https://doi.org/10.1351/goldbook.08658
Condition in photoacoustic spectroscopy in which all bands with greater than a certain absorption intensity appear to have the same intensity.
Note:
Photoacoustic saturation arises when the sample is optically opaque and thermally thin, i.e., when the thermal diffusion depth, \(L\), is greater than the optical absorption depth, \(\mu_{\beta}\), and less than the sample thickness. The condition may be relieved by increasing the modulation frequency sufficiently that \(L\) becomes less than \(\mu_{\beta}\), i.e., that the sample becomes thermally thick.
Photoacoustic saturation arises when the sample is optically opaque and thermally thin, i.e., when the thermal diffusion depth, \(L\), is greater than the optical absorption depth, \(\mu_{\beta}\), and less than the sample thickness. The condition may be relieved by increasing the modulation frequency sufficiently that \(L\) becomes less than \(\mu_{\beta}\), i.e., that the sample becomes thermally thick.