Intracavity dye laser spectroscopy

Continuous-Wave Intracavity Dye Laser Spectroscopy Dependence of Enhancement on Pumping Power... 

Intracavity dye laser spectroscopy (IDLS) can be a powerful technique for detecting trace species important in combustion. The technique is based on the phenomenal sensitivity of a laser to small optical losses within the laser cavity. Since molecular absorptions represent wavelength-dependent optical losses, the technique allows detection of minute quantities of free radicals by placing them inside the laser cavity and monitoring their effect on the spectral output of the laser. 

Harris Continuous-Ware Intracavity Dye Laser Spectroscopy... 

R.G. Bray, W. Henke, S.K. Liu, R.V. Reddy, M.J. Berry, Measurement of highly forbidden optical transitions by intracavity dye laser spectroscopy. Chem. Phys. l tt. 47,213 (1977)... 

Fig. 3. Diagram of continuous wave (cw) laser sources suitable for metalloprotein resonance Raman spectroscopy. The best quality spectra are provided by Ar, Kr, He-Ne, and He-Cd lasers operating at fixed frequencies (the lengths of the lines indicate the relative output for a given laser) throughout the visible and near-UV region. An intracavity frequency-doubled (ICFD) Ar laser has been developed with five useful cw excitation wavelengths in the far-UV region (257, 248, 244, 238, and 228.9 nm). The high-powered Ar and Kr lasers can also be used to pump dye lasers which are tunable between the near-UV and near-IR region. The cw Nd YAG laser with a fundamental at 1064 nm is the primary excitation source in FT Raman spectrometers.

Although most experiments have so far been performed with dye lasers, the color-center lasers or the newly developed vibronic solid-state lasers such as the Tiisapphire laser, with broad spectral-gain profiles (Vol. 1, Sect. 5.7.3) are equally well suited for intracavity spectroscopy in the near infrared. An example is the spectroscopy of rovibronic transitions between higher electronic states of the H3 molecule with a color-center laser [24]. The combination of Fourier spectroscopy with ICLAS allows improved spectral resolution, while the sensitivity can also be enhanced [25, 34, 35]. 

It will be noted, however, that the losses due to reflection of light from mirrors result in a shorter optical path. The method of intracavity-laser spectroscopy possesses no such disadvantage because the species studied is placed inside the cavity of a broad-band laser (for instance, in one using organic dyes). The great length of the optical path increases the method sensitivity as high as 10 particles/ cm [360, 411]. 

Although most experiments have so far been performed with dye lasers, the colour-center lasers or the newly developed vibronic solid-state lasers with broad spectral-gain profiles (Sect.5.7.3) are equally well suited for intracavity spectroscopy in the near infrared. An example is the spec-... 

E.N. Antonov, V.G. Koloshnikov, V.R. Mironenko Quantitative measurement of small absorption coefficients in intracavity absorption spectroscopy using a cw-dye laser. Opt. Commun. 15, 99 (1975)... 

---