Qumbs project is a quantum simulator platform made of ultracold atoms for engineering quantum cascade laser frequency combs.

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Project Progress and Achievements: May 2020

Researchers' summary

During the first reporting period the following activities have been carried out:

New QCL active regions for improved frequency comb operation have been designed and optimized. They have the potential of exhibiting enhanced nonclassical features in the emission.

Regarding the fermionic analog simulator, a large spacing 1D optical lattice to mimic the multiwell configuration of QCL heterostructures has been realized. In parallel, the behavior/dynamics of the Fermi gas in a single 2D layer is under characterization.

Regarding the bosonic analog simulator, an interferometric protocol producing, separating and recombining multiple copies of a single Bose-Einstein condensate has been developed. A multimode Kapitza-Dirac beam-splitter has been realized. To reduce the amplitude of oscillations in the trap we decided to shift to a “Bragg interferometer”, where only two momentum components are present. We found that interatomic interactions affect the fringe wave vectors k, both for the free-space and the in-trap Bragg interferometers. Understanding the role of such interactions has a key role for the project.

Several QCL devices have been fabricated implementing current technology and distributed among the project partners for characterization. In addition, optimized procedures for fabrication have been tested and used for developing new devices based on the design built within the project. Moreover, a new waveguide type, including a plasmonic layer in the top cladding, has been developed and realized. The first characterization results look promising in terms of emitted power, wall-plug efficiency and spectral coverage.

Regarding the characterization of new QCL devices an innovative technique for frequency combs characterization based on the dualcomb multiheterodyne detection and the Fourier transform analysis has been developed and applied. The analyses proved that the newly-fabricated devices are characterized by a high degree of phase coherence and a welldefined phase relation. Successively, the quest for nonclassical features (squeezing) in the new QCLs emission started. The search for nonclassical features in QCL-combs emission is ongoing, results are expected in the second project period. In parallel, the new devices have been tested for applications such as dual-comb spectrometers. 

More information 

Find more information about what Qombs has achieved here

To mark the mid-point of the Quantum Technologies Flagship’s eighteen-month ramp-up phase in May 2020, a mid-term review was published with information about the achievements of all the projects. Read it here.