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

Claim 1:
2. The method according to claim 1, wherein the determining step comprises:
determining a first phase difference value (ΔP) corresponding to the difference between the phase of the first main beam electrical signal (P1) and the phase of the second main beam electrical signal (P2),
determining a second phase difference value (ΔR) corresponding to the difference between the phase of the first reference beam electrical signal (R1) and the phase of the second reference beam electrical signal (R2),
subtracting the second phase difference value (ΔR), divided by a second wave number (k′), from the first phase difference value (ΔP), divided by a first wave number (k), to obtain a difference value (Q2=ΔP/k−ΔR/k′) which is independent of positional inclination conditions between said first detector and second detector, deriving from the relative position of the two detectors with respect to the beam propagation, and which is independent of phase variations due to disturbances suffered by the transmitted composite beam before reception,
where the first wave number (k) is the wave number corresponding to the main beam, defined as k=2π/λ, λ being the wavelength of said main beam, and where the second wave number (k′) is the wave number corresponding to the reference beam, defined as k′=2π/λ′, λ′ being the wavelength of said reference beam;
determining the orbital angular momentum of the main electromagnetic radiation beam based on said obtained difference value (Q2=ΔP/k−ΔR/k′).