摘要:

Organic electroluminescent (EL) devices with multilayered thin‐film structures which emitted bright blue light were constructed. Two empirical guides for the selection of blue‐emitting materials were established. The keys to obtain the EL cells with high EL efficiency were excellent film‐forming capability of an emitter layer and the appropriate combinations of emitter and carrier transport materials for avoiding the formation of exciplexes. In one of our organic electroluminescent devices, blue emission with a luminance of 700 cd/m2was achieved at a current density of 100 mA/cm2and a dc drive voltage of 10 V.

ISSN:0003-6951    

DOI:10.1063/1.103177

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We report on the fabrication and the characterization of low‐loss, single‐mode GaAs/AlGaAs single heterostructure ridge waveguides and a linear electro‐optic phase modulator on silicon substrate. The waveguides and the phase modulator were grown by molecular beam epitaxy and were characterized at a 1.3 &mgr;m wavelength. The average TE mode propagation loss of 1.24 dB/cm, obtained for a 6‐&mgr;m‐wide ridge waveguide, is the lowest loss so far reported. The measured phase shift efficiency of the phase modulator was 3.5°/V mm.

ISSN:0003-6951    

DOI:10.1063/1.102668

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Frequency modulation spectroscopy through a single‐mode optical fiber has been demonstrated for monitoring H2O vapor at 7665 cm−1. Using a 2.5 mW distributed feedback laser and 100 m of optical fiber, a minimum detectable absorption of 5×10−7was achieved. To obtain this sensitivity limit, very large spurious signals and technical noise were suppressed using a dual‐channel detection scheme.

ISSN:0003-6951    

DOI:10.1063/1.102669

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Gadolinium scandium gallium garnet (GSGG) was studied as a high average power laser host material utilizing diode array side pumping. Maximum optical slope efficiencies of 41.5% for Nd:GSGG in the rod geometry and 32.5% for a Nd:Cr:GSGG zig‐zag slab were obtained at 1.06 &mgr;m. Nd:GSGG and Nd:YAG have similar fluorescence lifetimes while Nd:GSGG has better energy storage capabilities due to its smaller stimulated‐emission cross section.

ISSN:0003-6951    

DOI:10.1063/1.102670

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Simultaneous two‐ and three‐band laser emissions were obtained in a process of mixing two and three kinds of dyes excited by a nitrogen laser. They were blue, green, and yellow in a coumarin 460 (C460)/disodium fluorescein (DF)/rhodamine 610 (R610) dye mixture, and blue, green, and red in a C460/DF/rhodamin 640 (R640) dye mixture. Strong energy transfers from DF to R610 and to R640 were shown. R610 and R640 laser emissions on mixing with DF were obtained at very low concentrations. They were 4×10−6mol/l  for R610 and 1×10−5mol/l  for R640, compared to the lasing threshold concentration of 1×10−4and 2×10−4mol/l  of each dye alone. Also, the R610 radiation moved about 35 nm to a shorter wavelength at the reduced concentration.

ISSN:0003-6951    

DOI:10.1063/1.103319

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

cw passive mode locking of a Ti:sapphire laser is achieved with 1,1’‐dietyl‐2,2’‐dicarbocyanine iodide as the saturable absorber dye, using a 5 &mgr;m thin dye jet flow. The pulse width is 4.0 ps, which is almost the transform‐limited pulse for the observed spectrum width. The output power is ∼50 mW, when it is pumped by a 5 W cw Ar laser, while the tuning range is 745–755 nm.

ISSN:0003-6951    

DOI:10.1063/1.102671

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A tuning range of 200 nm has been achieved with a step‐graded multiquantum well InGaAs/InP laser in an external‐cavity configuration. Continuous, single‐mode lasing could be observed from 1440 to 1640 nm. Depending on the current density, the laser can operate both at then=1 andn=2 quantized states. At low current density, then=1 state gives higher gain, whereas for higher carrier densities, then=2 level dominates. This gives rise to a flat gain profile and an extended operating range, in fact, the widest tuning range reported so far for semiconductor lasers.

ISSN:0003-6951    

DOI:10.1063/1.102672

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The diagnostic technique of the rf glow discharge at 13.56 MHz is developed by using the spatiotemporally resolved optical emission spectroscopy. New experimental evidence that the temporal excitation rate at the sheath peaks in phase with the maximum of the total current is obtained in a parallel‐plate geometry at 13.56 MHz in CH4(10%)/H2under a typical condition of the plasma chemical vapor deposition of amorphous carbon film at room temperature.

ISSN:0003-6951    

DOI:10.1063/1.103320

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Monitoring wafer changesinsituduring plasma treatment provides real‐time feedback for developing and controlling device processing. In this letter we report the use of photoluminescence spectroscopy to monitor epitaxial films of Al0.3Ga0.7As and semi‐insulating GaAs substrates during BCl3plasma etching and H2plasma passivation. Photoluminescence monitoring is used for etching endpoint detection, surface damage quantification, and wafer temperature measurement.

ISSN:0003-6951    

DOI:10.1063/1.102673

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Using the time‐of‐flight method, the drift velocity for minority electrons in highly dopedp‐GaAs was successfully measured at room temperature. The obtained velocity electric field relationships indicate that the velocity does not decrease but slightly increases and then saturates with increasing hole concentration above 1×1019cm−3. Such behavior is well explained by the effects of degeneracy, which reduces the electron‐hole interaction, and the hole distribution function dependence on electric field from the Monte Carlo calculation.

ISSN:0003-6951    

DOI:10.1063/1.102674

出版商:AIP    

年代:1990

数据来源: AIP