Patimisco, PietroSampaolo, AngeloBidaux, YvesBismuto, AlfredoScott, MarshallJiang, JamesMuller, AntoineFaist, JeromeTittel, Frank K.Spagnolo, Vincenzo2016-12-162016-12-162016Patimisco, Pietro, Sampaolo, Angelo, Bidaux, Yves, et al.. "Purely wavelength- and amplitude-modulated quartz-enhanced photoacoustic spectroscopy." <i>Optics Express,</i> 24, no. 23 (2016) The Optical Society: 25943-25954. http://dx.doi.org/10.1364/OE.24.025943.https://hdl.handle.net/1911/93723We report here on a quartz-enhanced photoacoustic (QEPAS) sensor employing a quantum cascade laser (QCL) structure capable of operating in a pure amplitude or wavelength modulation configuration. The QCL structure is composed of three electrically independent sections: Gain, Phase (PS) and Master Oscillator (MO). Selective current pumping of these three sections allows obtaining laser wavelength tuning without changes in the optical power, and power modulation without emission wavelength shifts. A pure QEPAS amplitude modulation condition is obtained by modulating the PS current, while pure wavelength modulation is achieved by modulating simultaneously the MO and PS QCL sections and slowly scanning the DC current level injected in the PS section.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articlehttp://dx.doi.org/10.1364/OE.24.025943