Theoretical design of an absorption hologram-based sensor for dose quantification in daylight photodynamic therapy.

Daylight photodynamic therapy (D-PDT) is an effective and almost painless treatment for many skin conditions, where successful treatment relies on daylight activation of a topical photosensitizer. Optimization of D-PDT requires accurate assessment of light dose received. There is a requirement for a small-area sensor that can be placed adjacent to the treatment site to facilitate accurate dose quantification. Here, a novel, to the best of our knowledge, configuration for a D-PDT dose sensor, consisting of a holographic absorption grating fabricated in a photosensitive film, is presented. Theoretical modeling of the sensor's response (i.e., change in grating diffraction efficiency due to change in grating absorption modulation,