Accepted papers to appear in an upcoming issue
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Influence of nonlinear effects on the three-photon excitation of L-Tryptophan in water using phase-shaped pulses
- received 04/01/2014; accepted 06/22/2014; posted 06/24/2014; Doc. ID 209137
- [full text: PDF (571) KB)]
- Abstract: We demonstrate the control of the three-photon excitation of L-Tryptophan in water using a pulse shaping setup. This can lead to selective excitation of amino acids by a near infrared femtosecond laser source. Furthermore we show that additional nonlinear effects like self-phase modulation in the sample have to be considered when using this approach. Simulations of the propagation of the laser pulses in the cuvette exhibit a good agreement to the experimental fluorescence scans at different laser intensities and show large discrepancies when neglecting nonlinear effects prior to the three-photon process.
- (190.7110) Nonlinear optics : Ultrafast nonlinear optics
- (300.2530) Spectroscopy : Fluorescence, laser-induced
- (300.6410) Spectroscopy : Spectroscopy, multiphoton
- (320.5540) Ultrafast optics : Pulse shaping
Analysis of One-Third Harmonic Generation in Waveguides
- received 05/07/2014; accepted 06/22/2014; posted 07/14/2014; Doc. ID 211426
- [full text: PDF (678) KB)]
- Abstract: This paper investigates the one-third harmonic generation (OTHG) by analytical methods with a nondepletion approximation and with an exact solution in continuous wave conditions. Nondepletion method shows that the OTHG with a small initial power is confined in a very small range except that the overlapping integrals of the pump and signal follow certain relation. The efficiency depends only on the initial conditions. Increasing pump power only shortens the interaction length to reach the maximum conversion. Furthermore, we exactly explore the OTHG by the elliptic functions whose expressions depend on the types of the roots derived from the integral and the initial power. We find that the output power level is limited by the initial conditions and the structure of waveguides while the pump power only determines the period. There is a constant value Γ that is determined by U₀, θ₀, and the overlap integrals, where U₀ and θ₀ are the initial power of signal and the initial phase difference between pump and signal, separately. We found that a high efficient conversion only occurs when Γ is larger than a specific value Γc, called as critical value. A Γc provides a relation between U₀ and θ₀. So a set of critical conditions of U₀ and θ₀ is obtained. A high efficient conversion may be supported if U₀ is larger than the power in this set. We investigated some typical structure parameters and find the minimum initial power supporting high conversion efficiency. In OTHG, the variation curve has a sharp peak pattern, which means that a variation of the initial phase difference leads to a great change of the conversion. We established a way to get the smallest initial power with a large phase tolerance. Finally, we find a relation among the overlapping integrals and phase mismatching that can support a high conversion efficiency with a small initial power. This study gives valuable suggestion on the experimental design.
- (190.0190) Nonlinear optics : Nonlinear optics
- (190.2620) Nonlinear optics : Harmonic generation and mixing
Potentials for large optical gain improvement of Erbiumdoped slot waveguide amplifiers in silicon photonics
- received 04/24/2014; accepted 06/21/2014; posted 06/30/2014; Doc. ID 210518
- [full text: PDF (3182) KB)]
- Abstract: The potentials for on-chip optical amplification at =1530 nm in silicon photonics using Erbium-doped rich polymers integrated in silicon slot waveguides are investigated by using a four level spectroscopic model and a pumping wavelength of 1.48μm. It is shown that the key parameter driving the whole amplification efficiency is the slot waveguide linear loss level, while optimization of the hollow core waveguide cross-section leads to a slot width around 130nm. Our investigations show that an on-chip optical gain of about 10dB can be obtained with 7dB/cm loss slot waveguides. Such a propagation loss is directly sustained by experimental results obtained for photonic structures fabricated using silicon technology. Due to the likelihood of improved technological processes in a near future, the slot waveguide loss level was swept in the 3dB/cm-10dB/cm range, showing that on-chip optical gain up to 30dB can be seriously envisaged for slot waveguides with optimized optical losses around 3dB/cm.
- (130.1750) Integrated optics : Components
- (130.3120) Integrated optics : Integrated optics devices
- (230.4480) Optical devices : Optical amplifiers
Three-photon excitation of upconversion random laser in ZnO-on-Si nanostructured films
- received 05/27/2014; accepted 06/20/2014; posted 06/30/2014; Doc. ID 212886
- [full text: PDF (4730) KB)]
- Abstract: We report the first observation of ultraviolet upconversion random laser (RL) emission from ZnO films excited by three near-infrared photons in the femtosecond regime. The nanostructured films of ZnO were fabricated on a silicon substrate using the Plasma Immersion Ion Implantation and Deposition method. The band-to-band excitation process led to RL emission with incoherent feedback, emitting light at ≈ 390 nm. RL emissions excited by one- and two-photons were also verified using the same pump geometry. The results are discussed and a comparison with previous studies is presented.
