Rapid updating of optical arbitrary waveforms via time-domain multiplexing

We demonstrate high-fidelity optical arbitrary waveform generation with 5 GHz waveform switching via time-domain multiplexing. Compact, integrated waveform shapers based on silica arrayed-waveguide grating pairs with 10 GHz channel spacing are used to shape (line-by-line) two different waveforms from the output of a 10-mode x 10 GHz optical frequency comb generator. Characterization of the time multiplexer's complex transfer function (amplitude and phase) by frequency-resolved optical gating permits compensation of its impact on the switched waveforms and matching of the measured and target waveforms to better than G'=5%.     

Wavelength derivative surface Raman gain spectroscopy of carbonate on silver

A technique for obtaining derivative spectra of Raman vibrations of a surface monolayer is demonstrated. Nearly shot noise limited performance is maintained by low frequency wavelength modulation of a high frequency amplitude-modulated picosecond pulse train. We demonstrate the technique by recovering a surface enhanced spectrum of carbonate on a silver surface obtained by integration of a measured derivative spectrum.     

Development of a microprocessor-based electrochemical instrument interfaced to a microcomputer system for differential-pulse stripping voltammetry in different time domains

An inexpensive, compact microprocessor-based instrument for polarographic and voltammetric analysis has been developed for use in chemically hazardous laboratories, radiation laboratories or clean laboratories. This low-cost unit controls the experiment, collects the data and can be regarded as expendable. The microprocessor-based instrumentation is interface to a microcomputer system, which is external to the laboratory and has all the required peripherals associated with larger laboratory computers. In this institution, four laboratories having the inexpensive microprocessor systems are linked to the larger microcomputer which is housed in an air-conditioned room better suited for computers. A new approach to data collection and evaluation using different time domains in differential-pulse stripping voltammetry is presented as an example of the use of such instrumentation.     

Two connected inverse spectral transforms

We establish a transformation which connects the potentials of the one-dimensional Dirac and Klein-Gordon operators. This transformation links the solutions of the nonlinear evolution equations solvable by means of the two inverse spectral transforms which use the Dirac and Klein-Gordon direct and inverse spectral problems.     

Relaxation dynamics of the first excited electronic singlet state of azulene in solution

An upper limit to the relaxation time of the first excited electronic singlet state (S₁) of azulene in cyclohexane has been determined for two excitation frequencies. The lifetimes of S₁ excited by single picosecond duration optical pulses of frequency 18910 cm^?1 and 16000 cm^?1 are ? 1 ps and ? 2 ps respectively.     

32 Phase X 32 amplitude optical arbitrary waveform generation

We describe the precise shaping and mode-resolved amplitude and phase characterization of optical arbitrary waveforms by using a 20 GHz optical frequency comb and integrated 64 x 20 GHz channel arrayed waveguide grating pair. Complex waveforms with large variations in phase and amplitude between adjacent modes were generated and characterized.