摘要:

We have studied the growth of InGaAs/GaAs multiple quantum wells (MQWs) on (111)A GaAs. Uniform thickness of (111)A quantum wells is observed by the cross‐sectional transmission electron microscopy (TEM). Growth induced long‐range In‐ and Ga‐rich InxGa1−xAs/InyGa1−yAs superlattice in (111)A is also observed by cross‐sectional TEM in the ternary InGaAs wells. In contrast, none of the above superstructure was observed by TEM on a side‐by‐side grown (100) oriented substrate. However, the photoluminescence (PL) linewidth is broadened by such compositional modulation. Low‐temperature (15 K) photoluminescence showed a broad PL linewidth of 27.5 meV for In0.16Ga0.84As/GaAs MQWs grown on (111)A substrates at 520 °C. A decreased PL linewidth of 15.7 meV and a reduced compositional modulation in InGaAs wells can be achieved at a higher growth temperature of 560 °C. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118133

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The change in position of fluorescent beads captured inside the focal volume of optical tweezers is monitored using fluorescence emission induced by two‐photon absorption of a continuous‐wave Nd:YAG laser (&lgr;=1064 nm). The displacement of a bead due to interactions with its environment leads to a fluorescence intensity variation that is used to design a novel spatial sensor. We determine changes in the axial position of a CY3‐labeled latex bead with a diameter of 1.03 &mgr;m to a precision better than 10 nm. At an intensity of 600 mW/ &mgr;m2the two‐photon bleaching rate is lower than 50% per 2000 s. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118134

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

A GaAs/AlAs planar cavity containing a collection of InAs quantum boxes in its core region has been grown in a single step by molecular beam epitaxy, and processed by electron‐beam lithography and reactive ion etching into pillar microresonators. The optical study by photoluminescence of these localized light emitters allows a systematic and precise determination of the energies of the first confined photon modes of such microstructures, in good agreement with theoretical estimates. More generally, such probes facilitate the experimental study of the modes of complex photonic microstructures and of the spontaneous emission alteration they entail on a quasimonochromatic light emitter. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118135

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We have developed a vacuum ultraviolet (VUV) flash lamp using a binary rare gas mixture excited by a pulsed silent discharge. In a Kr/Xe silent discharge, the VUV emission spectral width was extended up to 26 nm full width at half‐maximum (FWHM) at a center wavelength of 162 nm. According to kinetic analyses, such a spectral extension in mixed rare gases is attributed to the simultaneous emissions from heteronuclear rare gas excimers (KrXe*) and homonuclear rare gas excimers (Kr2*and Xe2*). ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118136

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

By using the effects of increasing hydrostatic pressure to counteract the effects of rising temperature, we demonstrate a technique to stabilize the wavelength of an uncooled diode laser. We use the differential thermal expansion between various materials incorporated into the laser package to automatically generate a temperature‐dependent pressure, and obtain a 50% reduction in the temperature sensitivity of the wavelength of a 1.55 &mgr;m GaInAsP/InP laser. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118137

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Lanthanum doped lead titanate (PLT) thin films with good surface morphology and perovskite structure were fabricated by the metalo‐organic decomposition process. Their nonlinear optical property was investigated byZ‐scan technique. PLT30 thin films on the quartz substrate display strong nonlinear optical effects. A nonlinear refractive index as high as 3.0×10−7esu was obtained for the thin film. All the results show that PLT ferroelectric thin films are promising materials for nonlinear optics. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118138

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Interdiffusion of a standard AlGaAs/GaAs quantum well is proposed as a viable alternative to the complex techniques necessary to fabricate parabolic quantum wells. The extent of the linear diffusion is optimized in order to produce an energy‐level ladder if four almost equally spaced eigenstates. The calculated third‐order susceptibility of 2700 (nm/V)2is comparable with that of the parabolic quantum well, which is more than six orders of magnitude compared to that of the bulk GaAs. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118139

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Vertical‐cavity surface‐emitting lasers (VCSELs) have been transferred from their original GaAs substrates to Cu substrates and continuous wave operation has been obtained on the VCSELs after epitaxial transfer. The resultant measurements show a doubling of the output power and a 20% reduction in the thermal impedance. Increased optical power is explained by improved thermal heat sinking as measured from the lasing spectra of horizontal‐cavity edge‐emitting lasers fabricated from the same VCSEL material. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118140

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Gain‐guided, injection lasers using AlAsSb for optical confinement and a strained InAsSb/InAs multiquantum well active region were grown by metalorganic chemical vapor deposition. The semi‐metal properties of ap‐GaAsSb/n‐InAs heterojunction are utilized as a source for injection of electrons into the active region of the laser. In pulsed mode, the laser operated up to 210 K with an emission wavelength of 3.8–3.9 &mgr;m. We also report on the two‐color emission of a light‐emitting diode with two different active regions to demonstrate multistage operation of these ‘‘unipolar ’’ devices. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118141

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The damage produced in silicon carbide single crystal by ion implantation was investigated byinsituoptical transmittance and reflectance at 633 nm and by Rutherford backscattering channeling spectroscopy. Implantations were performed at room temperature with different ions (He, N, Ar, Kr, and Xe) in the fluence range 1011–2.5×1016ions/cm 2. During irradiation a reduction of transmittance and a contemporary increase of reflectance occurred. RBS indicated a continuous accumulation of damage within a depth comparable with the ion range until the formation of an amorphous layer. A combination of optical and RBS data allowed to correlate the optical constant (n,k) to the damage produced during irradiation. Such a correlation was identical for every ion pointing out that the optical properties of the damaged material are independent of the energy density inside the single cascade. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118142

出版商:AIP    

年代:1996

数据来源: AIP