Abstract

We present a new approach to defining the “beam quality” of a broadband terahertz beam as it propagates through a first-order optical system. A new definition to beam variance is exhibited, taking into account the spectral weight function of the beam. The near-field far-field propagation product is presented by the general averaged ${\mathbb{M}}^2$, marked as ${({\overline{\mathbb{M}}}^{\text{Broadband}})}^2$. This parameter is invariant while the beam propagates through optical systems, and it obeys the rule of ${({\overline{\mathbb{M}}}^{\text{Broadband}})}^2\ge 1$. Moreover, we show that, in the special case of monochromatic radiation, the definitions we made are reduced to the known expressions of single frequency radiation. We demonstrate a practical procedure for measuring the beam quality of a broadband radiation. The importance of this procedure is emphasized by our experimental results.

©2012 Optical Society of America

Terahertz beam propagation measured through three-dimensional amplitude profile determination

Matthew T. Reiten, Stacee A. Harmon, and Richard Alan Cheville
J. Opt. Soc. Am. B 20(10) 2215-2225 (2003)

Ghost imaging via spectral multiplexing in the broadband terahertz range

Azat Ismagilov, Anastasia Lappo-Danilevskaya, Yaroslav Grachev, Boris Nasedkin, Victor Zalipaev, Nikolay V. Petrov, and Anton Tcypkin
J. Opt. Soc. Am. B 39(9) 2335-2340 (2022)

Radiation characteristics of large-area photomixer used for generation of continuous-wave terahertz radiation

Armaghan Eshaghi, Mahmoud Shahabadi, and Lukas Chrostowski
J. Opt. Soc. Am. B 29(4) 813-817 (2012)

Propagation of vectorial laser beams

Peter Muys
J. Opt. Soc. Am. B 29(5) 990-996 (2012)

On the role of photoionization in generation of terahertz radiation in the plasma of optical breakdown

Alexander V. Borodin, Mikhail N. Esaulkov, Ilya I. Kuritsyn, Igor A. Kotelnikov, and Alexander P. Shkurinov
J. Opt. Soc. Am. B 29(8) 1911-1919 (2012)