Low-cost, mid-infrared (IR) wavelength detector offers high responsivity without cryogenic coolingUCF researchers have invented a nanoscale IR detector that overcomes major limitations of today’s cooled and uncooled IR detectors. The Optical Frequency-Selective Absorber-Based Infrared Detector operates uncooled and can be tuned to a specific narrow bandwidth within the IR spectrum. The new detector also has a faster response time, zero back reflection, and can be fabricated using simple, lower cost nanoimprint lithography. Current IR detectors are either expensive or cannot obtain the high sensitivity required to detect the low photon energy of IR radiation. Though some detectors may provide high sensitivity, they require cryogenic cooling and expensive molecular beam epitaxy (MBE) manufacturing methods. Uncooled detectors are more cost-effective, but they suffer from low sensitivity, slow response and tedious multi-step complex lithographic processes. The detectors also lack multi-spectral imaging and detection capabilities.
The new uncooled IR detector consists of a sub-wavelength gold hole/disk array, that when coupled with a ground plane, induces extraordinary transmission through the hole/disk array and zero back reflection. The hole/disk array functions as a “light funnel” in coupling incident radiation into the cavity with approximately 100 percent efficiency over a narrow resonant bandwidth, resulting in frequency-selective perfect (~100 percent) absorption of the incident radiation. The metallic optical frequency-selective gold hole/disk surface comprises two layers that are optically coupled. The top layer is a perforated sub-wavelength-sized hole array, and the bottom layer is a sub-wavelength-sized disk array aligned underneath the hole array. The arrays together function as a resonant antenna to provide the highly efficient notch filter. Like an antenna, the new detector is tunable as a function of the coupling between the hole/disk by changing the hole/disk dimensions, relief depth, or array spacing.
- Operates uncooled.
- Detection sensitivity in the mid-IR range (~ 8-12µm) is not limited by the blackbody radiation limit.
- Tunable narrow-band wavelength-selectivity has much higher detectivity and faster response time.
- Cheaper to manufacture using simple nanoimprint-based fabrication methods.
- Enables multi-spectral pseudo “color” imaging in the IR domain.
- Space exploration
- Military and civilian defense
- Medical testing and forensic analysis