Generation of frequency sidebands on single photons with indistinguishability from quantum dots

Abstract

Generation and manipulation of the quantum state of a single photon is at the heart of many quantum information protocols. There has been growing interest in using phase modulators as quantum optics devices that preserve coherence. In this Rapid Communication, we have used an electro-optic phase modulator to shape the state vector of single photons emitted by a quantum dot to generate new frequency components (modes) and explicitly demonstrate that the phase modulation process agrees with the theoretical prediction at a single-photon level. Through two-photon interference measurements we show that for an output consisting of three modes (the original mode and two sidebands), the indistinguishability of the mode engineered photon, measured through the second-order intensity correlation [g 2 (0)] is preserved. This work demonstrates a robust means to generate a photonic qubit or more complex state (e.g., a qutrit) for quantum communication applications by encoding information in the sidebands without the loss of coherence. DOI: 10.1103/PhysRevA.98.011802 Quantum communication and computing protocols often require a flexible and customizable single-photon source that can form a link between distant nodes [1][2][3]. Swapping entanglement between these nodes can be achieved utilizing the two-photon interference [Hong-Ou-Mandel (HOM)] measurements [4][5][6], where the optimal interference to assure indistinguishability requires that the spatial, temporal, polarization, and spectral modes of the input photon wave functions must be identical [6,7]. Thus manipulation of the photonic degrees of freedom while maintaining coherence is very important for many quantum information applications.Single photons also function for cryptographic key distributions to enable transfer of information between two remote parties [2,8], where quantum information is encoded in the various degrees of freedom of a single photon. Polarization qubits are typical, but are prone to decoherence when transmitted through a fiber [9][10][11]. Frequency qubits [12], on the other hand, are known to be robust against any mechanically or environmentally induced fluctuation in a fiber [13][14][15]. Frequency qubits can be generated through phase modulation of a single photon [14,16], where the information is encoded in the relative amplitude between the sidebands. Recently, Lukens and Lougovski proposed a universal linearoptical quantum computing (LOQC) platform using frequency components generated from an electro-optic modulators [14]. Similarly, there has been proof-of-concept demonstrations of the 1984 protocol of Bennett and Brassard (BB84) using phase-modulated weak coherent sources [13,17]. A quantum analysis of phase modulation was first discussed by Louisell, Yariv, and Siegman [18]. Frequency conversion is described as a two-mode coupling process with sinusoidal coupling between the unmodulated and the new frequency component. The coupling between the two modes is generated through a periodic perturbation of the refractive index of the medium ...

Correlation functions with single-photon emitters under noisy resonant continuous excitation

“…in. [27][28][29] The difference lies in the introduction of the | G(1) (τ )| 2 term which describes the influence of the driving resonant source. Expressions ( 28) and ( 29) are only valid in the BPP regime.…”

Direct excitation of a single quantum dot with cavity-SPDC photons

“…By directly exciting a single QD with cavity-SPDC photons, we have demonstrated the direct coupling between the SPDC photon and a QD. The current work could be immediately extended to show a heralded transfer of a photonic qubit generated from the frequency modulated cavity-SPDC photons using an external modulator [55] to the spin ground states of a charge QD through a direct absorption measurement [12,14]. In addition, such photonic qubits could be teleported to the spin state of a single QD by interfering it with the photons of a spin-photon entangled state [56].…”

“…The optical experiment is performed in a dark-field microscopy setup [54,55] where the incident light is focused to a single QD with a high NA (0.65) aspheric lens and the same lens is used to collect the emitted photons. Using a narrowband continuous-wave laser, a single trion state is identified by performing resonance Rayleigh scattering measurement at a fixed non-zero dc bias point [55]. Then the transition energy of the QD is detuned relative to the incident laser by scanning the dc bias voltage while keeping the CW-laser at the fixed frequency.…”

Reconfigurable frequency coding of triggered single photons in the telecom C–band

“…Constructing a flying qubit Hilbert space in frequency domain is bound to boost quantum data communication bandwidth, following the steps of classical optical communication where generally a combination of time-division coding and frequency-division coding is used for high data-rate applications. The possible on-demand generation [15] of single photons with InAs/GaAs QD coupled with the frequency coding [28] we demonstrate here, using off-the-shelf components, makes the platform ideal for long distance and high bandwidth quantum communication. Paudel et al [28] recently demonstrated the preservation of indistinguishability of near-infrared photons emitted by a quantum dot through phase modulation.…”

“…Paudel et al [28] recently demonstrated the preservation of indistinguishability of near-infrared photons emitted by a quantum dot through phase modulation. We extend this result and move to a triggered QD system with an emission in the standard telecom 1.55 µm band.…”