Accepted papers to appear in an upcoming issue
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Dressed Four Four-Wave Mixing and Multi-Order Fluorescence Signals
- received 09/16/2014; accepted 10/27/2014; posted 11/20/2014; Doc. ID 223105
- [full text: PDF (832) KB)]
- Abstract: We mainly investigate four generated four-wave-mixing (FWM) signals, second- and fourth-order fluorescence (FL) signals simultaneously in a cascade three-level atomic system of sodium. The moving and immobile two-photon dressing effects on four FWM signals and multi-order FL, which exist in two coexisting electromagnetically induced transparency (EIT) windows, as well as the interaction of dressing effects are studied. Furthermore, we experimentally observe and theoretically investigate the spontaneous parametric FWM (SP-FWM) signal and spatial images of the probe transmission signal modulated by cross-Kerr nonlinearities effect of dressing field.
- (190.4380) Nonlinear optics : Nonlinear optics, four-wave mixing
- (260.2510) Physical optics : Fluorescence
- (270.1670) Quantum optics : Coherent optical effects
Multiplexing acousto-optic modulators to steer polychromatic laser beams
- received 08/01/2014; accepted 10/26/2014; posted 11/14/2014; Doc. ID 220248
- [full text: PDF (1131) KB)]
- Abstract: We demonstrate that two copropagating laser beams at different wavelengths may be deflected through the same angle by a conventional acousto-optic modulator driven with multi-tone RF signals. The beams are effectively decoupled, permitting the modulation of one beam without affecting the other. To demonstrate the multiplexing technique, we modulate an ultrafast pulsed laser that copropagates with an un-modulated continuous wave laser in order to perform lock-in detection of weak four-wave mixing signals while simultaneously implementing active interferometric stabilization. Multiplexed acousto-optic modulation permits a broad range of polychromatic laser applications.
- (120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
- (300.6240) Spectroscopy : Spectroscopy, coherent transient
- (300.6310) Spectroscopy : Spectroscopy, heterodyne
- (300.6380) Spectroscopy : Spectroscopy, modulation
- (300.6530) Spectroscopy : Spectroscopy, ultrafast
- (140.3298) Lasers and laser optics : Laser beam combining
Modulation instability in the oppositely directed coupler with a quadratic nonlinearity
- received 06/12/2014; accepted 10/08/2014; posted 10/08/2014; Doc. ID 214006
- [full text: PDF (1516) KB)]
- Abstract: We investigate modulation instability (MI) in nonlinear oppositely directed coupler with a quadratic nonlinearity, where one channel is made from an ordinary positive-index material (PIM) and another channel is fabricated from a negative-index material (NIM), trying to identify the different MI properties from those in conventional parametric gap system with grating. Both the analytic continuous wave (CW) solutions and dispersion relation are obtained. By using standard linear instability we in detail discuss how the ratio of the backward to forward propagating wave’s power, the phase mismatch and the ratio of coupled coefficient influence on the dynamical behavior of MI. Large stable regions are found if the fundamental harmonics (FH) falls in the normal dispersion, when compared to the case in the conventional Bragg grating with a quadratic nonlinearity where the CW solutions are unstable in most cases. In addition, we also observe the large stable regimes of the CW solutions even when the coupled strength for the second harmonics (SH) weaker than that of the FH. These ﬁndings suggest that the oppositely directed coupler with a NIM channel provides more ways to manipulate MI and soliton.
- (190.0190) Nonlinear optics : Nonlinear optics
- (190.3100) Nonlinear optics : Instabilities and chaos
- (160.3918) Materials : Metamaterials
Cooperative plasmon-mediated effects and loss compensation by gain dyes near a metal nanoparticle
- received 08/13/2014; accepted 09/23/2014; posted 11/04/2014; Doc. ID 220628
- [full text: PDF (424) KB)]
- Abstract: We here present the first unified theory of the response of plasmonic nanoshells assisted by optical gain media, in the case of a nanoshell coated with a layer of optically active dipolar dyes. We obtain the optical coherent response of the core-shell aggregate in terms of its equivalent polarizability composed of the direct response from the nanoshell and the contribution raising from the cooperative coupling between dyes and surface plasmon of nanoshell. We identify mechanism of superradiance-like plasmonic aggregate emission similar to conventional Dicke effect with reduced intraband relaxation bandwidth due to the loss compensation in the system. The analysis of the aggregate resonances based on the system eigenvalues provides a physical insight into the total loss compensation mechanism and resonance frequency shifts.
- (160.4760) Materials : Optical properties
- (160.4236) Materials : Nanomaterials
- (250.5403) Optoelectronics : Plasmonics