| Imaging cellular structures in vivo with molecular level resolution is Holy Grail of Biological Science. However, the resolution of optical microscopy is limited by the diffraction of light to approximately lambda/2 (250 nm for visible light). While electron microscopy, STM and AFM provide much higher resolution, in vivo imaging is hardly possible. That's why it is important to significantly improve the resolution for optical microscopy, which also provides molecular specific information about the structures of interest.; We proposed, designed and built a prototype of a novel type of microscope, which is called Trapped Particle Optical Microscope (TPOM) and uses nanoparticle as a probe.; Trapped particle is detected by Dark Field (DF) illumination built upon conical lens and combined with polarization imaging. We believe that for the first we are able observe the motion of colloidal particles as small as 10nm and protein molecules in solution.; We were able to trap and steer 10nm to 3 micron particles in 3 dimensions and detect the Third Harmonic (TH) signal generated in particle by trapping continuous wave Near InfraRed (NIR) laser.; Based on our ability to trap and steer gold nano sphere and detect TH signal, generated by it, we propose to use TH as near-field detection signal for TPOM. The other great advantage of this microscope is that illumination and detection signals are significantly spectrally separated. |
