摘要:

A novel method to obtain boron and phosphorus concentration in silicon crystals by photoluminescent (PL) analysis at liquid‐helium temperature is reported. The intensity ratio between intrinsic and extrinsic components in the PL spectra reflects the impurity concentration. The tentative calibration curves for boron and phosphorus for our method are obtained by comparison with the results of the resistivity measurement. The detection limit of this method is estimated to be as low as 1×1011cm−3for boron and 5×1011cm−3for phosphorus. The degree of compensation can be estimated also. The PL method makes it possible to determine nondestructively the concentration of small amount of impurities in a small region of a specimen.

ISSN:0003-6951    

DOI:10.1063/1.89897

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

For short‐pulse energy extraction from a CO2laser amplifier it is desirable to use multiline/double‐band amplification. Multiline/double‐band oscillation including up to nine lines was obtained simultaneously from the 9.6‐ and 10.6‐&mgr;m bands by placing an etalon perpendicular to the optical axis of a CO2laser and adjusting its thickness in the oscillator cavity. Improvement in energy extraction was corroborated in the region of saturation amplification using a 1‐atm electron‐beam‐controlled amplifier.

ISSN:0003-6951    

DOI:10.1063/1.89898

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Described in this letter is a new dielectric reflector designed for injection laser facets which consists of alternating quarter‐wavelength layers of Al2O3and Si. The reflectivity for six layers can be made ≳0.98 over a wavelength range from ∼0.7 to ≳2 &mgr;m. By choosing the appropriate number of quarter‐wavelength layers and the final layer thickness the reflectivity can be varied between 0.01 and 0.98. Finally, both Si and Al2O3are impervious to the chemical cleaning and wetting agents and solders used during the mounting of (AlGa)As cw injection lasers.

ISSN:0003-6951    

DOI:10.1063/1.89899

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A sealed multiatmospheric CO2TEA laser is reported in which recombination of principle discharge products CO and O2is induced by recirculating the laser gas mixture through a room‐temperature oxide catalyst bed. No special gas mixtures are required and the catalyst is compatible with at least some trialkylamine seed gases.

ISSN:0003-6951    

DOI:10.1063/1.89900

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

We present a model of the synchronously mode‐locked cw dye laser which predicts a square root dependence of dye pulse width on pump pulse width and intracavity bandwidth (&ohgr;c). Experiments performed on the Rhodamine 6G laser confirm the &ohgr;−1/2cdependence. For a pump pulse width of 100 ps, subpicosecond dye pulses are obtained for intracavity bandwidths greater than 150 A˚, and the minimum pulse width is shown to be limited by the bandwidth of the dye to ∼0.5 ps.

ISSN:0003-6951    

DOI:10.1063/1.89901

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Measurements of instability onset in a spatially uniform electron‐beam‐sustained KrF* laser discharge have shown that the time at which instability occurs decreases from about 1 to 0.1 &mgr;sec asE/nis increased in the range required for efficient laser operation. This finding is in good agreement with computed ionization instability onset times determined on the basis of a comprehensive model of the discharge.

ISSN:0003-6951    

DOI:10.1063/1.89902

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Photolysis of KrF2has been used to measure the rates of collisional quenching of KrF(B) excimers in two‐ and three‐body collisions with Ar, Kr, and F2. In addition, the KrF(B→X) band radiative lifetime was determined to be 6.8±0.2 ns. The results are in good agreement with existing theory and demonstrate the importance of quenching to KrF laser performance.

ISSN:0003-6951    

DOI:10.1063/1.89903

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The dependence of an acoustically resonant optoacoustic signal on the molecular weight and thermodynamic and transport properpties of the buffer gas is reported. Our results show that careful selection of such gases can significantly increase the sensitivity and flexibility of optoacoustic spectroscopy. We also demonstrate that such thermodynamic quantities as &ggr; (≡Cp/Cv) and sound velocity can now be measured readily and accurately. Other potential applications are suggested.

ISSN:0003-6951    

DOI:10.1063/1.89904

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Using a long‐duration transverse discharge (300 ns) preionized by a short‐pulse electron‐beam gun (10 ns), laser emission has been obtained in the second positive system of nitrogen at &lgr;=3371 A˚ in nitrogen alone and at &lgr;=3577 A˚ in a N2‐CF4mixture. In the latter mixture, the laser emission lasts for 70 ns which is much longer than the radiative lifetime of the upper laser levelC 3&Pgr;u(&tgr;F=40 ns). We think that the blottleneck of the terminal laser level is avoided thanks to the vibrational deactivation of the nitrogenB 3&Pgr;gstate due to the irreversible transfer of vibrational energy of N2to CF4during collisions.

ISSN:0003-6951    

DOI:10.1063/1.89905

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The EPR study of optical‐quality AgGaS2has proven the existence of the point defects Ni3+, Fen+, (n⩽2), a shallow donor (ED<0.11 eV), and one associated defect Fe3+‐X, the charge states of which are all photosensitive. The effectiveness of the standard annealing procedures, employed to obtain crystals of low absorption in the 0.5–12‐&mgr;m range, is associated with an oxidation of these transition‐metal impurities.

ISSN:0003-6951    

DOI:10.1063/1.89906

出版商:AIP    

年代:1978

数据来源: AIP