EPic Laboratory

EPic news

Customizing supercontinuum generation via on-chip adaptive temporal pulse-splitting

20th November 2018
Nature Comms Ben FROG

Benjamin Wetzel, Maxwell Rowley, Alessia Pasquazi and Marco Peccianti have published an open access article in Nature Communications. 

Modern optical systems increasingly rely on complex physical processes that require accessible control to meet target performance characteristics. In particular, advanced light sources, sought for, for example, imaging and metrology, are based on nonlinear optical dynamics whose output properties must often finely match application requirements. However, in these systems, the availability of control parameters (e.g., the optical field shape, as well as propagation medium properties) and the means to adjust them in a versatile manner are usually limited. Moreover, numerically finding the optimal parameter set for such complex dynamics is typically computationally intractable. Here, we use an actively controlled photonic chip to prepare and manipulate patterns of femtosecond optical pulses that give access to an enhanced parameter space in the framework of supercontinuum generation. Taking advantage of machine learning concepts, we exploit this tunable access and experimentally demonstrate the customization of nonlinear interactions for tailoring supercontinuum properties.

More details can be found in the journal article itself or in the press release of the University of Sussex.

The Emergent Photonics Laboratory are looking for a new PhD candidate in Ultrafast Integrated Photonics

4th October 2018
alessia portrait

This fully funded 3.5 year studentship is funded by the Engineering and Physical Sciences Research Council (EPSRC). Granting them access to state-of-the-art photonics equipment available within the EPic infrastructure, the project involves the development of a self-stabilised micro-comb suitable for industrial deployment. 

The Emergent Photonics Laboratory are looking for a new PhD candidate in Ultrafast Photonics

4th October 2018
alessia portrait

This fully funded 3.5 year studentship is funded by the European Research Council (ERC). Granting them access to state-of-the-art photonics equipment available within the EPic infrastructure, the project involves the development of a complex imaging techniques applicable to THz systems. 

Dr Alessia Pasquazi has been promoted to Reader

3rd August 2018
alessia portrait

The Emergent Photonics laboratory are congratulating one of its directors in their promotion from Senior Lecturer to Reader in Physics. 

Dr Luke Peters Has Graduated Today

25th July 2018
luke graduating

Dr Luke Peters of the Emergent Photonics Laboratory had his graduation ceremony today for his thesis titled "Surface Terahertz Phenomena," the summary of which is:

With the massive advantages of THz radiation and the current technical difficulties in mind, I have chosen to undertake research into terahertz surface phenomena, which is the focal point of my thesis. Ultrathin surface terahertz emitters have many advantages as they have an extremely thin active region, typically hundreds of atomic layers. In this framework, III-V semiconductors, such as InAs and InSb, have record-breaking conversion efficiencies per unit thickness. In addition, the phase mismatch, which commonly limits the generation of terahertz from optical crystal, is negligible and so there is an opportunity
for enhancing the emitted bandwidth.
My thesis is born as the core of many research interests of my research lab (Emergent Photonics), which enabled the appropriate availability of resources that made my results possible. It also created several spin-out research lines. All the work presented is my work (with the exception of the background research). Parts of chapters have been published in journals and publications which see me as the first author.
The structure of this thesis is as follows. First I discuss optical pump rectification emission, and the saturation of InAs terahertz emissions. Then I introduce my work on terahertz enhancement emission through graphene. Finally, I present my work on an exotic terahertz emission mechanism, namely the all-optical surface optical rectification and I place my concluding remarks.

Time-Resolved Nonlinear Ghost Imaging

3rd July 2018
ACS Photonics Graphical Abstract

Luana Olivieri, Juan Sebastian Totero Gongora, Alessia Pasquazi and Marco Peccianti have published an open access article in ACS Photonics. 

Terahertz (THz) spectroscopy systems are widely employed to retrieve the chemical and material composition of a sample. This is single-handed the most important driving motivation in the field and has largely contributed to shaping THz science as an independent subject. The limited availability of high-resolution imaging devices, however, still represents a major technological challenge in this promising field of research. In this theoretical work, we tackle this challenge by developing a novel nonlinear Ghost Imaging (GI) approach that conceptually outperforms established single-pixel imaging protocols at inaccessible wavelengths. Our methodology combines nonlinear THz generation with time-resolved field measurements, as enabled by state-of-the-art Time Domain Spectroscopy (TDS) techniques. As an ideal application target, we consider hyperspectral THz imaging of semi-transparent samples with non-negligible delay contribution and we demonstrate how time-resolved, full-wave acquisition enables accurate spatiotemporal reconstruction of complex inhomogeneous samples.

