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A tunable hollow waveguide with distributed Bragg reflector (DBR) mirror and a high-index-contrast-grating (HCG) mirror has been proposed. We numerically show the possibility of 2D-confinement and reduction in polarization-dependence of the proposed hollow waveguide.
We report helicoidal long-period grating by twisting photonic crystal fiber under CO2 laser irradiation and investigated its novel characteristics. The fabricated PCF-LPG endows unique resonance tuning capability with low polarization-dependent loss and thermal shift.
A blazed grating is used for the separation of single photons from photon pairs. The Fraunhofer far field of the two-photon rate depends on the spatial correlation strength of the photons and enables correlation characterizations.
In this paper, cascading plasmonic gratings were investigated. The angle dependent reflection spectrum of the proposed structure displays a resonance peak at a specific angle. The FWHM of the resonant peak is smaller than 2deg. The angular dispersion of the cascading plasmonic gratings is about dthetas/dlambda=0.15deg/nm. The cascading plasmonic gratings can be used as a spatial filter which can improve...
We implement in plane launching and focusing surface plasmons by fabricating Fresnel zone-plate like grating on a thin gold film. A subwavelength focal spot, with transverse FWHM=712 nm, is observed at 830 nm vacuum wavelength.
In this work we show how the spectral properties of the pump are transferred to signal and idler in a mirrorless optical parametric oscillator and that the idler properties strongly depend on the grating vector.
A novel ultra-low loss single-mode hollow-core waveguide using high-contrast grating (HCG) is proposed and simulated. The loss can be as low as 0.006 dB/m, three orders of magnitude lower than the state-of-art chip-scale waveguides.
The effect of dispersion of the excitation pulse in two-photon microscopy is examined with a photon-counting microscope in both stationary and scanning modalities, and it is demonstrated that transform-limited pulses provide the best signal yield despite increased bleaching rates.
A 65-nm quasi-continuous tuning range is reported for a 3.5-mm-wide optically pumped type-II chirped-grating distributed-feedback laser at 3.2 mum. Methane absorption spectra demonstrate the utility of this source for atmospheric-pressure molecular spectroscopy.
We report pronounced light-induced change of the optical activity at terahertz frequency in metal chiral gratings on semiconductor substrates. This result opens new horizons in the active terahertz polarization control.
The fabrication of a reduced phase error, distributed feedback fiber laser in erbium-doped fiber is presented. Using the Trace Grating technique, the overall phase error has been reduced by a factor of 2.5.
We have generated the backward terahertz pulses with record-high average powers of 2.3-11 muW and narrowest bandwidth of 6 GHz from multi-grating periodically-poled lithium niobate by optical rectification at room temperature.
We present for the first time measurement of the dynamic SMSR during fast laser channel transitions. A highly sensitive heterodyne method is employed in order to achieve signal to noise ratios in excess of 60 dB.
We introduce novel method of precise compressor alignment for Petawatt-scale CPA lasers. The method is using compressor gratings as gratings of diffraction interferometer. It meets accuracy requirements (~10-5) and allows simple procedures of alignment.
Mid-infrared beam shaping is demonstrated by using grating coupled surface emitting quantum cascade ring lasers. The devices allow for far-field tuning, ranging from highly symmetric spot-to ring-shaped beam patterns, depending on the grating period.
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 demonstrate an Er doped fiber laser line source whose output coupler is a 9 cm, 45deg tilted fiber grating. Our approach shows potential for improved efficiency and simplicity over previously described line sources.
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.
We propose a technique for sub-diffractional focusing in the far field of optical elements. The method combines subwavelength analogs of Fresnel lenses and planar anisotropic metamaterials, used to generate and propagate sub-diffractional information, respectively.
We show the effects of shrinking the high contrast grating size on a wavelength-tunable VCSEL experimentally and theoretically. With a grating having only 4 periods, we demonstrate the fastest tunable VCSEL with speed >25 MHz.
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