Application of an Intracavity Laser Spectroscopy Based on Ar+ Laser for the Detection of Unstable Molecules in Liquid Phase

An intracavity laser spectroscopy (ILS) method is one of the most high-sensitive and high-speed method in optical spectroscopy for the molecule detection in gas and liquid phases[I]. Mainly molecules in aqueous solutions have broad-band absorption spectra in visible and UV ranges. These spectra are sufficiently broader than the laser bandwidth. While placing such broad-band absorbers inside the laser cavity all laser modes are being quenched equally. And there is no mode competition as it occurs between those modes which are affected by selective losses and other modes of the laser while having been detected of narrow-band absorbers (molecules in the gas phase). So the intracavity sensitivity for the detection of molecules in aqueous solutions is not as high as for the detection of molecules in the gas phase. But however the intracavity detection of broad-band absorptions in aqueous solutions is more sensitive than a single pass detection — an ordinary spectroscopy.