This will be a short post building off a previous blog post about my depth calculator tool. The principle is also based on Karl Deisseroth’s irradiance calculator, only this time the calculation is reversed. The goal is to predict the in vivo optogenetics power required for your experiment.
So, instead of predicting effective opsin stimulation depth, you input the effective depth you want for you study, and the calculator with predict an estimate of the light power you need out the end of your optic cannula:

As with my depth calculator, I have got some recommended starting values for fibre core, NA and irradiance threshold. Then press “Calculate” and it will estimate the power you need to achieve effective stimulation at your desired depth:

That’s it for today, and I hope some people use my free tool to gain insight into their in vivo optogenetics power requirements.