摘要:

Retinal derivatives were synthesized and their third‐order nonlinear optical properties were measured by degenerate four‐wave mixing with temporally incoherent nanosecond laser pulses. Fast optical nonlinearities, whose response time was shorter than 30 ps, were observed. The magnitudes of resonant third‐order hyperpolarizability were found to be 10−31∼10−29esu. The large optical nonlinearities were of electronic origin.

ISSN:0003-6951    

DOI:10.1063/1.102796

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Sharp spectral lines are obtained for the Cu i511 nm and the Au i628 nm transitions from a sputtering‐based laser operating at room temperature. The Au iline exhibits a single peak with a linewidth of 360 MHz and the Cu iline consists of three well‐resolved peaks with linewidths of 800, 700, and 700 MHz in order of increasing frequency. The spectral lines result from saturated emission on the strongest hyperfine components.

ISSN:0003-6951    

DOI:10.1063/1.102797

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Time‐division interferometry with 430 fs tunable laser pulses is used for direct femtosecond measurements of the wavelength dependence of the nonresonant nonlinear index of refraction,n2, in AlGaAs waveguides at room temperature. Below band‐gapn2values of ∼10−12cm2/W are observed with resonant enhancement as the laser wavelength is tuned toward the band edge.

ISSN:0003-6951    

DOI:10.1063/1.102798

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Monolithically integrated reduced‐confinement antennas are shown to produce reductions of >35% in the far‐field beam divergence for radiation emitted from single‐mode GaAlAs slab waveguides, yielding far‐field beams as narrow as 8.2° FWHM along the direction perpendicular to the wafer surface. Reduced confinement of the guided mode near the output endface is achieved using a novel molecular beam epitaxy growth technique to produce a longitudinal variation in the refractive index and thickness of the waveguide film. Unlike present horn antennas, the reduced‐confinement geometry has the distinct advantage of being compatible with two‐dimensional antenna development.

ISSN:0003-6951    

DOI:10.1063/1.102776

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Single crystals of the new nonlinear optical material 3‐methyl‐4‐methoxy‐4’‐nitrostilbene (MMONS) have been grown by a seeded solution growth technique and the linear and nonlinear optic and electro‐optic properties determined. MMONS is highly birefringent withnz−nx=0.75 (0.532 &mgr;m), has large nonlinear optical coefficients withd33=184 pm/V andd24=71 pm/V (1.064 &mgr;m), has large electro‐optic coefficients withr33=39.9 pm/V (0.6328 &mgr;m), and can be efficiently type II phase matched for Nd lasers emitting ∼1 &mgr;m.

ISSN:0003-6951    

DOI:10.1063/1.102777

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Isolation ratios as large as 3000 to 1 (−35 dB) at wavelengths near 1.55 &mgr;m have been measured on ridged waveguide Faraday rotation isolators. These are the best results ever reported for any waveguide isolator. Single‐mode, triple‐layer bismuth yttrium iron garnet films were chemically etched to reduce the linear birefringence of the active top layer to zero at 1.49 &mgr;m. Ion implantation enhanced etching was used to create ridges 8 &mgr;m wide and 0.5 &mgr;m high. Using fiber coupled light from a tunable color center laser, isolation ratios of −25 dB or better were achieved over a wavelength range of ±0.03 &mgr;m near 1.5 &mgr;m. A silica overlayer was used to increase the effective thickness of the active layer and raise the optimum wavelength from 1.49 to 1.55 &mgr;m.

ISSN:0003-6951    

DOI:10.1063/1.102778

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We report the monolithic integration of a quantum well laser array and a transparent waveguide with higher band‐gap material using asinglestep of molecular beam epitaxy on a patterned, nonplanar substrate. The substrate has a periodically corrugated patterned sectionlongitudinallyadjacentto an unpatterned, planar section. The laser heterostructure on the corrugated section of the substrate has a thicker quantum well and, thus, lower effective band gap than that of the one grown on the planar section. Hence, a waveguide transparent at the laser array emission wavelength is formed on the planar section. We demonstrate phase locking of the otherwise uncoupled laser array using diffraction coupling through the transparent waveguide section. Emission wavelength tuning of ∼80 A˚ is also obtained using carrier injection into the waveguide section.

ISSN:0003-6951    

DOI:10.1063/1.102779

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

For making surface‐emitting lasers such as InGaAsP/InP double‐heterostructure lasers, it is important to select and study the resonator properly. The authors have compared the relative light output power of two different structures, the plane‐parallel and the hemispherical resonators. The InGaAsP/InP double‐heterostructure was grown by liquid phase epitaxy. The different resonators on the same wafer were fabricated using chemical etching, lithography, evaporation, and other integrated circuit process techniques. Output optical power of the devices with the hemispherical resonator is a factor of 2 larger than those with the plane‐parallel resonator. This is because the hemispherical resonator structure has a smaller diffraction loss than the plane‐parallel structure.

ISSN:0003-6951    

DOI:10.1063/1.102756

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We report, for the first time, the identification of extrinsic dislocation loops lying on the {100} planes with 1/2⟨100⟩ types of Burgers vectors in a zinc blende structure in InGaAsP lattice matched to InP. These dislocation loops generated only in nonradiative recombination assisted point‐defect motion process under intensed laser light, and form the ⟨100⟩ type dark line defects in degraded 1.3 &mgr;m wavelength laser diodes.

ISSN:0003-6951    

DOI:10.1063/1.102757

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Thin diamond films were deposited on different substrates at temperatures below 500 °C by a microwave plasma‐enhanced chemical vapor deposition system. The deposited films were amorphous carbon or diamond films depending on the different gas mixtures used. The addition of oxygen to the gas mixtures was found to be critical for diamond growth at low temperatures. Without oxygen, the deposited films were white soots and easily scratched off. Increasing the oxygen input improved the quality of the Raman peaks and increased the film transparency. The diamond films were also characterized by scanning electron microscopy.

ISSN:0003-6951    

DOI:10.1063/1.102758

出版商:AIP    

年代:1990

数据来源: AIP