Mechanism For Optical Bistability Research Articles

Optical bistability with low intensity threshold (1.83 MW/cm2) in SPPs resonator multilayer nanostructure

A low intensity threshold optical bistability with multilayer nanostructure containing Kerr nonlinear medium has been demonstrated. The mechanism of optical bistability is the light-intensity dependent refractive-index change of the Kerr nonlinear medium inside the multilayer nanostructure, that can be treated as a Fabry–Perot etalon. Significant enhancements of the localized field at corresponding transmission peak are observed with SPP modes resonance excitation. To make the field amplitude more focused on the Kerr nonlinear medium films in the structure, the resonance angles can be amended as needed. So the average field amplitude by a factor of ∼16.1 compared to that of incident beam is predicated in the multilayer nanostructure for the wavelength of 1064nm. Furthermore a very low bistability threshold of 1.83MW/cm2 is obtained.

Formation mechanism of optical bistability in end-pumped quasi-three-level Tm, Ho:YLF lasers

We report on optical bistability and its formation mechanism in an end-pumped quasi-three-level 2 μm Tm,Ho:YLF laser with only a bulk laser crystal. We have experimentally observed that the characteristic output versus input curve is not linear and shows bistability when the laser crystal is singly end pumped by a 792 nm laser diode. The width of the bistable region is 1.6 W and the jump power at the turning point is 82.5 mW. However, the laser shows linear output when the laser crystal is dual end pumped. The formation mechanism of optical bistability is explained by solving coupled rate equations in which energy transfer upconversion and ground-state reabsorption are considered.

Diode-end-pumped optical bistability laser with a bulk Tm,Ho:YLF crystal as gain medium and saturable absorber

We demonstrate strong optical bistability in a 2 μm continuous wave Tm,Ho:YLF laser at 253 K. The laser is end-pumped by a 792 nm fiber coupled laser diode. The width of the bistable region is 1.6 W and the jump power at the turning point is 82.5 mW. The quasi-three-level rate equations of bistable Tm,Ho:YLF laser are given under considering energy transfer upconversion and the nonlinear saturation of the ground state reabsorption effect that varies depending on whether the laser is on or off. The optical bistable performance of the Tm,Ho:YLF laser is numerically investigated by solving the coupled rate equations. The theoretical result provides a good description of the experimental results. The theoretical result shows the mechanism of optical bistability in Tm,Ho:YLF lasers is mainly due to the nonlinear saturation of the ground state reabsorption; furthermore, the energy transfer upconversion and excited state absorption have important influences on the optical bistability.

Theory of optical bistability in a non-linear quasi-waveguide

Optical bistable behavior in a quasi-waveguide containing non-linear film has been experimentally investigated in several publications in the past years; however, the physical mechanism for optical bistability has not been theoretically explained. In the present letter, we propose a theoretical model and successfully explain the observed optical bistability of both the reflected light and the scattered light (m-lines) in a non-linear quasi-waveguide. The optical bistability in the non-linear quasi-waveguide is due to the scattering-type wavevector mismatch mechanism.

On the possibility of detecting the relaxation optical bistability in an extended medium

The possibility for efficient detection of wave phenomena in an optically extended semiconductor in the case of development of instability in a system with the relaxation mechanism of optical bistability was studied. It is shown that the use of two-wave action allows the development of processes in the bulk of the semiconductor to be detected with the help of probing radiation. The influence of diffusion and thermal conductivity on the characteristics of wave processes in a semiconductor and the possibility of realizing the detection are revealed.

Dielectric superlattices for nonlinear optical effects

Dielectric superlattices show a lot of new phenomena that are promising in applications, such as nonlinear optical frequency conversion and optical bistability. This paper reviews the main achievements in this field. Much has been focused on the work done in our Lab. Since 1980, we have extended the concept of superlattice from semiconductor to dielectrics. When quasi-phase-matching technique is introduced into a quasiperiodic dielectric superlattice, more interesting phenomena can occur. For example, multiwavelength second-harmonic generation and coupled parametric processes such as direct third-harmonic generation have been realized with high efficiency. A new mechanism for optical bistability in a 2-dimensional dielectric superlattice, i.e. a 2-dimensional nonlinear photonic crystal, has been proposed theoretically had proved experimentally.

Optical bistability in a nonlinear-linear interface with two-wave mixing

We introduce a new mechanism for optical bistability at an interface between nonlinear (Kerr or photorefractive) and linear media for a light wave that propagates from the nonlinear side near the critical angle. The origin for this effect is the nonlinear coupling between the incident and reflected (from the interface) waves. We derive the laws of reflectivity and transmissivity and find a bistable behavior as a function of the incident power or the angle.

Analysis of optical bistability through rapid water desorption from hard coatings

The mechanism of optical bistability in TiO2/SiO2 nonlinear interference filters is investigated and found to be due to water sorption in the pores of the material.

A new mechanism of optical bistability

A new mechanism is suggested to obtain optical bistability (OB) in bulky semiconductors near the two-phonon biexciton resonance.

Optical bistability by photothermal displacement in prism coupling into planar waveguides

We have identified photothermal displacement as a mechanism for optical bistability (OB) in prism coupling into absorbing planar waveguides: heating by the absorbed incoupled power causes a buckling of the waveguide, a reduction in air-gap width, and thus an increase in incoupling efficiency and a positive feedback. We developed a theory of this OB that qualitatively agrees well with experimental results obtained by coupling argon-laser light into indium-tin oxide layers as strongly absorbing waveguides. This new OB is quite different from dispersive OB in prism or grating couplers caused by a power-dependent effective guide index.