Ryan M Gelfand

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We present a new structure that combines a metal-dielectric-metal sandwich with a periodic structure to form a plasmon polariton photonic crystal. Three-dimensional finite-difference time-domain simulations show a clear bandgap in the terahertz regime. We exploited this property by adding a defect to the crystal, which produces a cavity with a quality(More)
—Exploiting optical nano-antennas to boost the near-field confinement within a small volume can increase the limit of molecular detection by an order of magnitude. We present a novel antenna design based on Au–SiO 2 –Au single nanorod integrated on the facet of a quantum cascade laser operating in the midinfrared region of the optical spectrum.(More)
Optical nanoantennas are capable of enhancing the near-field intensity and confining optical energy within a small spot size. We report a novel metal-dielectric-metal coupled-nanorods antenna integrated on the facet of a quantum-cascade laser. Finite-difference time-domain simulations showed that, for dielectric thicknesses in the range from 10 to 30 nm,(More)
We report on the signal-to-noise performance of a nanoinjection imager, which is based on a short-wave IR InGaAs/GaAsSb/InP detector with an internal avalanche-free amplification mechanism. Test pixels in the imager show responsivity values reaching 250 A/W at 1550 nm, -75 degrees C, and 1.5V due to an internal charge amplification mechanism in the(More)
We present spatial mapping of optical force generated near the hot spot of a metal-dielectric-metal bowtie nanoantenna at a wavelength of 1550 nm. Maxwell's stress tensor method has been used to simulate the optical force and it agrees well with the experimental data. This method could potentially produce field intensity and optical force mapping(More)
We report on a novel nanoinjection-based shortwave infrared imager, which consists of InGaAs/GaAsSb/InAlAs/InP-based nanoinjection detectors with internal gain. The imager is 320Â256 pixels with a 30-m pixel pitch. The test pixels show responsivity values in excess of 2500 A/W, indicating generation of more than 2000 electrons/photon with high quantum(More)
We report a type of infrared switchable plasmonic quantum cascade laser, in which far field light in the midwave infrared (MWIR, 6.1 μm) is modulated by a near field interaction of light in the telecommunications wavelength (1.55 μm). To achieve this all-optical switch, we used cross-polarized bowtie antennas and a centrally located germanium nanoslab. The(More)
An apertureless near-field scanning optical microscope (a-NSOM) setup is described. Special consideration is given to important system components. Surface plasmons are defined, as is their relationship to a-NSOM and their interaction with the scanning probe tip. We used this setup to measure a metal-dielectric-metal (MDM) antenna integrated with a quantum(More)
Surface plasmons (SPs) can be generated at the interface between two materials having opposite signs of dielectric susceptibility. [ 1 ] This principle has recently been exploited in many applications, ranging from enhanced optical transmission (EOT), [ 2 ] which can be used for enhanced photodetec-tion, [ 3 ] biosensing, [ 4 ] optical trapping of small(More)
Many important bio and chemical molecules have their signature frequency (vibrational resonance) matching the mid infrared region (2-10 μm) of the optical spectrum. But building a bio-sensor, sensitive in this spectral regime, is extremely challenging task. It is because of the weak light-particle interaction strength due to huge dimensional mismatch(More)