The superconscious mind encompasses a level of awareness that sees both material reality and also the energy and consciousness behind that reality.
If we have a really good meditation and feel “fully calm” as you have stated, then we are beginning to experience a level of superconsciousness. As we go deeper in meditation and experience a deepening peace, calmness, divine love, and even bliss, then we are experiencing deeper levels of the superconscious. The superconscious is where true creativity is found. Expressions of this kind of creativity are distinctive from those that come from the subconscious. The superconscious is where ideas for truly great works of art, music, prose, poetry, great scientific discoveries, and deep spiritual experiences are found.
Paramhansa Yogananda made an interesting statement. He said that, “Thoughts are universally, not individually, rooted.” This means that as we elevate our consciousness and access the superconscious, we are accessing the thoughts that live on that level of consciousness. These thoughts don’t belong to us, but are universally available to those who live more on that level of consciousness.
The opposite is also true. If we live mainly on the conscious or subconscious level, then we attract the kinds of thoughts that live on those levels of consciousness.
Generally speaking the conscious mind sees everything as separate from each other. A chair is only a chair, a person is simply the body they inhabit and nothing more. It has a very limited view of the world around it.
The superconscious mind sees that everything is, in reality, made of energy and consciousness and, therefore, it sees the underlying unity behind the outer forms.
The subconscious mind consists of “the unprocessed residue of thoughts, actions, and memories that are ever present, but more or less unnoticed. They greatly influence the conscious mind, which doesn’t often realize how ungoverned by free will its decisions really are.” (from Awaken to Superconsciousness, by Swami Kriyananda) In other words, the subconscious influences a lot of what we do each day, but those influences are from past actions and the habits we have created from them. This means that ideas that are drawn from the subconscious are not going to be new and creative. Looking in the subconscious can be like rummaging around the closet to see what we’ve stored away. This is why the usual dream state often has a confused and murky feel to it. There are also superconscious dreams, but they will have an uplifting and life-changing effect on us, and feel quite different from the usual dreams we may have.