Patent ID: 11956014
Assignee: UNIVERSITA' DEGLI STUDI DI MILANO
Field: Telecommunications (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 0:
1. A method for transmitting and receiving an electromagnetic radiation beam, adapted to determine an orbital angular momentum of the received electromagnetic radiation beam, comprising the steps of:
generating at least one main electromagnetic radiation beam (F1) characterized by a first orbital angular momentum (L1), a first spectrum in a first frequency band, and a first beam radius of curvature;
generating a reference electromagnetic radiation beam (F0), characterized by a second orbital angular momentum (L0), a second spectrum in a second frequency band which is distinct from said first frequency band, and a second beam radius of curvature substantially coinciding with said first beam radius of curvature;
generating a composite electromagnetic radiation beam (Q1), consisting of the superposition of said at least one main beam (F1) and the reference beam (F0);
transmitting said generated composite electromagnetic radiation beam (Q1);
receiving said composite electromagnetic radiation beam, by means of a first beam detector (1) located in a first position, to generate a first composite beam electrical signal (D1), representative of the electric and/or magnetic field and/or of the intensity of the electromagnetic radiation of the composite beam in said first position;
receiving said composite electromagnetic radiation beam, by means of a second beam detector (2) located in a second different position with respect to said first position, to generate a second composite beam electrical signal (D2), representative of the electric and/or magnetic field and/or of the intensity of the received electromagnetic radiation of the composite beam in said second position;
performing a frequency discrimination of said first composite beam electrical signal (D1) with reference to said first frequency band and second frequency band to obtain, respectively, a first main beam electrical signal (P1), representative of the electric and/or magnetic field and/or of the intensity due to the main beam in said first position, and a first reference beam electrical signal (R1), representative of the electric and/or magnetic field and/or of the intensity due to the reference beam in said first position;
performing a frequency discrimination of said second composite beam electrical signal (D2) with reference to said first frequency band and second frequency band to obtain, respectively, a second main beam electrical signal (P2), representative of the electric and/or magnetic field and/or of the intensity due to the main beam in said second position, and a second reference beam electrical signal (R2), representative of the electric and/or magnetic field and/or of the intensity due to the reference beam in said second position;
determining the orbital angular momentum (L1) of the main electromagnetic radiation beam and/or the spatial phase variation of the main electromagnetic radiation beam due to said main beam orbital angular momentum (L1), based on said first main beam electrical signal (P1), second main beam electrical signal (P2), first reference beam electrical signal (R1) and second reference beam electrical signal (R2).