Photonic-jet Coupled Optical Antenna for Near Room Temperature Infrared Detectors and Imagers

Although optical antenna is not a new idea1, the steady progress in nano-processing and recent theoretical insights into plasmonics and metamaterial have helped rapid progress in this field, and led to well controlled demonstration of optical antenna over a wide wavelength range covering UV to infrared. Here we propose to use a combined dielectric/metallic antenna to produce very efficient coupling of long wavelength infrared light with small detectors, and to achieve background limited infrared photodetection (BLIP) near room temperature. Long-wave Infrared (LWIR) detector arrays have found wide range of medical, industrial, and security applications such as thermal imaging for diagnosis of breast cancer2, dental3 and thyroid4 diseases, fast detection of the hidden cracks5,6, remote sensing7, and non-metallic landmine detection8. In many of these applications, the detector is limiting the performance of the over system, unless BLIP condition is achieved. Despite significant efforts by many groups, including the PI52, to develop novel material systems for near room temperature operation, LWIR detectors still require cryogenic cooling to achieve BLIP performance. We present a material independent approach, which should in principle produce two orders of magnitude enhancement in detectivity, and hence room temperature BLIP operation. Plasmonics can collect and squeeze light into small volumes, much smaller than half of its wavelength, which is the limit of conventional optics. We show that novel metal-dielectric-metal plasmonic crystals can act as “light compressors” and squeeze light several orders of magnitude in each direction, to achieve a mode volume of ~λ3/106. We propose to use these to realize detectors with many orders of magnitude smaller electrical volume. The noise power of such detector is dramatically reduced, while their optical quantum efficiency is kept high. Furthermore, we show a plasmonic device that not only achieves squeezing in-plane light, but also redirects normal incidence light into lateral (in-plane) directions, and thereby creates 3-D mode compression. The proposed devices could achieve high quantum efficiency even for very thin detectors layers.