PROSPECTS OF THE USE OF GRADIENT GRATES IN THE LASERS OF TERAHERTZ RANGE

DOI: https://doi.org/10.15407/rpra23.04.302

M. I. Dzyubenko, V. A. Maslov, E. N. Odarenko, V. P. Radionov

Abstract


PACS number: 42.60.By

Purpose: The improvement and development of terahertz radiation sources is required for the further development of the terahertz frequency range. Submillimeter lasers are one of the few sources of terahertz radiation. Metal periodic structures are often used as output mirrors of these lasers. The periodic structure advantage is that by selection of its parameters it is possible to provide the optimal transmittance of the output mirror and the required polarization of laser radiation. The use of concave mirrors in a laser cavity is often required to reduce the diffraction loss and to reduce the output laser beam divergence. However, such mirrors are much more expensive and more complicated in manufacture than the flat ones. The periodic structure with a non-flat substrate is particularly difficult to manufacture. The aim of this work is to study the flat gradient metal gratings that possess the properties of spherical mirrors and lenses simultaneously.

Design/methodology/approach: Flat gradient metal gratings in the form of concentric rings with varying parameters in the radial direction are proposed for solving the focusing problem. The technique for modeling the phase characteristics of such annular gradient gratings is given. Simulation of the properties of a ring grating in which the distance between the rings decreases in the direction from the center to the edges is carried out.

Findings: The image of the change in the wave phase front which occurs when an electromagnetic field interacts with a gradient grating is obtained as a result of numerical simulation. The grating considered has the properties of a concave mirror and a focusing lens simultaneously. Such combination of gradient gratings properties allows to use them as output mirrors of terahertz lasers. This allows us to improve the energy and spatialangular characteristics of the output radiation of terahertz lasers. Сonclusions: Using the circular gradient gratings as output mirrors of terahertz lasers makes it possible to reduce the diffraction losses and divergence of the laser beam that allows to increase the efficiency of terahertz lasers.

Key words: terahertz range, laser, output mirror of a laser cavity, gradient gratings

Manuscript submitted  21.08.2018

Radio phys. radio astron. 2018, 23(4): 302–312


REFERENCES

1. DZYUBENKO, M. I., KAMENEV, YU. E. and RADIONOV, V. P., 2017. Gas-discharge lasers of the terahertz range. Radiophys. Electron. vol. 22, no. 3, pp. 58–80. (in Russian). DOI: https://doi.org/10.15407/rej2017.03.058

2. DEGTYAREV, A. V., MASLOV, V. A. and TOPKOV, A. N., 2016. Lasers of terahertz range with optical pumping. Chapter 11. In: A. E. HRAMOV, A. G. BALANOV, V. D. EREMKA, V. E. ZAPEVALOV and A. A. KORONOVSKIY, eds. Generation and amplification of terahertz range signals: collective monograph. Saratov, Russia: Saratov State Technical University Publ. pp. 404–459. (in Russian).

3. VAYNSHTEYN, L. A., 1963. To the electrodynamic theory of gratings. Part 1. The ideal grating in free space. In: High Power Electronics. Moscow, Russia: AS USSR Publ. vol. 2, pp. 26–56. (in Russian).

4. SHESTOPALOV, V. P., KIRILENKO, A. A., MASALOV, S. A. and SIRENKO, YU. K., 1986. Resonance scattering of waves. Diffraction gratings. Vol. 1. Kiev, Ukraine: Naukova dumka Publ. (in Russian).

5. BARON, T., EUPHRASIE, S., MBAREK, S. B., VAIRAC, P. and CRETIN, B., 2009. Design of metallic mesh absorbers for high bandwidth electromagnetic waves. Prog. Electromagn. Res. C. vol. 8, pp. 135–147. DOI: https://doi.org/10.2528/PIERC09052204

6. WEITZ, D. A., SKOCPOL, W. J. and TINKHAM, M., 1978. Capacitive-mesh output couplers for optically pumped far-infrared lasers. Opt. Lett. vol. 3, is. 1, pp. 13–15. DOI: 10.1364/OL.3.000013

7. GURIN, O. V., DEGTYAREV, A. V., LEGENKYI, M. N., MASLOV, V. А., SVICH, V. A., SENYUTA, V. S. and TOPKOV, A. N., 2014. Generation of transverse modes with azimuthal polarization in a terahertz band waveguide laser. Telecommunications and Radio Engineering. vol. 73, is. 20, pp. 1819–1830. DOI: https://doi.org/10.1615/TelecomRadEng.v73.i20.30

8. SHMAT’KO, A. A., 2008. Millimeter-wave electron wave systems. Volume 1. Kharkiv, Ukraine: V. N. Karazin Kharkiv National University Publ. (in Russian).

9. EGOROV, M. B. and SHMAT’KO, A. A., 1987. Scattering of the field of a linear distributed source on an irregular array in a waveguide with an arbitrary law of variation of its parameters. Reports of the Academy of Sciences of the Ukrainian SSR. Ser. A. no. 6, pp. 42–45. (in Russian).

