Optimal Super-Oscillations

Michael Berry

Fu-Ming Guo, Yujun Yang, Jin Ming-Xing +2 more

Using a linearly polarized, phase-stabilized 3-fs driving pulse of 800 nm central wavelength shape-optimized on its ascending edge by its an amplitude-reduced pulse irradiating on a superposition state of the helium atom, we demonstrate theoretically the generation of a super strong isolated 176-attosecond pulse in the spectral region of 93–124 eV. The unusually high intensity of this attosecond pulse is marked by the Rabi-like oscillations emerging in the time-dependent populations of the ground state and the continuum during the occurrence of the electron recombination, which is for the first time observed in this work.

Xinyuan Hu, Shulin Wang, Chengzhi Qin +8 more

Super-Bloch oscillations (SBOs) are amplified versions of direct current (dc)-driving Bloch oscillations realized under the detuned dc- and alternating current (ac)-driving electric fields. A unique feature of SBOs is the coherent oscillation inhibition via the ac-driving renormalization effect, which is dubbed as the collapse of SBOs. However, previous experimental studies on SBOs have only been limited to the weak ac-driving regime, and the collapse of SBOs has not been observed. Here, by harnessing a synthetic temporal lattice in fiber-loop systems, we push the ac-field into a strong-driving regime and observe the collapse of SBOs, which manifests as the oscillation-trajectory localization at specific ac-driving amplitudes and oscillation-direction flip by crossing collapse points. By adopting arbitrary-wave ac-driving fields, we also realize generalized SBOs with engineered collapse conditions. Finally, we exploit the oscillation-direction flip features to design tunable temporal beam routers and splitters. We initiate and demonstrate the collapse of SBOs, which may feature applications in coherent wave localization control for optical communications and signal processing.

Andrew N. Jordan, John C. Howell, A. Nick Vamivakas +1 more

F. Suekane

Alon Bahabad, Yaniv Eliezer, Liran Hareli +2 more

We experimentally broke the temporal Fourier focusing limit of an ultra-short optical pulse and used it to demonstrate temporal super-resolution detection of a temporal event [1]. The envelope function of the pulse is synthesized in the form of a Super-Oscillating Beat (SOB) signal, made of pairs of optical modes (i.e. beat modes) centered around a common carrier frequency. The mathematical form for the synthesis of the SOB signal is based on a known super-oscillatory function [2]. Suited with the right amplitude and phases these beat modes interfere to create a lobe in the temporal waveform of the field’s envelope which can be arbitrarily narrow, at the cost of reduced amplitude at the fast oscillation. In our case, we achieved a temporal feature that is approximately three times shorter than the duration of a transform-limited Gaussian pulse having a comparable bandwidth while maintaining 30% visibility of the super-oscillating feature. We then used this SOB signal to demonstrate experimentally temporal super-resolution. Specifically, the SOB signal was used to resolve the existence of a temporal double-slit, a pair of adjacent pulses which are detected as a single temporal event by a transform-limited Gaussian pulse having the same bandwidth. Formally, this experiment constitutes a temporal analogue to super resolution imaging by using a super oscillating point-spread-function [3,4]. Numerical simulations analyse in which cases the SOB signal outperform transform-limited signals for detection of short temporal events. [1] Y. Eliezer, L. Hareli, L. Lobachinsky, S. Froim and A. Bahabad, “Breaking the Temporal Resolution Limit by Superoscillating Optical Beats”, Physical Review Letters, 119, 043903 (2017). [2] M. V Berry and S. Popescu, "Evolution of Quantum Superoscillations and Optical Supperresolution without Evanescent Waves," J. Phys. A. Math. Gen. 39, 6965 (2006). [3] A. M. H. Wong and G. V Eleftheriades, "An Optical Super-microscope for Far-field, Real-time Imaging Beyond the Diffraction Limit" Sci. Rep. 3, (2013). [4] E. T. F. Rogers, J. Lindberg, T. Roy, S. Savo, J. E. Chad, M. R. Dennis, and N. I. Zheludev, "A Super-oscillatory Lens Optical Microscope for Subwavelength Imaging," Nat. Mater. 11, 432 (2012).