Author Archives: wvk_sm9je57j

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%).

Image of the setup of the beam diameter measurement

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.


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


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.


FOMO 2018 on Crete

We will organise the next Frontiers of Matterwave Optics conference and summer school!

The school will be held in Archanes close to Heraklion and the conference close to Chania. We have already assembled a very nice list of speakers… more news soon  to come.

CONFERENCE: Crete 17.Sept. – 21.Sept. 2018
SUMMER SCHOOL 10.Sept. – 14.Sept. 2018

More info to come soon at


Collimation of laser beams from optical fibers

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.

ZERODUR collimator

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.