Disorder-mediated enhancement of fiber numerical aperture.

The numerical aperture (NA) of a multimode optical fiber sets the limit of the information transport capacity along the spatial degree of freedom. In this Letter, we report that the application of a highly disordered medium can overcome the capacity limit set by the fiber NA. Specifically, we coated the input surface of a multimode fiber with a disordered medium made of ZnO nanoparticles and transported a wide-field image through the fiber with a spatial resolution beyond the diffraction limit given by the fiber NA. This was made possible because multiple scatterings induced by the disordered medium physically increased the NA of the entire system. Our study will lead to enhancing the spatial resolution of fiber-based endoscopic imaging and also improving the information transport capacity in optical communications.

[1]  V I Bobrinev,et al.  Direct image transmission through a multimode optical fiber. , 1996, Applied optics.

[2]  K. Dholakia,et al.  Exploiting multimode waveguides for pure fibre-based imaging , 2012, Nature Communications.

[3]  Gabriel Popescu,et al.  Hilbert phase microscopy for investigating fast dynamics in transparent systems. , 2005, Optics letters.

[4]  Moonseok Kim,et al.  Scanner-free and wide-field endoscopic imaging by using a single multimode optical fiber. , 2012, Physical review letters.

[5]  Silvio Bianchi,et al.  A multi-mode fiber probe for holographic micromanipulation and microscopy. , 2012, Lab on a chip.

[6]  Demetri Psaltis,et al.  High-resolution, lensless endoscope based on digital scanning through a multimode optical fiber , 2013, Biomedical optics express.

[7]  Michael S Feld,et al.  Overcoming the diffraction limit using multiple light scattering in a highly disordered medium. , 2011, Physical review letters.

[8]  W. Choi,et al.  Maximal energy transport through disordered media with the implementation of transmission eigenchannels , 2012, Nature Photonics.

[9]  Stuart,et al.  Dispersive multiplexing in multimode optical fiber , 2000, Science.

[10]  B. Fischer,et al.  Image transmission and interferometry with multimode fibers using self‐pumped phase conjugation , 1985 .

[11]  U Levy,et al.  Parallel image transmission by a single optical fiber. , 1978, Optics letters.

[12]  Jungho Moon,et al.  Experimental measurement of the number of modes for a multimode optical fiber. , 2012, Optics letters.

[13]  Ruo Yu Gu,et al.  Resolution limits for imaging through multi-mode fiber. , 2013, Optics express.