图 1  (a) 实验装置和(b) 实验能级示意图

Fig. 1.  Schematic diagram of experimental setup (a) and energy levels (b).

图 2  理论模拟注入信号光s₁光(红色实线)和s₂光(蓝色虚线)的色散 χ'、吸收χ'' 及腔透射谱T 随信号光频率失谐的变化　(a), (b)只有c₁光作用时的χ' 和 χ''; (d), (e) 只有c₂作用时的χ' 和 χ''; (c), (f) 分别对应只有c₁光和只有c₂作用时的T. 在计算中参数设置为: (a)—(c)中, $ {\varOmega _{{c_1}}} = 20{\text{ MHz, }}{\varOmega _{{c_2}}} = 0 $; (d)—(f)中, ${\varOmega _{{c_1}}} = 0,\;{\varOmega _{{c_2}}} = 20{\text{ MHz}}$. 其他实验参数为: r = γ_in = 0.9, γ_ca = 14.4 MHz, γ_ab = 0.3 MHz, L = 526 mm, l = 75 mm, $ {\varDelta _{{c_1}}} = {\varDelta _{{c_2}}} = {\varDelta _{\text{q}}} = 0 $

Fig. 2.  Theoretical plots of the dispersion χ', absorption χ'' and cavity transmission T of the input s₁ (red solid lines) and input s₂ (blue dashed lines) versus signal frequency detuning: (a), (b) χ' and χ'' for only c₁ used; (d), (e) χ' and χ'' for only c₂ used; (c), (f) T corresponding to only c₁ and only c₂ corresponding to panel (a), (b) and (d), (e), respectively. The parameters used in the calculation are $ {\varOmega _{{c_1}}} = 20{\text{ MHz, }}{\varOmega _{{c_2}}} = 0 $ for panel (a)–(c); ${\varOmega _{{c_1}}} = 0{, }~{\varOmega _{{c_2}}} = 20{\text{ MHz}}$for panel (d)–(f). The other parameters are r = γ_in = 0.9, γ_ca = 14.4 MHz, γ_ab = 0.3 MHz, L = 526 mm, l = 75 mm, $ {\varDelta _{{c_1}}} = {\varDelta _{{c_2}}} = {\varDelta _{\text{q}}} = 0 $.

图 3  理论模拟了当c₁光和c₂光同时作用时, 不同频差δ_c下s₁光(红色实线)和s₂光(蓝色虚线)的色散χ'、吸收χ''及腔透射谱T (a)—(c) δ_c = 0; (d)—(f) δ_c = –20 MHz; (g)—(i) δ_c = –40 MHz. 主要计算参数为$ {\varOmega _{{c_1}}} = {\varOmega _{{c_2}}} = 20{\text{ MHz}} $, 其他参数与图2中的相同

Fig. 3.  Theoretical plots of χ', χ'' and T of the input s₁ (red solid lines) and input s₂ (blue dashed lines) versus signal frequency detuning for different frequency difference δ_c when coupling lights c₁ and c₂ are used simultaneously: (a)–(c) δ_c = 0; (d)–(f) δ_c = –20 MHz; (g)–(i) δ_c = –40 MHz. The parameters used in the calculation are $ {\varOmega _{{c_1}}} = {\varOmega _{{c_2}}} = 20{\text{ MHz}} $, and other parameters are the same as in Fig. 2.

图 4  (a), (c) 实验测量了只有c₁光和c₂光作用下的腔透射谱; (b), (d) 当c₂光为脉冲光时在原子共振跃迁中心(Δ_s = 0)的腔透射强度. (1) 代表s₁光的腔透射(红色线), (2) 代表s₂光的腔透射(蓝色线), (3) 代表c₁光强度(灰色线)和(4)代表c₂光强度(黑色线). 主要实验参数为$ {P_{{c_1}}} = {P_{{c_2}}} = 10\;{\text{mW}} $, $ {P_{{s_1}}} = {P_{{s_2}}} = 1.5{\text{ mW}} $, T_Cs = 28.5 °C, $ {\delta _c} = {\varDelta _{{c_1}}} = 0 $

Fig. 4.  (a), (c) Experimental measured cavity transmission for only light c₁ (a) and light c₂ (c) used. (b), (d) The transmission intensity at the atom resonance center (Δ_s = 0) when light c₂ is as pulsed light. Red curves (1) are the cavity transmission of light s₁, blue curves (2) are those of light s₂, gray lines (3) and black lines (4) are the intensity of lights c₁ and c₂, respectively. The main experimental parameters are:$ {P_{{c_1}}} = {P_{{c_2}}} = 10{\text{ mW}} $, $ {P_{{s_1}}} = {P_{{s_2}}} = 1.5{\text{ mW}} $, T_Cs = 28.5 °C, $ {\delta _c} = {\varDelta _{{c_1}}} = 0 $.

图 5  实验测量了c₁光和c₂光同时作用下的腔透射谱, 其中主要实验参量为(a) $ {\varDelta _{{c_1}}} = {\delta _c} = 0 $; (b) $ {\varDelta _{{c_1}}} = 10{\text{ MHz, }}{\delta _c} = - 20{\text{ MHz}} $; (c) $ {\varDelta _{{c_1}}} = 20{\text{ MHz, }}{\delta _c} = - 40{\text{ MHz}} $. 其他参数与图4相同

Fig. 5.  Experimental measured cavity transmission for lights c₁ and c₂ simultaneously used. The main experimental parameters are: (a) $ {\varDelta _{{c_1}}} = {\delta _c} = 0 $; (b) $ {\varDelta _{{c_1}}} = 10{\text{ MHz, }}{\delta _c} = - 20{\text{ MHz}} $; (c) $ {\varDelta _{{c_1}}} = 20{\text{ MHz, }}{\delta _c} = - 40{\text{ MHz}} $. The other parameters are the same as in Fig. 4.