Figure 2
Optical force and torque on the ring resonator when it is located at (0,0), and only port 1 is excited. (a) Transmission spectrum T1,2 of the system (left y-axis, red solid curve) and the x, y components of the optical forces (right y-axis, green color for x component, and cyan color for y component) exerted on the ring resonator. The four gray vertical solid lines represent four typical wavelengths λb2, λ0, λ a , λr3 (resonant wavelength is λ0) and the eight blue star labels represent different extent excitation wavelengths that λb1–b4(λr1–r4) are the blue (red) detuned wavelength, which are analyzed detailedly in the following sections. (b1~b4) Distribution of electric field E z and optical force density vector on the integral path (green arrows) overlapped by the positive and negative components of the optical forces in x and y directions, respectively (denoted by OFxp, OFxn, OFyp and OFyn, respectively). (c) Optical torque exerted on the ring resonator (right y-axis, blue dotted curve). The transmission curve (left y-axis, red solid curve) is also drawn for reference. Here, negative (positive) OT means clockwise (anti-clockwise) rotation of the ring resonator. (d1–d4) Relative values of the positive and negative components of OT. For comparison, the blue arrows are also shown next to the red ones.
