Research

Flat optics & Metasurfaces

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Imaging & Sensor

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Biomedical imaging: 

Nano-optic endoscopes

Improvement in the accuracy of endoscopic biopsy for small peripheral lesions is necessary if bronchoscopy will play a major role in lung cancer diagnosis. Endoscopic optical coherence tomography (OCT) with commercial catheters that rely on graded-index (GRIN) lenses or ball lenses, however, exhibit strong astigmatism and spherical aberration and thus deviate from diffraction-limited focusing.  Shown is an artistic impression of the nano-optic endoscope that uses a metalens, with the ability to modify the phase of incident light at subwavelength level, to enable high-resolution endoscopic imaging at extended depth-of-focus by avoiding monochromatic aberrations. High-resolution three-dimensional images are captured by inserting the nano-optic endoscope into the lungs endo-bronchially visualize airway tissue microstructures. The combination of the superior resolution and higher imaging depth of focus of the nano-optic endoscope is likely to increase the clinical utility of endoscopic optical imaging.

Reference: 

Nature Photonics 12, 540−547(2018), link, pdf

Design

The metalens was designed to image a point source to a diffraction-limited spot with working distance 0.5 mm.

Photographic image

The distal end of the nano-optics endoscope

SEM image of a metalens

An individual metalens building block consisting of an amorphous silicon nanopillar on a glass substrate

OCT image

Structural features of lung tissue are clearly visible, , including moderately scattering epithelium (epi), highly scattering basement membrane (bm), cartilage (car), blood vessel (ves) and alveoli (alv)

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Comparison with the state of the art

The ability to tailor the phase at will allows metalenses to be free of spherical aberration and astigmatism

Structured Light

(coming soon) 

 

Wearable Technology

(coming soon) 

 

Optical Multifunctionality

(coming soon) 

 

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