Method and structure for nonlinear optics
A nonlinear optical crystal having a chemical formula of Y i La j Al k B 16 O 48 , where 2.8≦i≦3.2, 0.8≦j≦1.2, i and j sum to about four, and k is about 12 is provided. The nonlinear optical crystal is useful for nonlinear optical applications including frequency conversion. Nonlinear optical crystals in a specific embodiment are characterized by UV blocking materials (e.g., some transition metals and lanthanides) at concentrations of less than 1,000 parts per million, providing high transmittance over portions of the UV spectrum (e.g., 175-360 nm).
1. An optical system comprising:
a laser system operable to provide an output at a first wavelength propagating along an optical path; and
a frequency conversion stage disposed along the optical path and operable to convert the first wavelength to a second wavelength, wherein the frequency conversion stage includes a nonlinear optical element having a chemical formula of Y i La j Al k B 16 O 48 , where 2.0 ≦i ≦3.6, 0.4 ≦j ≦2.0, i and j sum to about four, and k is about 12 and having an optical transmittance greater than 0.7 at 250 nm.
2. The optical system of claim 1 wherein the first wavelength is about 532 nm, and the second wavelength is about 266 nm.
3. The optical system of claim 2 wherein the frequency conversion stage is further operable to convert the first wavelength and a third wavelength to a fourth wavelength, wherein the third wavelength is about 1064 nm and the fourth wavelength is about 355 nm.
4. The optical system of claim 1 wherein 2.8 ≦i ≦3.2, 0.8 ≦j≦1.2.
5. The optical system of claim 1 wherein the nonlinear optical element comprises a nonlinear optical crystal associated with the trigonal crystal class of space group R32.
6. The optical system of claim 5 wherein a concentration of molybdenum in the nonlinear optical crystal is less than 1,000 parts per million.
7. The optical system of claim 1 wherein the nonlinear optical element includes one or more surfaces exposed to ambient humidity.
8. The optical system of claim 1 wherein a nonlinear optical element is characterized by an optical transmittance of greater than 0.7 at 200 nm.
9. The optical system of claim 1 wherein the nonlinear optical element is characterized by a size between about 1 mm 3 and 1,000 mm 3 .
10. The optical system of claim 9 wherein the nonlinear optical element is characterized by a size between about 10 mm 3 and 200 mm 3 .