摘要:

102‐laser arrays with a period of 4.5 &mgr;m were fabricated using single‐step metalorganic chemical vapor deposition and were operated uniformly with a threshold current of 1.8 mA per laser and a total output power of 850 mW/facet under continuous wave conditions at room temperature. The active layer of each laser, which was grown on a periodic‐ridge‐shaped GaAs substrate and was of a multi quantum well structure, was separated from the active layer of adjacent lasers by a current blocking layer, so each laser operated in a stable fundamental lateral mode.

ISSN:0003-6951    

DOI:10.1063/1.105225

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Preferential excitation of the3P°1state of the lead atom and enhanced emission in the Pb(3P°1Pb(3P°1→1D2) transition at 722.9 nm have been observed following the detonation of lead azide, Pb(N3)2. The detonation is initiated by a short laser pulse and the products are expanded through a supersonic nozzle. It is suggested that the enhanced emission is due to preferential excitation of Pb(3P°1) via energy transfer from electronically excited N2combined with the effect of self‐trapping of the emission from3P°1to the3P0,1,2states. The implications to short‐wavelength chemical lasers are discussed.

ISSN:0003-6951    

DOI:10.1063/1.104674

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A high frequency, low dark current, 1.3 &mgr;m metal‐semiconductor‐metal photodetector on GaAs is reported. The measured frequency response of this photodetector up to 10 GHz agrees with a model that assumes different collection times for electrons and holes.

ISSN:0003-6951    

DOI:10.1063/1.104675

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A many‐body theory that includes band‐gap renormalization, plasma screening, and interband Coulomb effects is used to calculate the linewidth enhancement factor &agr; in quantum well lasers. We find significant variations in &agr; with carrier density, suggesting that improvements in the laser linewidth and reduction in filamentation effects are possible for some laser configurations.

ISSN:0003-6951    

DOI:10.1063/1.104676

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Phase‐shifted distributed feedback laser with linearly chirped grating (PS‐CG‐DFB) was analyzed. The field distribution, threshold gain difference between the lasing mode and the next lowest threshold gain mode, linewidth of the lasing mode, and output power of PS‐CG‐DFB were self‐consistently calculated under different injection levels. It is found that the lasing mode pattern and the carrier concentration distribution are ‘‘locked’’ at high injection level due to the strong interaction between carriers and photons. The chirped grating compensates the spatial hole burning effect to the mode stability and makes the mode stable in the whole injection region.

ISSN:0003-6951    

DOI:10.1063/1.104677

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report the first study of the room‐temperature electroabsorption effects in CdZnTe/ZnTe multiple quantum well structures which exhibit sharp excitonic absorption peaks. The magnitude of the Franz Keldysh and quantum‐confined Stark Effects are found to be comparable to those of III‐V semiconductors. With optimized structures we expect II‐VI semiconductors to be important components for information processing in the visible spectrum.

ISSN:0003-6951    

DOI:10.1063/1.104678

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Optically pumped stimulated emission is reported for the first time from Hg1−xZnxTe (x≊0.23) epilayers grown by liquid phase epitaxy. Pulsed lasing was observed up to 70 K. Maximum single mirror peak power output of 23 and 2 mW was measured at 12 and 70 K, respectively. The laser emission spectra consisted of a strong line around 5.4 &mgr;m, and a weaker one, 6–7 meV below it, which were attributed to band‐to‐band and to band‐to‐acceptor transitions. Far‐field patterns with angular width of &thgr;⊥=4° and &thgr;∥≊2.5° have been observed perpendicular and parallel to the layer plane, respectively.

ISSN:0003-6951    

DOI:10.1063/1.104679

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We describe electro‐optic polymer films that also exhibit photoconductivity. An acrylic polymer containing (as a side chain) a stilbene chromophore with a high second‐order nonlinear susceptibility was doped with a perylene sensitizer for photocharge generation and a triarylamine hole transporting molecule. A polymer film was fabricated that had an electro‐optic coefficient of 2.5 pm/V. Absorption of light by the sensitizer, that occurs in a region in which the polymer is otherwise transparent, results in a photocurrent and charge trapping. The quantum efficiency of photocharge generation and photorefractive figures of merit were calculated.

ISSN:0003-6951    

DOI:10.1063/1.104680

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Buried‐heterostructure tunable PbEuSeTe/PbTe lasers were fabricated using a two‐stage molecular beam epitaxy growth procedure. Improvements in the processing technique yielded lasers that show performance characteristics significantly better than those reported previously. A continuous wave (cw) operating temperature of 203 K was realized, which is the highest cw operating temperature ever reported for lead‐chalcogenides diode lasers. This laser exhibited exceptionally low‐threshold currents of 1.4 mA at 90 K and 43 mA at 160 K with single‐mode operation for injection currents up to 30Ithand 0.18 mW power at 100 K. The usefulness of the laser, when operating cw at 200 K, was demonstrated by the ability to perform high‐resolution spectroscopy of a low‐pressure CO2gas sample.

ISSN:0003-6951    

DOI:10.1063/1.104652

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A method is proposed for eliminating prepulses associated with high‐power ultrashort laser pulses. In this method the high‐power portion of the pulse is refractively guided due to relativistic effects associated with the plasma electrons. The low‐power prepulse, however, is unaffected and diffracts away. Optical guiding is achieved by appropriately choosing the plasma density, laser power, and wavelength. In addition, a wavebreaking stabilization mechanism for the Raman backscattering instability for intense laser pulses is proposed, which indicates that the pulse should not be significantly backscattered by the plasma.

ISSN:0003-6951    

DOI:10.1063/1.104653

出版商:AIP    

年代:1991

数据来源: AIP