Optically modulated beam THz amplifier: realization

The main objective is to demonstrate the feasibility of a THz electron tube based on THz optical control of electron emission. The principle uses the sensitivity of the emission process to the electrical field of the optical wave, together with the nonlinear dependence of the emitted current on the electric field at the apex of the nanotube. The emission can then be THz modulated by the beat of two optical waves with a frequency shift in the THz range. In order to increase the efficiency of the process, the optical field has to be aligned with the CNT axis, and concentrated at the CNT locations. For both these purposes, we will use a completely new design concept allowing the efficient excitation of a localized surface mode near each CNT of the cathode, by normal incidence laser beam (patent N° EP 2004/053324). This structure is named concentrator. The WP will study the concentrator and CNT array (Task 4.1), how the electron beam will be modulated at THz frequency , the most suitable interaction structure and the laser coupling .The assembly and the test phase will conclude the WP4.

Deliverables 

D4.1:Growth of CNTs on the optical concentrators (T0+ 18)

D4.2:Validation of optical control of field emission with a low frequency intensity modulated laser (T0+21)

D4.3:First assessment of GHz optical control of CNT electron emission using nonlinear photomixing of two optical waves with a frequency off-set in the GHz range and measure of modulation depth of the electron current (T0+24)

D4.4:Validation of THz optical control of CNT electron emission using nonlinear photomixing of two optical waves with a frequency off-set in the THz range (T0+29)

D4.5: Realization of the sealed tube for testing the optically modulated beam THz amplifier (T0 + 32)

D4.6: Characterization and verification of THz amplifier performances, final results analysis report, production of final report on the reliability of the amplifier (T0+36).

Duration
34 months (from T0+2 to T0+36)