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We investigate propagation of a transverse magnetic field through a nonlinear metamaterial slab of subwavelength thickness and with a very small and negative linear dielectric permittivity. We prove that, for a given input intensity, the output intensity is a multivalued function of the field incidence angle so that the transmissivity exhibits angular multistability and a pronounced directional hysteresis behavior. The predicted directional hysteresis is a consequence of the fact that the linear and nonlinear contributions to the overall dielectric response can be comparable so that the electromagnetic matching conditions at the output slab boundary allow more than one field configuration within the slab to be compatible with the transmitted field.

Transverse instabilities are shown to accompany counterpropagation of optical beams through reflection gratings in Kerr media. The instability threshold of continuous waves is analytically derived, and it is shown that the presence of the grating broadens and narrows the stability region of plane waves in focusing and defocusing media, respectively. Furthermore, counterpropagating soliton stability is numerically investigated and compared with the transverse modulation instability analysis, revealing an underlying physical link.

We investigate (1+1D) spatial optical solitons embedded in a fixed-volume grating in centrosymmetric photorefractive crystals. We numerically identify a two-parameter soliton family and deduce both its existence surface and soliton profiles. For shallow gratings, the soliton Fourier spectrum exhibits three lobes located at the reciprocal lattice points −K, 0, and K. Soliton trapping is a consequence of both the self-induced nonlinear waveguide and the grating reflectivity, which prevents the breakaway of the lateral components. To provide a preliminary evaluation of soliton stability, we also investigate the propagation of slightly perturbed soliton profiles.

We analytically predict the existence of both spatial bright and dark counterpropagating solitons in a reflection grating in the presence of the Kerr nonlinearity. The basic trapping mechanism consists of a twofold balance where diffraction is compensated by self-focusing and reflection is altered by the nonlinear-induced interferometric grating. We find that, whenever the spectral soliton profile lies within the grating stop band, bright and dark solitons exist only if the mutual phase of the counterpropagating solitons is π or 0, respectively.

We demonstrate electro-optic spatial two-dimensional mode switching in a bulk sample of potassium lithium tantalate niobate. Spatial confinement, mode coupling, and electro-optic functionality are mediated by two photorefractive needle solitons of opposite electroholographic charges embedded together in their anisotropic lobular structure.

A novel interferometric configuration has been used as an efficient, narrow-band output coupler for high-power lasers. Its application to a TEA CO_2 laser has resulted in extremely reliable (100%) single transverse- and longitudinal-mode operation of this laser with a fine-frequency tunability of up to 3 GHz.

We present a novel electro-optic configuration that is capable of switching unpolarized light with high efficiency. Its application as the output coupler of a high-repetition-rate, Q-switched (up to 50 kHz), cavity-dumped high-power cw Nd:YAG laser is reported.

The effect of dispersive elements, such as intracavity étalons and multipass interferometric output couplers, on the mode separation of a resonator has been studied. We demonstrate, both theoretically and experimentally in a TEA CO_2 laser, that the separation of the two adjacent longitudinal modes closest to the interferometer reflection peak is strongly reduced when a high-finesse interferometer is used as an output coupler. This effect must be taken into account in the design of single-mode lasers.

The effect of optical cavity length perturbations on the intrapulse frequency stability of laser cavities terminating in reflective multipass interferometers is investigated. We demonstrate both theoretically and experimentally, in a long-pulse single-mode TEA CO_2 laser, that intrapulse frequency chirping can be strongly reduced by using relatively long high-finesse interferometers. These results can be applied to the design of single-mode lasers with negligible chirping.

A novel multipass grating interferometer is presented that is capable of operating as an efficient, very-narrow-band output coupler for high-power, large-bandwidth lasers. Its application for tunable (up to 3.5 GHz), single-mode operation of a TEA CO_2 laser is discussed.