The asset selector lets you browse, search, and filter assets in Adobe Experience Manager Assets. You can also fetch the metadata of assets that you select using the asset selector. To customize the asset selector interface, you can launch it with supported request parameters. These parameters set the context of the asset selector for a particular scenario.
Contextual Parameters - https://experienceleague.adobe.com/docs/experience-manager-64/assets/managing/asset-selector.html?lang=en#contextual-parameters
You can pass the request parameters in a URL to launch the asset selector in a particular context.
Here we are interesting only in dialog parameter
Use these parameters to open the asset selector as Granite Dialog. This option is only applicable when you launch the asset selector through Granite PathField, and configure it as pickerSrc URL.
I and others tried using this in a dialog but unfortunately it does not work. and A lot people queried about it to make it work.
I tried fixing this problem and now it work with dialog as well. In below section, I have explained what I have tried.
Asset selector in Dialog
1. Used pickerSrc URL as /libs/dam/gui/content/assetselector/jcr:content/body/items/assetselector.html?dialog=true, this will allow to see picker popup but when you select as assets and click on select button, nothing happens.