Is it possible to mirror from my laptop to tv via Apple TV?

Only if your laptop is a Mac.

See here: Use AirPlay to stream video or mirror your device’s screen - Apple Support

This is pretty much a main thing that Apple TV does.

• Link your Apple TV to your television via HDMI cable.
• On your laptop Airplay your content to your Apple TV, the material will show on your TV.

If you have a Windows PC, you will need a small software to help with that.

Check this article:

https://www.lifewire.com/where-to-get-airplay-for-windows-2000736