Photonic design and optimization of thin-film polycrystalline diamond waveguides are shown, serving as advanced evanescent field transducers in the mid-infrared fingerprint regime (2000-909 cm(-1);5-11 mu m). Design c...
详细信息
Photonic design and optimization of thin-film polycrystalline diamond waveguides are shown, serving as advanced evanescent field transducers in the mid-infrared fingerprint regime (2000-909 cm(-1);5-11 mu m). Design constraints inherent to optical/system considerations and the material were implemented in a finite element method (FEM)-based simulation method that allowed three-dimensional modeling of the overall structure. Thus, lateral mode confinement, attenuation in the direction of radiation propagation, and physical resilience were evaluated. In a final step, the designed structures were fabricated, and their utility in combination with a broadly tunable external cavity quantum cascade laser for chemical sensing of a liquid phase analyte was demonstrated.
Recently emerging broadly tunable quantum cascade lasers (tQCL) emitting in the mid-infrared (MIR) are a versatile alternative to well established thermal emitters in combination with interferometers as applied in Fou...
详细信息
Recently emerging broadly tunable quantum cascade lasers (tQCL) emitting in the mid-infrared (MIR) are a versatile alternative to well established thermal emitters in combination with interferometers as applied in Fourier transform infrared (FTIR) spectroscopy. The wide and highly spectrally resolved wavelength tuning characteristics along with superior spectral energy density renders laser-based vibrational spectroscopy methods an efficient alternative vs. conventional molecular spectroscopies. Using diamond in attenuated total reflection (ATR) sensing formats benefits from the physical robustness and chemical resistivity of the internal reflective element (IRE) material. While inherent material absorption frequently limits the optical path length within diamond ATR elements, the herein presented design combining bright tQCLs with a multi-reflection polycrystalline diamond (PCD) ATR element enables an optical beam path length of approximately 5 cm. Thereby, sensitive spectroscopic measurements in the MIR are enabled. As an example, non-invasive glucose monitoring in human saliva is examined, highlighting the potential benefits of the proposed analytical concept with regards to exquisite sensitivity and selectivity in combination with a robust sensing interface, i.e., diamond. This approach paves the way towards directly analyzing molecular constituents in complex and potentially corrosive biomedical and biochemical matrices.
Si 3 N 4 rib optical waveguides suitable for evanescent-wave photonic biosensors are analyzed to derive the conditions for single-mode propagation. A photonic biosensor structure at a wavelength of 0.63 µm based ...
详细信息
Si 3 N 4 rib optical waveguides suitable for evanescent-wave photonic biosensors are analyzed to derive the conditions for single-mode propagation. A photonic biosensor structure at a wavelength of 0.63 µm based on two-mode interference is proposed, and the rib width, rib thickness and rib-core thickness for single-mode and two-mode waveguides (corresponding to sensing region) are proposed to be 3 µm, 2 nm, and 150 nm, and 3 µm, 2 nm, and 340 nm, respectively. The optical characteristics and propagation of each guided-wave mode are investigated utilizing the film-mode-matching and eigenmode-expansion methods.
A technique is proposed for determining which sound field components are weakly sensitive to variations in the parameters of the speed of sound field in a marine waveguide. Such components are formed by narrow ray bea...
详细信息
We report on the design, fabrication and experimental demonstration of single-crystal diamond (SCD) waveguide devices with integrated grating couplers optimized for 850 nm, 635 nm, and 405 nm wavelengths, respectively...
