In a collaboration with Prof. Geoff Blake we developed a micro-spectrometer based on continuously tunable lasers (280 nm - 20 mm) using optical parametric oscillator technology. Postdoc Zifu Wang collaborated with Blake's group which is developing the basic laser technology. Our new spectrometer was based on tunable optical parametric oscillators (OPOs).  It allows a single pump laser to be tuned over a broad (100's to 1000's of nm) wavelength range.  It is pumped at either 355 (for visible operation) or 532 nm (for NIR operation).  The OPOs are based on type II phase matching in b-BaB2O4 (BBO) and cover the wavelength range from 410 to 3200 nm. These instruments have immensely more intense output compared to the conventional instruments we now use. To test the feasibility of characterizing extremely small samples, we conducted absorption spectral measurements in the near-IR wavelength range on several single-crystal samples masked with pinholes of diameter 5 to 12.5 mm.

The OPO spectrometer

 More information and images on the OPO spectrometer