All optical poling and second harmonic generation in glasses: theory and experiment

Induced crystallization and physical properties of Li2O–CaF2–P2O5:TiO2 glass system

“…Earlier, this oxide was considered as a nucleating agent for crystallization in silicate glasses. However, there are certain recent reports, where titanium ions were used as nucleating agents and observed to induce phase separation during the cooling of the melt in other glass systems like P 2 O 5 , GeO 2 [9,10].…”

Demonstration of a cylindrically symmetric second-order nonlinear fiber with self-assembled organic surface layers

“…The small discrepancy between the theoretical predictions and the experimental results in the shorter wavelength region can be attributed to the absorption of the second harmonic signal by the PAH/PB film. This absorption of nonlinear molecule is due mainly to their electronic excitation, and it is generally a trade-off between short wavelength in which the molecules are transparent and the magnitude of ( 2 )  . There are extensive studies on molecular design and synthesis for secondorder nonlinear chromophores that can simultaneously provide large nonlinear coefficient and exhibit low optical absorption at the desired wavelength [33].…”

“…It was found that the second-order nonlinear tensor of the film was dominated by the zzz component with ( 2 ) zzz  = 21 pm/V, approximately two third the value of LiNbO 3 [23]. (The z direction is normal to the planar glass substrate.)…”

“…Since molecular orientation of the PAH/PB film is maintained through electrostatic and covalent interactions, the nonlinear susceptibility of the film is thermodynamically stable. For example, the self-assembled films exhibit excellent thermal and temporal stability with no decrease of ( 2 ) zzz  after a temperature cycles to 150° C for 24 hours or under ambient condition for more than two years [23]. They are also mechanically stable and impervious to immersion in water and most organic solvents.…”

“…Most such methods are based on poling silica glass using external fields, with examples including optical poling [2,4], electrical poling [5][6][7][8][9], UV poling [10,11], corona poling [12][13][14], or doping microstructures into fibers [15][16][17]. However, since all such techniques introduce a preferred direction into silica glass, the induced second-order nonlinearity is thermodynamically unstable and tends to decay over time [2,[18][19][20].…”