Nonlinear optical crystal of compound R.sub.2 MB.sub.10 O.sub.19 and producing method and producing method and uses thereof

A crystal, which is produced with the compound having a chemical formula of R.sub.2 MB.sub.10 O.sub.19, wherein R is one or more elements selected from the group consisting of rare-earth elements and Y;

• M is Ca, Sr, or Ba;
• and which is noncentrosymmetric, belonging to space C2 of monoclinic system.

A process for the manufacturing of NLO devices, which contain means to direct at least one incident beam of electromagnetic radiation into at least one said MLO crystal to produce at least one output electromagnetic radiation beam with a frequency different from that of the incident electromagnetic radiation comprising administering a crystal, which is produced with the compound having a chemical formula of R.sub.2 MB.sub.10 O.sub.19, wherein R is one or more elements selected from the group consisting of rare-earth elements and Y;

• M is Ca, Sr, or Ba;
• and which is noncentrosymmetric, belonging to space C2 of monoclinic system into a NLO device.

A method of using a crystal, which is produced with the compound having a chemical formula of R.sub.2 MB.sub.10 O.sub.19, wherein R is one or more elements selected from the group consisting of rare-earth elements and Y;

• M is Ca, Sr, or Ba;
• and which is noncentrosymmetric, belonging to space C2 of monoclinic system in Laser NLO multifunctional devices comprising, placing said crystal in an optical resonant cavity, and exciting said crystal by a pump source to produce a fundamental laser and at least one laser output with a frequency different from the fundamental frequency.