Broadband tuning of external cavity bound-to-continuum quantum-cascade lasers

Abstract

A quantum-cascade structure based on a bound-to-continuum design exhibiting a broad gain curve is presented. The full width at half maximum of the measured luminescence spectrum is 297 cm−1 at room temperature. Grating-coupled external cavity lasers using this active region could be tuned over 150 cm−1 (1.45 μm), which is equal to 15% of the free running wavelength (λ≅10 μm), in pulsed mode at room temperature. Time resolved spectra showed a single-mode operation with a 30 dB side mode suppression ratio after the first 12 ns of the pulse.