摘要:

When GaAs quantum wells are optically excited with intensities ≳10 kW/cm2new peaks appear in the photoluminescence spectrum at low temperatures. The excitation spectra are used to demonstrate that the new peaks correspond to the recombination of electrons in excited well states,n≳1, with holes inn= 1 states. These parity‐forbidden transitions, &Dgr;nodd, derive their strength from three body interactions that occur at high excitation levels.

ISSN:0003-6951    

DOI:10.1063/1.92548

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Constricted double‐heterojunction diode lasers of positive‐index lateral guiding and low‐threshold‐current design are found to operate cw to 170 °C (ambient temperature) and pulsed to 280 °C. High threshold‐current temperature coefficients (T0≳230 °C) and constant differential quantum efficiencies are found up to 100 °C. Above 100 °C the temperature‐dependent current‐focusing effect responsible for high‐T0behavior appears to saturate. Single‐longitudinal‐mode cw operation is recorded up to 150 °C. Two effects, a strong temperature dependence of the threshold current density above 180 °C (T′0= 40–50 °C), and sublinear spontaneous emission above 220 °C, are believed to reflect the same nonradiative Auger recombination process currently proposed to explain InGaAsP laser behavior near room temperature.

ISSN:0003-6951    

DOI:10.1063/1.92556

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

An optically pumped propyne laser with tunable output in the 609–637‐cm−1region is reported. The pump source is a transverse electric atmosphere CO2laser, and 16‐&mgr;m laser energies as high as 6 mJ are obtained.

ISSN:0003-6951    

DOI:10.1063/1.92519

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The optical spectrum of gallium atoms produced and excited near a self‐formed high‐field emission tip of a liquid metal gallium ion source has been observed in detail. The spectrum reveals several interesting features. The dispersed neutral gallium lines exhibit asymmetric tails extending over tens of angstroms. The broadening is identified as due to quadratic stark effect. The maximum broadening is limited by field ionization of the atom from its excited state. The agreement with classical results is reasonable. A background continuum has also been observed, which may be due to transition radiation arising from collision of electrons, produced during field ionization, with the liquid‐metal tip.

ISSN:0003-6951    

DOI:10.1063/1.92532

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Single crystals of CuCl at 8 K were excited with the low‐intensity frequency‐doubled output of an actively mode‐locked R6‐G dye laser. The time dependence of the bound exciton luminescence was measured directly by a synchronously operating electron‐optical streak camera accumulating data at the dye laser repetition rate of 82 MHz. The instrumental time resolution was ∼25 ps. The observed bound exciton lifetime for theIline (3898 A˚) was typically ∼130 ps with a formation time of less than 10 ps.

ISSN:0003-6951    

DOI:10.1063/1.92544

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

We have fabricated a repetitively pulsating stripe geometry GaAlAs double‐heterostructure laser with a stripe by a shallow Zn‐diffusion inton‐GaAs top layer, generating high‐power fundamental transverse‐mode optical pulse trains. Spatially inhomogeneous current injection for exciting pulsations is achieved by a nonuniform breakover in space‐charge region under the Zn‐diffused stripe. These generated optical pulses have a peak power of more than 10 mW, a width of 0.4 ns, and a repetition frequency of 200 MHz–1 GHz.

ISSN:0003-6951    

DOI:10.1063/1.92545

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Warm phasematching LiNbO3(Tpm∼120 °C) has been used to achieve greater than 40% SHG efficiency of an acousto‐opticQ‐switched Nd:YAG laser. The growth of high‐quality LiNbO3crystals suitable for efficient noncritical second‐harmonic generation is possible owing to the significantly lowered index damage annealing temperature.

ISSN:0003-6951    

DOI:10.1063/1.92546

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Results of a new excitation technique for excimer lasers are reported. The B→X band of Xef at 352 nm has been pumped in a longitudinal low‐pressure discharge. Low‐power, 20‐nsec laser pulses of high beam quality have been generated.

ISSN:0003-6951    

DOI:10.1063/1.92547

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Band‐to‐band Auger recombination in InGaAsP lasers is studied theoretically. An approximation method for the calculation is derived and the Auger coefficient is given explicitly as a function of injected carrier density. Auger lifetime and the threshold current density for the InGaAsP laser are calculated with good agreement with reported experimental results. This shows that Auger recombination is one of the dominant factors which causes the poor temperature characteristics of InGaAsP laser threshold current.

ISSN:0003-6951    

DOI:10.1063/1.92549

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A red‐shift in the diode modes with increasing optical feedback is observed in external‐cavity AlxGa1−xAs injection lasers. This shift is due to a change in the refractive index in the active region resulting from a reduction in the population‐inversion induced by the optical feedback. This leads to a new determination of the carrier dependence of the refractive index at the laser wavelength in the active region of semiconductor lasers independent of current‐induced thermal effects.

ISSN:0003-6951    

DOI:10.1063/1.92550

出版商:AIP    

年代:1981

数据来源: AIP