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A Winston cone is used to concentrate the emitted radiation of a mid-infrared LED onto a small spot on the side of one prong of a quartz tuning fork acting as a detector. The Winston cone is used as an absorption cell as well, thus providing a very compact and cost efficient mid-infrared sensing system.
This paper presents a label free colorometric sensor fabricated by rapidly imprinting silk fibroin thin films with periodic nanoholes. The fabricated sensor is sensitive to index variations of Deltan = 0.007.
We demonstrate sensitive optical readout of the motion of a wavelength-scale mechanical resonator via its scattering within a high-finesse optical cavity. Static calibration, dynamic monitoring and feedback cooling are presented.
A bidirectional single-aperture modulating retroreflector is realized by superimposing a small low-frequency signal on the interrogating beam. Transmitted and received data are frequency-separated, enabling full-duplex operation and autodetection of illumination.
Military operations in the future will involve a variety of nation-state and non-nation-state adversaries. The ability to operate in complex domains will require sophisticated information gathering and exploitation tools. The Air Force Research Laboratory is working on such technologies. This paper highlights a subset of those technologies that operate in the electro-optical domain. The approach to...
We show that with sufficient gain, a mixture of two semiconductor quantum dots can produce an isotropic effective dielectric constant that is lossless and negative. This permits small-scale optical mode volume and lossless waveguides.
We investigate the temperature sensitivity of silicon-based optofluidic photonic crystal double-heterostructure resonators. We systematically study the optical properties of these resonators as function of temperature, specifically demonstrating the potential for creating temperature-insensitive photonic crystal devices.
We demonstrate single-shot optical sampling using a time lens based on four-wave mixing in a silicon nanowaveguide. The eye diagram for an 80-Gb/s data is characterized at 1.3 TS/s sampling rate using a 5-GHz oscilloscope.
We introduce an improved method for standoff chemical detection of films and residues on solid targets which scatter or reflect the incident light using single-beam Coherent anti-Stokes Raman Scattering.
Effects of gas-phase collisions on active optical sensing and use of picosecond laser spectroscopy for their characterization are reviewed. Additionally, novel time-resolved approaches to reduce collisional sensitivity and to exploit species-dependent collision rates are discussed.
We have investigated optical read-out of uncoated polymer micrometer-sized cantilever sensors by self-mixing interference in VCSELs for single-molecule gas sensing. A resolution ~0.2 nm is measured, which is much better than current methods.
Using the excitation of a Bloch Surface Wave (BSW), we demonstrate a 45-fold diffraction enhancement for a protein grating printed on a-SiN:H multilayers. This may lead to a new generation of high sensitivity diffraction-based biosensors.
We present a high-speed, high-resolution, non-mechanical time-domain method for low coherence interferometry, utilizing multiheterodyne detection via two mode-locked femtosecond lasers. Tomographic depth sensing over 150 mm with 5.9 kHz scanning rates and 8 mum depth resolution is demonstrated.
We investigate the use of gratings on porous silicon structures for sensing applications. Examples of two classes of systems are studied: grating-coupled waveguide biosensors, and diffraction-based biosensors.
Direct near-field optical imaging of a bowtie nano-antenna was observed using a UV near field scanning optical microscope. A strong localized UV light spot was observed at the tip of the bowtie structure.
A prototype three-node wireless sensor network of portable, battery-powered spectroscopic trace-gas sensors equipped with custom 24-pass Herriott cells has been developed. Individual sensor performance and sensor network localization of a gas plume will be reported.
A portable sensor for CO2 monitoring based on quartz enhanced photoacoustic spectroscopy (QEPAS) technology and using a DFB diode laser operating at lambda = 1.57 mum will be described. The sensor is primarily intended for studies of CO2 penetration through soil.
We have generated and measured an approximation of an optical Schrodinger cat state by photon subtraction from a squeezed state. Using single-photon avalanche photodiode detectors and photon-number-resolving transition edge sensors, we were able to extract Wigner distributions for one or two photons subtracted from the squeezed state, resulting in both an odd and even cat state. The one-photon-subtracted...
A refractive index sensor was designed as a 1D resonator incorporated in a microfluidic channel, where aqueous solutions were injected. A sensitivity of 480 nm/RIU and a minimum difference of Deltan = 0.002 were determined.
We measure the in-plane electric field above a photonic crystal waveguide with a polarization- and phase-sensitive near-field microscope. We find polarization singularities and study the topology of the surrounding electric field at the nanoscale.
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