详细信息
We report on the design, fabrication and experimental demonstration of single-crystal diamond (SCD) waveguide devices with integrated grating couplers optimized for 850 nm, 635 nm, and 405 nm wavelengths, respectively. The devices are fabricated on SCD thin films using electron-beam lithography and reactive-ion etching technologies. To reduce the wafer wedge typically present in commercial diamond plates, we introduce a novel tilted-etching technique in the preparation of the thin films. We obtain 60% reduction of the wafer wedge, namely from 300 to 120 nm mm(-1), enabling us to properly fabricate the devices designed for the short to ultra-short wavelengths considered here. Using light in- and out-coupling with 50 mu m core tapered fibers, we measure total (input plus output) grating coupling losses of 20.6 dB and 22.7 dB, and waveguide losses of 11 dB mm(-1)and 20.5 dB mm(-1)for the 850 nm and 635 nm wavelength devices, respectively. The 405 nm wavelength devices, tested with a lensed 9 mu m core input fiber and with the same tapered output fiber as employed for the other devices, also demonstrate light guidance, and feature total grating coupling and waveguide losses on the order of 33.1 dB and 46.7 dB mm(-1), respectively. These results showcase the possibility of down-scaling grating-coupled SCD devices for VIS-UV operation, and pave the way for exploiting diamond's properties on photonic chips at extremely short wavelengths.
In this paper, we proposed a graphene-silicon nitride (GSN) waveguide model, which was unveiled to unveil its second-order dispersion (SOD) characteristics. The influences of the different thicknesses of graphene laye...
详细信息
In this paper, we proposed a graphene-silicon nitride (GSN) waveguide model, which was unveiled to unveil its second-order dispersion (SOD) characteristics. The influences of the different thicknesses of graphene layer and the different heights from graphene to the core material of silicon nitride on SOD were investigated in detail. The tunability of SOD via controlling the bias voltage applied to the graphene layer was demonstrated and a 50 nm wavelength tuning was achieved with a small perturbation in voltage while keeping the geometric structure of the waveguide unchanged. Moreover, a flat SOD curve of the GSN waveguide was obtained with a large bandwidth of 700 nm between the two zero-dispersion wavelengths (ZDWs). These results provided significant insights for potential applications of graphene-related optoelectronic devices, integrated optics, and optical communications.
We show in simulation an ultra-broad continuous four-wave mixing conversion band over an octave span (covering 1.1-2.5 mu m wavelength range) by taking advantage of the high-order phase-matching and the ultra-high eff...
详细信息
ISBN:
(纸本)9781943580576
We show in simulation an ultra-broad continuous four-wave mixing conversion band over an octave span (covering 1.1-2.5 mu m wavelength range) by taking advantage of the high-order phase-matching and the ultra-high effective nonlinearity of AlGaAs-on-insulator waveguides. (C) 2019 The Author(s)
We consider the time-harmonic scattering wave problem in a 2D waveguide at wavenumber k such that one mode is propagating in the far field. In a first step, for a given k, playing with one scattering branch of finite ...
详细信息
We consider the time-harmonic scattering wave problem in a 2D waveguide at wavenumber k such that one mode is propagating in the far field. In a first step, for a given k, playing with one scattering branch of finite length, we demonstrate how to construct geometries with zero transmission. The main novelty in this result is that the symmetry of the geometry is not needed: the proof relies on the unitary structure of the scattering matrix. Then, in a second step, from a waveguide with zero transmission, we show how to build geometries supporting trapped modes associated with eigenvalues embedded in the continuous spectrum. For this second construction, using the augmented scattering matrix and its unitarity, we play both with the geometry and the wavenumber. Finally, the mathematical analysis is supplemented by numerical illustrations of the results.
waveguides in high index contrast GaAs/Oxidized AlGaAs layers directly grown on silicon are presented. These are very similar to waveguides in Si photonics and can be the basis of very high performance photonic integr...
详细信息
ISBN:
(纸本)9781943580576
waveguides in high index contrast GaAs/Oxidized AlGaAs layers directly grown on silicon are presented. These are very similar to waveguides in Si photonics and can be the basis of very high performance photonic integration platform. (C) 2019 The Author(s)
Polarization dependence of second/third-harmonic and supercontinuum generation in silicon-nitride waveguides is mapped from 350-1750 nm. We identify parameters suited for generating coherent signals near 500 and 1000 ...
详细信息
ISBN:
(纸本)9781943580576
Polarization dependence of second/third-harmonic and supercontinuum generation in silicon-nitride waveguides is mapped from 350-1750 nm. We identify parameters suited for generating coherent signals near 500 and 1000 nm for optical clocks, f(CEO) and beatnote detection. (c) 2019 The Author(s)
暂无评论