摘要:

We introduce a novel method for generating an arbitrary binary phase wave front with a metal on glass binary amplitude computer‐generated hologram. Use is made of the phase delays that occur in total internal reflection and in reflection from a glass‐metal interface. The experimental verification is presented by applying the method to reconstruction of a Dammann grating [H. Dammann and K. Go¨rtler, Opt. Commun.3, 312 (1971)] array generator.

ISSN:0003-6951    

DOI:10.1063/1.102557

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We report the successful fabrication of a two‐dimensional phase‐locked array of vertical‐cavity surface‐emitting lasers. The array was comprised of more than 160 vertical‐cavity surface‐emitting lasers of 1.3 &mgr;m diameter with a separation of less than 0.1 &mgr;m between each lasing element. The array had a 25 &mgr;m diameter and each of the elemental lasers was located on a two‐dimensional rectangular lattice. The threshold current of the two‐dimensional array 45 mA yields a threshold current of 280 &mgr;A for an elemental laser. The far‐field beam angle of the array was as narrow as 7°, and the spectral purity was found to be good enough to allow for a clear holographic image reconstruction of a holographic memory.

ISSN:0003-6951    

DOI:10.1063/1.102558

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We report large‐ and small‐signal gain characteristics of 1.5 &mgr;m multiple quantum well optical amplifiers. We demonstrate a 350‐&mgr;m‐long amplifier with a peak gain of 15 dB. At a wavelength where the small‐signal gain is 13.5 dB, the 3 dB saturation output power is as large as 45 mW. The 3 dB saturation output energy is 5.1 pJ and the calculated gain recovery time is 57 ps. We also demonstrate a 625‐&mgr;m‐long device with a gain of 19 dB and a saturation output power of 42 mW.

ISSN:0003-6951    

DOI:10.1063/1.102559

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The linear and nonlinear optical properties of well‐ordered Y‐type Langmuir–Blodgett (LB) multilayers of 2‐docosylamino‐5‐nitropyridine (DCANP) have been investigated. The nonlinear optical susceptibilities have been determined for the wavelengths &lgr;=1064 nm [d33=(7.8±1) pm/V,d31=(2.0±0.5) pm/V] and &lgr;=1318 nm [d33=(5.6±1) pm/V]. In first waveguiding experiments carried out TE0and TM0modes propagating over more than 20 mm could be excited. Coupling experiments allowed the determination of the dispersion of the refractive indexn3(n632.8 nm3=1.598). Guided wave attenuation coefficients as low as 12 dB/cm (at the wavelength &lgr;=632.8 nm) are reported.

ISSN:0003-6951    

DOI:10.1063/1.102560

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Mid‐wavelength HgCdTe was grown by metalorganic chemical vapor deposition at 390 °C on CdTe/GaAs/Si substrates. Resistance‐area products as high as 107&OHgr; cm2were measured for 320×5 arrays of detectors having a &lgr;coof 4.6 &mgr;m at 77 K. Rudimentary thermal imaging was demonstrated for 1×32 hybrid HgCdTe/Si arrays having a &lgr;coof 2.8 &mgr;m. Temperature cycling of these arrays between room temperature and 77 K caused no significant degradation of the resistance‐area products of the HgCdTe detectors.

ISSN:0003-6951    

DOI:10.1063/1.102561

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Quantum well lasers based on strained InxGa1−xAs/InP were grown by atmospheric pressure metalorganic vapor phase epitaxy. Buried‐heterostructure lasers with the active layer consisting of three quantum wells, each ∼50 A˚ thick, placed in a continuously graded waveguide, exhibit threshold currents as low as 15 mA, high quantum efficiency (24%), and power output (∼100 mW), independent of composition. Changing the In concentration fromx=0.48 to 0.62 results in the lasing wavelength shift from 1.45 to 1.62 &mgr;m. These wavelengths are in excellent agreement with the calculated energies of the electron–heavy hole exciton transition.

ISSN:0003-6951    

DOI:10.1063/1.102562

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We present the first demonstration of all‐optical phase modulation in the waveguides of an organic material {poly[bis‐(p‐toluene sulfonate) of 2, 4‐hexadiyne‐1, 6‐diol]}. The phase change as a function of optical intensity has been measured via the Mach–Zehnder interferometric method. A &pgr; phase shift has been observed for a 2‐mm‐long waveguide as the peak intensity is increased by ∼7 MW/cm2for polarization parallel to the chain axis (&lgr;=1.06 &mgr;m). Through detailed polarization‐selective measurements we have established that the observed phase change is electronic (nonthermal) in origin. The results are highly encouraging in terms of all‐optical device applications of the material.

ISSN:0003-6951    

DOI:10.1063/1.102563

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Collisional behavior of HgX(Bstate) (X=Cl, Br, I) has been studied during collisions of Ar+2ions with CH3HgX(X=Cl, Br, I) molecules in the kinetic energy (lab.) range 100–1000 eV. By using the integrated intensity of the most intense band of the (B,v’=0−X,v‘=22) transitions in HgCl, HgBr, and HgI at 558, 502, and 443 nm, respectively, emission cross sections were measured at various kinetic energies of the projectile ions. The maximum values of these cross sections for dissociative excitation were found to be 3.8×10−19, 5.7×10−19, and 6.1×10−19cm2for HgCl (B), HgBr (B), and HgI (B), respectively.

ISSN:0003-6951    

DOI:10.1063/1.102519

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A new surface‐emitting diode laser has been demonstrated, which consists of a buried‐heterostructure waveguide gain region on one side of the substrate and a bifocal microlens of 210 &mgr;m diameter on the other side. The bifocal microlens is composed of a collimating lens in the center (70 &mgr;m diameter) and a spherical mirror in the surrounding region, for output collimation and optical feedback, respectively. Accurate alignment between the gain region and the microlens has been obtained by using the focused light spot produced by the latter. Initial device results show room‐temperature pulsed threshold currents around 92 mA (with a low of 70 mA) and far‐field patterns with a narrow central lobe of 1.25°.

ISSN:0003-6951    

DOI:10.1063/1.102520

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We have examined static properties of step and continuously graded single and multiple quantum well InGaAs/InP lasers grown by atmospheric pressure metalorganic vapor phase epitaxy. Systematic changes in the band gap of InGaAsP waveguide layers have resulted in lasers with low threshold current (<10 mA), high quantum efficiency (26% per facet) and power output (∼70 mW), and the effective loss of 2–5 cm−1. We show that the changes in threshold current in short lasers can be explained by a switch from then=1 ton=2 level. The level switching results in a very flat and wide (>1000 A˚) gain profile.

ISSN:0003-6951    

DOI:10.1063/1.102521

出版商:AIP    

年代:1990

数据来源: AIP