LUMI is the newest interferometer in the group, and currently in the construction phase. As the name suggests, its most unique feature is its long length. With a full one-meter separation between two gratings, LUMI will open a new avenue for molecular interferometry in a mass and complexity range not accessible by previous interferometers. It will also allow for 100x improved sensitivity in molecule metrology due to the quadratic dependence of interferometer fringe shift on device length and transit time.
Like the KDTLI and OTIMA experiments, LUMI will rely on the Talbot-Lau effect, a near-field interference effect that is particularly suitable for large molecules. In a first version of LUMI 1.0 we will operate it as a Kapitza-Dirac-Talbot-Lau Interferometer (KDTLI), with two nanomechanical gratings and one optical phase grating - all at d=266 nm. In the course of the project, the device shall be upgraded to LUMI 2.0, which will additionally allow to operate the instrument with all optical UV photo-depletion gratings.
LUMI has the potential of extending current interferometry into the range of 100 000 amu with continuous molecular sources. LUMI shall also explore interference of complex biomolecules such as peptides, or, eventually, proteins. A key challenge here is the development of soft methods of creating a beam of fragile molecules. Succesful interferometry of such molecules, and the information about molecular properties that could be gained, would be of interest to various disciplines such as physical chemistry.