Table 3.

Biophysical properties of two-photon–suitable probes specific of brain cells and structures: peak wavelength of two-photon action cross-section (λ_2PA) ; peak two-photon action cross-section (σ₂φ) ; peak wavelength of molecular brightness (λ_{ε_max}) ; peak molecular brightness (ε_max) ; fluorescence wavelength (λ_fluo). Probes discussed in the text are in bold.

Probe	λ2PA[nm]	σ2φ [GM]	λεmax [nm]	εmax [kcpsm]	λfluo [nm]	Comment	Reference
Alexa Fluor 633			820	~24	647b	Arteries (Shen et al. 2012)	Figure 2 in (Mütze et al. 2012)
Ant2-PHEA (in water)	800	490			654	Endothelium	Figure 6 in (Mettra et al. 2016)
Sulforhodamine 101	910	118	900	38.4	~605b	Astroglia (Nimmerjahn et al. 2004)	Figure 5 in (Mütze et al. 2012)
Sulforhodamine B	810				~586b	Astroglia	Figure 2A in (Appaix et al. 2012)

^a: calculated from the σ₂ and φ values

^b: data from commercial provider