Optically-driven photoconductive switches are one of the predominant sources currently used in terahertz imaging systems. However, owing to their low average powers, only raster-based images can be taken, resulting in slow acquisition times. In this work, we show that placing a photoconductive switch within a cavity, we are able to generate absolute THz powers of 181 µW. The cavity is based on a metal-insulator-metal structure that permits an enhancement of the average power by almost one order of magnitude whilst conserving a broadband response. We demonstrate real-time imaging using this source, with the broadband spectrum permitting to eliminate diffraction artefacts.
Reaching high average powers and room temperature operation for THz sources has become the key challenge for the uptake of THz applications that require real-time imaging. In this work, we show that by placing a photoconductive switch within a quasi-resonant cavity based on a metal-insulator-metal geometry, we are able to generate, at room temperature, average THz powers greater than of 200 µW, with the frequency of the THz emission centred at 1.5THz, specifications ideally adapted to NDT. We demonstrate proof-of-principle real-time THz imaging.
We report the analyses of the photo induced anisotropy generated by a mesogenic azobenzene dye complex that is doped
in isotropic and anisotropic matrices. By using time resolved polarized spectroscopy and photo induced dichroism
studies, we show that this specific dye composition undergoes photo isomerization process, but has very limited angular
mobility in all tested matrices.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.