Month: January 2014

This photo shows the fluorescence of Coumarin 102 dye (dissolved in methanol) as a laser beam (445 nm, 1.3 W cw) passes through.

The end of the laser can be seen in the right-hand side of the photo. The image shows how the blue laser beam is invisible as it passes through the air, but its path becomes beautifully clear as it traverses the dye solution.

The laser drives electronic transitions in the dye, resulting in broad-band fluorescence. The beam is considerably attenuated as the dye is strongly absorbing at this wavelength, with almost all of the energy absorbed by the solution.

We will use this dye as the gain medium in our pulsed dye laser, pumping it at 355 nm to generate pulsed laser radiation at 486 nm, to drive the 1s -> 2p transition in positronium atoms.

2014 has started with the arrival of our pulsed laser system – a Surelite Nd:YAG laser which pumps a Sirah pulsed dye laser.

Ps Spectroscopy lab, January 2014. Optical table and pulsed dye laser now installed.

We will use this dye laser for driving electronic transitions in Ps, such as the 1s – 2p transition at 243 nm. The dye laser uses coumarin 102 as the gain medium, lasing at 486 nm, which is then doubled in BBO.