![]() ![]() Following this idea, several different types of plasmonic metamaterials lenses, such as super-lenses and hyper-lenses, have broken the diffraction limit. Furthermore, experimental realization of Negative Index Medium (NIM) opened new opportunities towards super-resolution research when British scientist John Pendry theoretically showed how a slab of NIM can work as a perfect lens thanks to the enhancement of evanescent waves through the slab, instead of decaying. Such near-field imaging techniques require a longer time to acquire the image and cannot study the dynamic behavior of biological samples in real-time. Pohl is known as the first high-resolution imaging technique, which exploits nanoscale-sized tiny tip positioned close to specimen to collect the evanescent waves from the near-field and to transfer these lost subwavelength details into the far-field. Near-field scanning optical microscope (NSOM) invented by D.W. In this regard, several methods have been implemented to circumvent this resolution limit by converting these evanescent waves to propagating waves reaching the far-field. This limits the resolution of subwavelength structures and results in an imperfect image. ![]() The physical origin of diffraction limit arises due to the loss of exponentially decaying evanescent waves, which carry high spatial frequency subwavelength information from an object and are not able to propagate in the far-field. ![]() Such resolution limit is also known as Abbe’s diffraction limit, which predicts the smallest objects that one can see through the objective lens of an optical microscope. The resolution limit in optics was discovered by the German physicist Ernst Abbe in 1873 by giving the expression, d = λ/(2NA) where d is the minimum distance between two structural elements as two objects instead of one, λ is the illuminating wavelength and NA is the numerical aperture of the used objective lens. However, the imaging resolution of a classical optical microscope is limited to almost half of its incident wavelength. The optical microscope is the most common imaging tool known for its simple design, low cost, and great flexibility. This opens new possibilities in developing more powerful, robust, and reliable super-resolution lens and imaging systems. The results show that TiO 2 meta-superlens performs consistently better over BTG superlens in terms of imaging contrast, clarity, field of view, and resolution, which was further supported by theoretical simulation. Super-resolution imaging performances were compared using the same sample, lighting, and imaging settings. In this work, we designed and fabricated TiO 2 metamaterial superlens in full-sphere shape for the first time, which resembles BTG microsphere in terms of the physical shape, size, and effective refractive index. High-index BaTiO 3 Glass (BTG) microspheres are among the most widely used dielectric superlenses today but could potentially be replaced by a new class of TiO 2 metamaterial (meta-TiO 2) superlens made of TiO 2 nanoparticles. All-dielectric superlens made from micro and nano particles has emerged as a simple yet effective solution to label-free, super-resolution imaging. ![]()
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