摘要:

New results on the study of slow dynamics in ferromagnetic amorphous alloys are presented. Experimental evidence has been obtained of low‐frequency relaxation phenomena in highly magnetostrictive amorphous alloys submitted to various anneal treatments. Dynamics of the amplitude and phase of intrinsic magnetic noise in the metallic glass Metglas 2605S‐2 have been measured with a fiber‐optic interferometer. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113098

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The fabrication of single quantum well (SQW) ridge waveguide ring laser in strained InGaAs is described which utilizes direct‐write laser lithography followed by cryogenic UV laser‐assisted etching. The laser has a threshold current of 270 mA and emits ∼14 mW of single‐frequency output. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113099

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A simple technique for variable microsecond (1.5–5 &mgr;ms) pulse generation with neodymium laser has been demonstrated using a laser cavity with a rotating mirror and amplifier configuration. Pulse energies up to 0.5 J have been achieved. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.113100

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Temperature dependence of threshold in 1.3 &mgr;m semiconductor lasers is analyzed in terms of contributions due to gain, internal efficiency, internal loss, and nonradiative recombination. Rapid decrease of differential gain and roughly proportional increase in transparency carrier density are determined to dominate temperature dependence of threshold current. Auger recombination is found to play a secondary role in reducingT0by compounding the effects of rapidly increasing threshold carrier density. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113101

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We describe studies of an index‐guided ∼4×3 &mgr;m2vertical cavity surface emitting laser with a cw, room temperature 133 &mgr;A threshold current and 53% slope efficiency fabricated using selective wet thermal oxidation to provide optical and electrical confinement. While the device operates strictly single mode, a large number of transverse modes are evident in the subthreshold luminescence observed in both vertical and lateral directions. Despite the lumped nature of the index region, the transverse mode wavelengths agree very well with those predicted for a conventional distributed waveguide structure. Waveguide dimensions and an effective index step of 2% between the active and cladding region are determined by fitting the modal data. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113102

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

An asymmetric coupled quantum well structure is theoretically investigated as a means of tailoring the conversion efficiency of the four‐wave mixing process at terahertz detuning rates. In this structure, a coherent electronic oscillation between the two wells can be excited that introduces a resonance peak in the four‐wave mixing frequency response. A calculation based on the density matrix formalism shows that an increase in the power conversion efficiency on the order of 10 dB can be attained at the selected resonance frequency for low temperature operation. Finally, we propose a novel technique for exciting the interwell oscillations that takes advantage of the polarization dependence of the interband optical transitions in alternating strain quantum wells. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113103

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The frequency doubling and subsequent pulse compression of pulses from an additive‐pulse mode‐locked Nd:YLF laser have been reported. Pulses as short as 245 fs with an average power of 140 mW corresponding to a peak power of 4 kW at 523.5 nm are generated using a simple fiber‐grating pulse compressor. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113104

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A debris‐free, narrow‐bandwidth, single‐line laser‐plasma soft x‐ray source has been developed suitable for water‐window microscopy using zone‐plate optics. The 10 Hz table‐top source utilizes microscopic ammonium hydroxide droplets as target. The N VI emission at &lgr;=2.88 nm is ∼1×1012photons/(sr pulse). As an alternative to ammonium hydroxide, it is demonstrated that urea dissolved in water also produces strong emission from nitrogen ions, thereby extending the applicability of the droplet x‐ray source to a new range of target materials. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113105

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A waveguide electro‐optic grating coupler modulator based on a single straight channel waveguide and an interdigital modulation electrode structure on an electro‐optic substrate, has been reported. Both single‐mode and multimode operations are possible. Preliminary experiments have demonstrated the modulation on a proton exchanged LiNbO3waveguide device. Modulation performed on other electro‐optic waveguides, such as GaAs, LiTaO3, and EO polymers, are also possible. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113106

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

An electro‐optic polymer with chlorophenol red dye and type‐A photolime gel was demonstrated. The electro‐optic coefficient &ggr;33in the direction of the poling field was measured to be 28 pm/V. Chlorophenol red in polymer showed a 1/erelaxation time constant of 820 h, which is more stable than other dye demonstrated previously to be electro‐optic in the same polymer. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113107

出版商:AIP    

年代:1995

数据来源: AIP