Photonic Band Diagram Microscope "FA･CEED" is a device that enables high-speed and easy measurement of the entire band diagram of various structures including photonic crystals and metamaterials.
In conventional evaluation methods, it is necessary to set up an optical system suitable for each sample, and it takes time for adjustment of the optical system, measurement time, and evaluation time. This system solves these problems and makes it possible to easily and quickly measure the physical properties of various photonic structures.
Photonic structures (microstructures smaller than the wavelength of light arranged with a certain periodicity) enable various manipulations of light by utilizing the interaction of light and matter within the structure. Typical examples are photonic crystals, topological photonic crystals, and metamaterials, which are realized by microfabrication of semiconductors using nanoprocessing technology. The photonic band diagram is one of the important indicators to determine the optical properties of such structures. This system can measure the photonic band diagram at high speed, and can predict various optical phenomena observed in various photonic structures, such as slow light effect, polarization-dependent unidirectional propagation, and negative refractive index.
By using this system, the characteristics of various photonic structures can be clarified and used as an index for exploring fundamental properties. It also facilitates the design of optical devices that employ various photonic structures, which will lead to the expansion of related markets and the development of new research areas using these devices.
This device was developed in collaboration with Assistant Professor Tomohiro Amemiya of the Tokyo Institute of Technology through the research project "Development of novel properties of topological states based on artificial graphene" in the area of "Creation of materials and devices with innovative functions based on topological materials science" of CREST, a strategic creative research promotion project of the Japan Science and Technology Agency.
Features and Applications
High speed measurement
This system uses infrared hyperspectral imaging to obtain Fourier images for each wavelength, and then reconstructs photonic band diagrams based on these images.
This makes it possible to perform extremely fast and versatile measurements, and the entire photonic band diagram can be measured in about five minutes.
Obtain a band diagram at a specified orientation.
By specifying an arbitrary path in the infrared Fourier image, band diagrams for all orientations can be obtained. You can also obtain a band diagram in three dimensions by automatically extrapolating the vertical direction of the sample.
Excite a specific band diagram
By controlling the state of the incident light with various polarizers and wavelength plates/ retarders, and by exciting a specific mode in the photonic structure, it is possible to obtain only the information of that band diagram.
- Clarifying the characteristics of photonic structures
- Design of optical devices
Usage and measurement data
Square lattice photonic crystals
The following movie shows a square lattice photonic crystal being measured.
As the center wavelength of the tunable filter is changed, the Fourier image changes to various shapes along with it. The reconstructed photonic band diagram based on this result is almost identical to the theoretical result expected for a square lattice photonic crystal.