Computational imaging enables a "see-through" lens-less camera.

Conventional cameras obscure the scene that is being recorded. Here, we place an image sensor (with no lens) on the edge of a transparent window and form images of the object seen through that window. This is enabled first, by the collection of scattered light by the image sensor, and second, by the solution of an inverse problem that represents the light scattering process.

Lensless photography with only an image sensor.

Photography usually requires optics in conjunction with a recording device (an image sensor). Eliminating the optics could lead to new form factors for cameras. Here, we report a simple demonstration of imaging using a bare CMOS sensor that utilizes computation.

Numerical analysis of computational-cannula microscopy.

Microscopy in hard-to-reach parts of a sample, such as the deep brain, can be enabled by computational-cannula microscopy (CCM), where light is transported from one end to the other end of a solid-glass cannula. Computational methods are applied to unscramble the recorded signal to obtain the object details. Since the cannula itself can be microscopic (∼250  μm in diameter), CCM can enable minimally invasive imaging.

Deep-brain imaging via epi-fluorescence Computational Cannula Microscopy.

Here we demonstrate widefield (field diameter = 200 μm) fluorescence microscopy and video imaging inside the rodent brain at a depth of 2 mm using a simple surgical glass needle (cannula) of diameter 0.22 mm as the primary optical element. The cannula guides excitation light into the brain and the fluorescence signal out of the brain.

Increased photovoltaic power output via diffractive spectrum separation.

In this Letter, we report the preliminary demonstration of a new paradigm for photovoltaic power generation that utilizes a broadband diffractive-optical element (BDOE) to efficiently separate sunlight into laterally spaced spectral bands. These bands are then absorbed by single-junction photovoltaic cells, whose band gaps correspond to the incident spectral bands. We designed such BDOEs by utilizing a modified version of the direct-binary-search algorithm.

Design and analysis of multi-wavelength diffractive optics.

We present an extension of the direct-binary-search algorithm for designing high-efficiency multi-wavelength diffractive optics that reconstruct in the Fresnel domain. A fast computation method for solving the optimization problem is proposed. Examples of three-wavelength diffractive optics with over 90% diffraction efficiency are presented.