Learn More
In this paper, we demonstrate that the the bandwidth of the supercontinuum spectrum generated in a large mode area sapphire fiber can be enhanced by employing triple pumping sources. Three pumping sources with wavelengths of 784 nm, 1290 nm, and 2000 nm are launched into a single crystal sapphire fiber that is 5 cm in length and has a core diameter of 115(More)
In this article, we report a new type of fluorescence confocal microscope: frequency division multiplexed multichannel fluorescence confocal microscope, in which we encode the spatial location information into the frequency domain. In this microscope, the exciting laser beam is first split into multiple beams and each beam is modulated at a different(More)
A simple and highly sensitive phase-demodulation technique is proposed, and its use for a fiber Bragg grating strain sensor is experimentally demonstrated. Sampling a phase-modulated Mach-Zehnder output with controlled time delay produced two quadrature data streams that have relative quadrature phase difference (90 degrees ). The Bragg wavelength-dependent(More)
In this paper, we conduct a quantitative study on the physical mechanism of electrons dynamics near the nanostructured metal film surfaces, as well as the efficiency of generated terahertz radiation associated with different types of nanostructures. The simulation results show that although the oscillating motion of emitted electrons outside the metal(More)
Ultra short long-period gratings (LPGs) fabricated using the electric arc discharge method are demonstrated with regular single-mode fibers. The gratings were as short as two periods, which were the shortest LPGs ever reported. The evolution of this short gratings and their characteristics are investigated in this paper. The excellent bending insensitivity(More)
Surface relief gratings are holographically fabricated in thin polybutadiene rubber films produced by both spin coating and dip coating on glass and metal substrates. These thin-film gratings are characterized for their application as efficient transducers for detecting dynamic strain in solids. The performance of these rubber-grating transducers is(More)
A short distance standoff Raman technique is demonstrated for detecting economically motivated adulteration (EMA) in extra virgin olive oil (EVOO). Using a portable Raman spectrometer operating with a 785 nm laser and a 2-in. refracting telescope, adulteration of olive oil with grapeseed oil and canola oil is detected between 1% and 100% at a minimum(More)
Investigation of four-wave mixing 6.4-mum core-diameter fiber with 520-610-nm pump light is used to develop a new technique for characterizing the refractive-index profiles of non-step-index fibers. Deviation from the step-index profile is measured. Small variations in the refractive index between different segments of the same commercial fiber is measured(More)
We introduce a concept of dynamic sensing that uses fiber speckle fields. By autonomously updating the fiber speckle patterns (i.e., using a moving reference to perform frame-to-frame comparison) on an electronically addressable spatial light modulator, we can exploit the dynamic fiber status. In other words, by joint transforming the rapidly changing(More)
The performance of the fiber specklegram sensor (FSS) by use of the waveguide coupled-mode theory is analyzed. The analyses are based on the microbending effect on the sensing fiber, in which we have found that the sensitivity of the FSS is affected by the core diameter and the bending geometry. Experimental confirmations of the analyses are also provided(More)