Borate nonlinear optical crystals

Currently used nonlinear optical crystals are potassium dihydrogen phosphate (KDP) and barium borate (BBO). Compared to KDP, the advantages of BBO are its transparency in the UV and its larger quantum efficiency of up-conversion by a factor of 4—6. For a given position of the crystal, only a narrow band of the fluorescence spectrum is up-converted. Therefore, if the full fluorescence spectrum is of interest, the crystal must be rotated at a series of angles. An example of experimental set-up is presented in Figure 11.2. The fwhm of the response is 210 fs. 

Development of New Nonlinear Optical Crystals in the Borate Series... 

C.T. Chen, Development of New Nonlinear Optical Crystals in the Borate Series Vol. 15 Laser Science and Technology an International Handbook (Harwood Academic, Chur, Switzerland, 1993). 

Figure B2.1.1 Femtosecond light source based on an amplified titanium-sapphire laser and an optical parametric amplifier. Symbols used P, Brewster dispersing prism X, titanium-sapphire crystal OC, output coupler B, acousto-optic pulse selector (Bragg cell) FR, Faraday rotator and polarizer assembly DG, diffraction grating BBO, p-barium borate nonlinear crystal.

Xue D., Betzler K., Hesse H. and hammers D., Nonlinear optical properties of borate crystals. Solid State Commm., 114 (2000) pp. 21-25. 

A large amount of the information in this section is taken from the compilations of low- and high-frequency properties of dielectric crystals in Landolt-Bdmstein, Group m, Vols. 29 and 30, especially Vol. 30b. Since 1992-1993, the date of publication of the first of these volumes, a large amount of new data on the physical properties of dielectrics has appeared in the literature. In particular, various linear and nonlinear optical properties of new crystals in the borate family (BBO, LBO, CBO, and CLBO) and of new organic crystals (DLAP, MNMA,... 

T, Honma, Y, Benino, T. Fujiwara, R, Sato, T, Komatsu, New optical nonlinear crystallized glasses and YAG laser-induced crystalline dot formation in rare-earth bismuth borate system. Opt. Mat., 20, 27-33 (2002),... 

The NLO properties in nanoparticle sizes have been obtained [419] (Figure 6.32). From the reported data one can see that decreasing nanocrystalline sizes favor enhanced second-order susceptibilities. For all the samples the optimal ratio between the fundamental and writing beams was equal to about 15. For the samples larger than 300 nm, the effect was independent of the nanoparticle sizes. The relaxation of the optically formed nonlinear grating was not less than 80%. The obtained effective optical susceptibilities are comparable to those of the excellent borate crystals. 

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