- (140.3610) Lasers and laser optics : Lasers, ultraviolet
- (140.5960) Lasers and laser optics : Semiconductor lasers
- (160.6000) Materials : Semiconductor materials
- (190.4180) Nonlinear optics : Multiphoton processes
- (290.4210) Scattering : Multiple scattering
Saturation of atomic transitions using sub-wavelength diameter tapered optical fibers in rubidium vapor
- received 03/27/2014; accepted 06/16/2014; posted 07/03/2014; Doc. ID 209013
- [full text: PDF (945) KB)]
- Abstract: We experimentally investigate ultralow-power saturation of the rubidium D₂ transitions using a tapered optical fiber (TOF) suspended in a warm Rb vapor. A direct comparison of nonlinear absorption measurements for the TOF system with those obtained in a standard free-space vapor cell system highlights the differences in saturation behavior for the two systems. The effects of hyperfine pumping in the TOF system are found to be minimized due to the short atomic transit times through the highly confined evanescent optical mode guided by the TOF. The TOF system data is well-fit by a relatively simple empirical absorption model that indicates nanoWatt-level saturation powers.
- (190.4360) Nonlinear optics : Nonlinear optics, devices
- (300.6210) Spectroscopy : Spectroscopy, atomic
- (300.6460) Spectroscopy : Spectroscopy, saturation
- (350.4238) Other areas of optics : Nanophotonics and photonic crystals
Kerr effect in Y-configuration double quantum dot System
- received 03/10/2014; accepted 06/14/2014; posted 06/26/2014; Doc. ID 207814
- [full text: PDF (457) KB)]
- Abstract: We introduce a y- configuration model from double quantum dot QD system, where it is modeled for kerr nonlinearity using the density matrix theory. Inhomogeneity in QDs is included in the calculation of the real part Kerr and imaginary part absorption of the density matrix which is not covered befor inthe earlier kerr calculations. Our system shows high controllability, it shows a giant kerr dispersion , prpagation without distortion, wide electromagnetic induced transparency, and switching between subluminal and superluminal propagation by tuning its fields.
- (190.3270) Nonlinear optics : Kerr effect
- (250.5590) Optoelectronics : Quantum-well, -wire and -dot devices
Elliptic cylindrical pseudo optical black hole for omnidirectional light absorber
- received 03/18/2014; accepted 06/11/2014; posted 06/24/2014; Doc. ID 208133
- [full text: PDF (2606) KB)]
- Abstract: An elliptic cylindrical omni-directional light absorber forming a pseudo optical black hole is studied both analytically and numerically. The conditions for permittivity tensors to trap optical rays are obtained from the semiclassical analysis of the ray optic Hamiltonian. The dispersive finite difference time domain (FDTD) method is used to study the performance of these light absorbing structures numerically. It is found that the largest part of the plane wave’s energy is absorbed at one of the foci of the elliptic cylinder as predicted by the semiclassical theory.
- (160.3918) Materials : Metamaterials
- (080.5692) Geometric optics : Ray trajectories in inhomogeneous media
- (260.2710) Physical optics : Inhomogeneous optical media
Nonlinear interaction of two trapped-mode resonances in a bilayer fish-scale metamaterial
- received 03/03/2014; accepted 06/06/2014; posted 07/21/2014; Doc. ID 207512
- [full text: PDF (850) KB)]
- Abstract: We report on a bistable light transmission through a bilayer "fish-scale" (meander-line) metamaterial. It is demonstrated that an all-optical switching may be achieved nearly the frequency of the high-quality-factor Fano-shaped trapped-mode resonance excitation. The nonlinear interaction of two closely spaced trapped-mode resonances in the bilayer structure composed with a Kerr-type nonlinear dielectric slab is analyzed in both frequency and time domains. It is demonstrated that these two resonances react differently on the applied intense light which leads to destination of a multistable transmission.
- (190.1450) Nonlinear optics : Bistability
- (230.1150) Optical devices : All-optical devices
- (230.4320) Optical devices : Nonlinear optical devices
- (160.3918) Materials : Metamaterials
Light scattering from coupled plasmonic nanospheres on a substrate: Erratum
- received 07/18/2014; accepted ; posted 07/18/2014; Doc. ID 216961
- [full text: PDF (245) KB)]
- Abstract: Below Eq. (1) in Ref , the statement “ is the incident electric field (a three dimensional vector).” should be replaced.
- (120.2130) Instrumentation, measurement, and metrology : Ellipsometry and polarimetry
- (290.5825) Scattering : Scattering theory