10. GAN, Q., FU, Z., DING, Y. J. and BARTOLI, F. J., 2008. Ultrawide-bandwidth slow-light system based on THz plasmonic graded metallic grating structures. Phys. Rev. Lett. vol. 100, is. 25, id. 256803. DOI: https://doi.org/10.1103/PhysRevLett.100.256803

11. XU, Y., FU, Y. and CHEN, H., 2015. Steering light by a sub-wavelength metallic grating from transformation optics. Sci. Rep. vol. 5, id. 12219. DOI: https://doi.org/10.1038/srep12219

12. VERSLEGERS, L., CATRYSSE, P. B., YU, Z., WHITE, J. S., BARNARD, E. S., BRONGERSMA, M. L. and FAN, S., 2009. Planar lenses based on nanoscale slit arrays in a metallic film. Nano Lett. vol. 9, is. 1, pp. 235–238. DOI: https://doi.org/10.1021/nl802830y

13. XU, Y., FU, Y. and CHEN, H., 2016. Planar gradient metamaterials. Nat. Rev. Mat. vol. 1, id. 16067. DOI: https://doi.org/10.1038/natrevmats.2016.67

14. FENG, D. and ZHANG, C., 2011. Optical focusing by planar lenses based on nano-scale metallic slits in visible regime. Phys. Procedia. vol. 22, pp. 428–434. DOI: https://doi.org/10.1016/j.phpro.2011.11.067

15. LIN, H. and HUANG, C.-S., 2016. Linear variable filter based on a gradient grating period guided-mode resonance filter. IEEE Photonics Technol. Lett. vol. 28, is. 9, pp. 1042–1045. DOI: https://doi.org/10.1109/LPT.2016.2524655

16. SHI, H., WANG, C., DU, C., LUO, X., DONG, X. and GAO, H., 2005. Beam manipulating by metallic nanoslits with variant widths. Opt. Exp. vol. 13, is. 18, pp. 6815–6820. DOI: https://doi.org/10.1364/OPEX.13.00681

17. CHEN, M., FAN, F., XU, S.-T. and CHANG, S.-J., 2016. Artificial high birefringence in all-dielectric gradient grating for broadband terahertz waves. Sci. Rep. vol. 6, id. 38562. DOI: https://doi.org/10.1038/srep38562

18. GURIN, O. V., DEGTYAREV, A. V., MASLOV, V. A., RYABYKH, V. N. and TOPKOV, A. V. 2016. Terahertz laser waveguide resonators with internal spherical mirrors. Telecommunications and Radio Engineering. vol. 75, is. 18, pp. 1665–1677. DOI: https://doi.org/10.1615/TelecomRadEng.v75.i18.60

19. DZYUBENKO, M. I., MASLOV, V. A. and RADIONOV, V. P., 2016. Applying of the flat circular metal gratings as spherical output mirrors of terahertz lasers. In: 9th International Kharkiv Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves (MSMW) Proceedings. Kharkiv, Ukraine, 20-24 June, 2016. DOI: https://doi.org/10.1109/MSMW.2016.7538117

20. DZYUBENKO, M. I., MASLOV, V. A. and RADIONOV, V. P., 2017. Azimuthal output mirror of the laser cavity. Ukraine Patent No. 115126.

21. DZYUBENKO, M. I., RADIONOV, V. P., MASLOV, V. A. and ODARENKO, E. N., 2017. Plane circular gradient grating that combines the functions of a spherical mirror and a focusing lens. In: IEEE Microwaves, Radar and Remote Sensing Symposium (MRRS) Proceedings. Kiev, Ukraine, 29-31 August, 2017. pp. 139–142. DOI: https://doi.org/0.1109/MRRS.2017.8075047

22. DZYUBENKO, M. I., MASLOV, V. A., ODARENKO, E. N. and RADIONOV, V. P., 2017. Planar Gradient Metamaterial with the Properties of Spherical Partially Transparent Terahertz Mirror. In: Second International Conference on Information and Telecommunication Technologies and Radio Electronics (UkrMiCo’2017) Proceedings. Odesa, Ukraine, September 11–15, 2017. pp. 189–192.

23. TAFLOVE, A. and HAGNESS, S. C., 2000. Computational Electrodynamics: The Finite-Difference Time-Domain Method. Norwood, MA, USA: Artech House, Ink.

24. OSKOOI, A. F., ROUNDY, D., IBANESCU, M., BERMEL, P., JOANNOPOULOS, J. D. and JOHNSON, S. G., 2010. MEEP: A flexible free-software package for electromagnetic simulations by the FDTD method. Comput. Phys. Commun. vol. 181, is. 3, pp. 687–702. DOI: https://doi.org/10.1016/j.cpc.2009.11.008


Keywords


terahertz range; laser; output mirror of a laser cavity; gradient gratings

Full Text:

PDF


Creative Commons License
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0)