Photonic Crystal Based Ultra-Sensitive Interferometric Sensor with Spatial Resolution up to 1 nm

We report a very high precision interferometric sensor with resolution up to ~{\lambda}/1024, exploiting hollow photonic bandgap waveguide-based geometry for the first time. Here sensing has been measured by a complete switching in the direction of the outgoing beam, owing to transverse momentum oscillation phenomena. Using a 1.32 {\mu}m source and core-width of 7.25 {\mu}m, a complete switching cycle is obtained even due to a small change of ~1 nm in the core-width. Using hollow-core photonic bandgap waveguide, Talbot effect, revivals of the initial phase, oscillation in the transverse momentum along with multi-mode interference served as the backbone of the design. The ultra-sensitive multi-mode interferometric sensor based on photonic crystals will certainly open up a paradigm shift in interferometer-based sensing technologies toward device-level applications in photonic sensing/switching and related precision measurement systems.