In nature, reflecting superposition compound eyes (RSCEs) found in shrimps, lobsters and some other decapods are extraordinary imaging systems with numerous optical features such as minimum chromatic aberration, wide-angle field of view (FOV), high sensitivity to light and superb acuity to motion. Here, we present life-sized, large-FOV, wide-spectrum artificial RSCEs as optical imaging devices inspired by the unique designs of their natural counterparts. Our devices can form real, clear images based on reflection rather than refraction, hence avoiding chromatic aberration due to dispersion by the optical materials. Compared to imaging at visible wavelengths using conventional refractive lenses of comparable size, our artificial RSCEs demonstrate minimum chromatic aberration, exceptional FOV up to 165° without distortion, modest aberrations and comparable imaging quality without any post-image processing. Together with an augmenting cruciform pattern surrounding each focused image, our large-FOV, wide-spectrum artificial RSCEs possess enhanced motion-tracking capability ideal for diverse applications in military, security, medical imaging and astronomy.
We present micro cameras that provide multiple viewpoint imaging from one single image capture and without moving the camera. The micro cameras are based on lightfield photography where the camera captures the 4-D lightfield and images it onto a 2-D charge-coupled device (CCD) sensor through the use of a microlens array. The microlens array was fabricated using the photoresist reflow process. Two micro cameras were realized. One camera has a 15.2-mm aperture, a 97 × 97 microlens array of 230-μm pitch size, and a 1-megapixel CCD and is capable of 100 different viewpoints with a viewing angle of approximately 20 • . The other camera has a 9-mm aperture, a 56 × 42 microlens array of 80-μm pitch size, and a 5-megapixel CCD and is capable of around 1000 different viewpoints with a viewing angle of approximately 4.7 • . The resolution of the images rendered from the two cameras is 97 × 97 and 56 × 42 pixels, respectively.[
2011-0314]Index Terms-Lightfield, micro camera, microlens array, multiple viewpoints, plenoptic camera.
Microlenses are important components of optofluidics systems and their lab-on-a-chip applications. We report on liquid microlenses that can be in situ formed in microchannels in a single batch via pneumatic control. These microlenses have optical axes that are parallel to the substrate, and their focal length can be pneumatically tuned separately and independently. In addition, the microlenses can also be pneumatically removed individually and reformed on demand. The parameters affecting the profiles and optical properties of the microlenses, such as the pressure difference and gravity, were investigated by simulation. We then demonstrated the enhancement of fluorescence emission in a microfuidic channel using our microlenses to focus attenuated excitation laser beams into regions of interest in the channel. With the microlenses, the region with visible fluorescence response was enlarged by up to 13 times and the intensity of fluorescence emission was enhanced by up to 38 times, compared to the cases without the lenses.
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