March 2022
Our paper about ​​a diamond-confined open microcavity featuring a high quality-factor and a small mode-volume is out:

June 2021
Our paper about low-charge-noise nitrogen-vacancy centers in diamond created using laser writing with a solid-immersion lens is out:

April 2020
To create NVs for our project we employed the newly developed femtosecond laser-assisted creation of NV centers (Chen et al. Nat. Photonics11, 77–80) and upgraded it by implementing a solid immersion lens in the process. 

After installation of a new setup and establishing fabrication procedures, we succeeded in fabricating NV centers with unprecedented quality. Their zero-phonon line spectral linewidth, which is the key parameter determining suitability for applications of NV centers as sources of quantum light has a statistical distribution peaking at a record-low value of around 60 MHz. This includes the effect of long-term spectral diffusion induced by a 532 repump laser for charge state stabilization. About 95% of NVs feature a linewidth below 100 MHz, which is an excellent result not only when compared to NVs created with implantation, but also when comparing to all other fabrication methods. The SIL allowed for vacancy formation close to a diamond surface without inducing surface graphitization.

Such high-quality NVs are excellent candidates for practical implementations employing two-photon quantum interference with separate NV centers.  

January 2020
We examined the effect of a novel approach of creating NV centers in thin diamond samples, where the nitrogen is implanted after all etching processes have been completed. Results of our studies are described here. Among other resutlts described in the paper we observed two narrow (< 250MHz) optical linewidths in the 1.57 µm-thick area of a sample created with this method. 

Confocal scan of laser-written NV centers

Zero-ohonon line optical linewidth statistical distribution in the presence of 532 nm repump laser 

Zero-phonon line power broadening in NV centers

Zero-phonon line power broadening in NV centers

Confocal scan of diamond platelets with binary identification markings

Photoluminescence tomography of laser-written NV centers, with surface and bulk created NVs