Figure 1

(Color online) (a) Schematic of the coupled-ring-cavity model. Partially transmitting mirrors (dashed lines) represent coupling between the fiber and the first sphere and coupling between the two microspheres. The incident light (i) is partially reflected (ii), and partially coupled into the first sphere (iii). On encountering the second sphere, part of this light is reflected (iv) and continues its propagation inside the first sphere, while part of the light is transmitted into the second sphere (v). Light from the second sphere tunnels back into the first sphere and interferes with the light circulating there. Part of the resulting wave (vi) escapes and interferes destructively with the initially reflected signal (ii). (b) Mode splitting in noncoresonant coupled microspheres with radii $a_1=240$ and $a_2=200\mu \mathrm{m}$. The two traces have the same scale, but different vertical axis origins. The single-sphere dip has $M=0.69$. Solid curves, experimental data; circles, calculated profiles based on coupled-ring-cavity model. Inset: a schematic of the experimental configuration.Reuse & Permissions

Figure 2

(Color online) (a) Induced transparency in coupled coresonant microspheres with radii $a_1=240$ and $a_2=375\mu \mathrm{m}$. The traces have the same scale, but different vertical shifts. The dip in trace 1 has $M=0.43$. (b) Linewidth narrowing in the same coupled microresonators as in (a), but without coresonance. The traces have the same scale, but different vertical shifts. The central dip in trace 1 has $M=0.67$. In both (a) and (b), the coupling between microspheres increases with increasing trace number, the decrease in sphere separation $d$ for successive traces is of the order of $1\mu \mathrm{m}$, and trace 1 is for the first microresonator alone.Reuse & Permissions

Figure 3

(Color online) Induced absorption in coupled microresonators with radii $a_1=180$ and $a_2=220\mu \mathrm{m}$.Reuse & Permissions