. Solomon
    [Show abstract] [Hide abstract] ABSTRACT: Generating strong interactions between single quanta of light and matter is central to quantum information science, and a key component of quantum computers and long-distance quantum networks. In quantum information processing, these interactions are required to create elementary logic operations (quantum gates) between stationary matter quantum bits (qubits) and photonic qubits that can be transmitted over long distances. Efficient quantum gates between photonic and matter qubits are a crucial enabler for a broad range of applications that include robust quantum networks, nondestructive quantum measurements, and strong photon-photon interactions. So far these qubit-photon gates have been achieved using single atoms and at microwave frequencies in circuit QED systems. Their implementation with solidstate quantum emitters, however, has remained a difficult challenge. We demonstrate that the qubit state of a photon can be controlled by a single solid-state qubit composed of a quantum dot (QD) strongly coupled to an optical nanocavity. We show that the QD acts as a coherently controllable qubit system that conditionally flips the polarization of a photon reflected from the cavity mode on picosecond timescales. This operation implements a controlled NOT (cNOT) logic gate between the QD and the incident photon, which is a universal quantum operation that can serve as a general light-matter interface for remote entanglements and quantum computations. Our results represent an important step towards an all solid-state implementation of quantum networks and quantum computers, and provide a versatile approach for controlling and probing interactions between a photon and a single quantum emitter on ultra-fast timescales.
    Article · Sep 2014 · Proceedings of SPIE - The International Society for Optical Engineering
  • Ranojoy Bose · Tao Cai · Kaushik Roy Choudhury · [...] · Edo Waks
    [Show abstract] [Hide abstract] ABSTRACT: When an atom strongly couples to a cavity, it can undergo coherent vacuum Rabi oscillations. Controlling these oscillatory dynamics quickly relative to the vacuum Rabi frequency enables remarkable capabilities such as Fock state generation and deterministic synthesis of quantum states of light, as demonstrated using microwave frequency devices. At optical frequencies, however, dynamical control of single-atom vacuum Rabi oscillations remains challenging. Here, we demonstrate coherent transfer of optical frequency excitation between a single quantum dot and a cavity by controlling vacuum Rabi oscillations. We utilize a photonic molecule to simultaneously attain strong coupling and a cavity-enhanced AC Stark shift. The Stark shift modulates the detuning between the two systems on picosecond timescales, faster than the vacuum Rabi frequency. We demonstrate the ability to add and remove excitation from the cavity, and perform coherent control of light-matter states. These results enable ultra-fast control of atom-cavity interactions in a nanophotonic device platform.
    Article · Aug 2014 · Nature Photonics

Publication Stats

3k Citations

Institutions

  • 2009-2012
    • Loyola University Maryland
      Baltimore, Maryland, United States
  • 2011
    • National Institute of Standards and Technology
      Maryland, United States
  • 1999-2007
    • Stanford University
      • E. L. Ginzton Laboratory
      Palo Alto, CA, United States