8.7 Summary and Future Prospects

After decades of development, solid-state dye lasers have obtained great progress in both materials and devices and some have reached the commercial market place. These were made possible mainly by three factors: synthesis of new laser dyes and host matrix, development of fabrication techniques and new findings in photophysical and photochemical process.

Before the late 1990s, the major obstacle in this field is the photostability of laser dye itself. For instance, there is rarely a laser dye more efficient and stable than the traditional rhodamine family dyes in the yellow to red region, until the synthesis of pyrromethene and perylene dyes. Two order of magnitude or even greater improvement has been observed in the photostability of dyes doped in solid matrix in this spectrum region. In the future, high performance laser dyes emitted at other regions are highly needed, for instance, stable infrared laser dyes will be synthesized. New kind of dyes with various non-linear optical properties will also generate interests.

As mentioned before, each laser dye has its specific preferred host matrix. ^[25] Photophysical and photochemical processes and the mechanism responsible for the dye degradation have been extensively investigated during the last decade. These efforts provided the theoretical and experimental basis for the designing and controlling on the microenvironment of dye molecules. New solid host matrix and the fabrication techniques will be developed. Organic-inorganic hybrid materials via sol-gel process are superior due to versatility and low cost. Concerning the actual use in integrated...