摘要:

It is shown that stresses caused at the interface of a AlxGa1−xAs&sngbnd;GaAs heteroboundary are due to the different thermal expansion coefficients of the two layers involved. These interface stresses are elastic and depend on the crystallographic orientation of the heteroboundary plane. Based on these experimental observations, a planar stress model for double heterostructure (DH) devices is developed which results in stress levels in the order of 108dyn/cm2for typical low‐threshold DH laser structures. It is demonstrated that this type of stress is responsible for the occasional preference of TM modes over the TE modes in DH lasers.

ISSN:0021-8979    

DOI:10.1063/1.1662726

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Apart from the usual bound‐exciton luminescence due to Te and N centers, broader peaks which appear at high excitation may be explained by free‐carrier screening of the free excitons, or by high‐density excitonic effects. A weak‐luminescence structure observed around 2.8 eV, which has not been reported before, may be due to conduction electrons at theLpoint with holes at &Ggr;15bound to the neutral donors.

ISSN:0021-8979    

DOI:10.1063/1.1662727

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A scheme for phase matching in the parametric generation of far infrared is analyzed. It makes use of the periodic variation of the nonlinear coefficients. It is shown that a device can be constructed which is tunable over a wide range of generated frequencies.

ISSN:0021-8979    

DOI:10.1063/1.1662728

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

It is shown that the degradation of theC‐Vproperties of the SiO2/Si interface caused by low‐energy ion bombardment may be completely removed by annealing to temperatures of 900 °C or higher. The low‐energy ion bombardment, however, also causes damage to the dielectric strength of the SiO2. This damage only partially anneals out, even at the highest annealing temperatures. Annealing to temperatures between 400 °C and 600 °C apparently removes allC‐Vdamage, as measured at room temperature, but bias‐temperature instabilities, which require the higher temperature for their removal, remain. Annealing of any oxide to temperatures in the range 700–850 °C is not recommended, as it may introduce instabilities independent of ion bombardment. The same annealing procedure is required for 50, 500, and 1400 eV ion bombardment, leading to the conclusion that, in terms of ion bombardment damage, low‐voltage sputtering gives no advantage over high‐voltage sputtering. The dielectric breakdown damage is also independent of the ion energy in the range of 50–1500 V used in this study. We conclude that since all dielectric breakdown damage is not annealable, a method of prevention of oxide charge buildup during backsputtering is essential if this technique is to be used on insulating substrates. Appropriate choice of rf backsputtering voltage as a function of the insulator film thickness can significantly reduce or eliminate the bulk dielectric degradation.

ISSN:0021-8979    

DOI:10.1063/1.1662729

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Copper‐coated ZnS : Mn powdered phosphors which can be excited with dc field were prepared and time responses of electroluminescence to unidirectional rectangular voltage pulses were studied at room temperature. Over the manganese concentration range studied (5×10−4−8×10−3g/g Mn) emission decay time was found to be nearly proportional to the average nearest distance of Mn2+to Mn2+luminescent centers. An electroluminescent panel using the phosphor with 1×10−3g/g Mn was most efficient under the pulsed voltage which has pulse width of 120 &mgr;s and repitition rate of 60 Hz.

ISSN:0021-8979    

DOI:10.1063/1.1662730

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Excitation of the molecular nitrogen laser by a high‐energy electron beam is shown to be controlled byE/pin a manner similar to other forms of electrical excitation. The electric field is produced by the increasing net current. Both the beam current and the nitrogen pressure for maximum laser power are found to vary directly as the laser diameter for the two diameters considered. Scaling of laser power with length is found to be limited by the high optical gain of the laser transition which causes the active medium to become superradiant before the full length is excited.

ISSN:0021-8979    

DOI:10.1063/1.1662731

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Thin nitrocellulose membranes (pellicles) are shown to exhibit properties which make them suitable for intracavity tuning elements in high‐energy pulsed dye lasers. Uncoated pellicles of 2‐&mgr;m and 8‐&mgr;m thickness with surface figures of &lgr;/1 are shown to closely approximate the properties of low‐finesse etalons with wide free spectral ranges. Pellicles of 8‐&mgr;m thickness and coated on both surfaces with 50% reflectivity multilayer dielectrics are shown to be effective as spectral narrowing elements with peak transmission greater than 80% and resultant laser linewidths of 0.57 nm full width at half‐maximum (FWHM).

ISSN:0021-8979    

DOI:10.1063/1.1662732

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

An experimental setup of a pulsed dye laser for holographic applications is described. The capabilities of the dye laser with tunable frequency for recording holograms are demonstrated.

ISSN:0021-8979    

DOI:10.1063/1.1662733

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A method is described for rapidly recording permanent ir spectrograms of the output of a pulsed chemical laser. The method also lends itself to the simultaneous observation of the time behavior of several spectral lines. Spectra from an HF laser under different operating conditions are reported to demonstrate the utility of the method.

ISSN:0021-8979    

DOI:10.1063/1.1662734

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Infrared and ultraviolet absorption spectra arising fromf→fandf→dtransitions of Ce3+in YAlO3crystals are presented and used to derive the 4fand 5denergy levels. Excitation and fluorescence spectra of 5d→4femission are also reported. The 5dfluorescence has a decay time of 16 nsec and a radiative quantum efficiency of near unity at 300 °K. Possible use of Ce3+as a sensitizer for rare‐earth and iron‐group ion fluorescence in YAlO3is surveyed; included is an investigation of energy transfer in a Ce, Nd, Cr‐codoped crystal.

ISSN:0021-8979    

DOI:10.1063/1.1662735

出版商:AIP    

年代:1973

数据来源: AIP