Figure 1 (IMAGE) Institute for Basic Science Caption The quantum scar state in a chaotic optical microcavity embedded in a photonic crystal can be engineered employing the “cavity-momentum locking” phenomenon. It is discovered that when the chaotic cavities are periodically arranged, the new degree of freedom, the “Bloch Crystalline momentum,” brings about the emerging transmutation of the quantum scar states. This allows us to devise novel control schemes of light integrating the intra-cavity chaos and the crystalline momentum of the cavity array. Credit Institute for Basic Science Usage Restrictions Attribution Required License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.