An open-ended photothermal cell for in vivo measurements

Abstract

A new photothermal open-ended cell particularly adapted for in vivo spectroscopic measurements is described. The detector is a transparent LiNbO3 crystal or a crystalline quartz transducer in direct contact with the sample. The cell can be attached to an optical fiber cable for light excitation. The cell has a high signal-to-noise ratio and its frequency variation is proportional to w-t.16. In vivo and in vitro measurements performed on green leaf and carbon black samples are presented.