摘要:

Optical transmission studies have been performed on ZnSe thin films and two (Zn,Mn)Se superlattices (Eg&bartil;2.8 eV) of varying barrier compositions and well widths grown by molecular beam epitaxy. The excitons in these samples ranged in character from three dimensional to quasi two dimensional. The spectra, obtained at 77 K as a function of incident light intensity, clearly show the saturation of the excitonic resonance. This is the first demonstration of nonlinear excitonic absorption in the (Zn,Mn)Se system. Mechanisms for the saturation are discussed with estimates for the relative contributions from Coulombic screening and phase space filling.

ISSN:0003-6951    

DOI:10.1063/1.96866

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We obtained for the first time efficient room‐temperature cw lasing at 2.086 &mgr;m in Cr,Tm,Ho:YScAl‐garnet and Cr,Tm,Ho:YScGa‐garnet crystals. Double cross pumping via Cr3+and Tm3+with a krypton pump laser yields threshold pump powers of 25 mW and slope efficiencies up to 13%. Broad band pumping can also be expected.

ISSN:0003-6951    

DOI:10.1063/1.96867

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

High peak power subpicosecond optical pulses have been generated by parametric amplification of a white‐light femtosecond continuum in a new organic crystal,N‐(4‐nitrophenyl)‐L‐prolinol or (NPP), with an emission spectrum extending in the 1.0–1.6 &mgr;m range.

ISSN:0003-6951    

DOI:10.1063/1.96868

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A photorefractive oscillation between two cascaded passive phase conjugate mirrors (2C‐PPCM) with intracavity phase and amplitude modulation and multimode fibers is described. The two semilinear PPCM’s operate via four wave mixing in BaTiO3crystals. A single beam pumps only one PPCM and generates all other self‐starting beams of the two PPCM’s

ISSN:0003-6951    

DOI:10.1063/1.96869

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The dependence of brightness on the concentration ratio of fluorine to terbium was studied in thin‐film electroluminescent devices with rf‐sputtered ZnS:Tb,F active layers. It was found that the device exhibits a maximum brightness at the concentration ratio of about 1. By optimizing not only the concentration ratio but also the terbium concentration, a brightness more than 300 fL is obtained under 1 kHz pulse excitation.

ISSN:0003-6951    

DOI:10.1063/1.96870

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The fabrication and performance characteristics of a InGaAsP laser structure with semi‐insulating current confining layers are reported. The semi‐insulating layers are Fe‐doped InP and are grown using the metalorganic chemical vapor deposition growth technique. The lasers have threshold currents in the range 20–30 mA and external differential quantum efficiency ∼0.2 mW/mA/facet at 30 °C. The bandwidth for small‐signal response is ∼2 GHz which suggests that the laser structure is suitable for high bit rate lightwave transmission systems. Initial aging results yield an estimated operating lifetime of 10 years at 20 °C.

ISSN:0003-6951    

DOI:10.1063/1.96871

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

High efficiency x‐ray preionized discharge XeCl laser excitation has been achieved by combining spiker/sustainer excitation techniques with a simple and reliable magnetic isolator. The troublesome rail‐gap switch has been eliminated by using the laser discharge itself as the switch. An efficiency of 4% with 2.7 J optical energy was demonstrated.

ISSN:0003-6951    

DOI:10.1063/1.96872

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A back projection (acoustic holography) algorithm has been developed and implemented on a computer‐controlled scanning laser acoustic microscope. The algorithm permits the reconstruction of clear well‐defined images of acoustic features which are far below (by tens of acoustic wavelengths) the laser‐scanned surface of the substrate. In essence, the algorithm corrects for the diffraction of the incident acoustic beam caused by the feature being insonified. Experimental results obtained using an electron microscope locator grid as the test feature and a compressional wave source of 100 MHz are presented.

ISSN:0003-6951    

DOI:10.1063/1.96873

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We report for the first time results for acousto‐optic interaction in proton‐exchange waveguides inY‐LiNbO3. The value of acousto‐optic diffraction efficiency was as high as 72% for an electrical input power of 540 mW at 425 MHz.

ISSN:0003-6951    

DOI:10.1063/1.96874

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We investigate the edge effect on foil fuses in a cylindrical enclosure containing a tamping medium. This type of fuse is being considered for use in microsecond switching of high power electromagnetic pulses. By using the exact magnetostatic solution for axial current lines in a cylindrical enclosure, we find a circuitlike model for the foil fuse and the driving external circuit. The foil resistivity is a function of the joule heat per unit volume dissipated at each position along the width of the foil. In the extreme example given in this letter, we find that the strong edge effects observed at the beginning of the pulses ‘‘heal’’ faster than the time it takes for the foil to switch and hence, edge effects, even in such cases are not important.

ISSN:0003-6951    

DOI:10.1063/1.96875

出版商:AIP    

年代:1986

数据来源: AIP