For optical manipulation, a nano-optical conveyor belt consisting of an array of gold plasmonic non-concentric nano-rings (PNNRs) is demonstrated for the realization of trapping and unidirectional transportation of nanoparticles by polarization rotation of excitation beam. These hot spots of an asymmetric plasmonic nanostructure are polarization dependent, therefore, one can use the incident polarization state to manipulate the trapped targets. Trapped particles could be transferred between adjacent PNNRs in a given direction just by rotating the polarization of incident beam due to unbalanced potential. The angular dependent distribution of electric field around PNNR has been solved using the three- dimensional finite-difference time-domain (FDTD) technique. For optical enhanced catalytic activity, the spectral properties of dimers of Au nanorod-Au nanorod nanostructures under the excitation of 532nm photons have been investigated. With a super-resolution catalytic mapping technique, we identified the existence of "hot spot" in terms of catalytic reactivity at the gap region within the twined plasmonic nanostructure. Also, FDTD calculation has revealed an intrinsic correlation between hot electron transfer.
For a space downlink laser communication system with an EDFA as a power amplifier, the
performance of its BER deteriorates because the EDFA’s characteristics are badly impacted by space
radiation. As is investigated in this paper, small divergence-angle, lower than 30μrad, assures that the
BER is lower than10-20 although the increase of radiation dose from 0Gy to 250Gy leads to 20 orders of
magnitude increase of the BER. Such perfection results from our selection of optimal parameters. In
the case of zenith angle, the BER increases smoothly when the zenith angle is lower than 10 degrees.
After the point of 10 degrees, however, the BER starts its linearly fast increase. Increasing the radiation
dose makes the BER increase and such evolution trend more smooth. Moreover, the increase of
receiving diameter leads to linear reduce of BER. It is interesting to note that the evolution becomes
nonlinear in region of low receiving diameter when we change the divergence-angle to a higher value
60μrad. Besides, suffering radiation makes the non-linearity mentioned above more apparent. Another
try to change the zenith angle to higher value 45° does not show obvious nonlinear effect but it worsens
the performance of BER quite a lot. Commonly, the impact of radiation will reach its saturation when
the dose of radiation continues to increase. The work will benefit the design of practical space laser
communication system with EDFAs.