Cladding‐Free Antiresonance in Tubular Structures

Abstract

Antiresonance reflection (ARR) effectively turns tubular structures into functional devices ranging from waveguides to spectrometers and sensors, thus attracting a growing number of interests in recent years. Yet, ARRs are generally enabled inside the designed tube cladding with certain structural properties, which essentially acts as a quasi‐Fabry–Pérot (F–P) cavity. This limits the application of the ARR effect on popular tubular entities in non‐F–P cladding morphology, such as the chiral helical material or the self‐rolled‐up ultrathin/meshy membrane. Here, the scheme of core‐antiresonant reflection (core‐ARR or CARR) based on the leaky F–P effect is proposed, which validates ARRs inside the central core rather than the cladding of hollow tubes, hence expanding the optional scope of materials and constructions for tubular substances. Briefly, the CARR behavior is demonstrated in cylindrical, polyhedral, spiral, meshy, and notched hollow tubes with either transparent or opaque cladding materials. More importantly, tubular structures with CARR modes can be flexibly tuned in terms of the resonant frequency, which is used herein for sensitive detection of the environmental pressure, humidity, and thermal influence. As the CARR effect promotes interactions between light and various tubular structures, it holds promise for future opportunities in fields of physics, biophotonics, and material science.