Fast quantum dot single photon source triggered at telecommunications wavelength

Abstract

We demonstrate a quantum dot single photon source at 900 nm triggered at 300 MHz by a continuous wave telecommunications wavelength laser followed by an electro-optic modulator. The quantum dot is excited by on-chip-generated second harmonic radiation, resonantly enhanced by a GaAs photonic crystal cavity surrounding the InAs quantum dot. Our result suggests a path toward the realization of telecommunications-wavelength-compatible quantum dot single photon sources with speeds exceeding 1 GHz. [5,6]. Among these systems, semiconductor quantum dots have the highest emission rates and can be most easily integrated with semiconductor technology, including microcavities with high quality factor, small volume, and directional emission that increase the emission rate, efficiency, and indistinguishability of the generated single photons. [3,7] However, the generation rate of demonstrated optically triggered quantum dot single photon sources has been limited by excitation (Ti:Sapphire) lasers to around 80 MHz [3]. Electrical excitation [8,9] can circumvent this; however, resonant optical excitation [7] improves the indistinguishability of output photons, and many desirable microcavity structures such as photonic crystal cavities have geometries that are challenging to pump electrically [10]. Furthermore, while telecommunications wavelengths are desirable for transporting photons over long distances, excitation and emission in many quantum dot materials systems, determined by material parameters, occurs at much shorter wavelengths.Recently [11,12], we demonstrated that photonic crystal cavities fabricated in III-V semiconductors with large χ (2) nonlinearities can greatly enhance nonlinear frequency conversion efficiency, as a result of light recirculation inside an ultrasmall volume. Here, we apply a similar approach to excite a single InAs quantum dot (with transitions ∼900 nm) using a commercially available telecommunications wavelength (∼1550 nm) laser that can serve as a trigger at * Electronic address: krivoire@stanford.edu

Deterministic generation of an on-demand Fock state

“…More precisely we take U JC = e −iτ T (1+δτ)H s /h , where δτ is a normally distributed additional noise in timing with a standard deviation given by a parameter σ n . The excitation probability of the cavity to state |n + 1 when the NV is in the excited state is thus now given by P g = sin 2 [gτ T √ n + 1 (1 + δτ)]. Once the SEF is turned off, the STED laser pulse is switched on.…”

“…Single-photon sources have been realized in a variety of quantum systems such as nitrogen-vacancy (NV) centres in diamond [1], or using quantum dots [2]. However the creation of photonic Fock states with a high photon number is an open challenge to date.…”

Second harmonic generation in GaP photonic crystal waveguides

“…Such devices are useful as on-chip light sources at otherwise inaccessible wavelengths, as well as for interfacing between multiple quantum emitters with different frequencies or between quantum emitters and telecommunications wavelengths [7,8].…”

Anomalous dip observed in intensity autocorrelation function as an inherent nature of single-photon emitters

“…Optical properties of the QDs were examined by a standard micro-photoluminescence (µ-PL) setup equipped with a modelocked Ti:sapphire laser (photon energy of 1.3920 eV, pulse repetition period of 13.2 ns, pulse duration of ∼ 5 ps) and a Si charge-coupled-device detector. Figure 1 Here, we analyze the measured intensity autocorrelation function with a commonly accepted formula under nonresonant pulsed excitation 6,7,10,18,19 …”

“…a) Electronic mail: nakajima@es.hokudai.ac.jp 1 A variety of single-photon emitters (SPEs) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] have been widely investigated for applications in quantum key distribution (QKD) 21 , quantum information processing 22 , and quantum metrology 23 .…”