Optical power of Smartphone (Galaxy S20) torch

[Techni]

TL;DR Summary

Looking for effective optical power of smartphone torch

In doing a project on phototransistors I am using my smartphone as illumination source.

In order to find the responsivity of the induced current from the light, I need to know the surface power density, which I could estimate, if I knew the effective optical power of the light from the smartphone torch.

I have scoured the internet (and even contacted Samsung tech support) with no luck, and am hoping someone can help me find a source for the info.

 

[Algr]

Perhaps a light meter would help? They used to be a critical tool in photography.

https://duckduckgo.com/?q=light+meter&atb=v314-1&ia=web

 

[Techni]

Perhaps a light meter would help? They used to be a critical tool in photography.

https://duckduckgo.com/?q=light+meter&atb=v314-1&ia=web

Thank you for the response.

I ended up using a Thorlabs photodetector (https://www.thorlabs.com/thorproduct.cfm?partnumber=PDA100A-EC).

While I ran into the problem with the responsivity of the photodetector being wavelength dependent, due to the smartphone torch covering a wide spectrum, choosing an average responsivity of the photodetector gives a decent enough order of magnitude estimation.

 

[Tom.G]

average responsivity of the photodetector gives a decent enough order of magnitude estimation.

And what number did you get?

 

[Techni]

I ended up with a rough estimate for the surface power density of the optical light of 1.92 mW/cm^2 at a distance of 2.5 cm normal to the torch plane (backside of the phone)