Coherent Optics for Long-Baseline Molecule Interferometry (COLMI)

Abstract

We have realized LUMI, the world’s first and only long-baseline universal matter-wave interferometer. It has a total base line of 2 meters, which makes it 10 times longer than all previous macromolecule experiments. The novel instrument can universally and coherently manipulate complex many-body systems and allows exploring a new mass and complexity regime that had remained inaccessible so far.  

We were able to demonstrate de Broglie wave interference with a large variety of different atom species, fullerenes, polyaromatic hydrocarbons, biomolecules such as tripeptides, and tailored nanoparticles even including particles beyond 25.000 Da and composed of almost 2000 atoms.

The extended length and small grating periods of LUMI allowed us to see quantum interference with de Broglie wavelengths down to 50 fm, i.e. an order of magnitude smaller than in any matter-wave interferometer so far.    

We have explored new beam splitting techniques, explored UV enhancement cavities, and successfully demonstrated the first Bragg diffraction (at 532 nm) for hot molecules. An optical phase grating was also integrated into the LUMI interferometer.

We have advanced our interferometer concepts, designed a new interferometer support for vibration isolation and monitoring and compensated the Coriolis acceleration by gravity. The high thermal and mechanical ruggedness of the novel machine makes it robust for routine operation with fluctuations in fringe visibility of the order of a few percent per day.

The interferometer is systematically sensitive to forces well below 10-26 N. The long base line allows operation with long coherent interaction times which determine the interferometric phase and fringe shift in proportion to T^2 for a three-grating interferometer.

In contrast to established atom interferometers our new machine is a genuine multi-species interferometer which accepts vastly more complex particles than any previous interferometer. This has allowed us to calibrate molecular effects to atomic constants. Our successful project

  • sets a new world record in mass and complexity in matter-wave interference
  • sets new bounds on interferometric tests of the continuous spontaneous collapse models
  • sets the current record in quantum macroscopicity according to the Nimmrichter-Hornberger criterion (which also compares such experiments with SQUIDS, cantilevers, etc.)
  • has become a new standard for matter-wave assisted molecule metrology, with which we have improved polarizability values for fullerenes and were able to measure for the first time the magnetic susceptibility of Ba and Sr atoms in the ground state as well as of hot anthracene and adamantane.

 

The experiments have opened a new window to quantum optics and matter-wave research and shall be scaled to more massive clusters and nanoparticles, operate with complex bio-nanomatter and allow refined molecule metrology in the future. 

 

Publications