摘要:

TE polarization of optical emission from microdisk laser diodes of radiusR=5 &mgr;m, thicknessL=0.3 &mgr;m, is found to dominate both below and above room‐temperature lasing threshold current,Ith=2 mA. TE emission in the lasing mode at &lgr;=1560 nm wavelength is due to higher optical gain for TE modes in the quantum well device. In our device geometry, the intrinsic whispering gallery resonances have essentially no polarization selectivity. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113301

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Erbium‐doped silicon films are grown by ion beam epitaxy using a newly developed electric‐mirror sputtering‐type metal ion source in an ultrahigh vacuum. A precise and steep profile of the erbium concentration, ranging from 1×1016to 6×1020cm−3, is achievedinsituby sputtering the erbium metal pellet with ions extracted from the silicon ion source. The oxygen concentration in the films, which is important to effective luminescence of erbium in silicon, is controlledinsituin the range from below 1×1018to 2×1020cm−3by using argon gases containing oxygen impurities ranging from 1 ppb to 100 ppm. The oxygen concentration trapped in the silicon films strongly depends on the erbium concentration doped in the films. The erbium atoms are selectively oxidized in the host silicon film. As a result, the photoluminescence of 1.54 &mgr;m wavelength light is clearly observed in as‐deposited films. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113302

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We observe dynamic ferroelectric domain gratings in strontium barium niobate (SBN) induced by photorefractive space charge fields. The optically induced modulation of the spontaneous polarization attains a maximum of 1%. Quasi‐phase matched second harmonic enhancements are observed above the ferroelectric‐paraelectric phase transition due to the glassy ferroelectric nature of SBN. We find that the second harmonic power is significantly enhanced by recording gratings in optically fatigued rather than electrically poled crystals. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113303

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Experimental and theoretical data are presented for the nonlinear absorption of the organic laser dye 1,1’,3,3,3’,3’‐hexamethylindotricarbocyanine iodide (HITCI) using az‐scan technique. Experimental data show an induced absorption above laser fluences of 10 mJ/cm2and a saturation of the nonlinear absorption above fluences of 0.5 J/cm2. A self‐consistent theoretical analysis, based on rate equations, is used to predict accurately the results ofzscans taken at different pulse energies. Photophysical parameters, including the excited state lifetimes and absorption cross sections are derived for HITCI.

ISSN:0003-6951    

DOI:10.1063/1.113304

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The existence of two polarization dependent band edges in InGaAs/InP quantum well material has been used to demonstrate single wavelength all‐optical switching in a nonlinear guided wave Fabry–Perot resonator. The device had a single quantum well embedded in the optical waveguide and was characterized as a function of input pump power and laser wavelength using laser pulses of about 45 ps duration at a repetition rate of 82 MHz. A signal gain factor of over two was obtained for pump pulses of 1.2 pJ and the optimum operating wavelength of 1.51 &mgr;m was found to coincide with the heavy hole exciton absorption resonance. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113305

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The stability of homogeneously pumped single‐section laser diodes is analyzed theoretically and it is found that under certain bias conditions negative gain suppression factor laser diodes (NGSFLDs) self‐pulsate. An analytical condition for self‐pulsation in homogeneously pumped single‐section laser diodes is derived. The dynamics of self‐pulsating NGSFLDs under direct modulation are analyzed and a quasiperiodic route to chaos is found. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.113306

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The study of a HgBr excimer lamp (502 nm) excited by a microwave discharge is reported. Efficient operation in the blue‐green region was obtained with a HgBr fluorescence power of 42.8 W and an intrinsic efficiency of 9.4% at a 100 kHz operation frequency is obtained when 100 mg HgBr2and 25 Torr neon gas are introduced in a quartz discharge sphere with a 14.13 cm3discharge volume. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113307

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We propose and numerically study a simple scheme to obtain large pulse‐width reduction of optical pulses generated by semiconductor lasers. The scheme consists of modulating two single‐mode semiconductor lasers coupled through a normal dispersion fiber. The optimal pulse compression is obtained for a particular range of phase delay between the two modulated electrical injection currents. In addition, the optical pulses so obtained have a larger output power and are very close to transform‐limited as required for soliton communication systems. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113308

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We report optical second harmonic generation measurements in single crystal &agr;‐SiC of polytype 6H. The angular dependence of second harmonic intensity was consistent with two independent nonvanishing second order susceptibility components, as expected for a crystal with hexagonal symmetry. For the fundamental wavelength of 1.064 &mgr;m the magnitudes of the two components were determined to be &khgr;zzz(2)=±1.2×10−7and &khgr;zxx(2)=∓1.2×10−8esu. The corresponding linear electro‐optic coefficient computed from this value isrzzz=±100 pm/V. The wavelength dependence of the nonlinear susceptibility was examined for second harmonic wavelengths between the bandgap (400 nm) and the red (700 nm), and was found to be relatively uniform over this region. The refractory nature of this compound and its large nonlinear optical coefficients make it an attractive candidate for high power nonlinear optical waveguide applications. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113309

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Measurements of single‐photon photoelectric emission sensitivity of ion implanted polycrystalline tungsten surface by 3×1016K+ ions/cm2are reported. They are compared to the data previously obtained for pure tungsten tested under the same conditions. The enhancement of the photoelectric sensitivity up to a factor of 50 was measured as a consequence of the change in the electronic properties of the tungsten surface, induced by the implanted alkali metal ions. Compared with other techniques used to reduce the work function of pure tungsten, the implanted surface exhibits a lower work function than the pure metal, and is capable of supporting high laser intensity for a long time. For these reasons it seems possible to consider the ion‐implantation technique as a suitable new method to significantly improve the photoelectric performances of usual metals, under high laser intensity illuminations. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113310

出版商:AIP    

年代:1995

数据来源: AIP