摘要:

The field spectrum linewidth of a multiple quantum well laser immersed in a high magnetic field is measured at room temperature and at 165 K. The low‐temperature measurements show a decrease of linewidth with increasing magnetic field. We believe this behavior results from the formation of a totally discrete electronic state space. Measurements of the low‐temperature luminescence spectrum show that the emission is split into two peaks by the high field with the higher energy peak responsible for lasing action.

ISSN:0003-6951    

DOI:10.1063/1.98200

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A double heterostructure ridge waveguide with multiple quantum well InGaAs/InP core and InP cladding layers has been operated as a phase modulator at 1.52 &mgr;m wavelength. The observed phase shift coefficient was 12°/V mm. With a 1‐mm‐long device we have achieved a half wavelength shift at 15 V bias and a maximum phase shift of 420° at 35 V. Quantum confined Stark effect has been observed in the shorter 1.49–1.52 &mgr;m wavelength region. The ability to obtain &lgr;/2 modulation with a short device and relatively low voltage makes this device very attractive for practical applications.

ISSN:0003-6951    

DOI:10.1063/1.98201

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The use of picosecond,Q‐switched lasers and advanced polarization schemes has led to the development of a coherent Raman technique with the sensitivity of coherent anti‐Stokes Raman spectroscopy experiments but without the troublesome phase‐matching requirements. Experiments in dilute solutions of benzene indicate a limit of sensitivity for the current apparatus of 2.5×10−4M in two minutes of signal averaging over 150 cm−1. Possible applications to theinsitustudy of passive films and thin films on transparent media are discussed.

ISSN:0003-6951    

DOI:10.1063/1.98202

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

An output power of 110 mW cw has been achieved with a V‐grooved inner‐stripe laser diode on ap‐type substrate emitting at 1.5 &mgr;m wavelength. Output powers over 100 mW could be obtained by determining the appropriate cavity length and the reflectivity of the front mirror facet, a parameter that depends heavily on output power. These lasers were fabricated without introducing anti‐meltback layers. The meltback problem of the active layer was overcome using a low‐temperature liquid phase epitaxy technique.

ISSN:0003-6951    

DOI:10.1063/1.98203

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A micropole undulator is defined here as an undulator with a very short (submillimeter) period and correspondingly shorter poles. The availability of micropole undulators is expected to profoundly affect the development of x‐ray sources. For example, with such devices x‐ray beams comparable to those from conventional undulators will be attainable on storage rings of much lower energy (and emittance) than those presently in use. X‐ray instrumentation will also be affected, e.g., micropole undulators of sufficient length can provide extremely monochromatic outputs, obviating the need for expensive and complex ultrahigh vacuum monochromator systems. Here we describe the design and practical construction of a prototype 35 period micropole undulator whose total length is 2.54 cm. The device is of a novel hybrid/electromagnetic bias design. We also present results of field profile measurements along the central plane of the new device.

ISSN:0003-6951    

DOI:10.1063/1.98204

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Stable narrow‐linewidth (<100 kHz) operation has been demonstrated for a fiber‐extended‐cavity distributed‐feedback (EC DFB) laser emitting at 1.55 &mgr;m wavelength. We describe the observed oscillation frequency tuning characteristics of the laser obtained by controlling the temperature and injection current. The effects of distributed grating reflection and continuous frequency tuning schemes are examined for both the EC DFB laser and for the case of an EC DBR (distributed Bragg reflector) laser.

ISSN:0003-6951    

DOI:10.1063/1.98205

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We describe a new type of jet plating that uses a focused high‐frequency sound field directed through the center of the jet. The acoustic jet results in an improved morphology for gold and copper depositions although plating rates are not enhanced. Four‐point probe measurements of acoustic‐jet plated copper lines show up to a 50% decrease in electrical resistivity compared to jet plated deposits.

ISSN:0003-6951    

DOI:10.1063/1.98206

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A new low‐temperature film formation technique is proposed. It uses ionized species produced by an electron cyclotron resonance‐type microwave ion source with reactive gases and controlled in the low ion energy region, less than about 500 eV. Good quality homoepitaxial films on Si(111) are obtained at 600 °C and 100–500 eV ion energy by using SiH4as a material gas. By increasing the ion energy to 250‐300 eV, homoepitaxial growth at 400 °C can be achieved. Polycrystalline Si films on the same type of substrates can also be obtained at 200 °C.

ISSN:0003-6951    

DOI:10.1063/1.98207

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The crystalline structures of a sputtered Co‐doped iron oxide thin film have been successfully identified and correlated with magnetic properties. X‐ray diffraction analysis showed that the bulk of the sputtered film has been properly converted to ferromagnetic &ggr;‐Fe2O3. However, the surface of the film was found to be solely hexagonal &agr;‐Fe2O3. The formation of an antiferromagnetic &agr;‐Fe2O3surface on a ferromagnetic &agr;‐Fe2O3film caused the magnetically dead layer previously observed by polarized neutron reflection and Kerr rotation measurements.

ISSN:0003-6951    

DOI:10.1063/1.98208

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A laser array is described that makes use of edge injection into two sides (two ‘‘edges’’) of a stack of three AlxGa1−xAs‐GaAs multiple quantum well active regions. The edge‐injection array is realized by impurity‐induced layer disordering, which forms a higher gap Si‐dopedn‐type emitter that edge injects electrons into either side of a stack of three lower gap multiple quantum wellp‐type active regions. The far‐field beam divergence in the vertical direction (&thgr;⊥) of the array diode is reduced from 45° to 15° as determined by the laser operation, for comparison, of one of the quantum well active regions (oxide‐defined stripe geometry diode).

ISSN:0003-6951    

DOI:10.1063/1.98209

出版商:AIP    

年代:1987

数据来源: AIP