TY - JOUR
T1 - Tunable distributed-feedback quantum-cascade lasers for gas sensing applications
AU - Gmachl, Claire
AU - Capasso, Federico
AU - Faist, Jérôme
AU - Sivco, Deborah L.
AU - Baillargeon, James N.
AU - Hutchinson, Albert L.
AU - Cho, Alfred Y.
AU - Namjou-Khaless, Khosrow
AU - Cai, Simin
AU - Whittaker, Edward A.
AU - Kelly, James F.
AU - Sharpe, Steven W.
AU - Hartman, John S.
PY - 1998
Y1 - 1998
N2 - Continuously tunable single-mode emission of high performance quantum cascade (QC) lasers is achieved by application of the distributed feedback (DFB) principle. The devices are fabricated either as loss-coupled or index-coupled DFB lasers. Single-mode tuning ranges of ≈ 100 nm have been measured in both of the atmospheric windows at emission wavelengths around λ ≈ 5 μm and 8 μm. Linear thermal tuning coefficients of 0.35 nm/K and 0.55 nm/K have been obtained above 200 K for λ ≈ 5 μm and 8 μm, respectively. The side-mode suppression ratio is better than 30 dB. Pulsed single-mode operation has been achieved up to room temperature with peak power levels of 60 mW. The lasers also operated single-mode in continuous wave at temperatures above liquid Nitrogen temperature; a single-mode tuning range of 70 mn has been measured in the temperature range from 20 K to 120 K. The gas sensing capabilities of the QC-laser have also been demonstrated using both direct absorption and wavelength modulation techniques. A pulsed, room temperature, QC-DFB laser operating at λ ≈ 7.8 μm was used to detect N2O diluted in N2. The detection limit was found to be ≈ 500 ppb-m. In addition, the high resolution capability of the QC-DFB lasers (at 77 K) has been demonstrated via continuous, rapid-scan, direct absorption measurement of the Doppler limited R(16.5) lambda doublet of NO at λ ≈ 5.2 μm.
AB - Continuously tunable single-mode emission of high performance quantum cascade (QC) lasers is achieved by application of the distributed feedback (DFB) principle. The devices are fabricated either as loss-coupled or index-coupled DFB lasers. Single-mode tuning ranges of ≈ 100 nm have been measured in both of the atmospheric windows at emission wavelengths around λ ≈ 5 μm and 8 μm. Linear thermal tuning coefficients of 0.35 nm/K and 0.55 nm/K have been obtained above 200 K for λ ≈ 5 μm and 8 μm, respectively. The side-mode suppression ratio is better than 30 dB. Pulsed single-mode operation has been achieved up to room temperature with peak power levels of 60 mW. The lasers also operated single-mode in continuous wave at temperatures above liquid Nitrogen temperature; a single-mode tuning range of 70 mn has been measured in the temperature range from 20 K to 120 K. The gas sensing capabilities of the QC-laser have also been demonstrated using both direct absorption and wavelength modulation techniques. A pulsed, room temperature, QC-DFB laser operating at λ ≈ 7.8 μm was used to detect N2O diluted in N2. The detection limit was found to be ≈ 500 ppb-m. In addition, the high resolution capability of the QC-DFB lasers (at 77 K) has been demonstrated via continuous, rapid-scan, direct absorption measurement of the Doppler limited R(16.5) lambda doublet of NO at λ ≈ 5.2 μm.
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U2 - 10.1117/12.307601
DO - 10.1117/12.307601
M3 - Conference article
AN - SCOPUS:18544370843
SN - 0277-786X
VL - 3285
SP - 144
EP - 153
JO - Proceedings of SPIE - The International Society for Optical Engineering
JF - Proceedings of SPIE - The International Society for Optical Engineering
T2 - Fabrication, Testing and Reliability of Semiconductor Lasers III
Y2 - 29 January 1998 through 30 January 1998
ER -