CP-BASED LASERS

Another very new development in CP applications has been CP-based semiconductor lasers. The Friend group at Cambridge, England first noted [867] that one to study whether the photoexcited states in electroluminescent CPs such P(PV) are fundamentally non-emitting interchain species or emitting intrachain species was to confine solid films of the CP in a microcavity, where spontaneous and stimulated emission of the CP could be studied. What resulted in an early test of such a device [867] was the observation that upon excitation at 355 nm, stimulated emission, i.e. lasing activity (predominantly at ca. 550 nm), was observed. Fig. 18-7a shows a schematic of the microcavity structure used by these authors. Fig. 18-7b shows characterization data for such P(PV)-based microcavity (laser) devices [867, 868]. 

Lasing activity in CPs is not surprising, since CPs are semiconductors, and semiconductor lasers are well known. Work prior to that cited above had provided 

---

The electro-optic and optical devices based on CPs can be classified into three categories those based on second order NLO properties those based on third order NLO properties those based on properties other than NLO CP-based lasers. The driving forces behind the development of these devices are discussed elsewhere. 

---