Charge transport-assisted optical nonlinear effects in cadmium telluride and related II-VI compounds: Materials and devices

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:7243460

Ziari, M

The optical nonlinear effects that result from electrooptic index perturbations which are induced by space-charge fields that result from photocharge separation respond to low intensity levels. The photorefractive two-beam coupling, absorption and photoluminescence spectroscopy measurements in vanadium-doped cadmium-telluride reveals that photorefractive carriers are electrons that are excited from vanadium's V[sup 2+] ground level at 0.78 eV below the conduction-band. Measurements at 1.5 [mu]m wavelength confirm the theoretically expected high photorefractive sensitivity of CdTe. Application of nominally square ac field enhances the beam-coupling gain coefficient at 1.3 [mu]m to values at high as 10 cm[sup [minus]1]. The gain coefficient is influenced by pulse shape, beam ratio and field-screening. Optimum ac period needs to be shorter than the dielectric-relaxation time which is orders of magnitude shorter than the dielectric-relaxation time which is orders of magnitude shorter that the photorefractive response time. The author has observed two-wave mixing in vanadium-doped zinc-telluride at wavelengths from 0.6 to 1.3 [mu]m. Photorefractive effect in cadmium-zinc-telluride ternary alloy with 4% and 10% zinc content was also determined. The author studied the interelectrode electric field distribution in indium-doped CdTe. Below bandgap extrinsicly absorbed light light results in accumulation of the applied voltage across a narrow region under the negative electrode. The resulting high electric fields which have a charge-transport origin are used in various optical switching devices. The field-screening effect in CdTe:In is a versatile nonlinearity which the author has used for optical-limiting and various forms of optical neuron devices.

• Research Organization: Univ. of Southern California, Los Angeles, CA (United States)
• OSTI ID: 7243460
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CADMIUM TELLURIDES
CHARGE TRANSPORT
OPTICAL PROPERTIES
ZINC TELLURIDES
DOPED MATERIALS
ELECTRO-OPTICAL EFFECTS
FREQUENCY MIXING
NONLINEAR OPTICS
PHOTOLUMINESCENCE
REFRACTIVITY
VANADIUM IONS
CADMIUM COMPOUNDS
CHALCOGENIDES
CHARGED PARTICLES
IONS
LUMINESCENCE
MATERIALS
OPTICS
PHYSICAL PROPERTIES
TELLURIDES
TELLURIUM COMPOUNDS
ZINC COMPOUNDS
360606* - Other Materials- Physical Properties- (1992-)