Guys,

I have a question out of my curiosity about two-photon absorption/excitation.

I know that the TPA probability is dependent on the square of light intensity. Pulsed laser is usually used as it provides high enough intensity in space and time.

My question is: Is it correct "Now matter photon influx is continuous or pulsed, TPA can take place, as long as the light source is strong enough？“

Also, could anyone provide any references showing continuous light source elicit TPA or TPA-induced photoluminescence?

Thank you in advance.