摘要:

Pb1−xSnxTe diode lasers with cw output power over 10 mW, single‐longitudinal‐mode power up to 6 mW, and incremental external quantum efficiencies up to 0.16 have been obtained using polished rather than cleaved end mirrors. The results indicate that one of the major factors limiting the output power and external efficiency of these lasers is the optical quality of the mirrors.

ISSN:0021-8979    

DOI:10.1063/1.1662673

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

For thin insulating layers the observation of a linearI‐Vcurves is often cited asprima facieevidence that the carriers originate from thermal bulk generation. In the present paper we point out that a linearI‐Vcurve can also arise from an emission‐limited or contact‐controlled current. We present an unambiguous experimental criterion to determine whether a linearI‐Vcurve results from contact emission or bulk generation.

ISSN:0021-8979    

DOI:10.1063/1.1662674

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A certain fraction of the photon flux absorbed within the passive bulk of a GaAs photosource results in the creation of further photons. It is the subject of this report to measure the fraction of internal absorption events that do result in the further generation of spontaneous photons at band‐edge energy in GaAs. The luminescence described here is a special case of photoluminescence where the source excitation is the same energy range as the resulting generation. We have chosen to call this special case self‐excited luminescence (SEL). Measurements using cross‐ and parallel‐axis polarizer pairs are used to measure SEL quantum efficiency. Most GaAs samples tested indicate an SEL efficiency of less than 1% at 300°K. As a check on experimental precision, the photopeak energy of the source excitation was increased by approximately 0.04 eV and the quantum efficiency for the resulting internal luminescence increased to 3.3% at 300°K for one sample.

ISSN:0021-8979    

DOI:10.1063/1.1662675

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Ultrasonic velocities have been measured and used to determine the elastic moduli of the highly magnetostrictive compounds: TbFe2, TbFe3, and ErFe2. A huge &Dgr;Eeffect of 90% has been calculated for TbFe2from our static stress‐strain data.

ISSN:0021-8979    

DOI:10.1063/1.1662676

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Recrystallization of KCl crystals deformed in a <100> direction was utilized to develop polycrystalline microstructures, increasing yield stresses, thus making them more attractive as laser window candidates. Using press forging techniques (i.e., slow compressive deformation in the absence of lateral constraints), large plastic strains (≤ 70%) were achieved at temperatures as low as 150 °C, which resulted in recrystallized grain sizes as fine as 5 &mgr;m. Although a residual < 100 > texture was present, there was sufficient grain misorientation to result in general polycrystalline behavior. The yield stresses of the press forged materials increased with decreasing grain size, reaching about 35 MN m−2(∼5000 psi) at the finest (5 &mgr;m) grain size.

ISSN:0021-8979    

DOI:10.1063/1.1662677

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The hole drift velocity in high‐purity Ge as a function of electric field (2−104V/cm and temperature (8–220 °K) has been measured with the time‐of‐flight technique. The electric field was applied parallel to the ⟨100⟩ axis. The drift mobility in the Ohmic regime is in agreement with measurements of Hall mobility in high‐purity Ge and with theoretical predictions. At temperatures below 100 °K the drift velocity reaches limiting values, and at 8 °K it is 1.3×107cm/sec.

ISSN:0021-8979    

DOI:10.1063/1.1662678

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Thermomagnetic writing of single‐crystal MnBi films has been investigated. The magnetic state of the spot heated with a laser beam is reversed by the stray field resulting from the surrounding saturated film. The reversed spot serves as a magnetic nucleus from which magnetic domains emanate by wall motion due to the demagnetizing field. Thus the magnetic state of the film switches from the remanent saturated state to the demagnetized state of lower energy. The reverse domain does not penetrate into the adjacent crystals beyond the potential barriers of the crystal boundary.

ISSN:0021-8979    

DOI:10.1063/1.1662679

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The shock compression and unloading of several simple homogenous binary mechanical mixtures with polyethylene as the matrix is compared to that of an aluminum fiber/epoxy matrix composite. When both of these systems are unloaded from shock states lying in the liquid regime for the matrix, the latter physically separates from the rigid component and exhibits independent motion. The measured free‐surface velocity is that of the matrix material and is predicted by an internally adiabatic compression/isentropic expansion model.

ISSN:0021-8979    

DOI:10.1063/1.1662680

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Using a double‐excitation‐pulse technique, the measured relative excitation efficiency of a CO2laser as a function ofE/pwas found to be in qualitative agreement with the theoretical calculation of Nighan for the &ngr;3mode.

ISSN:0021-8979    

DOI:10.1063/1.1662681

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The variation of the conductivity of metal‐particle—insulator systems with the volume percent of metal is explained in terms of an ``effective medium'' theory.

ISSN:0021-8979    

DOI:10.1063/1.1662682

出版商:AIP    

年代:1973

数据来源: AIP