Author Archives: wvk_sm9je57j

Two new PhD positions

We have two new fully funded PhD positions available!

One is concerned with our ring-shaped wave guides and matterwave interferometry.
The other one will be on a novel optical intra-cavity microscopy technique, which will allow us to measure very small absorptions or changes in refractive index with high optical resolution.

For more information please contact Wolf von Klitzing

Simple precision measurements of optical beam sizes

The paper is in the top 10 most downloaded papers of Applied Optics for November and December 2018.

Applied Optics 57 9863 (2018)

M. Mylonakis, S. Pandey, K. G. Mavrakis, G. Drougakis, G. Vasilakis, D. G. Papazoglou, and W. von Klitzing

doi: 10.1364/AO.57.009863

Abstract: We present a simple high-precision method to quickly and accurately measure the diameters of Gaussian beams, Airy spots, and central peaks of Bessel beams ranging from sub-millimeter to many centimeters without special- ized equipment. By simply moving a wire through the beam and recording the relative losses using an optical power meter, one can easily measure the beam diameters with a precision of 1%. The accuracy of this method has been experimentally verified for Gaussian beams down to the limit of a commercial slit-based beam profiler (3%).

Setup of the beam diameter measurement

Plot of the real beam size calculated from the minimum transmitivity.

Real beam size as a function of the minimum transmitivity.

7th most downloaded paper of Applied Optics

Our paper on “Simple precision measurements of optical beam sizes” has been the seventh most downloaded paper of Applied Optics in November 2018.

Jules has passed his Thèse d’État!

Congratulations to Jules Grucker, he just passed his Thèse d’État, which is the highest degree available in France.

Antireflection coated semiconductor laser amplifier for Bose-Einstein condensation experiments

AIP Advances 8 095020 (2018)

S. Pandey, H. Mas, G. Drougakis, K. G. Mavrakis, M. Mylonakis, G. Vasilakis, V. Bolpasi, and W. von Klitzing

https://doi.org/10.1063/1.5047839

Abstract

We present a slave laser highly suitable for the preparation and detection of 87Rb Bose-Einstein condensates (BEC). A highly anti-reflection coated laser diode serves as an optical amplifier, which requires neither active temperature stabilization nor dedicated equipment monitoring the spectral purity of the amplified light. The laser power can be controlled with a precision of 10μW in 70mW with relative fluctuations down to 2 × 10^−4. Due to its simplicity and reliability, this slave laser will be a useful tool for laboratory, mobile, or even space-based cold-atom experiments. By the way of demonstration this slave laser was used as the sole 780nm light-source in the production of 3×10^4 BECs in a hybrid magnetic/dipole trap.

Figure 1: Stability of the power of a AR-coated diode lase slave.

Alexandra Roussou has given a very interesting talk on ring potentials

Alexandra Roussou is a PhD student with Georgios Kavoulakis (TEI Crete) and Nikos Efremidis (University of Crete)

Alexandra Roussou has given a very interesting talk on the Excitation Spectrum Of A Mixture Of Two Bose Gases Confined In A Ring Potential With Interaction Asymmetry.

Prestigious SPIE Scholarship for Deba Pal

Debapriya Pal (on an internship 05/2018-07/2018 working on laser optics) was awarded the prestigious 2018 Optics and Photonics Education Scholarship by the international society for optics and photonics SPIE, the international society for optics and photonics, for his potential contributions to the field of optics, photonics or related field.

Welcome Premjith!

Premjith joins us from the Cochin University of Science and Technology South Kalamassery in Kerala, India to do the research for his master thesis.

An ESA milestone reached.

Our ESA Space-Optics project has reached a major milestone: We have finished the development of a novel beam collimation technique, which works allows us to adjust the waist of the laser beam emitted from a fibre coupler to an arbitrary position simply by maximising the peak intensity of the laser beam at some other position.

This is a fiber collimator manufactured from the ultra-low expansion material ZERODUR.

In order to make the coupler space-compatible it is manufactured from ultra-low-expansion ceramics (ZERODUR) and has no moving parts.

Quantum Technologies in Space (QTSpace)

We have been appointed the Greek representatives of “Quantum Technologies in Space (QTSpace)”.

The scientific and technological legacy of the 20th century includes milestones such as quantum mechanics and pioneering space missions. Both endeavours have opened new avenues for the furthering of our understanding of Nature, and are true landmarks of modern science. Quantum theory and space science form building blocks of a powerful research framework for exploring the boundaries of modern physicsthrough the unique working conditions offered by experimental tests performed in space.

Space-based sources of entangled photons promise the formation of global quantum communication networks, long-distance tests of quantum theory and the interplay between relativity and quantum entanglement.

Long free-fall times enable high-precision tests of general relativity and tests of the equivalence principle for quantum systems.

Harnessing microgravity, high vacuum and low temperature of deep space promises allowing the study of deviations from standard quantum theoryfor high-mass test particles. Space-based experiments of metrology and sensing will push the precision of clocks, mass detectors and transducers towards the engineering of novel quantum technologies.