**Abstract**

Photobiomodulation (PBM) is the application of light therapy that utilizes photons to alter the activity of molecular and cellular processes in the tissue where the stimulation is applied. Because the photons associated with the therapeutic mechanisms of PBM affect processes associated with the mitochondria, it is hypothesized that PBM increases ATP synthesis. Alteration of the mitochondrial respiratory enzyme, cytochrome c oxidase (CCO), is hypothesized to induce healing to damaged tissues via regeneration. Utilization of PBM has been examined in clinical disorders which include but are not limited to Alzheimer's/dementia, epilepsy, and age-related macular degeneration. Transcranial PBM (tPBM) utilizes quantum dot light emitting diodes (QLEDs). QLEDs allow for narrow wavelength emissions from applications of PBM to alter electrophysiological activity and tissue regeneration. This chapter aims to evaluate the mechanisms of QLED applications of PBM and its applications as a photodynamic therapy in the medical sciences. Further, this chapter will examine the quantum mechanics of tPBM and its ability to affect electrophysiological activity according to the electroencephalogram (EEG) across the delta, theta, alpha, beta frequency bands.

**Keywords:** transcranial, stimulation, neurodegeneration, Alzheimer's, photobiomodulation, EEG, quantum, physics, photodynamic therapy
