Biomedical Engineering Reference
In-Depth Information
intensity, as its plasmonic resonance is located at the wavelength
below 900 nm.
13.2.5
Taiji Mark for Opto-Mechanical Oscillator
We now consider the application of electromagnetic energy vortex
ofTaijimark.Itiswellknownthattheinteractionbetweenlightand
matter is usually accompanied with force or torque [35-38]. The
optical force was first observed experimentally more than a century
ago [39, 40], and the optical torque has been reported by Beth more
than 70 years ago that the photons can induce a mechanical torque
via scattering or absorption [41]. The study on optical force/torque
grows dramatically after the invention of the laser in 1960s [42]
and it can be applied to optomechanics for optical motors [43-45],
optical wrenches [46, 47], and laser trapping [48, 49].
Figure 13.8
Evolution of the simulated optical torque and transmittance
spectra upon varying the diameter of the tangent circle. (a) and (b) show
the optical torque for 1 mW/
μ
m
2
incident intensity. The positive and
negativevaluesofopticaltorquecorrespondtoanticlockwiseandclockwise
rotation of Taiji pattern, denoted by red circular mark. (c) and (d) show
transmittancespectrawiththesimilartendencyofFig.13.3candd.Thered
arrow shows the polarization of incident wave.
