research papers
The etch figures of three forms ({110}, {20} and {101}) of the self-frequency-doubling crystal Yb:YAl3(BO3)4 were observed and the point group 32 was displayed. Etch figures of faces or sections with the same indices in Yb:YAl3(BO3)4 and quartz are very similar, although their crystal structures are very different.