In this work we report on the absorption spectra of ethanol and water in the region 430–700 nm using a homemade halogen lamp-based photothermal lens spectrophotometer with a multipass probe-beam ...configuration. The spectra also include well resolved, higher absorption overtones. The instrument achieves high sensitivity due to multiple reflections within the optical cavity containing the sample. Finally, an Arduino board was used for collecting and digitizing the signal, thus enabling a more compact device.
We have theoretically analyzed the possibility of a high-efficiency frequency conversion using first vibrational overtone transitions in a discharge-initiated nonchain (H
2
/SF
6
) HF chemical laser. ...In a pulsed operation, vibrational overtone HF laser energy can be obtained with a high conversion efficiency of 67% of the fundamental output energy by suppressing fundamental transitions perfectly. A multiline oscillation of 1.3–1.5 µm in wavelength is expected in the first vibrational overtone transitions. An overtone laser energy density of 0.87 mJ/cm
3
is achievable from a discharge-initiated, He-diluted gas mixture of SF
6
/H
2
/He=84/12/404–664 (Torr).
