Quantum photonic integrated circuits based on tunable dots and tunable cavities

Tunable resonators for quantum circuits

We have designed, fabricated and measured high-Q λ/2 coplanar waveguide microwave resonators whose resonance frequency is made tunable with magnetic field by inserting a DC-SQUID array (including 1 or 7 SQUIDs) inside. Their tunability range is 30% of the zero field frequency. Their quality factor reaches up to 3×10. We present a model based on thermal fluctuations that accounts for the dependa...

Flexible and tunable silicon photonic circuits on plastic substrates

Flexible microelectronics has shown tremendous promise in a broad spectrum of applications, especially those that cannot be addressed by conventional microelectronics in rigid materials and constructions. These unconventional yet important applications range from flexible consumer electronics to conformal sensor arrays and biomedical devices. A recent paradigm shift in implementing flexible ele...

Quantum dots in photonic crystal cavities

Fast-tunable resonators and quantum electrical circuits

In this thesis, measurements on superconducting electrical circuits that exhibit quantum mechanical effects are presented. Nonlinear superconducting circuits can be regarded as artificial atoms with energy spectra that can be engineered. The artificial atoms can be used as quantum bits for quantum computation. By coupling the artificial atoms to the electromagnetic field inside a transmission l...

A tunable kondo effect in quantum dots

A tunable Kondo effect has been realized in small quantum dots. A dot can be switched from a Kondo system to a non-Kondo system as the number of electrons on the dot is changed from odd to even. The Kondo temperature can be tuned by means of a gate voltage as a single-particle energy state nears the Fermi energy. Measurements of the temperature and magnetic field dependence of a Coulomb-blockad...