New-Generation Organic Polymer Lasers, Continuous-Wave (CW) Operation Using Dye Laser Discs (DLDs)

The tunable polymer laser developed at the University of Siegen combines the advantages of a solid-state laser with the versatility of a conventional dye laser.

Conventional dye lasers rely on an organic fluorescent dye as the actual laser medium, which is usually dissolved in a liquid. These liquids often pose a major problem during operation: The solvents and dyes used must be chemically extremely pure; otherwise, even the smallest impurities would immediately disrupt the laser process. Furthermore, the solutions degrade relatively quickly during use, and even the smallest leaks in the flow system immediately lead to significant contamination of the surrounding area. In addition, used solutions must be treated as hazardous waste.

For this reason, early attempts were made to bind the dyes within a solid matrix. It became apparent that this configuration solves many of the problems associated with other polymer lasers. Laser operation could be maintained for several hours using just a single laser disk (>=100 µs). This was even maintained at a power level in the upper mW range (continuous-wave power around 300 mW, peak 800 mW) with good spectral purity (= 1GHz) und feiner Abstimmung über einen großen Bereich (>= 30 nm at the 575 nm maximum). The beam quality M² is less than 1.2.

Further advantages of this system include minimal use of expensive and, in some cases, environmentally harmful chemicals, as well as the ability to replace the laser media very quickly and safely. The high power density in the resonator also allows, with the aid of nonlinear crystals, an extension of the tuning range into the deep UV region to 290 nm.