OPO Spectrometer


OPO Spectometer (Prof. George R. Rossman)

	In a collaboration with Prof. Goeff Blake we demonstrated the use of a continuously tunable laser spectrometer using optical parametric oscillator technology for mineral spectroscopic applications. Postdoc Zifu Wang collaborated with Blake's group which developed the basic laser technology. Our new spectrometer was based on a single pump laser tuned with optical parametric oscillator crystals (OPOs). It allows the pump laser to be tuned over a broad wavelength range. Our system 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).
	The OPO spectrometer.
	These instruments have an 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. Our prototype unit operated from about 410 to 3300 nm. The intensity of the laser source is so high that we can obtain satisfactory spectra through a 5 mm pinhole in front of the sample. An article describing our prototype is available: Wang Z., Rossman G.R., Blake G.A. (1998) A new microsampling visible-infrared spectrometer based on optical parametric oscillators (OPOs). Spectroscopy 13 pp. 44-47.

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