Fig. 1. (a) Schematic of the experimental setup. PBS, polarized beam splitter; HWP, half-wave plate; EOM, electro-optic modulator; AOM, acousto-optic modulator; PD, photodetector; AWG, arbitrary wave generator; DPO, digital phosphor oscilloscope. (b) Energy levels of the Rb87 atom and the frequencies of the lasers: |g,m⟩, hyperfine levels |52S1/2,F=1,F=2⟩; |e1,e2⟩, hyperfine levels |52P1/2,F=2⟩ and |52P3/2⟩; W, the Raman pump field; a^in, the initial input Stokes seed; a^out, the output Stokes field via SRS; OP, the optical pumping; S^, the atomic spin wave; R, the read field; b^out, the output anti-Stokes field by the reading process.

Fig. 2. Iteration diagram. a^in,a^in(1),…,a^in(i) are normalized initially input Stokes seeds; a^out,a^out(1),…,a^out(i) are output signals by SRS, corresponding to the ith iteration.

Fig. 3. (a) and (b) a^in is the initially input seed waveform and a^out(0) is the corresponding output signal of SRS. a^out(1) is the output signal of SRS in the first round, a^out(1) is stable waveform after several iteration rounds. (c) Pink circles and green solid triangles are a^out(f) corresponding to different a^in in (a) and (b), respectively.

Fig. 4. (a) and (b) The different energy fluctuations ΔEa^out(0) of a^out(0) and ΔEa^out(f) of a^out(f) during many measurement times. (c) E¯a^out is the average energy of the output Stokes field. Black square and red triangle curves are respective Var(E) for Ea^out(0) and Ea^out(f) both with 100 ns long square-W pulse.

Fig. 5. Black square and red triangle curves are respective Var(EDiff) for a^out(0) and a^out(f) both with the square-W and square-R pulse acquired in the experiment.