14.15 - 15.30 hrs, room: 6
Chairs: Pepijn Pinkse and Sonia Garcia Blanco
- 14.15 - 14.30 | Lisa Winkler (LPNO) - Widely Tunable Hybrid-Integrated Diode Laser at 637 nm
Chip-integrated diode lasers are highly promising light sources for quantum applications as they offer wide tunability and extremely narrow linewidths. Most importantly, their small form factor based on integration enables upscaling to larger system sizes. Recently, silicon nitride waveguide circuits have enabled chip-integrated diode lasers operating in the visible, unlocking a wide range of atomic and molecular transitions.
We present such a laser, operating at a central wavelength of 637 nm, allowing to address the zero-phonon line of nitrogen vacancy centers. The laser is widely tunable over 8 nm and has a narrow intrinsic linewidth below 10 kHz. Furthermore, it offers a record-wide mode-hop free tuning range of 43 GHz.
- 14.35 - 14.50 | Stefan van den Hoven (AQO) - Single photons in an interferometer: Forbidden outcomes
The famous first demonstration of perfect destructive interference of quantum amplitudes in a linear optical system, the Hong-Ou-Mandel effect (HOM), lies at the foundation of the field of quantum optics. The HOM effect is used on a daily basis in many quantum optics laboratories to characterize resources. It is therefore quite surprising that a generalization of the HOM-effect to this day not completely understood. Even for only slightly larger systems we fail to predict forbidden output states.
Here, we take a step towards the further understanding of so called bosonic suppression laws. We numerically find all three-mode interferometers that show bosonic suppressions. Furthermore, we quantify differences between interferometers by inspecting the resulting Fisher information. Based on this analysis, we propose a method for the characterization of single-photon sources which outperforms the commonly used characterization method based on the HOM effect.
- 14.55 - 15.10 | Mohammad Reza Aghdaee (NBP) - Spectral signatures of enhanced scattering from nanoscale objects by a plasmonic nanocavity
Nano-objects play important roles in our lives, and they include biomolecules, environmental pollutants, or defects in semiconductor devices. Despite the recent advances, detecting nano-objects is still challenging. Optical methods can detect nano-objects, such as interferometric scattering and super-resolution microscopy, but they suffer from low signal-to-noise ratio, labeling, or photobleaching.
Here, we use a plasmonic nanocavity to enhance the elastic scattering of sub-15 nm objects. A Au nanoparticle is placed on top of an Au film to form the nanocavity that enhances optical fields on the nano-object. We numerically calculated the scattering cross-section of the nano-object inside the plasmonic nanocavity. The results show distinct spectral features from the nano-objects, with sizes down to 5 nm. The spectral signature appears as a new mode that we attribute to the interaction of the nano-object with nanocavity. Our results have the potential to enable the imaging of nanoscale objects.
- 15.15 - 15.30 | Alfredo Rates Soriano (COPS) - Optical Communication using Speckle from Multiple Scattering Layers
Physical unclonable functions (PUF) are a promising solution for encryption in digital communication. A PUF takes advantage of the complexity of a macroscopic object to make a complex encrypted key. In optical communication, PUFs have been proposed for authentication for quantum communication systems, using a scattering layer as a PUF.
We extend this light-scattering system to a situation with multiple scattering layers, namely one to hide a sending device and another to hide a receiving device. We encode the message using a wavefront modulator device. Thus, an attacker in the middle cannot understand nor make an exact copy of the message. The complexity of the multi-layer system allows for many (in the order of tens of thousands) uncorrelated wavefronts to send the same message, making it harder for an attacker to decipher the encryption. We test the secrecy of the system using speckle correlation and classification algorithms.