摘要:

Accurate measurements of InP refractive indices in the 1300–1600 nm wavelength range are reported. They are obtained using the grating coupling technique within an asymmetrical slab waveguide where an intrinsic InP guiding layer was grown on a doped InP substrate (N=2×1018cm−3). Modal indices are obtained with an absolute precision of a few 10−4from either guided or reflected waves. Bulk refractive indices of intrinsic and N‐doped InP are then deduced from the allowed modes propagating in the layered structure. With sample temperature maintained to within 0.01 K, InP bulk indices are obtained with a typical accuracy of 5×10−4. Furthermore, a (2.02±0.02) 10−4K−1refractive index temperature coefficient has been measured for bulk InP at room temperature. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114723

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Solutions of a paraphenylene ethynylene copolymer simultaneously absorb three photons of intense near infrared radiation. When the polymer relaxes, it emits visible radiation which can be seen clearly by the naked eye. Intensity dependent transmission studies have been used to measure &agr;3, the three photon absorption coefficient. The value obtained for a 10−3M solution of the polymer is 10−22cm3 W−2, which is remarkably large in view of the low concentration employed. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114724

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We report the successful fabrication of planar waveguides in rare‐earth doped fluoroindate glass substrates. A new procedure for waveguide fabrication using a thermally evaporated AgF nonmetallic film was developed. The refractive index changes of more than 0.03, associated to low propagation losses achieved, open new perspectives and show the potentiality of using this glass family toward further developments in fabrication and design of integrated optical devices for optical communication wavelengths. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114725

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Room‐temperature gain coupled distributed feedback (GC‐DFB) lasers have been realized by implantation induced intermixing in the GaAs/AlGaAs material system. The implantation dose has been systematically varied to realize GC‐DFB lasers with different gain coupling coefficients due to different band‐gap modulation of the active quantum wells. It is demonstrated that a band‐gap modulation of 7 meV is sufficient to achieve a high single mode yield at room temperature. The results are discussed on the basis of calculations with the optical matrix theory. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114726

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We have examined the nonlinear optical properties of a main chain organic polymer waveguide in the 1.5 &mgr;m wavelength region. The nonlinear absorption coefficient was estimated to be &agr;2=0.8–2×10−11m/W in the 1.48–1.61 &mgr;m wavelength range. The wavelength dependence of the nonlinear absorption coefficient suggests that the strong nonlinear absorption originates from two step absorption through overtones of C–H vibrational absorption. The nonlinear refractive index was estimated to ben2=2.8(±0.3)×10−18 m2/W at a wavelength of 1.55 &mgr;m. The nonlinear absorption would restrict the applicability of the waveguide to all‐optical switching in this wavelength region. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114727

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

It is shown that for a cathode consisting of compressed graphite powder, the cathodic arc discharge is confined within deep erosion holes and the macroparticle emission is greatly reduced. Electron energy loss spectroscopy and scanning electron microscopy show that smooth tetrahedral amorphous carbon films with up to 85±10%sp3bonding can be deposited without the use of magnetic filters. The new carbon arc discharge process holds potential for deposition of smooth tetrahedral amorphous carbon films on large area substrates due to the elimination of the magnetic filtering stage. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114728

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

In order to obtain the optimum performance for the electron cyclotron resonance/reactive ion beam etching (ECR‐RIBE) reactor, we have examined the effect of Cl2flow rate on Cl concentration by utilizing the optical emission peak intensity from Cl as the index of its concentration. The peak intensity observed in the reactor not containing GaAs substrate decreases monotonically as the flow rate increases. However, when the GaAs substrate is introduced into the reactor, we observe the intensity decrease drastically at lower Cl2flow rates. At the same time, strong emission peaks from Ga are observed, and their intensity also shows flow rate dependency. These results can be explained using a simple model that divides the ECR‐RIBE reactor into two continuous stirred tank reactors (CSTRs). We believe that this model and the kinetic constants obtained here can contribute to the efficient optimization of the ECR‐RIBE process. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114729

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A new synthesis method of fullerenes has been investigated for microwave induced naphthalene‐nitrogen plasma at atmospheric pressure using a cylindrical coaxial cavity. The toluene extract solution of soot obtained after discharges showed HPLC peaks with retention times corresponding well to those of C60and C70. The production of fullerenes was also confirmed by mass‐spectrometric analysis. Gas temperature of nitrogen plasma determined from radiative transitions of N2+was 3800–5700 K. From a comparison of the gas temperature and the incident microwave power, it was found that the reaction efficiency for fullerenes decreases with the increase in the gas temperature of the plasma and shows a maximum at about 4500 K. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114688

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

With the application of voltage pulses, mounds of 20 nm in diameter and 2 nm in height on the average can be created on a gold surface with very high efficiency in nonconducting liquid from a gold tip. The created mounds are similar to those produced in air. Tungsten and PtIr tips are also used in this study and the dominant shapes of created structures are craters and volcanolike mounds, respectively. Our data show that these nanometer structures are created by a mechanical contact between the tip and the sample. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114689

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The reverse leakage current in strained multiple quantum well (MQW)p‐i‐nstructures has been measured for a range of different dimensions and strain. The magnitude of the leakage current is found to be dependent on the average strain of the MQW, the total MQW thickness and the thickness of the capping layer. Plan view transmission electron microscopy shows that misfit dislocation arrays form primarily at the upper and lower MQW interfaces and the total density of these determine the leakage current. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114690

出版商:AIP    

年代:1995

数据来源: AIP