A novel approach to Fabry-Pérot-resonance-based lens and demonstrating deep-subwavelength imaging.

During our research, we explored a novel way to represent subwavelength imaging and derived a transmission equation to explicate the FP (Fabry-Pérot) resonance phenomena. Subsequently, using analysis and observation, we performed deep-subwavelength imaging. Both numerically and experimentally, imaging with super-resolution was achieved at deep subwavelength scale of λ/56.53 with a lens thickness 212 mm. Our results also showed that by increasing lens thickness, higher resolution can be achieved. Moreover, via a single source study, we showed the full width at half maximum range and predicted the size of smallest detectable object. We also observed that with a greater lens thickness, finer features could be detected. These findings may open a new route in near-field imaging for practical applications such as biometric sensors, ultrasonic medical equipment, and non-destructive testing.

In-depth study on resonant tunneling for subwavelength imaging.

We report new frequency bands for subwavelength imaging by using the resonant tunneling method which have not been explored previously. As per the existing theory of resonant tunneling, imaging frequency is limited for a certain number of crystals. However, after conducting an analytical analysis over a wide range of frequencies, we observed that higher frequencies do exist for subwavelength imaging. We verified this observation both numerically and experimentally. We extended our study to observe the effect of lattice periodicity on image resolution. By reducing periodicity during experiment, we achieved a resolution of λ/9.5 at the conventional region and λ/2.45 at the higher band region.