Fig. 5: Experimental detection of the SDE with mode-filtering.
From: Doppler effect tailoring: extra-red shift of structured light
The probe beam is composed of two higher-order Bessel beams (α1 = 0.0014697, ℓ1 = − 3, and α2 = 0. 0035242, ℓ2 = 3). a Process of mode-filtering detection. The SDE signal beams are demodulated with a phase mask combined with a coaxial aperture. The overlap between the SDE signal beams and the predefined angular mode is revealed in the demodulated far-field patterns. b The time-varying Doppler signals obtained from the single-mode region in each frame of the demodulated far-field patterns. c The Fourier amplitude spectrum corresponding to b.
