摘要:

The spacing of layers in a sputtered, multilayer structure was rapidly and permanently increased by heating with a nanosecond laser pulse. During laser heating, the Bragg angle decreased and the peak reflectivity increased for diffraction of soft x‐ray radiation at 4.4 nm. Measurements were made using a time and space resolving x‐ray streak camera detector.

ISSN:0003-6951    

DOI:10.1063/1.98496

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We describe the structure and performance of a new, nonabsorbing, perpendicular geometry light modulator based on an electrically tunable, multilayer interference filter. The device consists of a GaAs/AlAs quarter‐wave stack with aluminum contacts, grown by molecular beam epitaxy. A strong, applied electric field changes the refractive indices through the Franz–Keldysh effect, shifting the transmission spectrum and modulating the intensity of light tuned to the edges of the high reflectance band. Modulation ratios up to 2.5:1 have been obtained for photon energies 0.05–0.2 eV below the GaAs band gap. The device has applications in arrays and for modulation of high power light.

ISSN:0003-6951    

DOI:10.1063/1.98497

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A superluminescent diode (SLD) based on a proven high power, high efficiency ‘‘window‐’’ type index‐guided buried heterostructure laser is demonstrated. Lasing is suppressed for SLD operation by antireflection coating and by incorporating an unpumped absorber section. The resulting device emits high optical power (14 mW) in the SLD mode at very low injection current (50 mA). The spectral modulation depth is below 14% over the entire emission spectral bandwidth of 20 nm, with a symmetrical beam divergence (20°×40°) and a stable transverse mode.

ISSN:0003-6951    

DOI:10.1063/1.98498

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Using time‐resolved techniques, absorption recovery, and degenerate four‐wave mixing, we directly observe the nonexponential intensity‐dependent recombination of free carriers photoexcited in semiconductor‐doped glasses. We assign this behavior to Auger recombination.

ISSN:0003-6951    

DOI:10.1063/1.98499

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We report on the first diode‐laser (nominal 200‐mW 10‐stripe laser diode) end‐pump lasing of Nd:YVO4. The lowest threshold (30 mW) and highest output power (120 mW) were observed from the Nd:YVO4laser as compared to a similar Nd:YAG laser. Over 50% optical slope efficiency was obtained, the highest yet reported for diode pumping. This device performed at a 10% overall efficiency. Measurements over a 21‐nm range show the advantages of the Nd:YVO4pump absorption band.

ISSN:0003-6951    

DOI:10.1063/1.98500

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The simultaneous energy delivery of neodymium:yttrium aluminum garnet (Nd:YAG) and CO laser beams by a single As‐S glass fiber is described. The transmission loss in the fiber of a Nd:YAG laser beam was 2.6 dB/m under the energy delivery. A fiber output of 14 W was obtained at an approximately 1:1 power ratio from these lasers with a 400‐&mgr;m core diameter fiber.

ISSN:0003-6951    

DOI:10.1063/1.98501

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The elastic properties of ZnO films deposited by rf magnetron sputtering on Al2O3substrates have been analyzed by means of an acoustic investigation technique. The phase velocities of a spectrum of acoustic modes propagating along the layered structure have been measured and the results exploited for determining the complete set of elastic constants of the film. The effective constants of the film are lower than those of the bulk material by amounts which depend on the elastic constant considered and range from −1.2% forc33to −24.8% forc11. The values obtained were used for determining the dispersion curves of acoustic modes propagating along ZnO layers deposited on fused quartz and silicon and showed good agreement with experimental results.

ISSN:0003-6951    

DOI:10.1063/1.98502

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A method is reported, which allows us to measure the dynamics of the surface thermoelastic deformations. We have obtained the time evolution of amplitudes of surface deformations induced by absorption of a laser beam in Plexiglas samples of different geometry. A qualitative discussion of the obtained results is made.

ISSN:0003-6951    

DOI:10.1063/1.98503

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We report the fabrication of epitaxial CoSi2layers on Si(111) as thin as 1 nm. The crystalline lattice of these layers is coherent with the Si lattice, and the silicide is electrically continuous. There are pronounced structural differences between films which are less than 3 nm thick and those which are thicker. The resistivity of the layers increases sharply with decreasing thickness. This is the first report of the growth of coherent, electrically continuous CoSi2layers on Si.

ISSN:0003-6951    

DOI:10.1063/1.98504

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Amorphous materials irradiated by cw lasers undergo structural changes, which depend quasiperiodically on the irradiation time. The changes in the transmitted light intensity are related to the changes of the Raman line shape. The structural changes between metastable states are favored by the photogenerated free carriers.

ISSN:0003-6951    

DOI:10.1063/1.98505

出版商:AIP    

年代:1987

数据来源: AIP