IEEE Journal of Quantum Electronics

A method for measuring the modal reflectivity of the antireflection coating applied to a laser diode is described and demonstrated. It is based on measurements of the Fabry-Perot modulation depth of the resulting superluminescent diode (SLD) output spectrum at the threshold current of the original laser. A modal reflectivity of less than2 times 10^{-4}has been obtained. View full abstract»

The optical properties of a GaAlAs superluminescent diode (SLD) are described. The spectra of this device exhibit a large number of longitudinal modes. The coupling efficiency into a 0.23 NA 50 μm diameter graded index fiber is ∼ 30 percent. The current required for constant light output at a temperatureTcan be written asI(T) sim I_{0} cdot exp (T/T_{2})whereT... View full abstract»

The pulse width compression effect of a malachite green (MG) dye upon subpicosecond pulses has been experimentally investigated in a CW passively mode-locked rhodamine 6G/DODCI dye laser. The pulse width reduces as MG concentration increases, and reaches 0.34 ps at1.5 times 10^{-6}M. By adding the MG dye, good mode locking is achieved in a rather wide pumping-power range. A computer sim... View full abstract»

A computer model is made of the colliding-pulse ring dye laser for mode-locked production of short pulses. Initial conditions of either noise or a small CW oscillation eventually result in the same final solution. Resolution is 10 ps in the model, and a digital filter represents dispersion. A gain-sharing long pulse mode often results, but large effective absorption cross section in the mode-locki... View full abstract»

We report simultaneous quantitative spectral and temporal measurements of the output pulses from a single-axial mode rhodamine 6G short cavity (1-8 mum) dye laser. The dye laser was pumped at 10 Hz with single second harmonic (532 nm) pulses from a mode-locked Nd+3:YAG laser. Spectral measurements made with a high resolution spectrograph and temporal measurements made with an... View full abstract»

Numerical computer models could be of high value in testing ideas for improving passive mode locking. Most of the known models for solid-state lasers lack realistic quantitative results, however. A new model is presented, using a rate-equation approach which has been refined to include interference effects by using field amplitudes and phases instead of energies. Also, the saturable absorber is tr... View full abstract»

A new type of laser which generates picosecond pulses is presented. 6 ps, ∼ 1 GW, 3 pps,lambda = 1.06 mum in a single pulse are obtained with good stability. Accurate timing of the pulses can be achieved, and no external pulse selection is required. In our laser, the pulse does not develop from quantum noise, but is the result of a nonlinear frequency and time processing in the ca... View full abstract»

The influence of the distance of an active modulator to one of the resonator's end mirrors is investigated both theoretically and experimentally and is found not to be critical for high-gain lasers. The effect of the active modulator on the pulse length of an active/passive mode-locked Nd:YAG laser is discussed qualitatively. Threshold, stability, pulse length, and output energy are investigated e... View full abstract»

A general tutorial survey is presented describing the use of ultrafast streak cameras in picosecond fluorometry. Current instruments exhibit time resolutions of 1-10 ps with detection sensitivities of a few photoelectrons. When linear photoelectric recording is employed, a real-time direct display of optical transients is provided. Representative examples from the literature in physics, chemistry,... View full abstract»

A soft X-ray streak camera is presented which offers wide application for picosecond recording of transient signals in the spectral range from the VUV to the very hard X-ray region. Specific demonstration results are presented from laser-fusion diagnostic studies. Dynamic characterization of the streak camera, new photocathode studies, and the application of intermediate and broad spectral selecti... View full abstract»

The general problem of extracting complete (amplitude and phase) information out of an optical signal is discussed. We have shown that the best one can do to determine all essential features of light pulses is to apply simultaneous temporal and spectral analysis to take spectrochronograms with the appropriate shape of the resolution cell on theomegat-plane. We use the term "spectrochron... View full abstract»

The performance of a new single-photon avalanche photodiode particularly suitable for the detection of fast and ultraweak light pulses is described. The advantages of this device over other available detectors are discussed. The electronic circuitry developed allows the measurement of fluorescence decays with a time resolution of 70 ps FWHM (full-width at half-maximum) and a data acquisition rate ... View full abstract»

A methodology for calculating the transient following sudden removal of photon or mass-particle excitation is developed for semiconductor devices in which high hole-electron recombination rates, rather than short transit times, yield picosecond response time. We suggest the name photoconductive circuit element (PCE) for these optoelectronic transducers to emphasize their potential application to d... View full abstract»

We present and discuss the results of picosecond transient grating self-diffraction measurements in germanium that can be understood in terms of an orientational grating produced by anisotropic (inkspace) state-filling. Although there have been predictions and indirect experimental evidence for isotropic state-filling in germanium, this is the first direct experimental indication of ani... View full abstract»

Amplitude and phase responses of bleachable dyes are experimentally investigated using a picosecond pump and probe pulse technique combined with light polarization measurements. In the measurements, the amplitude response appears in the form of dichroism of bleaching, and the phase response appears in the form of induced birefringence. The method of measurement is adapted for dyes with fast relaxa... View full abstract»

A single-block hexagonal LiNbO3electrooptical switch was developed. It has the advantages of easy operation, an integrated polarizer, a modulator, and an analyzer, low loss, and a high extinction ratio. It can be used as an intracavity electroopticalQ-switch for lasers, and as a switch for pulse selection in mode-locked lasers. View full abstract»

Photoinduced tunneling currents in thin-film Ni-NiO-Ni tunneling junctions were measured as a function of photon energy over the range 2.0 eVleq hf leq 2.7eV. The photoresponse mechanism was found to be consistent with a photon assisted tunneling mechanism. Inelastic electron-electron collisions were found to strongly influence the photoassisted tunneling currents. View full abstract»

A tunable diode laser (TDL) operating in the 2140-2310 cm-1wavenumber region is used to probe a conventional CW CO2laser discharge. Detailed vibrational populations in CO2are measured under lasing conditions, i.e., in the presence of an intense 10 μm field. The TDL is also used to investigate the rate of recovery of the populations in a variety of vibrational ... View full abstract»

Locking different components of stimulated Brillouin radiation is considered in an optical resonator for a partial filling of the resonator with a Brillouin-active medium exhibiting a coherent (parametric) interaction between the components. The dependence of the type of stable locking on the form of the longitudinal filling of the resonator with the Brillouin-active medium is shown and investigat... View full abstract»