Overview

Infrared sensors in the wavelength range of 3-25 m are of immense technological importance due to their use in a variety of military and civilian applications such as night vision systems, medical diagnostics and fire-fighting equipment. Multi-spectral Imagers (MSI) and Hyperspectral Imagers (HSI) offer additional advantages over single-color detectors, in that it is possible to produce an absolute temperature map of a scene, even if emissivities are unknown, provided all the sensed radiation originates only from the scene. The most primitive (and generally the simplest and cheapest) method for obtaining multi-spectral images (with typically 3-15 spectral bands) is through the use of spectral filters in front of the focal plane. The various spectral images can be collected either sequentially in time, by using the same focal plane and switching filters between images, or simultaneously by using multiple focal planes. Hyperspectral sensors (with >100 spectral bands) typically use some sort of a shearing optic (such as a grating or prism) to separate the light incident on the sensor into either spectral or interferometric paths. One obvious disadvantage of these approaches is that these systems are very complex and expensive.

The objective of the proposed research effort is to develop revolutionary infrared sensors with new functionality that would greatly limit the complexity, cost, and size of conventional imaging systems. The idea involves the creation of infrared detectors with nanoscale-patterned metallic or dielectric photonic crystal (PhC) structure in them that support optical resonances to (a) achieve dramatic improvement in the conversion efficiency of a detector and (b) to create hyperspectral or polarization sensitive pixels on a single focal plane array (FPA). These detector designs make use of an integral top metal contact that provides for electrical read-out simultaneous with electromagnetic field localization using surface plasmons. The proof of concept will be demonstrated using a quantum dot (QD) detector, although the proposed approach can be extended to most any photonic infrared detector technology.

References

1. Jessie Rosenberg's Candidacy Exam presentation on her research into the design of plasmon-enhanced mid-IR detectors (ppt)

2. M. Bahriz, O. Crisafulli, V. Moreau, R. Colombelli, and O. Painter, "Design of mid-IR and THz quantum cascade laser cavities with complete TM photonic bandgap," Opt. Express, v15 (10), pp. 5948-5965, May 1, 2007. This paper discusses the design concepts behind "double-metal" structures, which we plan to use for mid-IR detectors (pdf).

3. R.V. Shenoi, D.A.Ramirez, Y.Sharma, R. S. Attaluri, J.Rosenberg, O.Painter, and S.Krishna, “Plasmon Assisted Photonic Crystal Quantum Dot Sensors,” conference proceedings, SPIE Optics+Photonics Conference 2007 (pdf).

4. J. Rosenberg, K. Srinivasan, and O. Painter, "Design of surface-resonant-enhanced detectors: symmetry and critical-coupling," in preparation (pdf).

Questions?

Please contact Jessie Rosenberg or Oskar Painter if there are any questions.