Efficient Light Modulation Research Articles

Hydrated Transition Metal Oxide Films for Reversible Switching in Near IR Region

AbstractElectro-optical properties of thin films of hydrated transition metal oxides, WO3 2(H2O) and WO3 1/3(H2O), have been investigated in situ using photoelectrochemical methods. These films can reversibly change their light absorption in the near IR region due to the double charge injection upon the applied electric field in electrolyte media. Taking into account the high stability and fast switching time, these hydrated tungsten oxide films can be utilized for efficient light modulation in the near infrared region of the spectrum.

Impulsive stimulated Brillouin scattering in KD<inf>2</inf>PO<inf>4</inf>near the structural phase transition

Impulsive stimulated Brillouin scattering is used to characterize anomalous and highly dispersive acoustic behavior, including heavily overdamped acoustic motion, in KD 2 PO 4 crystals near the structural phase transition temperature T c . Photoelastic and electrooptic effects are observed to diverge near T c , suggesting applications in efficient light modulation and switching.

Multi-Functional Electrooptic Device with Feedback

The theoretical and experimental examination of an electrooptic device with feedback are discussed in the paper. It is shown that many functions such as multistability, hysteresis, differential gain and limiter action are possible, on the characteristics of the optical output power versus input power, depending on the feedback gain and phase retardation. The examination of the dependence of the optical output power on phase retardation indicates that more efficient light modulation and switching may be achieved by using this device than by using the conventional light modulator. In addition, hysteresis was observed in the relation between optical output power versus phase retardation at the higher input range.

Focusing of microwave acoustic beams: Cohen, M.G. and Gordon, E.I. Journal of applied physics, 38, no. 5, p. 2340 (1967)

A description is given of an experimental study, using Bragg scattering, of the properties of cylindrically‐focused longitudinal‐wave acoustic beams in fused quartz in the frequency range 200–425 Mc/sec. The results are analyzed and shown to be in good agreement with Fresnel diffraction theory indicating, as expected, that elastic waves at ultrasonic frequencies, because of the extremely short wavelengths involved, propagate as coherent, unguided beams. This allows fabrication of simple focusing elements and makes available efficient light modulation structures as well as techniques for studying the properties of acoustic transducers.

Focusing of Microwave Acoustic Beams

A description is given of an experimental study, using Bragg scattering, of the properties of cylindrically-focused longitudinal-wave acoustic beams in fused quartz in the frequency range 200–425 Mc/sec. The results are analyzed and shown to be in good agreement with Fresnel diffraction theory indicating, as expected, that elastic waves at ultrasonic frequencies, because of the extremely short wavelengths involved, propagate as coherent, unguided beams. This allows fabrication of simple focusing elements and makes available efficient light modulation structures as well as techniques for studying the properties of acoustic transducers.