Acousto-Optic Tunable Filter for Imaging Application with High Performance in the IR Region

Valle, S., Ward, J., Pannell, C. and Johnson, N.P. (2015) Acousto-Optic Tunable Filter for Imaging Application with High Performance in the IR Region. In: Optical Components and Materials XII, San Francisco, CA, USA, 7 Feb 2015, 93590E. (doi:10.1117/12.2077610)

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Acousto-Optic Tunable Filters with large acceptance angle (parallel tangent configuration) are the component of choice for imaging application in visible and NIR region wavelength. AOTF in the wavelength range above 2μm could be impractical due to the λ2 and interaction length dependencies on acoustic field intensity to achieve peak diffraction efficiency. A potential solution to reduce the RF power requirement for full diffraction efficiency is to realize a resonant acoustic cavity, and "recycle" the phonons. This configuration could give a theoretical advantage factor between 4 and 10. A prototype device with an operational wavelength range between 1μm and 2μm has been designed and tested and an optimized design to operate between 2μm - 4μm has been prepared and under construction. Due to the presence of standing wave, when the device is not in resonance a feedback signal from the device is affecting the electrical matching and the power delivered to the device is mostly reflected back (VSWR > 25), therefore a special RF driver is required in order to maintain in resonance the device. The resonance frequencies are also affected by the temperature of the device, thus a temperature control mechanism with high accuracy is required. We present the preliminary results of the first prototype, which are in good agreement with the mathematical model and an advantage factor of about 4 has been measured. Further investigation are planned in order to improve the device performance and develop the RF driver for the resonant configuration.

Item Type:Conference Proceedings
Additional Information:Proceedings of SPIE Volume 9359
Glasgow Author(s) Enlighten ID:Johnson, Dr Nigel
Authors: Valle, S., Ward, J., Pannell, C., and Johnson, N.P.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering

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