Ultra Low-Power All-Optical Switching

An outstanding goal in quantum optics is the realization of fast optical non-linearities at the single-photon level. Such non-linearities would allow for the realization of optical devices with new functionalities such as a single-photon switch/transistor or a controlled-phase gate, which could form the basis of future quantum optical technologies. While non-linear optics effects at the single-emitter level have been demonstrated in different systems, including atoms coupled ...

We experimentally investigate the dynamic nonlinear response of a single quantum dot (QD) strongly coupled to a photonic crystal cavity-waveguide structure. The temporal response is measured by pump-probe excitation where a control pulse propagating through the waveguide is used to create an optical Stark shift on the QD, resulting in a large modification of the cavity reflectivity. This optically induced cavity reflectivity modification switches the propagation direction of ...

We investigate the nonlinear optical response of suspended 1D photonic crystal nanocavities fabricated on a silicon nitride chip. Strong thermo-optical nonlinearities are demonstrated for input powers as low as $2\,\mu\text{W}$ and a self-sustained pulsing regime is shown to emerge with periodicity of several seconds. As the input power and laser wavelength are varied the temporal patterns change in period, duty cycle and shape. This dynamics is attributed to the multiple tim...

This paper theoretically analyzes the optical transmission characteristics of an optical waveguide when coupling to a micro cavity array. The results showed that not only were there sharp peaks on the transmission and reflection spectra, but also that a certain system configuration can produce a backward wave to obtain a phase shift in the small detuning range between the incident wave and the micro cavities. Based on a discussion of the relationship between the transmission ...

We propose an optical memory cell based on ultrafast wavelength switching in coupled-cavity microlasers, featuring bistability between modes separated by several nanometers. A numerical implementation is demonstrated by simulating a two-dimensional photonic crystal microlaser. Switching times of less than 10 ps, switching energy around 15--30 fJ and on-off contrast of more than 40 dB are achieved. Theoretical guidelines for optimizing the performance of the memory cell in ter...

The recent progress in nanotechnology [1,2] and single-molecule spectroscopy [3-5] paves the way for cost-effective organic quantum optical technologies emergent with a promise to real-life devices operating at ambient conditions. In this letter, we harness $\pi$-conjugated segments of an organic ladder-type polymer strongly coupled to a microcavity forming correlated collective dressed states of light, so-called of exciton-polariton condensates. We explore an efficient way f...

The distinctive characteristics of light such as high-speed propagation, low-loss, low cross-talk and power consumption as well as quantum properties, make it uniquely suitable for various critical applications in communication, high-resolution imaging, optical computing, and emerging quantum information technologies. One limiting factor though is the weak optical nonlinearity of conventional media that poses challenges for the control and manipulation of light, especially wi...

Quantum computers require technologies that offer both sufficient control over coherent quantum phenomena and minimal spurious interactions with the environment. We show, that photons confined to photonic crystals, and in particular to highly efficient waveguides formed from linear chains of defects doped with atoms can generate strong non-linear interactions which allow to implement both single and two qubit quantum gates. The simplicity of the gate switching mechanism, the ...

We investigate the switching dynamics in a $\mathcal{PT}$-symmetric fiber coupler composed of a saturable nonlinear material as the core. In such a saturable nonlinear medium, bistable solitons may evolve due to the balance between dispersion and saturable nonlinearity, which we extend in the context of the $\mathcal{PT}$-symmetric coupler. Our investigations of power-controlled and phase-sensitive switching show richer soliton switching dynamics than the currently existing c...

New functionalities in nonlinear optics will require systems with giant optical nonlinearity as well as compatibility with photonic circuit fabrication techniques. Here we introduce a new platform based on strong light-matter coupling between waveguide photons and quantum-well excitons. On a sub-millimeter length scale we generate sub-picosecond bright temporal solitons at a pulse energy of only 0.5 pico-Joules. From this we deduce an unprecedented nonlinear refractive index ...