Theory of Electro-optic Modulation via a Quantum Dot Coupled to a Nano-resonator

In this paper, we analyze the performance of an electro-optic modulator based on a single quantum dot strongly coupled to a nano-resonator, where electrical control of the quantum dot frequency is achieved via quantum confined Stark effect. Using realistic system parameters, we show that modulation speeds of a few tens of GHz are achievable with this system, while the energy per switching operation can be as small as 0.5 fJ. In addition, we study the non-linear distortion, and the effect of pure quantum dot dephasing on the performance of the modulator.Comment: 9 pages, 7 figure

Optimal pulse to generate non-classical photon states via photon blockade

The single photon character of nonclassical states of light that can be generated using photon blockade is analyzed for time domain operation. We show that improved single photon statistics (single photon around 85% with a multi-photon of 8%) can be obtained by adequately choosing the parameters (mainly amplitude and pulse-duration) of the driving laser pulses. An alternative method, where the system is driven via a continuous wave laser and the frequency of the dipole is controlled (e.g. electrically) at very fast timescales is presented. We also show that this non-classical state performs better than a weak coherent pulse, when applied to BB84 quantum cryptography protocol

Local temperature control of photonic crystal devices via micron-scale electrical heaters

We demonstrate a method to locally control the temperature of photonic crystal devices via micron-scale electrical heaters. The method is used to control the resonant frequency of InAs quantum dots strongly coupled to GaAs photonic crystal resonators. This technique enables independent control of large ensembles of photonic devices located on the same chip at tuning speed as high as hundreds of kHz

Theoretical and Experimental Investigation of Efficient Photonic Crystal Cavity-Waveguide Couplers

Coupling of photonic crystal (PC) linear three-hole defect cavities to PC waveguides is theoretically and experimentally investigated. An improved coupling is obtained by tilting the cavity axis by 60° with respect to the waveguide direction

Nanophotonic coherent light-matter interfaces based on rare-earth-doped crystals

Quantum light-matter interfaces (QLMIs) connecting stationary qubits to photons will enable optical networks for quantum communications, precise global time keeping, photon switching, and studies of fundamental physics. Rare-earth-ion (REI) doped crystals are state-of-the-art materials for optical quantum memories and quantum transducers between optical photons, microwave photons and spin waves. Here we demonstrate coupling of an ensemble of neodymium REIs to photonic nano-cavities fabricated in the yttrium orthosilicate host crystal. Cavity quantum electrodynamics effects including Purcell enhancement (F=42) and dipole-induced transparency are observed on the highly coherent 4I9/2-4F3/2 optical transition. Fluctuations in the cavity transmission due to statistical fine structure of the atomic density are measured, indicating operation at the quantum level. Coherent optical control of cavity-coupled REIs is performed via photon echoes. Long optical coherence times (T2~100 microseconds) and small inhomogeneous broadening are measured for the cavity-coupled REIs, thus demonstrating their potential for on-chip scalable QLMIs

Efficient Photonic Crystal Cavity-Waveguide Couplers

Coupling of photonic crystal (PC) linear three-hole defect cavities (L3) to PC waveguides is theoretically and experimentally investigated. The systems are designed to increase the overlap between the evanescent cavity field and the waveguide mode, and to operate in the linear dispersion region of the waveguide. Our simulations indicate increased coupling when the cavity is tilted by 60 degrees with respect to the waveguide axis, which we have also confirmed by experiments. We obtained up to 90% coupling efficiency into the waveguide

Gallium phosphide photonic crystal nanocavities in the visible

Photonic crystal nanocavities at visible wavelengths are fabricated in a high refractive index (n>3.2) gallium phosphide membrane. The cavities are probed via a cross-polarized reflectivity measurement and show resonances at wavelengths as low as 645 nm at room temperature, with quality factors between 500 and 1700 for modes with volumes 0.7(λ/n)^3. These structures could be employed for submicron scale optoelectronic devices in the visible, and for coupling to emitters with resonances in the visible such as nitrogen vacancy centers, and biomolecules and organic molecules

Generation and transfer of single photons on a photonic crystal chip

We present a basic building block of a quantum network consisting of a quantum dot coupled to a source cavity, which in turn is coupled to a target cavity via a waveguide. The single photon emission from the high-Q/V source cavity is characterized by a twelve-fold spontaneous emission (SE) rate enhancement that results in a SE coupling efficiency near 0.98 into the source cavity mode. Single photons are efficiently transferred into the target cavity through the waveguide, with a source/target field intensity ratio of 0.12 (up to 0.49 observed in other structures without coupled quantum dots). This system shows great promise as a building block of future on-chip quantum information processing systems.Comment: 9 pages, 6 figure