摘要:

A simple formula is derived for estimating the asymptotic solution for two‐dimensional diffraction when a cylindrical obstacle is illuminated by an anisotropic cylindrical wave. The result is applied to derive the asymptotic diffracted field by a half‐plane, by a wedge, or by a circular cylinder. The solution for a half‐plane has been derived by other methods and both results are found to agree. The numerical calculations of the asymptotic solutions for the diffracted field by a slit and by a circular cylinder are carried out for the case when the obstacle is illuminated by an isotropic cylindrical wave. These numerical results are then compared with the exact solutions. It is found that the asymptotic series solutions provide precise results for estimating a diffracted field.

ISSN:0021-8979    

DOI:10.1063/1.328189

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

We derive an equation to predict the output of an optically pumped far infrared oscillator as function of pump pulse and resonator parameters. Results of a parametric study are presented and a comparison is made with experimental results from a D2O laser at 66 &mgr;m.

ISSN:0021-8979    

DOI:10.1063/1.328190

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Spectral measurements of the output from a purely chemical chain reaction cw HF laser are reported. The laser is a subsonic H2‐F2flame, with supersonic premixing and spatially uniform initiation by a stationary normal shock. Initial chemical production of fluorine atoms is by the bimolecular reaction of F2with NO. Spectral measurements of the laser output near the initiating shock indicate lasing transitions in thePbranches of thev=3 → v=2,v=2 → v=1, andv=1 → v=0 HF bands. Further downstream, the upper vibrational levels are strongly deactivated, and lasing occurs only in thev=1 → v=0 band. Laser emission in thev=2 → v=1 band reappears at reduced NO flow rates, suggesting efficient deactivation of HF (v) by NO, possibly through multiquantumV‐Vexchange. An approximate rate of 5×10−13±0.5cm3/sec for deactivation of HF (v=2) by NO is inferred.

ISSN:0021-8979    

DOI:10.1063/1.328191

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The lasing characteristics of the GaInAsP/InP narrow planar stripe lasers which were prepared by using InP epilayers as Zn‐diffusion masks in order to reduce the introduction of defects during the fabrication procedures were investigated. The narrow (?7 &mgr;m) stripe lasers showed good mode characteristics to operate in a fundamental‐transverse mode up to the output power of more than 20 mW per facet and in a single longitudinal mode in the power region. The threshold current was found to increase significantly and shifts of the lasing output towards shorter wavelength occurred as the stripe width was reduced. Remarkably wide near‐field patterns along the junction plane were obtained and far‐field patterns were found to be characterized by twin peaks in the narrow stripe lasers.

ISSN:0021-8979    

DOI:10.1063/1.328192

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The3P0‐3H6(1) transition of Pr in PrF3was observed to undergo laser action under direct pulsed excitation at low temperature with a high conversion efficiency. Comparison with such behavior in other types of material is made and the usefulness of this stimulated emission behavior as a spectroscopic tool in characterizing concentrated materials is discussed. The parameters describing threshold conditions, linewidths, and energy conversion are measured and compared to theory.

ISSN:0021-8979    

DOI:10.1063/1.328193

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The Nd : YAG regenerative amplifier produces short‐duration, optical pulses with the stability and pulse width range characteristic of actively mode‐locked lasers and the pulse energy characteristic of passively mode‐locked lasers. Other important properties, including large amplification and optical pulse storage, have also been achieved.

ISSN:0021-8979    

DOI:10.1063/1.328194

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

A cw x‐ray generator was used as a preionizer for a pulsed‐discharge uv N2/SF6laser. We revealed experimentally that cw x radiation was effective for preionization of a N2laser discharge. We observed that the N2laser energy increased linearly with increasing initial electron number density generated by a cw x‐ray preionizer when the electron number density was below 6×107cm−3and the input energy loading was kept at 35 J/l. In the case of x‐ray illumination, the N2laser energy increased by a factor of 12 over that of pure N2gas when SF6was added.

ISSN:0021-8979    

DOI:10.1063/1.328195

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

An internally frequency‐doubled and synchronously mode‐locked dye laser has been operated. The average power ∼0.13 mW of the second‐harmonic wave with a pulse duration of ∼3 ps has been generated from a thin ADP crystal under pumping by the average power ∼800 mW of a mode‐locked Ar ion laser. The effect of intracavity second‐harmonic generation on the pulse duration of the fundamental wave is discussed.

ISSN:0021-8979    

DOI:10.1063/1.328196

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

Circular optical waveguides have been fabricated from vacuum‐deposited Ag layers by ion migration technique into soda‐lime substrate glass. In this method two different guide patterns, one of which is the mirror image of the other, are made. Later the guide patterns are placed on top of each other and circular guides are thus obtained. The ends of the guides are studied by optical microscope and the near‐field scanning method. The optical loss spectrum is measured from 450 to 1600 nm.

ISSN:0021-8979    

DOI:10.1063/1.328205

出版商:AIP    

年代:1980

数据来源: AIP

摘要:

The theory of prism coupling into multilayered dielectric slab waveguides is presented. In addition to including the possibility of high index cladding, the present theory also extends the region of validity of previously reported work to cover the regime of ’’strong coupling’’. The limiting conditions for validity of the present theory are that both &agr;m/kand &agr;m±p/kbe much smaller than either unity or ‖&bgr;m−&bgr;m±p‖, wheremis the mode under consideration, &agr;mis the leakage of that mode, and ‖&bgr;m−&bgr;m±p‖ is the separation of the effective indices of adjacent modes. A numerical example is presented in which the coupling efficiency into a uniform or slab waveguide with &Dgr;n=0.002 is calculated for various cladding thicknesses with a cladding index of 2.5. The introduction of cladding is found to reduce coupling efficiency in this example due to increased phase mismatch between the incident and ’’ideal’’ beams.

ISSN:0021-8979    

DOI:10.1063/1.328206

出版商:AIP    

年代:1980

数据来源: AIP