@article{ISI:000327007800024, title = {Indirect absorption spectroscopy using quantum cascade lasers: mid-infrared refractometry and photothermal spectroscopy}, author = {Pfeifer, Marcel and Ruf, Alexander and Fischer, Peer}, journal = {OPTICS EXPRESS}, volume = {21}, number = {22}, pages = {25643-25654}, year = {2013}, doi = {10.1364/OE.21.025643} }