摘要:

We have developed a mode‐locked, diode pumped, neodymium‐doped yttrium lithium fluoride (Nd:YLF) laser operating at 1.053 &mgr;m. The laser produces pulses of 18 ps duration at an average power level of 12 mW. WhenQswitched the duration of the pulse train was 140 ns, giving rise to peak powers of 15 kW.

ISSN:0003-6951    

DOI:10.1063/1.100976

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Experimental results are presented for a nonreciprocal phase shift of vertically polarized waves in four‐layer magneto‐optic rib waveguides. The structure consists of a high refractive index nonmagnetic layer of titanium oxide on top of a magneto‐optic film (a lanthanum and gallium substituted yttrium iron garnet film on a gadolinium gallium garnet substrate) to improve differential phase characteristics. The difference of phase constants for waves traveling in opposite directions is evaluated by observing the variation in the polarization coupled out of a straight waveguide when simultaneously exciting both horizontally and vertically polarized waves with equal amplitudes and phases. The phase shift difference varies with the thickness of the nonmagnetic film, and is larger than that of a previous three‐layer waveguide in the overlayer thickness range 0.15–0.45 &mgr;m. The maximum phase shift obtained is 2.5 times as large as that of uncoated waveguides.

ISSN:0003-6951    

DOI:10.1063/1.101567

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

An analysis of ideal Y‐junction arrays above threshold shows that the radiation patterns deteriorate and the array begins to lase in more than one mode with increasing output power.

ISSN:0003-6951    

DOI:10.1063/1.100959

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We report the generation of tunable femtosecond pulses in the 800–850 nm range. These pulses were obtained by generating a femtosecond continuum and selectively amplifying a portion of that continuum. The amplified femtosecond infrared pulses thus obtained were then compressed to a duration of 9 fs by a fiber followed by a grating and prism sequence.

ISSN:0003-6951    

DOI:10.1063/1.100936

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The efficiency of interfacial ion mixing is measured for metal/Al (metal=Ti, Cr, Ni, and Mo) thin‐film bilayers irradiated with 285 keV Xe+ions near 77 K. The results indicate that, as a group, mixing of 3d‐metal/Al pairs irradiated by Xe can be explained by neither a pure binary collision cascade nor a pure thermal spike model. Such a situation should exist; that it should be found at the average atomic numbers of the present bilayers is consistent with recent theoretical predictions.

ISSN:0003-6951    

DOI:10.1063/1.100937

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Filament‐assisted chemical vapor deposition (CVD) diamond film growth on Si(100) was studied using x‐ray photoelectron spectroscopy (XPS) to examine the sample at selected intervals during the nucleation and growth processes. The sample was transferred under vacuum from the growth chamber to the attached XPS analysis chamber without exposure to air. Before growth XPS showed that the Si sample is covered by a layer of SiO2and carbonaceous residue; however, after 15 min of growth both of these substances are removed and replaced by a distinct SiC layer [Si(2p)=100.3 eV andC(1s)=282.7 eV].

ISSN:0003-6951    

DOI:10.1063/1.100938

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We investigate the radiation due to transitions of ballistic electrons in a superlattice. The equations of motion for the populations of photons and electrons are used to analyze the system both as an amplifier and as an oscillator. We then calculate the gain of the system and the threshold current needed to overcome electromagnetic losses. Finally, we compare our proposed infrared active system with other existing lasers.

ISSN:0003-6951    

DOI:10.1063/1.100939

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A silicon wafer has been oxidized at room temperature in vacuum using a pure, ground‐state beam of O−ions. The beam was of sufficiently low energy that no displacement damage or implantation was energetically possible. The resulting SiO2films were analyzed with x‐ray photoelectron spectroscopy. A logarithmic dependence of oxide thickness on dose was observed, with an extrapolated oxidation efficiency of unity for the clean silicon surface. A distinct initial oxidation phase was observed, with an anomalously high level of silicon suboxides. In addition, the valence‐band offset between the silicon and the oxide was unusually small, suggesting a large interfacial dipole.

ISSN:0003-6951    

DOI:10.1063/1.101456

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Hydrogen neutralizes both donors and acceptors in GaP by a mechanism that is independent of the site of the impurity in the lattice, but is dependent on the identity of the impurity. Hydrogen also passivates an isoelectronic trap nitrogen, a phenomenon first encountered here in GaP. We propose a simple model for the NH binding based on a polarized N−H+bond. This model accounts for the relative passivation of a series of NN pairs, where the passivation depends critically on the NN separation distance. Our results also support the recently revised correlation of spectral lines with NN pairs of varying separations.

ISSN:0003-6951    

DOI:10.1063/1.100940

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Surfaces of microcrystalline silicon films prepared by the glow discharge method have been investigated by a scanning tunneling microscope (STM) in air. Grain‐like structures of 30–80 nm size which correspond to transmission electron microscope data have been observed. The film surface was found to be geometrically rather flat but the structure was observed electrically, that is, the resistivity seemed to be inhomogeneous due to preferential oxidation. Also, degradation of STM images of a HF‐etched microcrystalline silicon surface has been observed for the first time.

ISSN:0003-6951    

DOI:10.1063/1.100941

出版商:AIP    

年代:1989

数据来源: AIP