CLEO '99 Product Spotlight: Difference Frequency Generator Produces Output Tunable From 1.4 to 4.2 µm

By: Kristin Lewotsky

BALTIMORE, MD—Spectroscopists needing a broadly tunable source in the mid-infrared spectral region just got their wishes granted. The KTP-based FX-IR difference frequency generator from Continuum (Santa Clara, CA) combines the tunable short-wavelength output (approximately 355 nm) and the pump wavelength output (1064 nm) from the Sunlight optical parametric oscillator (OPO) to produce output ranging from 1.4 µm to 4.2 µm with a linewidth better than 0.15 cm^-1; systems incorporating KTA operate from 1.4 µm to 5.0 µm. The module won an Optical Society of America (OSA) product award at this week's Conference on Lasers and Electro-Optics (CLEO '99).

Closing the degeneracy gap
Many OPOs suffer a degeneracy gap between 690 and 730 nm, in which the signal and idler output wavelengths overlap, and system output power drops radically. The mirror-angle-tuned, beta barium borate (BBO) based Sunlight uses non-collinear pumping to significantly enhance output power in this range, providing useful performance across all but a 0.3-nm gap. Via the FX-IR module, this comprehensive wavelength coverage yields near-continuously-tunable output in the mid-infrared spectral region.

The computer-controlled system generates output powers from 6 mJ at 1.4 µm to 0.05 mJ at 4.2 µm. Spectral stability is estimated at better than 0.05 cm-^-1/°C, and pulse durations range from 3 to 6 ns. The system also offers energy stability of better than ±15% at 1.7 µm, with power drift of less than ±10% in thermally stable conditions.

For more information, contact Continuum at 408-588-4370 (tel), 408-727-3550 (fax).