  An innovative concept of thin-film organic solid-state laser is proposed,
with diffraction-limited output and a broad tuning range covering the visible
spectrum under UV optical pumping. The laser beam is tunable over 230 nm, from
440 to 670 nm, with a 3 nm full width at half maximum typical spectral width.
The structure consists of a compact fixed bulk optical cavity, a polymeric
intracavity etalon for wavelength tuning, as well as five different disposable
glass slides coated with a dye-doped polymer film, forming a very simple and
low-cost gain medium. The use of interchangeable/disposable "gain capsules" is
an alternative solution to photodegradation issues, since gain chips can be
replaced without realignment of the cavity. The laser lifetime of a single chip
in ambient conditions and without encapsulation was extrapolated to be around
107 pulses at a microjoule energy-per-pulse level.
