Antenna-Enhanced Infrared Sensors and Emitters

Hooman Mohseni* Bio-inspired Sensors and Optoelectronics Lab (BISOL), EECS Department,

Northwestern University, Evanston, IL 60208

BIOGRAPHY Hooman Mohseni: Received his Ph.D. degree in Electrical Engineering from Northwestern University. He joined Sarnoff Corporation in 2001, where he was a technology leader for several government, domestic, and international commercial projects. He joined Northwestern University in 2004 as a faculty member. He is a recipient of National Science Foundation’s CAREER Award in 2006, and Young Faculty Award from Defense Advanced Project Agency (DARPA) in 2007. He was selected by NSF as a US delegates in US-Japan Young Scientist Exchange Program on Nanotechnology in 2006, and US-Korea Nano-manufacturing Exchange program in 2007. He has served as the Advisory Board, Program Chair and Co-chair in several major conferences including IEEE Photonics, SPIE Optics and Photonics, and SPIE Security and Defense. Dr. Mohseni has published over 110 peer-reviewed articles, and holds 13 issued US and International patents on novel optoelectronic devices and nanoprocessing. He has presented more than 42 invited and keynote talks at different commercial, government, and educational institutes. He is a Fellow of SPIE, and Senior Member of IEEE.

TECHNICAL ABSTRACT

Novel devices based on optical antenna have attracted a lot of attention recently. We present our new findings regarding several different devices, all of which benefit from optical antenna in the infrared range. In particular, we are interested in producing plasmonic modes with very large momentum, and strongly couple them to free-space photons with minimum loss. These structures become intermediate moderators to transfer energy from photons to electrons within extremely short (nanometer) distances. For example, we demonstrate highly efficient and yet very thin far-infrared detectors. The overall measured photon-to-electron conversion efficiency is more than 42% for a device than is 16 times thinner than the wavelength of illumination at 8 μm. This is about two orders of magnitude better than devices without the optical antenna. In a different device, we show a very large optical pressure that is about three orders of magnitude larger than the radiation pressure of free-propagating photons. The measured pressure magnitude and distribution shows a good agreement with our theoretical calculations. As another example, we will show a type of infrared switchable plasmonic quantum cascade laser, in which far field light in the mid-wave infrared (MWIR, 6.1 μm) is modulated by a near field interaction of light in the telecommunications wavelength (1.55 μm), a viable method to modulate the far field of a laser through a near field interaction.

Keywords: optical antenna, quantum cascade laser, plasmonics, infrared detectors, optical force.

*email: hmohseni@northwestern.edu ; phone: +1 847-491-7108

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Figure 1 – (Left) Device schematic including position of field monitor used for reflected field. (Right) Scanning electron micrograph (SEM) of the completed device.

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Wavelength (nm) Figure 2 – Experimental measured and theoretical calculated signal at 6.1 μm versus the 1.55 μm laser power density (A), polarization (B), and wavelength (C). The measured signal difference at 6.1 μm, with and without the 1.55 μm laser. All measurements are at room temperature.