  Most of our current understanding of mechanisms of photosynthesis comes from
spectroscopy. However, classical definition of radio-antenna can be extended to
optical regime to discuss the function of light-harvesting antennae. Further to
our previously proposed model of a loop antenna we provide several more
physical explanations on considering the non-reciprocal properties of the light
harvesters of bacteria. We explained the function of the non-heme iron at the
reaction center, and presented reasons for each module of the light harvester
being composed of one carotenoid, two short $\alpha$-helical polypeptides and
three bacteriochlorophylls; we explained also the toroidal shape of the light
harvester, the upper bound of the characteristic length of the light harvester,
the functional role played by the long-lasting spectrometric signal observed,
and the photon anti-bunching observed. Based on these analyses, two mechanisms
might be used by radiation-durable bacteria, {\it Deinococcus radiodurans}; and
the non-reciprocity of an archaeon, {\it Haloquadratum walsbyi}, are analyzed.
The physical lessons involved are useful for designing artificial light
harvesters, optical sensors, wireless power chargers, passive super-Planckian
heat radiators, photocatalytic hydrogen generators, and radiation protective
cloaks. In particular it can predict what kind of particles should be used to
separate sunlight into a photovoltaically and thermally useful range to enhance
the efficiency of solar cells.
