Alex Dikopoltsev


Last Name

Dikopoltsev

First Name

Alex

ORCID

0000-0001-5765-7730

Organisational unit

09894 - Dikopoltsev, Alexander / Dikopoltsev, Alexander

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2023 - 202545
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Publications 1 - 10 of 45
  • Photonic simulator in synthetic space with fast-gain dynamics
    Item type: Other Conference Item
    Dikopoltsev, Alex; Heckelmann, Ina; Bertrand, Mathieu; et al. (2024)
  • Topological insulator quantum cascade laser in synthetic space: towards a realization
    Item type: Other Conference Item
    Dikopoltsev, Alex; Micheletti, Paolo; Senica, Urban; et al. (2023)
    2023 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)
    When optical nonlinearities are introduced to photonic topological insulators, the system starts separating from its original solid-state roots, and creating fertile ground to completely new inventions, one of which is the topological insulator laser [1]. This type of laser provides single mode lasing of semiconductor laser arrays through robust injection locking from one laser to the next despite inevitable variations and defects in semiconductor processing. Since the concept was first demonstrated [2], [3], it was far and wide applied in many systems [4]–[6], and now it seems that topological insulator lasers are currently the most auspicious application of topological photonics.
  • Frequency comb shaping through staggered phase flux in fast gain lasers
    Item type: Conference Paper
    Piciocchi, Diego; Dikopoltsev, Alex; Heckelmann, Ina; et al. (2025)
    Conference lecture held on September 2, 2025
  • Ultra-Stable Broadband Comb Laser with Tunable Free Spectral Range and Spectra
    Item type: Conference Paper
    Marzban, Bahareh; Miller, Lucius; Dikopoltsev, Alex; et al. (2025)
    EPJ Web of Conferences ~ EOS Annual Meeting (EOSAM 2025)
    We present a novel near-infrared broadband, flat-top optical frequency comb spanning 1.6 THz. This comb is generated using an interband gain medium operated in an ultrafast gain recovery regime within a unidirectional ring cavity. The remarkable stability of our approach is evidenced by a 1 Hz RF linewidth. The injected RF signal not only governs the spectral bandwidth and free spectral range but also tailors the comb-s spectral shape-a feat achieved by simultaneously injecting multiple modulation tones. This advanced level of control opens promising avenues for applications in communication, sensing, and ranging, where precise and stable frequency lines are essential for performance and reliability.
  • The theory of the quantum walk comb laser
    Item type: Journal Article
    Dikopoltsev, Alex; Heckelmann, Ina; Schneider, Barbara; et al. (2025)
    Nanophotonics
    The development of on-chip optical frequency comb devices paves the way for novel applications in environmental tracking, fast ranging and smart communication solutions. Recently, a new type of frequency comb device, based on a modulated ring quantum cascade laser, was introduced and demonstrated. Here we present a rigorous theoretical study of this type of device, also known as the quantum walk comb laser. We show that resonant phase modulation of a fast gain laser with a dispersive circular cavity is sufficient to support a broadband comb. This method requires the gain to have a sufficiently fast recovery time to support quasi-instantaneous suppression of intensity fluctuations. When this condition is met, the modulation leads to quantum walk dynamics, and then to stabilization onto a stable and controllable frequency comb. We show this type of dynamics through simulations using realistic parameters and reveal the impact of higher-order contributions from gain and dispersion. We also study the resilience of this type of mode-locked laser to noise injection and show its superiority to that of active mode-locking. We believe that this work will allow the development of comb devices with high wall-plug efficiency, arbitrary output spectral shaping and increased stability properties.
  • A Ultra-Stable Broadband Comb Laser with Tunable Free Spectral Range and Spectra
    Item type: Other Conference Item
    Marzban, Bahareh; Blatter, Tobias; Miller, Lucius; et al. (2025)
    We present a novel near-infrared quantum walk comb laser, with 14 nm bandwidth, up to 6% wall-plug efficiency, and a 1 Hz RF linewidth. This broadband comb offers in situ spectral shaping and demonstrates stable data transmission performance at 64 GBd QPSK.
  • Two-Dimensional Topological Edge States in Periodic Space-Time Interfaces
    Item type: Journal Article
    Segal, Ohad; Plotnik, Yonatan; Lustig, Eran; et al. (2025)
    Physical Review Letters
    Topological edge states in systems of two (or more) dimensions offer scattering-free transport, exhibiting robustness to inhomogeneities and disorder. In a different domain, time-modulated systems, such as photonic time crystals, offer nonresonant amplification drawing energy from the modulation. Combining these concepts, we explore topological systems that vary periodically in both time and space, manifesting the best of both worlds. We present topological phases and topological edge states in photonic space-time crystals-materials in which the refractive index varies periodically in both space and time, displaying band gaps in both frequency and momentum. The topological nature of this system leads to topological invariants that govern the phase between refracted and reflected waves generated from both the spatial and the temporal interfaces. The 2D (1D space + 1D time) nature of this system leads to propagating edge states, and a unique edge state that grows exponentially in amplitude while following the space-time edge.
  • In-situ frequency comb shaping by multi-frequency injection in fast-gain lasers
    Item type: Other Conference Item
    Dikopoltsev, Alex; Piciocchi, Diego; Heckelmann, Ina; et al. (2025)
    Shaping of the spectrum of frequency comb sources is highly beneficial for application that require controllable optical source, such as ranging or communications. However, efficient in-situ reconfiguration of the spectrum is a challenge. We demonstrate spectral shaping of frequency combs in fast-gain active devices by engineering an Aharonov-Bohm phase in a synthetic frequency lattice. By modulating a fast gain circular laser at its resonance and twice this frequency with a relative phase, we created a triangular ladder in the modal space, where the phase added with staggered phase flux. This broke the time-reversal symmetry in the system, allowing for non-trivial gauge fields that manipulate the light. This enable the control over the frequency lattice dynamics, enabling full bandwidth tuning of a strong central lobe in a Quantum Cascade Laser comb. This paves the wave to new efficient and simple reconfigurable optical frequency comb sources.
  • Time Refraction and Time Reflection above Critical Angle for Total Internal Reflection
    Item type: Journal Article
    Bar-Hillel, Lior; Dikopoltsev, Alex; Kam, Amit; et al. (2024)
    Physical Review Letters
    We study the time reflection and time refraction of waves caused by a spatial interface with a medium undergoing a sudden temporal change in permittivity. We show that monochromatic waves are transformed into a pulse by the permittivity change, and that time reflection is enhanced at the vicinity of the critical angle for total internal reflection. In this regime, we find that the evanescent field is transformed into a propagating pulse by the sudden change in permittivity. These effects display enhancement of the time reflection and high sensitivity near the critical angle, paving the way to experiments on time reflection and photonic time crystals at optical frequencies.
  • Quantum Walk Combs for spectroscopic applications
    Item type: Other Conference Item
    Heckelmann, Ina; Piciocchi, Diego; Dikopoltsev, Alex; et al. (2024)
    Summer School on Mid-Infrared Quantum Sensing and Technologies: Poster Session Book of Abstracts
Publications 1 - 10 of 45