摘要:

Single lobe operation of a 40‐element GaAlAs gain guided coupled stripe array emitting 500 mW cw is obtained in an external ring laser cavity. The cavity arrangement is equivalent to self‐injection locking of the array by its own output, which is first spatially filtered by a single mode fiber. Diffraction‐limited lobe width of 0.13° and single mode operation are demonstrated with a 90 mW single mode fiber output.

ISSN:0003-6951    

DOI:10.1063/1.98839

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Low threshold InGaAsP/InP lasers with planar buried heterostructure were grown entirely by low‐pressure metalorganic chemical vapor deposition (MOCVD). The threshold currentIth=10 mA and the differential quantum efficiency &eegr;d=60%, which are comparable to lasers grown by liquid phase epitaxy, were obtained. Most lasers randomly selected from one wafer have threshold currents ofIth=10–25 mA, because of high thickness uniformity of MOCVD growth. Stable fundamental transverse mode operation was also obtained up to an output power of 40 mW/facet, due to controlling the active layer width less than 2 &mgr;m.

ISSN:0003-6951    

DOI:10.1063/1.98840

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A transverse mode stabilized GaAlAs laser diode which includes a ZnSe layer for the waveguide has been developed. The double heterostructure of the GaAlAs laser is formed by low‐pressure metalorganic chemical vapor deposition (MOCVD), and a ZnSe layer is grown by adduct‐source MOCVD in order to block the injection current and change the real refractive index in the lateral direction. The fundamental transverse mode oscillation of more than 15 mW is obtained with a low threshold current of 28 mA and a high quantum efficiency of 76%. An output power as high as 25 mW is achieved.

ISSN:0003-6951    

DOI:10.1063/1.98841

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We describe an extensive characterization procedure developed to study multilayers for extended ultraviolet (XUV, 1 A˚≲&lgr;≲1000 A˚) optics. We present results of this procedure applied to sputtered Si/W multilayers designed as normal‐incidence XUV reflectors for ∼200 A˚. Techniques used were low‐angle x‐ray diffraction, Bragg–Brentano and Seemann–Bohlin diffraction, wide‐film Debye–Scherrer (Read) camera, Rutherford backscattering spectroscopy, and transmission electron microscopy. Reflectances at several incidence angles were measured with synchrotron radiation and found to agree very well with reflectance curves calculated without adjustable parameters. The information obtained from the different techniques forms a coherent picture of the structure of these materials.

ISSN:0003-6951    

DOI:10.1063/1.98842

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Optimizations of the F2/Ar/Ne gas composition and the optical cavity configuration were performed for an ArF* laser in the pressure range from 1 to 14 bar. The excitation source was a coaxial electron beam with a pulse length of 40 ns. From an active volume of 16 cm3a maximum output energy of 130 mJ at a total gas pressure of 14 bar was obtained when Ne was used as the buffer gas.

ISSN:0003-6951    

DOI:10.1063/1.98843

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The GaAs‐GaAlAs graded‐index separate confinement heterostructure was grown selectively by molecular beam epitaxy on a SiO2‐masked GaAs (100) substrate. The stripe windows on the SiO2mask were 10 &mgr;m in width and were oriented along [011¯] direction. The laser diodes thus fabricated lased in a single longitudinal mode with a side mode suppression ratio of 95:1. Both the longitudinal mode and the single‐lobe far‐field pattern were stable up to 4Ith.

ISSN:0003-6951    

DOI:10.1063/1.98844

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The first study of the photorefractive properties of doped CdTe has demonstrated high sensitivity for optical processing applications. Of the binary II‐VI and III‐V semiconductors, CdTe has the highest electro‐optic coefficientr41in the infrared, some three times larger than that of GaAs and InP. Deep levels introduced into CdTe exhibit appropriate absorption and photoconductivity at 1.06 &mgr;m by doping with V and Ti impurities. Photorefractive beam coupling experiments in CdTe:V gave small signal gains of 0.7 cm−1, and diffraction efficiencies with no applied electrical field of 0.7%. Thus, CdTe appears to be superior to previously studied III‐V semiconductors, in the near‐infrared spectrum. Optimization of doping and trap densities is expected to result in gain which exceeds the absorption loss, thereby allowing phase conjugation with infrared injection lasers.

ISSN:0003-6951    

DOI:10.1063/1.98845

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Photothermal spectra of an isocyanine dye monolayer, separated from a silver mirror by a varying number of cadmium arachidate layers, are recorded with a pyroelectric calorimeter. The spatial dependence of the light intensity in front of the silver mirror is observed. The phase angle of a light wave upon reflection from the silver surface is determined to be 124±5° at a wavelength of 578 nm. The quantum yield for radiationless deexcitation at that wavelength is found to be 33±7%.

ISSN:0003-6951    

DOI:10.1063/1.98846

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We have investigated the pulsation behavior of InGaAsP semiconductor lasers with a proton‐bombarded segment. These lasers emit picosecond (30–70 ps) pulses at gigahertz (0.6–3.0 GHz) rates. An antireflection‐coated diode in an external cavity is passively mode locked and multistable; as many as four co‐existing states are observed. Interlocking hysteresis loops are observed in the pulsation frequency, pulse width, and output power as functions of the bias current. A delayed feedback model explains qualitative features of the multistable mode locking. To our knowledge this is the first report of multistability of laser pulsation.

ISSN:0003-6951    

DOI:10.1063/1.98847

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Chlorine atoms have been detected in rf etching plasmas of CClF3and CCl2F2with three‐dimensional spatial resolution using a two‐photon laser‐induced fluorescence technique. The spin‐forbidden 4p(4S0)–3p(2P0) transition is pumped by absorption of two 233.3‐nm laser photons. Decay of the excited state results in 725–775 nm emission. Spatially resolved plasma concentration measurements under certain etching conditions indicate an anomalously large signal spike at the plasma/sheath boundary, an effect attributed to an aggregation of chlorine‐containing negative ions which are also detected by this technique. The negative ions are detected by laser‐induced photodetachment followed by two‐photon excitation of atomic Cl.

ISSN:0003-6951    

DOI:10.1063/1.98848

出版商:AIP    

年代:1987

数据来源: AIP