Intracavity laser absorption spectroscopy (ICLAS) is an extremely sensitive method for the detection of very weak absorptions. However, the conventional use of multimode lasers has thus far significantly reduced its ability to detect in situ molecules and its sensitivity. We propose the use of a new type of laser that overcomes these limitations: the turbulent detuned actively mode-locked (TDAM) Ti:sapphire laser, which owing to its short coherence length, eliminates harmful intracavity interferences. The proposed technique called TDAM-ICLAS is furthermore highly sensitive to intracavity absorption, continuously tunable and has no frequency chirp.