摘要:

Data are presented demonstrating the operation of a current‐injection laser diode with embedded reflectors instead of etched or cleaved facets. The laser structure, grown by molecular beam epitaxy, uses AlAs‐GaAs superlattices SL’s in place of conventional AlxGa1−xAs cladding layers. The sample is patterned, etched, and Zn diffused to selectively disorder the SL cladding layers producing a ∼200×∼100 &mgr;m rectangular laser cavity embedded in the surrounding AlxGa1−xAs. Following Si3N4deposition and metallization, the diodes are cut (not cleaved) with intentionally damaged edges. These devices operate as lasers (77 K, pulsed operation) with a mode spacing corresponding to either the ∼100‐&mgr;m or the ∼200‐&mgr;m cavity length formed by the selective interdiffusion of the SL cladding layer. This embedded‐mirror laser structure may be useful in the development of optical integrated circuits by allowing semiconductor lasers to be monolithically integrated with other optical devices.

ISSN:0003-6951    

DOI:10.1063/1.95309

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

It is desirable to increase the operating temperature of long wavelength lead‐chalcogenide diode lasers to simplify cooling system requirements. Recently, double heterostructure Pb1−xEuxSeyTe1−ydiode lasers (grown by molecular beam epitaxy) operated up to 147 K cw (180 K pulsed). The output photon energy of these devices is linear withxin the wavelength range 6.6– 2.7 &mgr;m. The growth of single quantum well lead‐chalcogenide diode lasers is now reported for the first time. These devices had PbTe quantum wells with PbEuSeTe confinement layers. The width of the quantum wells,Lz, was varied from 300 to 250 A˚. Strong quantum effects are observed forLz≲ 1200 A˚ because of the small carrier masses (me∼mh∼0.04mo). The shift in laser emission energy is in approximate agreement with that calculated from a finite square well potential. At low temperatures (≲100 K), these lasers appear to operate on transitions betweenn=1 states in the conduction and valence bands at threshold. Transitions between then=2 states require a higher current which decreases with increasing temperature until the laser switches to then=2 transition at threshold. The threshold current then increases relatively slowly with temperature, yielding cw operation up to 174 K (at 4.41‐&mgr;m wavelength), and pulsed operation up to 241 K (at 4.01 &mgr;m). These are the highest operating temperatures ever reported for lead‐chalcogenide diode lasers, and increases their potential usefulness for spectroscopic applications and for long wavelength fiber optics communications.

ISSN:0003-6951    

DOI:10.1063/1.95310

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

We demonstrate electro‐optic frequency shifting of laser light (&lgr;=723 nm), electronically tunable through more than ± 1 MHz, in a LiNbO3: Ti single‐mode stripe waveguide, using polarization conversion at a traveling index grating, driven by two phase‐quadrature voltages of ∼27 V at the offset frequency. The optical carrier and undesired sidebands are suppressed better than 30 dB by polarizers, conversion efficiency ≥70%, device length 4.5 mm, optical bandwidth ∼1 nm; direct butt coupling to fibers is possible.

ISSN:0003-6951    

DOI:10.1063/1.95311

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Electrical sampling with a temporal resolution of less than 500 fs has been achieved using coplanar transmission lines on electro‐optic substrates. The improved performance over the previously demonstrated balanced stripline is due to the reduced dimensions, i.e., distance between the electrodes and width of the electrodes, achievable with photolithographic technique. By further reducing the line dimensions to 10–20‐&mgr;m range, this technique makes the temporal resolution of electrical waveforms in the range of 100 fs possible.

ISSN:0003-6951    

DOI:10.1063/1.95312

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Multiplication of the pulse repetition rate of a mode‐locked laser beam using an all‐optical technique has been used to generate microwave radiation from an avalanche photodiode as well as from an optoelectronic switch.

ISSN:0003-6951    

DOI:10.1063/1.95313

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Laser cathode ray tube operation has been demonstrated at room temperature with GaAs/GaAlAs double heterostructure targets. An external efficiency of 2.7% was achieved with a 20‐A/cm2beam of 30‐keV electrons. Reasonable uniform emission over a 2 mm×2 mm area was observed.

ISSN:0003-6951    

DOI:10.1063/1.95314

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The solution of the electrode and pole piece reconstruction problem is given. The axial potential or flux density distribution is sought in the form of a simple curve with a continuous second derivative. The reconstruction procedure then is extremely simple and quite accurate. As an example the electrode system for an optimized electrostatic lens is shown.

ISSN:0003-6951    

DOI:10.1063/1.95315

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

We derive the modulation and noise properties of a semiconductor laser consisting of an active cavity loaded by a passive cavity. The results indicate that under certain conditions the direct modulation bandwidth can be doubled with simultaneous phase noise reduction as compared to a conventional laser.

ISSN:0003-6951    

DOI:10.1063/1.95316

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Thickness variation of visually opaque foils used as x‐ray and ultraviolet (XUV) photon filters and photocathodes can introduce anomalies in recorded intensities, images, and spectral line profiles. In laser fusion studies, mass thickness variations of laser‐accelerated foils can hydrodynamically disrupt their motion. We have used transmitted electrons to obtain quantitative local (area ≤1 &mgr;m2) measurements of mass thickness as well as qualitative images of mass thickness variations in free‐standing Be, C, and Al foils presently in use in the above areas of investigation. Substantial mass thickness variations, up to a factor of 4 for Al and 1.3 for Be, were found which can produce considerable modulations in transmitted XUV photon intensity.

ISSN:0003-6951    

DOI:10.1063/1.95294

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Single longitudinal mode output from a directly tuned, long pulse, magnetically switched XeCl laser is reported for the first time. Mode control was achieved using spatial aperatures and intracavity etalons. The narrow bandwidth laser output was diffraction limited with an optical pulse width of 30 ns, which would yield a transform limited bandwidth of 30 MHz.

ISSN:0003-6951    

DOI:10.1063/1.95295

出版商:AIP    

年代:1984

数据来源: AIP