摘要:

Based on an inverse transform method originally developed by Chandley and modified by us in the present work, we show that the height‐height correlation function of a rough Si surface can be obtained directly from a single intensity distribution profile of light scattering. A novel diode array detectors arrangement was used to obtain the intensity profile. The roughness parameters, including the interface width, lateral correlation length, and roughness exponent were extracted from the height‐height correlation function and were compared with that obtained by an atomic force microscope. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116423

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

In acousto‐optic interactions, the concept of momentum mismatch introduced by some books is misleading and nonexistent because the mismatch itself is caused by the approximate model used to explain the interactions. The so‐called mismatch is very small and should not be handled with an approximate model. We use an exact model to satisfy Bragg condition, conservation of energy, and conservation of momentum. The difference between the exact model and the approximate model is actually what causes the mismatch. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116424

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The tension on the core of single‐mode fibers is strongly increased by the formation of a Bragg grating. This tension increase lowers the refractive index because of the photoelastic effect. On the other hand, the compaction of the core network results in an increased refractive index. The two contributions are evaluated from axial stress measurements, from the determined index modulation amplitude, and from the mean index change of the Bragg gratings. The total Bragg grating index modulation is smaller than the compaction‐induced index modulation by 30%–35% because of the photoelastic effect. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116425

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Faraday rotation and magnetization in Hoya FR5 glass is investigated in a magnetic field up to 80 kG under cryogenic temperature between 4.2 K and 10 K at the wavelength of 514.5 nm. ForH/T≳10 kG K−1, the saturation is observed both in magnetization and in Faraday rotation and is interpreted by using the quantum theory of paramagnetism about the doped Tb3+active ion. It is found that the temperature dependence of the Verdet constant is correlated with the magnetic susceptibility and the dispersion of the Verdet constant is due to the effective electric dipole transition of 4f8→4f75d1with the resonance wavelength of 213 nm. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116426

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We report on intervalence‐band laser emission from Be‐ and Zn‐doped germanium crystals. The duty cycle of 10−3at a repetition rate of 1 kHz is one order of magnitude larger than the highest duty cycle reported forp‐Ge lasers doped by group II acceptors. This improvement is due to the much larger hole binding energy of double acceptors Be and Zn which results in a strong reduction of the internal absorption of the generated far‐infrared radiation. Laser action has been achieved with crystal volumes as small as 0.04 cm−3, and a laser pulse length of 25 &mgr;s has been reached. Germanium crystals doped with these acceptors may offer an opportunity for achieving the ultimate goal of continuous wave operation. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116427

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We report the use of a novel impurity free vacancy disordering technique which has been used to produce waveguides with different Kerr‐type nonlinear coefficients. The technique relies on standard SiO2dielectric caps to promote disordering and Ga2O3caps to suppress disordering. Band‐gap shifts of around 40 nm and consequent changes inn2of more than 60% are reported. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116428

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Coherent precipitates of vanadium dioxide have been formed in the near‐surface region of sapphire by the stoichiometric coimplantation of vanadium and oxygen combined with subsequent thermal processing at temperatures ranging from 700 to 1000 °C. The embedded VO2precipitates, which are three‐dimensionally oriented with respect to the Al2O3host lattice, undergo a first‐order monoclinic‐to‐tetragonal (and also semiconducting‐to‐metallic) phase transition at ∼77 °C. This transformation is accompanied by a significant variation in the optical transmission of the implanted region and results in the formation of an optically active, thermally ‘‘switchable’’ surface region on Al2O3. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116429

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We have studied optical changes induced by ArF (6.4 eV/193 nm) excimer laser light illumination of high purity SiO2implanted with Si 2+(5 MeV) at a fluence of 1015ions/cm2. Optical absorption was measured from 3 eV (400 nm) to 8 eV (155 nm) and showed evidence of several well‐defined absorption bands. A correlation in the bleaching behavior appears to exist between the so‐calledDband (located at 7.15 eV) and the well‐knownB2&agr; band which is attributed to oxygen vacancies. Changes in the refractive index as a function of ArF illumination were measured and found to be in good quantitative agreement with a Kramers–Kronig analysis of the optical absorption data. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116430

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

A fast and accurate microsizing method is introduced and analyzed for metallic protuberances on flat substrates. It is based on the measurement of the minima angular positions of theS‐polarized far field scattering patterns at normal incidence. The proposed method has been theoretically and experimentally checked for both cylindrical and spherical metallic protuberances on conducting flat substrates. The excellent agreement between theory and experiment proves the efficiency of the method. We also comment on the application of this method for other protuberance geometries and different substrates other than metallic. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116431

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Arsenic impurities in silicon can be electrically activated beyond their electrical solubility to as high as 4×1021/cm3by ion implantation and laser melting; further annealing decreases this activity to its equilibrium saturation level. To characterize the deactivation process, we used x‐ray standing‐wave spectroscopy. Hall effect, and secondary‐ion‐mass spectroscopy. Our results indicate that the As impurities remain in substitutional positions even after 85% of the activation has been lost, so deactivation cannot be due to As migration to interstitial sites or to large precipitates. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116432

出版商:AIP    

年代:1996

数据来源: AIP