EPic at the OSA Advanced Photonics Congress

2nd - 5th July 2018

The Emergent Photonics laboratory have presented two oral contributions at the OSA Advanced Photonics Congress.

Luke PresentingOn Monday 2nd July, Dr Luke Peters presented our results on the high energy limits of surface optical rectification to the Nonlinear Photonics meeting. 





Marco ChairingOn Wednesday 4th July, Professor Marco Peccianti opened the symposium on Microcomb Technology, organised as a joint meeting of Nonlinear Photonics and Integrated Photonics Research, Silicon and Nano-Photonics.

Jacob PresentingAlso on Wednesday 4th July, Jacob Tunesi presented our results on the experimental investigation of the THz emission from Black Silicon surfaces to the Integrated Photonics Research, Silicon and Nano-Photonics meeting.

Student Led Teaching Award for Professor Marco Peccianti

15th May 2018

sussex image of marcoMarco Peccianti, Professor of Photonics, has been awarded a Student led Teaching Award for Outstanding or Innovative Undergraduate Teaching.

The Student Led Teaching Awards are a partnership between the University of Sussex and the Students’ Union. Each year students are invited to say thank you to members of staff they feel have made a difference to their teaching and learning experience at Sussex by nominating them for an award.

Physicists Explore a Safe Alternative to X-Ray Security Scanners

9th April 2018

Marco and Luke in the lab
An article has been broadcast on the University of Sussex's news feed about the recent work published in Nano Energy by Luke Peters within the Emergent Photonics Laboratory. The article highlights some of the potential applications that can be impacted by the work and provides an introduction to the remarkable properties of Terahertz radiation. Since the broadcast the article has been picked up by several other outlets including Phys.org and Electronics360.

Benjamin Wetzel Has Been Promoted

27th March 2018

We congratulate Dr Benjamin Wetzel for his promotion today to Research Fellow B at the University of Sussex!

The Science of Ultrafast Photonics

14th March 2018

Professor Marco Peccianti is giving an outreach talk on Ultrafast Photonics, the talk is accessible to all and organised by the Brighton Café Scientifique. A brief description of the talk is:

A pulse of light can be compressed in time down to scales where even electrons look still and electromagnetic waves appear to move in slow motion. Pulses of fairly ordinary energies, when constrained into such a brief existence, show intensities like that on the surface of a star. Light itself becomes so strong that is able to expel electrons from matter, inhibiting the natural bonding between atoms. This world is rich in frontier physics and new forms of radiation that can now be harnessed.

High-Energy Terahertz Surface Optical Rectification

2nd February 2018
Nano Energy Graphical Abstract

Luke Peters, Jacob Tunesi, Alessia Pasquazi and Marco Peccianti have published an open access article in Nano Energy. 

The interest in surface terahertz emitters lies in their extremely thin active region, typically hundreds of atomic layers, and the agile surface scalability. The ultimate limit in the achievable emission is determined by the saturation of the several different mechanisms concurring to the THz frequency conversion. Although there is a very prolific debate about the contribution of each process, surface optical rectification has been highlighted as the dominant process at high excitation, but the effective limits in the conversion are largely unknown. The current state of the art suggests that in field-induced optical rectification a maximum limit of the emission may exist and it is ruled by the photocarrier induced neutralisation of the medium's surface field. This would represent the most important impediment to the application of surface optical rectification in high-energy THz emitters. We experimentally unveil novel physical insights in the THz conversion at high excitation energies mediated by the ultrafast surface optical rectification process. The main finding is that the expected total saturation of the Terahertz emission vs pump energy does not actually occur. At high energy, the surface field region contracts towards the surface. We argue that this mechanism weakens the main saturation process, re-establishing a clearly observable quadratic dependence between the emitted THz energy and the excitation. This is relevant in enabling access to intense generation at high fluences.

Professor Marco Peccianti Presents Emergent Photonics to BHASVIC Students

30th January 2018
Marco Peccianti presenting to A-Level students

Outreach is significantly important for ensuring that future generations continue to study and aspire to a career in physics. Today, Marco Peccianti gave a presentation on nonlinear optics and terahertz (THz) photonics to a group of A-Level physics students from BHASVIC. The presentation consisted of an introduction to nonlinear optics followed by a demonstration using commercial laser pointers. There was also an introduction to THz, showing some of the applications as well as discussing some of the experiments being conducted in the Emergent Photonics laboratory. 

