Related Experiment Video
Updated: Nov 5, 2025
10:26
Fabrication and Characterization of Superconducting Resonators
Published on: May 21, 2016
11.6K
Ultrawideband bandstop filter based on Fano resonance and rectangular resonators
Applied Optics
|May 13, 2021
Summary
Investigating stub length effects on Fano resonance in metal-insulator-metal waveguides led to an ultrawideband bandstop filter. This filter effectively blocks wavelengths between 850 nm and 1310 nm for optical circuits.
Area of Science:
- Photonics and optical engineering
- Nanophotonics
- Waveguide theory
Background:
- Fano resonance arises from the interference between a discrete state and a continuum of states.
- Metal-insulator-metal (MIM) waveguides offer subwavelength light confinement.
- Rectangular cavities coupled via stubs can support Fano resonance.
Purpose of the Study:
- To investigate the impact of stub length on Fano resonance formation in MIM waveguide structures.
- To design an ultrawideband bandstop filter utilizing Fano resonance.
- To demonstrate tunability of the filter's central wavelength by structural dimension adjustments.
Main Methods:
- Theoretical analysis using the transmission line model and temporal coupled mode theory.
- Numerical simulations employing the finite-difference time-domain (FDTD) method.
- Experimental validation of theoretical and numerical predictions (implied by comparison).
Main Results:
- The stub length significantly influences the formation and characteristics of Fano resonance.
- An ultrawideband bandstop filter was successfully designed, covering the 850 nm to 1310 nm telecommunication windows.
- The filter's central wavelength is tunable by altering structural dimensions, offering design flexibility.
Conclusions:
- The study confirms the relationship between stub length and Fano resonance in MIM waveguide structures.
- The proposed Fano resonance-based structure is a viable design for ultrawideband bandstop filters.
- The tunable nature and performance of the filter highlight its potential for integrated optical circuits.
Related Concept Videos
01:23Parallel Resonance
336
The parallel RLC circuit is an arrangement where the resistor (R), inductor (L), and capacitor (C) are all connected to the same nodes and, as a result, share the same voltage across them. The parallel RLC circuit is analyzed in terms of admittance (Y), which reflects the ease with which current can flow. The admittance is given by:
336
01:27Passive Filters
761
Passive filters are utilized to shape the frequency spectrum of signals across a diverse array of applications. These filters, using only passive elements like resistors (R), inductors (L), and capacitors (C), are capable of selectively allowing or blocking certain frequency ranges without the need for external power sources.
Low-Pass Filters
Low-pass filters are designed to transmit signals with frequencies lower than the cutoff frequency, ωc, and attenuate those above it. The cutoff...
Low-Pass Filters
Low-pass filters are designed to transmit signals with frequencies lower than the cutoff frequency, ωc, and attenuate those above it. The cutoff...
761
01:25Active Filters
1.1K
Active filters are electronic circuits that use operational amplifiers (op-amps), resistors, and capacitors to filter out unwanted frequency components from a signal. A first-order low-pass active filter is designed to pass signals with a frequency lower than a certain cutoff frequency and attenuate frequencies higher than that cutoff frequency. The transfer function for a first-order low-pass active filter is:
1.1K
01:17Bandpass Sampling
301
In signal processing, bandpass sampling is an effective technique for sampling signals that have most of their energy concentrated within a narrow frequency band. This type of signal is known as a bandpass signal. The key principle of bandpass sampling involves sampling the signal at a rate that is greater than twice the signal's bandwidth to prevent aliasing.
A bandpass signal has a spectrum with a lower frequency limit, denoted as ω1, and an upper frequency limit, denoted as ω2....
A bandpass signal has a spectrum with a lower frequency limit, denoted as ω1, and an upper frequency limit, denoted as ω2....
301
01:24Characteristics of Series Resonant Circuit
378
Series resonance occurs in a circuit containing inductive (L), capacitive (C), and resistive (R) elements connected sequentially. At the resonance frequency, the inductive and capacitive reactances are equal in magnitude but opposite in sign, effectively canceling each other. This causes the circuit's impedance is minimal, primarily determined by the resistance R. The resonant frequency of an RLC circuit is defined as:
378
01:17Series Resonance
326
The RLC circuit impedance is defined as the ratio of the supply voltage to the circuit current. Resonance in such a circuit occurs when the imaginary part of this impedance equals zero. This specific condition means that the inductive reactance is exactly equal to the capacitive reactance. The frequency at which this happens is known as the resonant frequency. Mathematically, the resonant frequency is inversely proportional to the square root of the product of the inductance (L) and capacitance...
326