Caracterización temporal de láseres en la zona visible-infrarrojo próximo

Benefit description

We can provide wavelength determinations for single.mode lasers, in the 350-1100 nm range with 10 MHz accuracy. The wavelength of both cw and pulsed lasers can be measured. For pulsed lasers, the repetition rate must be less than 500 Hz if a single-shot measurement is desired. Otherwise an average over several pulses will be obtained. For these measurements we use high accuracy wavemeters (three of them are available) calibrated with Ar+ lasers locked to metrologic standards (hyperfine transitions of I2 or Te2). These wavemeters are based on Fizeau interferometers and CCD detection, so fast and sensitive measurements are possible. We can also determine the mode structure of lasers emitting in the visible wavelength region, using spectrum analyzers with 7.5 GHz, 2 GHz, 300 MHz and 150 MHz free spectral range (FSR) and Finesse > 150. Depending on the particular wavelength one or more of those couls be used, and that will constrain the maximum allowable spectral bandwidth of the source (it should be less than the FSR for a totally unambiguous determination). For single mode lasers sweep rates are ~20 Hz, while for pulsed lasers (pulse width > 1 ns) a slow scan and single shot measurements are necessary, thus yiending an average of the mode structure should it be changing in time. Besides the wavelength meters and reference lasers, the necesarry electronics include ramp generators, digital scope, pulse generators, boxcar averager and PC's.