In 1994 he was granted a Docent Diploma by the Ministry of Education of Russian Federation and in the following year he received Doctor of Sciences degree from St. Petersburg State Technical University, Russia.

In 1996, he was promoted to full professor position in St. Petersburg State Technical University, where he also became a director of Complex Media Electromagnetics Laboratory.

[5] The thesis was devoted to the problem of diffraction at an edge of dense planar arrays of metal wires,[7][8] what is now referred as metasurfaces or two-dimensional metamaterials.

In 1997, Tretyakov and his colleagues demonstrated that chiral effects (optical rotation and circular dichroism) can be achieved even with an infinitely thin composite layer without broken mirror symmetry.

However, due to the absence of materials with such properties in nature, wide interest to the backward wave media was generated only in the early 2000s, when the team of David R. Smith experimentally demonstrated first negative-index metamaterial.

[24] Inspired by the idea of transformation-optics based electromagnetic cloaking, Tretyakov's team developed an alternative realization of the same effect for cylindrical objects.

[25] In contrast to the previous designs, Tretyakov's cloaking device exhibits significantly increased bandwidth and lower amount of dissipation loss.

[28] The concept of the superlens, introduced by John Pendry in 2000 as an extension of the work done by Victor Veselago, showed a theoretical possibility to achieve optical resolution well below the wavelength.

In 2003, Stanislav Maslovski and Sergei Tretyakov showed that an alternative to Pendry’s device can be constructed using layers that impose the necessary boundary conditions at two parallel planes in free space.

In 2008, Tretyakov and colleagues developed analytical formulas for the calculation of the grid impedance of electrically dense arrays of strips and square patches and their applications for HIS.

[33] More recently, he worked on modelling and applications of thin composite layers with engineered electromagnetic properties (metasurfaces), in particular, developing approaches to full control of reflected and transmitted waves.