label, can be misleading or inadequate. A study of post-consumer clothing found that 29% did not have a legible care label; of those that did, 41% had inaccurate composition information. [1] Missing or inaccurate knowledge around fiber composition can make textile recycling, with rates currently less than 15% in the United States, costprohibitive; leading to over 17 million tons of textiles being sent to the landfill each year. [2,3] The Sorting for Circularity Project Europe, covering Belgium, Germany, the Netherlands, Poland, Spain, and the United Kingdom, recently estimated that, with efficient sorting infrastructure, it would be possible to profitably recycle 74% of current end-of-life fabrics, either mechanically or chemically, into fibers for new garments. [4] Thus, a more efficient sorting system of textiles for recycling or upcycling into highvalue feedstocks is needed. A more accurate and durable labeling approach that also enables an automated, rapid sorting, and tracing system could dramatically increase recycling rates, detection of counterfeiting, and intellectual property or material theft. Deficiencies in the standard care label have been known for decades, and many alternatives have been proposed and prototyped. In the early 2000s, radio frequency identification (RFID) clothing tags were introduced due to the ability to scan many tags from a distance simultaneously, and while gaining broader market reach in recent years, have not been implemented widely due to high cost and privacy concerns. [5,6] More recently, quick response (QR) codes have increased in popularity, as they enable each item to be assigned a unique code, and are readable with now-ubiquitous smartphones. A major drawback to QR codes, or any tag-based barcode, is that they are typically attached at the stage where the garment is manufactured from the constituent textile, thereby missing critical steps that preceed and follow in the textile supply chain, and thus falling short on the product life cycle and traceability requirements, as Figure 1A illustrates. Furthermore, they are easily detachable and/or become unreadable over the lifetime of the garment. Focused on creating nonremovable tags, researchers also proposed using a randomized pattern of magnetic nanoparticles screen-printed onto a garment as a "secured" tag, as well as integrating a yarn segment that was colored and twisted in a particular manner to encode Circular supply chains require more accurate product labeling and traceability. In the apparel industry, product life cycle management is hampered in part by inaccurate, poorly readable, and detachable standard care labels. Instead, this article seeks to enable a labeling system capable of being integrated into the fabric itself, intrinsically recyclable, low-cost, encodes information, and allows rapid readout after years of normal use. In this work, all-polymer photonic crystals are designed and then fabricated by thermal drawing with >100 layers having sub-micrometer individual thickness and low refractive index contr...