摘要:

A new microbolometer for far‐infrared detection has been fabricated that allows an increase in sensitivity of a factor of 4 over the best previously reported bolometer. By suspending the detector in the air above its substrate a reduction in the thermal conductance out of the device by a factor of 5 has been achieved. At a modulation frequency of 100 kHz this microbolometer has an electrical noise equivalent power of 2.8×10−11W(Hz)−1/2. A thermal model is also presented that accurately fits the response of the detector.

ISSN:0003-6951    

DOI:10.1063/1.94718

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Sequence band operation of a transversely excited nitrous oxide laser is reported for the first time. The sequence laser could be tuned to eachV‐Rline fromR(25) toR(14) and fromP(14) toP(26) in the 10.7‐&mgr;m band. Output energies were 10 &mgr;J–1 mJ. Improved stability of the discharge at high specific energy loading and use of an intracavity hot cell made sequence band oscillation possible.

ISSN:0003-6951    

DOI:10.1063/1.94695

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The spectrum of semiconductor laser arrays with separate contacts is investigated. It is demonstrated that the individual laser currents can be selected such that the array operates in a single longitudinal mode in contrast to the multimode nature of its individual constituents. Moreover, it is possible to tune the lasing frequency by varying the laser currents. Wavelength tuning range of ∼50 A˚, with tuning rate of ∼5 A˚/mA, is demonstrated. It is suggested that these spectral features, characteristic of lasers which are coupled in parallel, result from the strong frequency dependence of their spatial mode pattern near the phase‐matching frequency of their coupled waveguides.

ISSN:0003-6951    

DOI:10.1063/1.94719

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The growth reproducibility of the separate optical confinement buried crescent laser has been studied in the wavelength region of 1.3<&lgr;≤1.62 &mgr;m. The performance and yield of &lgr;=1.55 &mgr;m lasers were found to be impaired by the competition between the (100) and (111) growth habits leading to the perturbed growth of the active layer. These results are discussed in terms of the crystallographic direction dependence of the liquid‐solid distribution coefficient.

ISSN:0003-6951    

DOI:10.1063/1.94720

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

An in‐cavity hot13C 16O2cell is used to obtain a 4.4‐&mgr;m lasing from a cascade process in a sealed off13C 16O2laser. The 4.4‐&mgr;m laser is tunable and operates on thePbranch (near 4.44 &mgr;m) and theRbranch (near 4.39 &mgr;m) of the ([10°1]I–[10°0]I) band of13C 16O2. The laser is mechanicallyQswitched producing peak powers in excess of 10 W with repetition rates greater than 500 Hz.

ISSN:0003-6951    

DOI:10.1063/1.94721

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The problem of coupling an external radiation field into a thin‐film waveguide characterized by a power‐dependent refractive index has been investigated theoretically. The optimum coupling efficiency is found to decrease with increasing power.

ISSN:0003-6951    

DOI:10.1063/1.94722

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Cross‐talk in optical directional couplers is usually considered to be limited only by the processing technology. We show that unequal coupling of an input wave to the even and the odd mode of the coupling region gives rise to another kind of cross‐talk. The extinction ratio is well approximated by the overlap integral of the fields in the two waveguides. For a given coupling length, the higher the index step a waveguide has, the less the cross‐talk is. For straight couplers without bends one way to eliminate the cross‐talk is to offset the input wave relative to the coupled guides with the penalty of power loss. A three‐waveguide coupler has a different cross‐talk problem of comparable magnitude.

ISSN:0003-6951    

DOI:10.1063/1.94723

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Stabilization and control of coupled‐cavity lasers are considered. Constant output power plots on theI1vsI2plane determine optimum dc bias points and how the rf modulation should be applied. A double feedback‐loop control circuit provides stable, single‐mode operation over wide ranges of temperature and power under modulation. Experiments demonstrate ≥24 dB of spurious mode suppression under almost complete on/off high‐speed modulation over >15 °C.

ISSN:0003-6951    

DOI:10.1063/1.94696

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The all‐optical operation of many logic elements (nor, etc.) on a single passive nonlinear Fabry–Perot etalon is discussed. An experiment using dye‐filled etalons verifies the prediction and agrees with a computer simulation. This kind of Fabry–Perot gate should be capable of very high speed operation with minimum energy per cycle.

ISSN:0003-6951    

DOI:10.1063/1.94697

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

We obtain an exact analytic solution of the equation of motion for a dye laser with a fluctuating pump parameter of finite correlation time. The exact solution is compared with recent experimental results on the intensity fluctuations of a dye laser. We also obtain a favorable comparison of the experiments to the results obtained from an approximate Fokker–Planck description of the laser.

ISSN:0003-6951    

DOI:10.1063/1.94698

出版商:AIP    

年代:1984

数据来源: AIP