摘要:

The effect of length on the yield of second‐order distributed feedback lasers with cleaved facets capable of operating in a single longitudinal mode and on their characteristics has been studied experimentally. The optimum length of 200 &mgr;m was determined in reference to the coupling coefficient and the end‐facet reflectivity. A yield of more than 70% was obtained for lasers 200 &mgr;m in length capable of operating at a level of at least 10 mW and over.

ISSN:0003-6951    

DOI:10.1063/1.98659

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A surface‐emitting AlGaAs second‐order distributed Bragg reflector laser using a graded index separate confinement heterostructure with a single quantum well has been fabricated. The surface emitted power is in excess of 30 mW with an external differential quantum efficiency of 20%. These values approach the performance of present commercially available edge‐emitting diode lasers. Under severe current modulation conditions, the stable single longitudinal mode had nearly 30 dB wavelength sidemode rejection, and a near diffraction limited 0.51° full width half‐power beam divergence of the single‐lobe far‐field pattern.

ISSN:0003-6951    

DOI:10.1063/1.98660

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Three image processing experiments were performed by degenerate four‐wave mixing in photorefractive GaAs. The experiments were imaging by phase conjugation, edge enhancement, and autocorrelation. The results show that undoped, semi‐insulating, liquid‐encapsulated Czochralski‐grown GaAs crystals can be used as effective optical processing media despite their small electro‐optic coefficient.

ISSN:0003-6951    

DOI:10.1063/1.98661

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The linear and nonlinear optical properties have been determined for a new organic nonlinear material 4‐(N,N‐dimethylamino)‐3‐acetamidonitrobenzene. Room‐temperature angularly tuned type I phase matching for doubling of 1.064 &mgr;m radiation was achieved with adeff=27 pm/V. Favorable crystal growth habits were observed.

ISSN:0003-6951    

DOI:10.1063/1.98662

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The effects of a birefringence in a semiconductor laser are reported. We demonstrateN&pgr; (whereNis an odd integer) phase retardation between the TE and TM modes in the laser output beam resulting in the phenomenon of counter rotation of the output polarization. A numerical value for the birefringence is estimated.

ISSN:0003-6951    

DOI:10.1063/1.98663

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A chemically pumped oxygen iodine laser system has been operated employing 35 wt. % H2O2rather than commonly used 90 wt. % H2O2. Laser power as high as 40 W has been extracted. The maimum overall efficiency of 20.7%, which is almost 25% higher than the previously reported best data, has been achieved.

ISSN:0003-6951    

DOI:10.1063/1.98664

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Commercial avalanche photodiodes have been operated as single‐photon detectors at an optimum operating temperature and bias voltage. These detectors were found to be 1.5–3 times more sensitive than presently available photomultiplier tubes (PMT’s). Both single‐photon detection probability and detector noise increase with bias voltage; detection probabilities greater than twice that of a PMT were obtained with detector noise levels below 100 counts per second. Higher probabilities were measured at higher noise levels. The sources of noise and their dependence on temperature and bias voltage are discussed.

ISSN:0003-6951    

DOI:10.1063/1.98665

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Measurements on the production of negative hydrogen ions at a barium surface, in contact with a hydrogen plasma, are presented and discussed. In spite of the high work function of barium compared to more conventional cesiated converter surfaces, considerable yields of negative ions were produced. Conversion efficiencies up to 4% were achieved. No negative barium ions were observed.

ISSN:0003-6951    

DOI:10.1063/1.98613

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Direct writing onto Si has been demonstrated by electron beam induced surface reaction using a XeF2source. The electron beam stimulated etched depth for Si(100) is proportional to the electron dose. Etch depth by electron beam stimulated etching is 500 nm at 10 kV accelerating voltage, 4×10−3C/cm2dose, and 5 mTorr XeF2gas pressure. An enormously high etching yield of about 100 Si atoms per electron has been observed for electron stimulated etching using the XeF2source. A 0.5‐&mgr;m linewidth pattern has been fabricated at a 4×10−3C/cm2dose.

ISSN:0003-6951    

DOI:10.1063/1.98614

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

It has been found that a relatively low‐dose focused ion beam irradiation makes an organogold film insoluble to its solvents (e.g., trichloroethylene), resulting in submicron pattern formation. Ion beam induced, low conductivity as with resistivities of (4–4000) M&OHgr;/&laplac; has been observed for more than 1×1015ions/cm2dose for a 0.65‐&mgr;m‐thick film. However, by heat treatment at 300 °C after low‐dose ion beam patterning, gold patterns with resistivity of 3×10−4&OHgr; cm, which is about 100 times the bulk gold value, are obtained.

ISSN:0003-6951    

DOI:10.1063/1.98615

出版商:AIP    

年代:1987

数据来源: AIP