Tunable high harmonic pulses from nanorings

Significance 

The present advancement is said to be the use of radiation emission by accelerating the charge in synchrotron ring. The synchrotron ring is powered by applying magnetic field pulses. For smaller ring, large magnetic fields are needed and weak charges are often produced with large magnetic field after consuming high power. The use of nano synchrotron ring is a better alternative that distribute charge looping around. It has a nanorings that can be deposited and help to enable local probing. It is believed that the ability of the nanorings to offer nanoscale optical source will lead to wide range use from life sciences, quantum information to optical telecommunications..

 Dr. Jonas Waetzel and Prof. Dr. Jamal Berakdar at the Institute for Physics, Martin-Luther-University Halle-Wittenberg in Germany developed a tunable high harmonic pulse from nanorings swirled by optical vortices. The authors’ objectives were to replace the conventional synchroton rings with more efficient Nano synchroton ring. They introduced optical vortices which is also called beams carrying orbital angular momentum OAM which are more flexible. In their system, the conventional circular polarized Gaussian pulses were replaced with optical vortices. They generated high tunable harmonic pulses from nanoring by just changing the winding number of optical vortex. The research work is published in Optics Express.

The researchers used the electric field of an optical vortex, combined with a smart engineering for charge confinement in form of intercalated nanorings to yield an elegant and efficient nano synchroton. While the laser intensity is kept moderate to avoid complications related to multiphoton and other strongly nonlinear processes that can lead to higher energy modes and strong current relaxation heating the sample. They also used explicitly the single-particle picture which bases on neglecting Coulomb interactions between the charge carriers

The authors kept the laser intensity moderate to avoid complications related to multiphoton and other strongly nonlinear processes that can lead to higher energy modes and strong current relaxation heating the sample. They used explicitly the single-particle picture which bases on neglecting Coulomb interactions between the charge carriers. They designed the multiple quantum ring system to be free from impurities to determine the appropriate value for the relaxation time.

 The researchers observed that time-dependent emission spectra depend on the emitted frequency of the vortex winding number. In another finding, emission in case of even topological charge leads to an odd number of nodal structures. Jonas Waetzel and Jamal Berakdar successfully produced a turnable high harmonic pulses from nanorings swirled by optical vortices and generated non-destructive and short vortex pulses as planned. This offers a versatile tool for nanoscale optical and spectroscopic applications such as local, single beam pump-probe experiments. The frequencies of the emitted harmonics are tunable by simply changing the waist and the winding number of the optical vortex.

Reference

Jonas Waetzel and Jamal Berakdar. Tunable high harmonic pulses from nanorings swirled by optical vortices. Optics Express, Vol. 25, No. 22, 30 Oct 2017

 

Go To Optics Express

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