The present invention includes a fundamental laser light source configured to generate fundamental wavelength laser light, an optical crystal configured to receive fundamental laser light from the fundamental laser light source, the optical crystal configured to generate alternate wavelength light by frequency converting a portion of the received fundamental laser light to alternate wavelength light, an auxiliary light source configured to generate auxiliary wavelength light, the auxiliary wavelength light having a wavelength different from the fundamental wavelength laser light and the alternate wavelength light, the fundamental laser light source and the auxiliary light source oriented such that the fundamental laser light copropagates with the auxiliary light through a surface of the optical crystal, and a detector configured to detect at least one of fundamental wavelength laser light scattered by the optical crystal, alternate wavelength light scattered by the optical crystal, or auxiliary light scattered by the optical crystal.