Optics and Photonics Research
Integrated and Free Space Optics and Photonics Research:
• Free Space Optics:
– Classical holographic diffractive optical elements revisited:
• Research in application of novel material and emulsions: High sensitivity allows practical and repeatable fabrication of optical elements such as lenses, mirrors and diffraction gratings.
• Application of ultra compact lasers with extremely long coherence lengths allows low cost components .
– Novel methods and apparatus for Optical Spectroscopy:
• Low cost, high performance Raman based spectroscopy systems.
• Low cost Near Infra Red spectrometer.
• Mobile device based spectroscopy systems.
• Integrated diffractive optical elements and spectroscopic systems:
-Photonic crystal based, ultra wide band spectrometer.
-Novel integrated diffractive optical elements, such as lenses, gratings, and Bragg mirrors.
Holography setup at THz lab: Holographic optical elements revisited:
• 4 Interferometric setups for fabrication of free space diffractive optical elements at CIARS THz and Photonics lab.
• Ongoing projects:
-Holographic lens for NIR applications.
-1800 l/mm grating in novel low scatter emulsion (already fabricated and optimized to yield 85 percent peak efficiency. The grating is lossy for UV light).
-Fully diffractive optics based single pixel detector systems.
Cell phone based spectrometer for educational purposes:
• A cell phone based spectrometer was developed which is a f/4 system with near 1nm resolution.
• An iPhone applications has been developed that offers live dynamic view and the basic spectroscopy software requirements.
• Research on novel methods in obtaining Raman and Fluorecence spectra using a mobile device based spectrometer.
• Advanced post processing of acquired data to increase the limit of detection of the mobile device based spectrometer.
CFL Lamp spectra
Neon Lamp spectra
First Integrated Photonics Project at CIARS:
• Design and fabrication of an on-chip photonic crystal based spectrometer by Behrooz Semnani, to be co-supervised by Arash Rohani.
• The structure would stand on the photonic crystal waveguides and cavities to separate the different spectral components of the incoming photons.
• A photonic crystal based spectrometer was reported in 2012 by Gan et. al.
• Our structure is novel in many aspects, including the way of integration and flexibility of the design to enhance the spectral resolution. Furthermore single detector configurations are being studied.
• Literature review and preliminary modelling and simulation underway.
THz and mm-wave Imaging:
A High Power sub-mm-wave/THz Generation via Electron Beam-Wave Interaction:
The lack of a compatible, powerful and reliable THz source had limited the applications of THz spectroscopy. In this project, a novel sub-mm/THz source is introduced. Using the electron beam-wave interaction, a powerful coherent THz electromagnetic radiation can be generated. Starting from a honey-comb Photonic Crystal (PC) structure, double defected Slow Wave Structure (SWS) was designed. Since all copper SWS have no axial discontinuity, the fabrication process is easy, compact and relatively inexpensive. Using the modal analysis, the SWS has a resonance frequency of almost 135GHz. Using a home built electron beam simulation software, the interaction between the THz wave and electron beam was modeled. According to simulation results, the structure was able to provide up to 9W.
A Sub-THz Beam Antenna Array:
The research is focusing on a Sub-THz Beam Antenna Array on High Resistivity Silicon substrate. The array incorporates antennas, phase shifters, Butler matrix/ power combining network and possible the amplifiers, providing the full chip solution. The envisioned array size for the design is 4 to 1. The Phase Array will be tested for return loss, radiation pattern, beam steering and so on, comparing measurement and simulated result.