Table 1.

Requirements for light-based diagnostic and therapeutic applications

Techniques	Light intensity (mWcm–2)	Wavelength (nm)	Skin penetration depth (mm) (Bashkatov et al., 2005)	Ref.
Pulse oximetry	≤ 1	600–1,000	1.5–2.8	Khan et al., 2018; Jinno et al., 2021; Kim et al., 2016
Functional near-infrared spectroscopy	≤ 10	700–1,000	2–2.8	Wyser et al., 2017
UV light therapy	20–80	290–320	< 0.1	Zhang et al., 2021
Photobiomodulation	≤ 100	400–1,200	∼0.3–3.5	Zein et al., 2018
Photodynamic	50–150	400–700	∼0.3–2	Bäumler (2001)
Photothermal	900–1900	700–1,000	2–2.8	Cortezon-Tamarit et al. (2017); Eskiizmir et al. (2017)

Applications generally require >1 cm² illumination area.