摘要:

We have measured the femtosecond dynamics of the nonlinear optical response &khgr;(3)in polydiethynylsilane (C4H2SiBu2)x, a novel class of &pgr;‐conjugated polymers incorporating Si, using degenerate four‐wave mixing and photoinduced absorption techniques. In resonance conditions at 620 nm we found &khgr;(3)=3×10−9esu, which decays in a record time of 135 fs, followed by a slower decay component of 750 fs, without a long tail even at high laser intensities. This material is an excellent candidate for nonlinear optical devices in the sub‐THz frequency range.

ISSN:0003-6951    

DOI:10.1063/1.105111

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A novel internal light‐coupled optical device (ILCOD) array is proposed, where the element consists of apnpndigital optoelectronic switch and annpnphototransistor. The ILCOD with seven point‐symmetric elements was fabricated. Quenching the light emission of the center element due to light coupling between the peripheral elements is observed. This quenching is achieved with an input optical power of 2.5 &mgr;W.

ISSN:0003-6951    

DOI:10.1063/1.105112

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We have observed an amplified spontaneous emission of the Na2violet diffuse band in electron beam excited mixtures of sodium vapor with either argon or helium buffer gas. The strong continuum emission centered at 436 nm was attributed to the 23&Pgr;+g→a3&Sgr;+ubound‐free triplet band of Na2, which was already observed in the optical pumping.

ISSN:0003-6951    

DOI:10.1063/1.105113

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report the growth and fabrication of InGaAs/GaAs strained quantum well (QW) lasers with a very low threshold current density,Jth, of <50 A cm−2emitting at 0.98 &mgr;m. The lasers, 1350 &mgr;m long, had two InGaAs 80 A˚ quantum wells in the active region and Al0.6Ga0.4As in cladding layers, and were grown on 3° off (100) towards ⟨111⟩AGaAs substrate. Misorienting the substrate towards ⟨111⟩Aimproves the material quality and device performance substantially forx≊0.6 in the cladding layer, but degrades it somewhat forx≊0.35. TheJthincreased about 25% with decreasingxfrom 0.6 to 0.35 due to decreased optical confinement. Single QW stripe lasers withx=0.35 tested on a 3.0 cm×1016 &mgr;m size bar, representative of the whole 5‐cm‐diam substrate, exhibited a yield of ≳90% and an excellent spatial uniformity ofJthand emission wavelengths which were 212±4 A cm−2and 989±1 nm, respectively.

ISSN:0003-6951    

DOI:10.1063/1.105114

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A microwave discharge pumped XeCl laser of a pulse energy of 1.3 mJ was demonstrated for the first time with nonrelativistic microwave sources. The pulse duration was measured to be 16 ns. This corresponds to peak powers of the order of 100 kW. The repetition frequency was so far 10 Hz.

ISSN:0003-6951    

DOI:10.1063/1.105115

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We developed a novel technique to switch the lasing wavelength of picosecond pulses in an optically pumped quantum well laser by utilizing spatially localized and homogeneous excitation. The applications of these phenomena to ultrafast logic gating operations are successfully demonstrated.

ISSN:0003-6951    

DOI:10.1063/1.105116

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Self‐diffraction from laser‐induced gratings is observed in a 13 &mgr;m‐thick film of rhodamine B doped epoxy. The decay of the grating is measured to be 2.05 ns. Degenerate forward four‐wave mixing in a guided geometry is observed by coupling out all beams after propagation over 1 mm. At 595 nm the third‐order nonlinear susceptibility of the film is measured to be 1.5×10−19m2 V−2.

ISSN:0003-6951    

DOI:10.1063/1.105117

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

It is theoretically and experimentally demonstrated that a peculiar amplitude/phase coupling characteristic between the modulated and noise output of gain‐levered lasers leads to a simultaneous increase in the modulation efficiency and a reduction in the intensity noise by interferometric frequency→intensity conversion.

ISSN:0003-6951    

DOI:10.1063/1.105118

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Simple spectroscopic control of a &bgr;‐barium borate optical parametric oscillator is achieved by seeding at its visible signal wavelength with light from a tunable pulsed dye laser. This yields continuously tunable narrowband infrared output at the corresponding idler wavelength. The spectroscopic potential of this device is demonstrated by recording photoacoustic spectra of the near‐infrared (&ngr;1+2&ngr;3+&ngr;51) band of acetylene gas.

ISSN:0003-6951    

DOI:10.1063/1.105119

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Photothermal deformation measures optical energy absorption by thermal expansion of a solid. This work describes how deflection amplitude is increased by a factor of 104by mechanically resonating thin bars in a flexural mode of vibration. Small (∼10−5–5×10−3fractional) infrared optical absorptions from Si:O surfaces are reported in various reactive gases using a tunable CO2drive laser. Alternately, conventional low‐power light sources can be used to provide sufficient excitations for submonolayer infrared absorption measurements.

ISSN:0003-6951    

DOI:10.1063/1.105120

出版商:AIP    

年代:1991

数据来源: AIP