摘要:

We demonstrate that Nd3+:ethylene glycol can be used as an amplifier gain medium for a Nd3+:YLF laser. It has been known that Nd3+:liquid is hard to use as a gain medium due to fluorescence quenching. However, we could use Nd3+:ethylene glycol as a gain medium by using a new amplification system, and we also measured the stimulated emission cross section of Nd3+:ethylene glycol. A maximum gain of ∼2 was obtained in our experimental setup, and the stimulated emission cross section of Nd3+:ethylene glycol was measured to be 1.5(±0.5) ×10−19cm2. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114472

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We experimentally investigate a gain‐switched Fabry–Perot semiconductor laser externally injection seeded with a narrow linewidth continuous wave laser. We determine the dependence of pulse width, side‐mode suppression ratio, and timing jitter on seeding power and seeding wavelength. As external seeding power is increased up to a certain value, we observe negligible change in pulse width, a linear increase in side‐mode suppression ratio, and a linear decrease in timing jitter. Exceeding a certain value leads to substantial pulse broadening. By tuning the seeding wavelength across a chirped mode of the laser, we observe the lowest timing jitter and the largest side‐mode suppression when the seed wavelength is aligned with the center of the chirped spectrum of a desired mode. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114473

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Differential carrier lifetime as a function of subthreshold bias current in 1.3 m bulk active lasers is obtained by measurement of small‐signal modulation of amplified spontaneous emission together with careful characterization of frequency‐ and current‐dependent device impedance. The strong influence of rapidly varying device impedance upon these measurements is illustrated. In contrast to other studies, neither saturation of differential lifetime at low currents nor linear dependence of spontaneous emission on carrier density is observed. Recombination parameters, fit from current versus carrier density, along with consistent fits of spontaneous emission versus carrier density, are presented. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114474

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Optimal conditions for reducing threshold current are investigated for quantum structure (QS) semiconductor lasers. The filling factor of whole QSs to an active region is introduced. A general procedure is presented for obtaining the relation between the threshold current and filling factor from the relation of gain to injected carrier density of the individual QS. It is shown that there is a filling factor that minimizes the threshold current. From this value, the optimal areal coverage is shown to be about 0.1 for a quantum box and 0.8 for a quantum wire for an ordinary surface emitting laser with a single In0.53Ga0.47As/InP. The effects of various imperfections in actual QSs are also discussed. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114475

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The authors demonstrate that in 1.55 &mgr;m InGaAsP/InP quantum well lasers proper inclusion of the conduction‐valence coupling is essential to obtain accurate gain characteristics. It is shown that the orbital character of the confined subbands, and the resulting optical matrix elements, play a dominant role. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114476

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The impurity‐related and band‐to‐band photoluminescence of a commercially available III–N blue‐light‐emitting diode is time‐resolved using femtosecond excitation and streak‐camera detection. Photoluminescence decay times are reported and stimulated band‐to‐band emission is observed. The data are compared to a simple recombination model capable of explaining the measured behavior of the photoluminescence. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114477

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A blue frequency shift in a distributed‐feedback laser diode (DFB‐LD) induced by light injection is described. It is observed in an experiment that the lasing wavelength shifts toward the shorter wavelength and the carrier number increases when external light is injected into a DFB‐LD in a particular condition. AnFmatrix analysis shows a similar behavior, where spatial distribution of the carrier density induced by the external light is taken into account. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114478

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

An excess heat from an exothermic reaction of metastable Ar (43P0) and Ar (43P2) atoms with N2molecules at low contents of N2in Ar was found to be responsible for an enhanced thermionic emission, an enhanced production of Ti target vapor, an increased ionization, and consequently for an enhanced deposition rate of TiN films in the radio frequency hollow cathode plasma jet (RHCPJ). This finding emphasizes favorable geometry of hollow cathodes, as well as an important role of metastables in plasma‐assisted processes. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114479

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A free energy diagram of the Ag–Mo system with a very positive heat of formation of +57 kJ/mol was constructed, with special consideration to the interfacial free energy in the multilayered films for ion mixing. It was found that amorphization was possible to achieve within two separate composition ranges toward Ag and Mo ends, respectively, if 12 layers, or about 13% of the interfacial atoms were included in the films. Accordingly, ion mixing of the Ag–Mo multilayered films was conducted at liquid nitrogen temperature by 190 keV xenon ions and the formation of amorphous phases was in good agreement with the calculation. Besides, a new metastable fcc phase was formed and, more interestingly, it transformed into an amorphous state upon aging, which can also be interpreted by a related free energy calculation. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.114480

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

High resolution images of individual molecules of the liquid crystalline material adsorbed on a photopolymer treated transparent conducting (indium oxide coated) glass plate have been obtained with a scanning tunneling microscope (STM). The ultrathin layer of the photopolymer poly‐vinyl‐4‐methoxy‐cinnamate (PVMC) on the conducting glass plate was deposited by the bulk induced alignment technique reported earlier [S. C. Jain and H.‐S. Kitzerow, Appl. Phys. Lett.64, 2946 (1994)]. The liquid crystal molecules exhibit a positional order, in addition to a high degree of orientational order of the bulk nematic. This surface ordering of the nematic liquid crystal at the polymer interface is quite different from the ordering observed on graphite and molybdenum disulphide substrates. A small ensemble of molecules show antiparallel ordering of the cyano‐phenyl‐cyclo‐hexane molecules in agreement with the calculations of Schadtetal. [Liq. Cryst.5, 293 (1989)]. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114481

出版商:AIP    

年代:1995

数据来源: AIP