Format

Send to

Choose Destination
Light Sci Appl. 2016 Apr 8;5(4):e16060. doi: 10.1038/lsa.2016.60. eCollection 2016 Apr.

Pixel super-resolution using wavelength scanning.

Luo W1,2,3, Zhang Y1,2,3, Feizi A1,2,3, Göröcs Z1,2,3, Ozcan A1,2,3,4.

Author information

1
Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA.
2
Bioengineering Department, University of California, Los Angeles, CA 90095, USA.
3
California NanoSystems Institute (CNSI), University of California, Los Angeles, CA 90095, USA.
4
Department of Surgery, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.

Abstract

Undersampling and pixelation affect a number of imaging systems, limiting the resolution of the acquired images, which becomes particularly significant for wide-field microscopy applications. Various super-resolution techniques have been implemented to mitigate this resolution loss by utilizing sub-pixel displacements in the imaging system, achieved, for example, by shifting the illumination source, the sensor array and/or the sample, followed by digital synthesis of a smaller effective pixel by merging these sub-pixel-shifted low-resolution images. Herein, we introduce a new pixel super-resolution method that is based on wavelength scanning and demonstrate that as an alternative to physical shifting/displacements, wavelength diversity can be used to boost the resolution of a wide-field imaging system and significantly increase its space-bandwidth product. We confirmed the effectiveness of this new technique by improving the resolution of lens-free as well as lens-based microscopy systems and developed an iterative algorithm to generate high-resolution reconstructions of a specimen using undersampled diffraction patterns recorded at a few wavelengths covering a narrow spectrum (10-30 nm). When combined with a synthetic-aperture-based diffraction imaging technique, this wavelength-scanning super-resolution approach can achieve a half-pitch resolution of 250 nm, corresponding to a numerical aperture of ~1.0, across a large field of view (>20 mm2). We also demonstrated the effectiveness of this approach by imaging various biological samples, including blood and Papanicolaou smears. Compared with displacement-based super-resolution techniques, wavelength scanning brings uniform resolution improvement in all directions across a sensor array and requires significantly fewer measurements. This technique would broadly benefit wide-field imaging applications that demand larger space-bandwidth products.

KEYWORDS:

holographic imaging; on-chip microscopy; pixel super-resolution; wavelength scanning; wide-field imaging

Conflict of interest statement

The authors declare no conflict of interest.

Supplemental Content

Full text links

Icon for PubMed Central
Loading ...
Support Center