Patent ID: 7170911

Claim:
A wavelength conversion apparatus comprising: a case; an input window mounted in the case at an input end of the case and substantially transparent to at least one input laser beam; a nonlinear optical crystal located within the case, having an incident facet opposite and spaced from the input window, on which the at least one input laser beam is incident along an optical axis, the nonlinear optical crystal converting the at least one input laser beam to light at an output wavelength that different from wavelengths of the at least one input laser beam, the nonlinear optical crystal having an output facet at which the light at the output wavelength is output, the output surface being inclined, relative to the optical axis, at the Brewster angle of the crystal and ambient within the case; and an output window mounted in the case at an emission end of the case, opposite and spaced from the output facet of the nonlinear optical crystal, the output window having a prism shape which has a cross-section in a plane containing the optical axis that has a width, parallel to the optical axis, that continuously decreases along a direction perpendicular to the optical axis.