Related Experiment Video
Updated: May 29, 2026
11:08
Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
Reflective cavity couplers based on resonant waveguide gratings
Stefanie Kroker1, Thomas Käsebier, Frank Brückner
1Institut für Angewandte Physik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany. stefanie.kroker@uni-jena.de
Optics Express
|September 22, 2011
Summary
Researchers developed novel reflective diffractive cavity couplers using resonant waveguide gratings. These gratings offer low transmission, reducing thermal noise in high-precision metrology components.
Area of Science:
- Optics and Photonics
- Materials Science
- Nanotechnology
Background:
- Conventional cavity couplers rely on multilayer dielectric coatings.
- Multilayer coatings are susceptible to thermal noise, limiting precision in metrology.
- Subwavelength structures offer an alternative for optical component design.
Purpose of the Study:
- To introduce a novel concept for reflective diffractive cavity couplers.
- To explore the use of resonant waveguide gratings as an alternative to multilayer coatings.
- To achieve ultra-low transmission for enhanced performance in optical systems.
Main Methods:
- Designing reflective diffractive cavity couplers based on resonant waveguide gratings.
- Inducing diffracting/beam-splitting properties via periodic parameter modulation of subwavelength structures.
- Analyzing configurations with two and three reflectors to minimize transmittivity using silicon and silica.
Main Results:
- Calculated transmittivities below 10⁻⁴ are achievable with silicon and silica.
- Demonstrated the feasibility of stacked T-shape structures through initial technological tests.
- Proposed a total effective layer thickness not exceeding 1.1 μm.
Conclusions:
- The novel resonant waveguide grating approach offers a promising alternative to conventional multilayer coatings.
- This technology has the potential to significantly reduce coating thermal noise in high-precision metrology.
- The developed components are compact, with a low effective layer thickness, enabling advanced optical applications.
Related Concept Videos
01:28Standing Waves in a Cavity
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
01:23Parallel Resonance
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:
01:24Characteristics of Series Resonant Circuit
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: