摘要:

Acoustic surface wave attenuation in LiNbO3caused by ion implantation was studied as a function of fluence and surface wave frequency. 80‐keV Ne+ions were implanted at five fluences covering the range 1014–1016ions/cm2. TheyzRayleigh surface waves were generated spanning the interval 100–1000 MHz by interdigital transducers operating at odd harmonics. Attenuation was measured directly by a standard laser probe using reflected light. At low acoustic power densities, the data can be fit byP(z)/P0=10−Af2z, wherePis acoustic power,fis the surface wave frequency, andAis a constant for each fluence used. The values ofAshow a definite peak with fluence at around 1015ions/cm2, whereA=9 × 10−5dB cm−1MHz−2±10%. This is about twenty times the value ofAfor an unimplanted surface.

ISSN:0003-6951    

DOI:10.1063/1.1654529

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

We show in this letter that nonlinear interactions between noncollinear elastic waves can be analyzed by using the well‐known mathematical formalism of wave propagation in periodic media, which leads to a set of coupled amplitude equations much like those found in the optoacoustic interaction case. The behavior predicted from these equations for isotropic media is well consistent with results known for Bragg diffraction in anisotropic media. The conditions for an experiment using a lead molybdate crystal are derived. By using the optoacoustic analogy, some device applications may be thought of and the scope of the present work may be extended to cover interactions involving elastic surface waves.

ISSN:0003-6951    

DOI:10.1063/1.1654530

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Dauphine´ twins in quartz have been directly observed and photographed by using second‐harmonic light. A theoretical analysis shows that a plane twin boundary in a plane parallel slab of quartz produces a system of interference fringes at the crystal output surface, corresponding to the existence of two second‐harmonic beams with different directions. This was experimentally verified, and thus a topography of the twins has been obtained. Furthermore, the orientation of the twins relative to a twinless quartz crystal has been determined.

ISSN:0003-6951    

DOI:10.1063/1.1654531

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Optically induced birefringence change (``optical damage'') has been studied in undoped LiNbO3from 400 to 800 nm by using an incoherent light source. Optical damage was observed over the entire wavelength range, with damage peaking near 415 nm. Structure, which could not be observed by normal optical absorption measurements, was seen in at least three regions of the damage‐wavelength curve.

ISSN:0003-6951    

DOI:10.1063/1.1654532

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

By studying the photovoltage developed across the amorphous silicon‐electrolyte interface on illumination with monochromatic light, the mobility gap in amorphous silicon is found to be about 1.7 eV. The effect of preparation conditions is very significant, with unannealed films deposited by electron beam evaporation showing considerable structure in the spectral response. After low‐temperature annealing, typically at 120°C for 20 h, the spectral response shows a sharp edge and is similar to that of single‐crystal silicon but is displaced to higher energies by about 0.6 eV. Sputtered films, even when unannealed, show almost identical spectral response as fully annealed films, which is attributed to the process of film growth in the sputtering process.

ISSN:0003-6951    

DOI:10.1063/1.1654533

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The lowering of breakdown voltage and the softening ofV‐Icurves of silicon diodes, caused by the precipitation of impurity carbon, have been observed.

ISSN:0003-6951    

DOI:10.1063/1.1654534

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The formation mechanisms in an excited‐state‐reaction coumarin laser dye are investigated by measurements of the saturation characteristics of the laser. By recording the influence of intense cavity oscillation on the single‐ and double‐pass amplified spontaneous emissions of the two different ``exciplex'' species, it is found that a ``serial'' model applies, the green‐emitting species being formed from the blue‐emitting one.

ISSN:0003-6951    

DOI:10.1063/1.1654535

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Field strengths at which optical damage is initiated in NaCl have been measured with a mode‐locked Nd: YAG laser with pulse durations of 15 and 300 psec. Comparison with previously reported data with aQ‐switched laser shows that the field strength required for intrinsic optical damage increases by almost one order of magnitude from 106V/cm at 10−8sec to over 107V/cm at 1.5 × 10−11sec. This is in qualitative agreement with published estimates based on the electron avalanche breakdown mechanism.

ISSN:0003-6951    

DOI:10.1063/1.1654536

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Double‐heterostructure (GaAl)As&sngbnd;GaAs injection lasers have been made with very narrow active regions in the range 0.11–0.14 &mgr;m. In addition to giving narrow angular beam widths down to 16°, they show high peak power handling capacity up to 40‐W/mm junction width at threshold current densities of less than 1500 A/cm2. The results are consistent with the relatively wide near‐field distribution perpendicular to the junction plane, which is deduced from the properties of the heterostructure optical waveguide.

ISSN:0003-6951    

DOI:10.1063/1.1654537

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Substantial interactions between drifting carriers in a semiconductor and slow circuit waves on meander lines have been demonstrated for the first time. Electronic gains in the meander‐meander line signal of up to 40 dB/cm were obtained with Ge at 4.2°K. Although no net gain was achieved with respect to the ports of the meander lines due to the structure's high transmission loss of 20–30 dB, the results demonstrate the possibility of solid‐state slow‐wave amplification which has been the subject of many previous theoretical studies.

ISSN:0003-6951    

DOI:10.1063/1.1654538

出版商:AIP    

年代:1973

数据来源: AIP