摘要:

A simple technique, based on the absorption of far−infrared radiation, is shown to provide direct electron number density data in atmospheric large−volume plasmas. Spatially and temporally resolved measurements of electron density were obtained from a 10−cm plasma over the range 1011−3×1013cm−3using a 337−&mgr;m laser source. The measurement configuration allowed a 0.5−cm spatial resolution and a 200−nsec temporal resolution.

ISSN:0003-6951    

DOI:10.1063/1.87973

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Measurements of the interactions of CO2laser radiation with a theta pinch plasma have been made using laser scattering as a diagnostic technique. The plasma was heated axially with a TEA CO2pin laser. The scattering measurements have shown the time evolution of the laser−heated plasma during and after heating by the ’’spike’’ of the CO2laser. The energies involved in the change of plasma conditions agree well with the theoretical absorption associated with the inverse bremsstrahlung mechanism.

ISSN:0003-6951    

DOI:10.1063/1.87976

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

A differential measurement between two thermocouples of the same type, one under hydrostatic pressure and the other at zero pressure, was undertaken at temperatures up to 950 °C and pressures to 2 kbar, for platinum/platinum−10% rhodium (P/P10R) and Chromel/Alumel (C/A) couples, using an externally heated pressure cell. The correction term for P/P10R rises monotonically and levels off to a value of −0.44±0.02 °C/kbar at 800 °C. The correction term for C/A is in the opposite sense: it remains less than 0.1°C/kbar up to 450 °C where it begins to rise, eventually reaching 0.42±0.02 °C/kbar at 950 °C.

ISSN:0003-6951    

DOI:10.1063/1.87967

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

We report optical waveguiding of a LiNbO3single−crystal film grown onto ac−plate LiTaO3substrate by liquid phase epitaxy from a new Li2O−V2O5flux. A film of about 3−&mgr;m thickness supported seven TE and two TM modes. Measurements of the mode indices indicated that the film is a ’’uniform’’ waveguide having constant refractive indicesno=2.2884andne=2.1914throughout the film. Attenuation was measured to be 5 and 11 dB/cm for TM and TE, respectively.

ISSN:0003-6951    

DOI:10.1063/1.87977

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

We have observed the formation of growth strains due to interfacial dislocations in thin films made by the diffusion of niobium into LiTaO3. These dislocations become significant for films wherein &Dgr;n0≳0.01; their effect is to increase the scattering loss of the optical guided waves in the film.

ISSN:0003-6951    

DOI:10.1063/1.87968

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The effects of the absorption of the pump light by the first excited singlet state on the output of a Rhodamine 6G cw dye laser are investigated. Experimental results show a change in the incremental photon efficiency with pump wavelength. Theoretical expressions are derived for the output power, including the effects of excited state absorption. By matching experimental and theoretical results, values for the excited state absorption cross sections are found at four different wavelengths.

ISSN:0003-6951    

DOI:10.1063/1.87969

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

A continuous train of <500 ps (detector limited) pulses has been produced with a cw dye laser pumped by a mode−locked argon ion laser. The cavity lengths of the dye laser and argon laser were made equal in order to synchronously amplify a single pulse oscillating in the dye laser. An intracavity acousto−optic modulator was used to dump dye laser pulses at rates as high as 10 MHz.

ISSN:0003-6951    

DOI:10.1063/1.87970

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Cresyl violet solutions have been shown to lase when pumped with a N2laser or a rhodamine 6G dye laser. In the latter case the efficiency is much higher, and for appropriate solution concentrations the dye lases at the wavelength peak of its spontaneous emission. Under these conditions, the gain is so high that superradiance is obtained using only a 10−kW exciting pulse with 10% lasing efficiency.

ISSN:0003-6951    

DOI:10.1063/1.87971

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Absorption resonances in the &ngr;2band of D2O in near coincidence with CO2laser lines are reported and assigned. Optical pumping induces strong laser emission at new submillimeter wavelengths, confirming the assignments. Acousto−optic modulation is used to tune theR(22) line of the CO2laser into coincidence with the 000,533−010,422D2O transition. Its center frequency is 1079.8628 cm−1; the linewidth (HWHM) due to collisional broadening is 13 MHz/Torr. D2S and HDS transitions in near coincidence with CO2laser lines are also reported.

ISSN:0003-6951    

DOI:10.1063/1.87972

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Birefringence changes are induced in a cubic potassium tantalate niobate crystal with an external electric field by two−photon absorption of picosecond optical pulses. The recording sensitivity of 100 &mgr;J/cm2for elementary holograms with a few percent reconstruction efficiency is comparable to the sensitivity of holographic silver halide emulsions. The high sensitivity of KTN is shown to be due to efficient charge transport of photoexcited carriers.

ISSN:0003-6951    

DOI:10.1063/1.87974

出版商:AIP    

年代:1975

数据来源: AIP