Nocturnal animals are active during the night instead of the day - so, they hunt and mate during night. Technically, not all cats are nocturnal animals.
This means that cats are primarily active during the twilight period. Cats can see their way around in low light. They are great at detecting motion, but, their vision isn't' as clear as humans.
Cats have the pineal gland which is responsible for hormone melatonin production. Leaving light for a cat at night might cause issues with the melatonin production and disrupt the cat’s sleep. So, cats don't really need light at night.
Although light is not necessary for cats, complete dark might be stressful for small kittens. You can leave it a dim light, or pull the curtains aside to let some natural light in.
So, Should You Leave Light For Your Kitten At Night?
First you should create a safe space to leave your kitten alone. Always leave a water bowl and a food bowl, as well as a litter box for your cat. Also, ensure your kitten will not hurt herself while you are away.