Figure 4From: Polarization compensation method based on the wave plate group in phase mismatch for free-space quantum key distributionSolution existence regions for each wavelength. (a) 850 nm (b) 1064 nm (c) 1550 nm. Top, \(R_{d}\) rotates to the vertex above the Poincaré sphere; bottom, \(R_{d}\) rotates to the vertex below the Poincaré sphere; \(\delta _{1}\) and \(\delta _{2}\) are the phases of the two phase-mismatched waveplates at each wavelengthBack to article page