Author Archives: wvk_sm9je57j

PhD/Master Scholarships in Guided Matterwave Interferometry

Project Objectives

In matterwave interferometry, atoms are put into a superposition of two different momentum states. They are then made to travel in two different paths (yes, during part of the interferometry sequence every individual atom is at two distinct places at the same time) before being recombined. Depending on the phase accumulated in the two different paths the atoms end up in two different distinguishable states. The accumulated phase is extremely sensitive to minute entry differences between the two paths travelled, making ultra-sensitive measurements of gravitation, acceleration, or rotation possible. Atoms, however, have the tendency to fall under the influence of earth’s gravitation. This means, that in order to measure at the highest precision, the apparatus has to be very large (some reaching tens or even one hundred of meters in height). The ideal solution would be to contain the atoms in waveguides (much like the optical fibres in optical gyroscopes). Until recently, this has not been possible, because even the smallest roughness in these guides destroys the coherence of the travelling matterwaves.

Our recent contributions

In a recent paper (published in Nature), we have demonstrated for the first time coherent guiding of matterwaves over macroscopic distances. This will make possible, for the first time ever, to perform guided matter-wave spectroscopy over macroscopic distances and in non-trivial geometries. This will greatly enhance the interaction time of the atoms and thus the sensitivity of matterwave interferometers.

PhD Project

The new PhD student will work together with our current Giannis Drougakis on the first guided matterwave interferometry. En route to this he/she will explore the limits on the roughness of waveguides, thus providing invaluable input to the design of any guided matterwave interferometer. The student(s) will work under the supervision of Wolf von Klitzing and Dimitris Papazoglou and be enrolled in the University of Crete

Top 10 of Applied Optics for two months running

 

Our paper on “Simple precision measurements of optical beam sizes” in now in the TOP 10 most downloaded paper of Applied Optics for two months in a row:

Applied Optics December 2018
Most Downloaded:

  1. Phase retrieval algorithms: a comparison Vol. 21, Issue 15, pp. 2758-2769 (1982)
  2. Laser Beams and Resonators Vol. 5, Issue 10, pp. 1550-1567 (1966)
  3. OpenFilters: open-source software for the design, optimization, and synthesis of optical filters Vol. 47, Issue 13, pp. C219-C230 (2008)
  4. Optical Constants of Water in the 200-nm to 200-μm Wavelength Region Vol. 12, Issue 3, pp. 555-563 (1973)
  5. Optical glass and glass ceramic historical aspects and recent developments: a Schott view Vol. 49, Issue 16, pp. D157-D176 (2010)
  6. Design and realization of a wide field of view infrared scanning system with an integrated micro-electromechanical system mirror Vol. 57, Issue 36, pp. 10449-10457 (2018)
  7. Absorption spectrum (380–700 nm) of pure water. II. Integrating cavity measurements Vol. 36, Issue 33, pp. 8710-8723 (1997)
  8. Optical properties of metallic films for vertical-cavity optoelectronic devices Vol. 37, Issue 22, pp. 5271-5283 (1998)
  9. Simple precision measurements of optical beam sizes Vol. 57, Issue 33, pp. 9863-9867 (2018)

  10. Lensless photography with only an image sensor Vol. 56, Issue 23, pp. 6450-6456 (2017)

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.