Solid-state polymer laser diodes

Crystalline silicon is the most widely used semiconductor material today, with a maiket share of above 90%. Because of its indirect electronic band structure, however, the material is not able to emit light effectively and therefore carmot be used for key applications like light-emitting diodes or lasers. Selected one- or two-dimensional silicon compounds like linear or branched polysilylenes [1] or layered structures like siloxene [2], however, possess a direct band gap and therefore exhibit intense visible photoluminescence. Siloxene, a solid-state polymer with a sheet-like layered structure and an empirical formula Si H (OH) , in particular, is considered as an alternative material for Si-based liuninescent devices. Detailed studies of stmctural and photophysical properties of the material, however, are strraigly impeded by its insolubility in organic solvents. 

It has been found that nanosized carbons, such as single-waUed carbon nanotubes and graphenes, can be used as SAs for ML of solid-state lasers, as long as these carbon materials are semiconductive. For example, semiconducting SWCNTs with a high content of 80 % have been produced by using a polymer extraction technique. These SWCNTs exhibited a saturation intensity of 1.7 MW cm, modulation depth of 6 %, and nonresidual loss of 5.5 %, which ensured to generate stable pulses of 8.3 ps, with a repetition rate of 90 MHz, when combined with a 0.5 at.% Nd YAG ceramic laser pumped with a CW 808-nm diode [164]. 

---