Fig. 1. Lensing effect, imaging ability, and optical manipulation of the microlenses. (a) Light irradiation without a microsphere. The divergent laser beam illuminates the neural cells. (b) Focusing by the microsphere that acts as a microlens near the neural cells. (c) The microlenses effectively focus incident light into PNJs. Inset shows an SEM image of the microsphere. (d) Schematic of the microlens collecting the near-field signals from an object to form a virtually magnified image. (e) Schematic of rotating the microlens using the SOT. (f) The microlens rotates along a predefined circular path.

Fig. 2. Lensing effect of the resin microspheres. (a) FEM-simulated energy density distributions of light at the wavelength of 1064 nm without (a1) and with (a2) the microlens. (b) Energy density profiles at the focal planes of the output light from the microlens in the x direction. (c) Optical microscope image of the PS nanoparticles obtained with the assistance of microlens. (d) Intensity variation along the transverse cross section through the center of two light spots (NP1 and NP2) from the PS nanoparticles (D=80  nm). (e) Fluorescence images of the NPs without (e1) and with (e2) the assistance of microlens. Insets show the optical intensity distributions. (f) Energy density distributions of the emitters without (f1) and with (f2) the microlens.

Fig. 3. Imaging of subcellular structures. (a) Fluorescence images of a living neural cell. The inset shows the magnified image of the view field of the microlens. (b) Normalized intensity distribution along the observation lines through the axon without and with the microlens. (c) Bright-field scanning imaging of the axon. (d), (e) Fluorescent imaging of the axon without (d) and with (e) the microlens scanning. (f)–(h) Fluorescence images of lysosomes (f), mitochondria (g), and actin filaments (h) in a neural cell with the microlens.

Fig. 4. Stimulation and imaging of neuron cells via PNJs. (a) Schematic of the effect of the microlens on synapses. (b) Schematic of optical stimulation via PNJs from a microlens. (c) Fluorescence images of the axon of a living neural cell. (d) Fluorescence image of a microlens connecting the synapses of two neurons. (e), (f) Light-induced fluorescent intensity from the neural cells with or without microlenses.