Multiphoton generation of electron–hole pairs in crystals with deep impurities. II. Cascade processes

Левицкий Р.С., Перлин Е.Ю., Попов А.А. Многофотонная генерация электрон-дырочных пар в кристаллах с глубокими примесями. II. Каскадные процессы // Оптический журнал. 2011. Т. 78. № 9. С. 13–19.

Levitskiy R.S., Perlin E.Yu., Popov A.A. Multiphoton generation of electron–hole pairs in crystals with deep impurities. II. Cascade processes [in Russian] // Opticheskii Zhurnal. 2011. V. 78. № 9. P. 13–19.

R. S. Levitskii, E. Yu. Perlin, and A. A. Popov, "Multiphoton generation of electron–hole pairs in crystals with deep impurities. II. Cascade processes ∗∗The first part of this article, “Multiphoton generation of electron–hole pairs in crystals with deep impurities. I. Two-photon band–impurity transition probabilities,” was published in <i>Opticheskiĭ Zhurnal</i> No. 10, 3 (2010) [<i>J. Opt. Technol.</i> <b>77</b>, 593 (2010)].," Journal of Optical Technology. 78(9), 570-574 (2011). https://doi.org/10.1364/JOT.78.000570

This paper discusses the generation of nonequilibrium electron–hole pairs in broad-band crystals as a result of a cascade of two-photon valence-band–deep-impurity and deep-impurity–conduction-band transitions. The balance equations are formulated and solved for the electron and hole populations in the band and impurity states. The proposed mechanism, even in the case of moderate deep-impurity concentrations and light frequencies less than a quarter of the crystal’s band gap, makes it possible to obtain an appreciable free-carrier concentration at exciting-light intensities of j≈100 MW/cm2.

The research was supported by analytical departmental traget program "Development of higher school scientific potential" (projects Nos. 2.1.1/9200, 9653) and RFBR (grant No. 09-02-00223).