Nerefa

There's a state of sleep in which you can be aware without perceptions (neither physical or mental). No imagery, sight, sound, or touch. No perception-based thoughts. Just pure existence in the moment.

I got into doing this by accident when using intention for dream recall. So here's what I did, for those who want to try for themselves:

Set your intention to be aware at the ends of dreams. These can be in between dream cycles, when you wake up naturally in the night, or waking up in the morning.
Placing intention on awareness at this time is key. This allows you to be aware between the dream and waking states.
We naturally switch states at this time (going from sleep to waking), so you have a moment of change and heightened awareness going from one state to the next. It's a gentle shift you can influence. Instead of making that full switch, you choose to stay asleep, allowing the dream to have ended without waking life beginning. You'll stay in the in-between moment. It's uneventful, but in a good way—very calm and quiet.

Enjoy!