Natasha Tomm

Nadine Leisgang wins the Swiss Nanotechnology PhD award 2021!

Nadine Leisgang was recognized with the Swiss Nanotechnology PhD award sponsored by the Hightech Zentrum Aargau for the publication “Giant Stark splitting of an exciton in bilayer MoS2”. Congratulations!! Read more here: https://nanoscience.ch/en/2021/08/09/excellent-prizes-for-outstanding-doctoral-students/

Nadine Leisgang wins the Nano Image Award 2021!

Nadine Leisgang received the Nano Image Award 2021 for the optical micrograph image of a gated van der Waals heterostructure. The device consists of two monolayers of transition metal dichalcogenides encapsulated between insulating hexagonal boron nitride flakes. Direct gold contacts allow tuning the carrier concentration in the optically active layers in the middle of the

Laser writing of low-charge-noise nitrogen-vacancy centers in diamond

In our recent publication in ACS Photonics, we report on the pulsed-laser-induced generation of high-quality nitrogen-vacancy (NV) centers in diamond facilitated by a solid-immersion lens (SIL). The SIL enables laser writing at energies as low as 5.8 nJ per pulse and allows vacancies to be formed close to a diamond surface without inducing surface graphitization.

Tuning the polarization splitting of a microcavity with stress

In our recent open-access publication at Physical Review Applied we report a technique to control the frequency splitting of two orthogonal polarization modes in an open semiconductor microcavity. We employ the photoelastic effect by stressing uniaxially the sample and controlling the birefringence of the semiconductor crystal. The semiconductor mirror is mounted on a strain piezo,

Natasha Tomm wins the QCQT Excellence Award!

Natasha Tomm was one of the 3 PhD students from the QCQT PhD school to be awarded with the QCQT Excellence award. The prize is awarded by the Basel Center for Quantum Computing and Quantum Coherence in recognition of her outstanding work “A bright and fast source of coherent single photons“. Congratulations! Read more here:

Surface passivation of GaAs mitigates surface-related losses in a microcavity

We found that GaAs surface passivation is key to minimize losses in a gated semiconductor microcavity and thus increase its quality factor by almost two orders of magnitude. The procedure not only eliminates a Franz-Keldysh-like surface loss inherent to gated semiconductor microcavities, but also mitigates the effect of surface scattering due to roughness. We elucidate

QSIT features Nadine Leisgang in #NCCRWomen 2021 campaign

Nadine Leisgang was featured by NCCR (National Centres of Competence in Research) in their new campaign #NCCRWomen. In the video, Nadine explains a bit about her work as a physicist at the University of Basel and her motivation to do science. Congratulations! Read more here: https://nccr-qsit.ethz.ch/equal-opportunity/NCCRWomen_campaign.html Video here: https://www.youtube.com/watch?v=3eaSz3fry84  

Silicon quantum dots with a self-aligned gates

In our recent publication at Applied Physics Letters we present our work on silicon-finFET quantum dots with perfectly self-aligned 2nd gate layer and gate lengths down to 15 nm. The fabrication is industry compatible and scalable and gives very high-quality devices. We observe Pauli spin blockade and extract the hole g-factor and strong spin-orbit coupling

A record-breaking single photon source

In our recent publication in Nature Nanotechnology we present the results of our record-breaking single photon source. The source, based on InAs quantum dots coupled in a carefully designed open-access microcavity, is able to emit up to 1 billion single photons per second with an end-to-end efficiency of 57%. Furthermore, photons present high single-photon purity

Interlayer excitons in bilayer MoS2

In our recent paper, we have shown that interlayer excitons in bilayer MoS2 exhibit both a high oscillator strength and highly tunable energies in an applied electric field. Owing to this very large tunability, we were able to optically probe the interaction between intra- and interlayer excitons as they were energetically tuned into resonance. These

Daniel Najer wins the Swiss Nanotechnology PhD award!

Daniel Najer was one of the 5 young scientists to win the Swiss Nanotechnology PhD award. The prize is awarded by the company Bühler for Daniel’s publication on an efficient light-matter interface, coupling a semiconductor QD strongly to an optical microcavity. Congratulations! Read more here: https://nanoscience.ch/en/2020/07/15/five-awards-for-young-scientists/ 

Strong-coupling of a semiconductor quantum dot in a microcavity

A coherent exchange of a single energy quantum between an “atom” (in our case a gated InAs quantum dot) and an optical cavity has been reported by our group in Nature. We achieve an atom-cavity Cooperativity of 150, and probe the transitions between singly and doubly excited photon-atom system using photon-statistics spectroscopy.

Tomek secures Marie-Skłodowska-Curie Fellowship

Our Post-doctoral research, Tomek, has been awarded a Marie-Skłdowska-Curie Individual Fellowship! Tomek’s project, entitled “High-Frequency Spin Entanglement Generation in Diamond” (Hi-FrED) aims at establishing the Nitrogen-Vacancy center in diamond not only as spin-coherent, but also as an optically-coherent efficient emitter of single photons. More details about the project, starting in September 2019, can be found

Hi-FRED Project

Host: Prof. Dr. Richard J. Warburton, in collaboration with the Quantum Sensing group (prof. Patrick Maletinsky) and the Nano-phononics group (prof. Ilaria Zardo) Fellow: Dr. Tomasz Jakubczyk Core participants: Viktoria Yurgens, Sigurd Flågan, Brendan Shields The ultimate goal of the project is to achieve high-frequency generation of spin-spin entanglement in spatially separated nitrogen vacancy (NV)