Eric W. VanStryland

Coherent interactions for all-optical signal processing via quadratic nonlinearities

Based on processes involving the cascading of two successive second-order nonlinear interactions, we show how novel, all-optical approaches to signal processing can be exploited by coherent interactions between three waves in noncentrosymmetric materials. Specifically, we emphasize the coherent seeding of the second-harmonic generation process with waves at one of the participating frequencies. >

ALL-OPTICAL MODULATION VIA NONLINEAR CASCADING IN TYPE II SECOND-HARMONIC GENERATION

Utilizing a type II interaction for second‐harmonic generation in a crystal of potassium titanyl phosphate, we experimentally demonstrate the all‐optical action of a light modulator with both signal and output at the same optical wavelength. This modulator is controlled by the intensity of the injected signal, a characteristic that makes it a suitable candidate for all‐optical transistor action and ultrafast analog processing in transparent networks for telecommunications.

Cascaded second-order effects in N-(4-nitrophenyl)-L-prolinol, in a molecular single crystal

An investigation of cascaded second-order optical effects resulting in effective third-order interactions, temporal and spatial self-action, are presented for N-(4-nitrophenyl)-l-prolinol (NPP) a molecular single crystal with one of the largest phase-matchable second-order nonlinear coefficients known in the visible and near-infrared portions of the spectrum. We emphasize the effects of temporal and spatial walk-off in the nonlinear-optical propagation in NPP and discuss their consequences for cascaded second-order nonlinear applications. Walk-off effects play a detrimental role in cascaded all-optical switching. Whereas in standard second-harmonic generation walk-off reduces the efficiency but does not prevent the generation, in the case of cascading backconversation is required and more-deleterious effects occur: a portion of the field is lost in that the overlap between fundamental and second-harmonic wavelengths is reduced.

Frequency doubling of femtosecond pulses in walk-off-compensated N-(4-nitrophenyl)-L-prolinol.

We show how to exploit the high quadratic nonlinear coefficient of the organic crystal N-(4-nitrophenyl)-L-prolinol for generation and parametric mixing of ultrashort pulses by use of tilted-pulse techniques. The effective crystal length for subpicosecond operation is shown to be enhanced from tens of micrometers to tens of millimeters. Efficient frequency doubling of 100-fs pulses is predicted in walk-off-compensated geometries with peak intensities of a few megawatts per square centimeter.

Polarization dependent four-wave-mixing and two-photon coherence in solids

Polarization dependent degenerate-four-wave-mixing experiments on semiconductors (ZnSe, CdS) and dielectrics (NaCl, PbF/sub 2/) reveal the essential mechanisms of the bound-electronic /spl chi//sup (3)/. We show, for the first time, that the observed anomalous dispersion of the polarization dependent phase-conjugate reflectivity can be explained using a simple 3-band model. The near vanishing reflectivity in the two-photon coherence geometry is shown to be a consequence of the interference between transitions originating from heavyand light-hole valence bands. We also present measurements on the polarization dichroism of the nonlinear refractive index (n/sub 2/), in good agreement with this simple theory. >

Nonlinear refraction and absorption in highly transmissive one-dimensional metal-organic photonic bandgap structures

We report on the optical properties of a metal-organic photonic bandgap structure showing a peak transmission ~44% and that enhances the nonlinear optical properties of bulk Copper by up to an order of magnitude.

Influence Of Self-Focusing On Bulk Laser-Induced Damage

In previous work [1] we reported that the power of importance in self-focusing experiments using Gaussian spatial profile is the second critical power, P2, defined by P2=3.77 P1 rather than the often quoted P1=Cλ2/(32π22). Here n2 is the nonlinear refractive index, c the speed of light and A the wavelength (both in vacuum). The factor of 3.77 is a numerical factor coming from computer calculations as discussed by Marburger [2]. We also presented a method by which we could obtain n2 at irradiances very near to damage In addition, we showed the experimental conditions under which self-focusing is unimportant in damage experiments. We have now extended these results so that in damage experiments where self-focusing is important we can estimate the reduced spot size within the bulk at damage and, thus, obtain the damaging electric field magnitude. This we do by observing the far field time integrated spatial irradiance distribution. We present data for Si02, NaCl, BK-7, and CS2.