Mouhamad Al-Mahmoud E-mail: mouhamadmahmoud1@gmail.com Phone: +359893831068 Institution: Foundation for Theoretical and Computational Physics and Astrophysics supervisor: Andon Rangelov

 

Project Title: Composite and adiabatic schemes for robust photonics (mainly WP1, also WP2 & WP3)

Standard frequency conversion techniques deliver either complete frequency conversion for very narrowband spectrum or inefficient conversion for broad bandwidth. Recent experiments on frequency conversion using ideas from rapid adiabatic passage in quantum optics demonstrated high-efficiency broadband conversion from the near-IR into the visible. Adiabatic approaches, however, require very high input intensity and/or very long nonlinear crystals. This project will design composite nonlinear crystals in analogy with the technique of composite pulses. Composite pulses use less energy than adiabatic techniques while they deliver higher efficiency and similar robustness to parameter variations; similar advantages are expected in frequency conversion too. By using the similarity of the relevant equations, these ideas will be extended to the design of composite antireflection coatings, which are robust to variations of the refractive index (as it occurs in EIT), and to the reduction of polarisation mode dispersion in optical fibres, which is the main limitation to higher optical communication rates. Mouhamad will be co-supervised by TUDA. During the secondment, Mouhamad will evaluate the feasibility of experimental implementation of the theoretical concepts for composite antireflection coatings and frequency conversion in composite crystals.

Expected Results: Using the concepts of composite pulses, adiabatic evolution and shortcuts to adiabaticity, we shall (1) design new efficient broadband and tunable frequency conversion schemes and optical parametric amplification schemes; (2) construct novel antireflection optical coatings; (3) reduce polarization mode dispersion in telecommunication fibres.

 

TUDA = Technical University of Darmstadt
 

Articles and reports:

– Article published in Applied Sciences (2020)
– Article published in Physical Review Applied (2020), preprint
– Article published in Journal of Optics (2019), preprint