摘要:

Time‐of‐flight mobility and trapping results for zinc selenide are presented. The data were obtained at room temperature for electric fields in the range 3×104−8×105V/cm. A relatively constant hole mobility (∼50 cm2/V sec) was found for the entire range of investigated fields. The electron mobility was approximately constant (∼400 cm2/V sec) up toE≃3×105V/cm, above which the drift velocity remained constant. No obvious negative differential mobility was observed, even though the Gunn effect has been reported for the field range investigated. Trapping and detrapping times in the vicinity of 1 nsec are reported for both holes and electrons. The field dependence of the electron‐trapping times is unusual and remains unexplained.

ISSN:0003-6951    

DOI:10.1063/1.1654174

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Some weak structure on the high‐energy side of the L23MM Auger peaks for Al and Si has been recently interpreted as being possibly due to the simultaneous decay of an inner‐shell vacancy and a volume plasmon. It is shown here that similar structure due to multiple ionization is to be expected and that photoemission caused by internally generated x rays can be observed if the fluorescent yield is not too small. Relatively strong structure of the latter type has been observed in the secondary‐electron energy distribution of evaporated Al on the high‐energy side of the KL23M Auger peak.

ISSN:0003-6951    

DOI:10.1063/1.1654175

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The threshold for domain formation and the characteristics of domains have been measured over an extended frequency range. Comparison with the Helfrich‐Orsay theory shows a good fit of the threshold over a wider than expected variation of cell thicknesses. This is even true near the ``critical'' frequency where the domain size decreases with increasing frequency. In addition, a new domain regime is described at frequencies smaller than the inverse ion transit time.

ISSN:0003-6951    

DOI:10.1063/1.1654176

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A frequency‐modulation (FM) demodulation scheme for the measurement of instantaneous velocity of turbulent flow by laser Doppler velocimeter is proposed. An analysis based on the theory of optical‐mixing spectroscopy is given.

ISSN:0003-6951    

DOI:10.1063/1.1654177

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

An intracavity gas‐cell technique is demonstrated for restricting the carbon monoxide (CO) laser oscillations to lines coincident with the transmission bands of the atmosphere. Using an intracavity water‐vapor cell, the CO laser gain was spoiled in lines that are highly absorbed by the atmospheric water vapor, permitting the oscillations to build up only on the higher transmission lines.

ISSN:0003-6951    

DOI:10.1063/1.1654178

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Mesa‐stripe‐geometry double‐heterostructure lasers which operate at low‐current level have been fabricated. Lasers of this geometry are made by etching the heterostructure layers, leaving a stripe region with a width ranging from 10 to 40 &mgr;m. The current‐spreading effect inherent in stripe‐geometry lasers is eliminated in this structure. As a result of the small active region and the low‐threshold current density, a significant reduction of total threshold current has been realized. The lowest‐threshold current is 50 mA in pulsed operation, and 75 mA in dc. The thermal resistance of the diode of this structure is nearly as low as that of the stripe‐geometry laser.

ISSN:0003-6951    

DOI:10.1063/1.1654179

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

An unusually orderly excited state of a degenerate resonant molecular system occurs when all the resonant molecules are polarized in the same phase. The largest obtainable optical polarization of the medium is obtained under such conditions. Here we describe a technique by which such a maximally orderly excited state may be approached. Adiabatic fast half‐passage is used. Neither a tunable laser nor a tunable resonant medium is required, and disorder is not introduced by local intensity variations or degeneracy of the resonant levels. Nearly complete polarization of the available molecules has been measured by means of a phase‐switching technique.

ISSN:0003-6951    

DOI:10.1063/1.1654180

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Photoconductivity methods are used to investigate high‐resistivityn‐type andp‐type silicon implanted with doses of ∼1014B+/cm2of 100 keV. Besides the photoconductivity band associated with the divacancy, a photoconductivity level at ∼0.4 eV is detected in the spectrum. This level anneals at ∼300°C; it has been associated with boron interstitial atoms in sites of trigonal symmetry for boron‐doped silicon irradiated with electrons. The appearance of this level is not so clear in the case of thep‐type silicon substrate where the substrate contribution to the photoconductivity is larger.

ISSN:0003-6951    

DOI:10.1063/1.1654181

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Picosecond light pulses passing through a saturable absorber show considerable pulse shortening. For instance, under special favorable conditions the pulse duration was found to be reduced from 8 to 2. 6 psec in a single transit. Using a multiple‐absorber‐amplifier system, light pulses were shortened from 8 to 0.7 psec in five transits. The shortest pulse seen in our experiments had a duration of less than 0.5 psec. Calculations based on a two‐level approximation of the absorbing medium agreed well with the experimental results.

ISSN:0003-6951    

DOI:10.1063/1.1654182

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Uniform direct‐current discharges in atmospheric‐pressure mixtures of He/N2/CO2have been achieved by the use of an organic gas additive. Best results were obtained using xylene as an additive with a concentration of 0. 5% in a 90/5/5 gas mixture. Observed current densities were limited by external circuitry, but uniform pulsed discharges with current densities over 3 A/cm2were obtained when the dc discharge was pulsed.

ISSN:0003-6951    

DOI:10.1063/1.1654183

出版商:AIP    

年代:1972

数据来源: AIP