Daylight Solutions Breaks Single-Chip Tuning Record

07.29.10

Jul 29, 2010 – Daylight Solutions has pushed the broad tuning envelope again. We have built a pulsed, single-chip laser that tuned over 525 cm-1. This ECqcL™ (External Cavity quantum cascade Laser) tunes so broadly that we had to modify our tuning mechanics in our Über Tuner broad tuning laser platform to cover the entire range in a single scan. Figure 1 is the tuning curve for the performance of this laser. The tuning range covers 3.78 – 4.71 µm (2,122 – 2,647 cm-1). The chip was successfully designed not only for super broad gain bandwidth, but also to lase below 4 µm as we strive to provide the market with both the broadest tuning in a single laser as well as the most wavelength coverage. This chip encompasses the entire CO2 absorption band at 4.25 µm. The peak power at the top of the gain curve is just over 200 mW with a 5% duty cycle and 100 kHz pulse repetition rate.

Figure 1. Tuning curve of new ECqcL™ performance
After obtaining the above tuning curve, we reopened the 1 m path to atmospheric CO2, decreased the step size, and scanned over the region where CO2 absorbs. The result is shown in Figure 2a. Figure 2b is the same spectrum overlaid by a calculated HITRAN spectrum assuming a laser linewidth of 0.7 cm-1. When the variation in power of the laser as a function of wavelength (the gain curve of the QCL) is taken into consideration, the agreement between the observed and calculated spectra is quite good.

Figure 2a. Observed spectrum of CO2 with broad tuning, pulsed ECqcL™. Inset of laser tuning curve shows range of observed spectrum.

Figure 2b. Observed spectrum overlaid by HITRAN simulated spectrum with an instrument linewidth of 0.7 cm-1 and a total pressure of 1 atm.

Broad tuning and new wavelength coverage will continue to drive Daylight Solutions’ ECqcL™ development as this will facilitate molecular sensing, imaging, and spectroscopy applications.

What might look like an elephant under a blanket to some, looks like another world’s record to Daylight Solutions.

Daylight Solutions offers a commercial version of our broad-tuning pulsed laser system with over 250 cm-1 of continuous tuning.  The company provides narrow-band, high-brightness tunability in various ECqcL™ platforms from 3.8-12.2 µm.  For further information, please contact Chris Armacost at carmacost@daylightsolutions.com.


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