Solid-state-biased coherent detection of ultra-broadband terahertz pulses

31st October 2017
Optica 2017 Figure

Marco Peccianti and Alessia Pasquazi have published an article in Optica. 

Significant progress in nonlinear and ultrafast optics has recently opened new and exciting opportunities for terahertz (THz) science and technology, which require the development of reliable THz sources, detectors, and supporting devices. In this work, we demonstrate the first solid-state technique for the coherent detection of ultra-broadband THz pulses (0.1–10 THz), relying on the electric-field-induced second-harmonic generation in a thin layer of ultraviolet fused silica. The proposed CMOS-compatible devices, which can be realized with standard microfabrication techniques, allow us to perform ultra-broadband detection with a high dynamic range by employing probe laser powers and bias voltages much lower than those used in gas-based techniques. Eventually, this may pave the way for the use of high-repetition-rate ultrafast lasers and commercially available electronics for the coherent detection of ultrashort THz pulses.

Parametric control of thermal self-pulsation in micro-cavities

25th August 2017

OPRELuigi Di Lauro, David J. Moss, Roberto Morandotti, Sai T. Chu, Marco Peccianti and Alessia Pasquazi have published an article in Optics Letters. 

We propose a scheme for bifurcation control in micro-cavities based on the interplay between the ultrafast Kerr effect and a slow nonlinearity, such as thermo-optical, free-carriers-induced, or opto-mechanical one. We demonstrate that Hopf bifurcations can be efficiently controlled with a low energy signal via four-wave mixing. Our results show that new strategies are possible for designing efficient micro-cavity-based oscillators and sensors. Moreover, they provide new understanding of the effect of coherent wave mixing in the thermal stability regions of optical micro-cavities, fundamental for micro-resonator-based applications in communications, sensing, and metrology, including optical micro-combs.

Optical Pump Rectification Emission: Route to Terahertz Free-Standing Surface Potential Diagnostics

29th August 2017

OPRELuke Peters, Jacob Tunesi, Alessia Pasquazi and Marco Peccianti have published an open access article in Scientific Reports. 

We introduce a method for diagnosing the electric surface potential of a semiconductor based on THz surface generation. In our scheme, that we name Optical Pump Rectification Emission, a THz field is generated directly on the surface via surface optical rectification of an ultrashort pulse after which the DC surface potential is screened with a second optical pump pulse. As the THz generation directly relates to the surface potential arising from the surface states, we can then observe the temporal dynamics of the static surface field induced by the screening effect of the photo-carriers. Such an approach is potentially insensitive to bulk carrier dynamics and does not require special illumination geometries.

EPic Welcomes its Newest Post-Doctoral Research Fellow

1st August 2017

juan portraitToday Dr Juan Sebastian Totero Gongora has started his new job with the Emergent Photonics Group as post-doctoral research fellow in Experimental Photonics. Juan will be joining the team as part of the European Research Council project TIMING as well as helping us to develop efficient surface THz radiation emitters. Before joining us he was a PhD student in the PRIMALIGHT group at the King Abdullah University of Science and Technology where he defended his thesis titled "Disordered Plasmonics and Complex Metamaterials". In which, Juan investigated the theoretical modeling of disordered plasmonic systems, the complex emission dynamics of nanolasers and he has proposed a new kind of nanolaser by integrating anapole lasers onto a silicon-based chip in order to develop an on-chip ultrafast optical pulse source. 

Professor Marco Peccianti at the OSA Advanced Photonics Congress

24th July 2017

Professor Marco Peccianti is going to be giving five oral presentations throughout the week at the Advanced Photonics Congress, please keep an eye out to see the latest from the Emergent Photonics Group:

  • "Route to Photo-enabled Random Terahertz Metasurfaces" at 12:15 CDT on 24th July 2017 in Grand Ballroom D.
  • "Filter-driven Four Wave Mixing Laser with a Controllable Repetition Rate" at 17:00 CDT on 24th July 2017 in Grand Ballroom D.
  • "Type II Micro-comb based on a Filter-Driven Four Wave Mixing Laser" at 17:45 CDT on 24th July 2017 in Grand Ballroom D.
  • "Dynamically Unstable Regimes and Chaos Control through Four Wave Mixing in Ring Microresonators" at 08:30 CDT on 27th July 2017 in Grand Ballroom A.
  • "Optical Pump Rectification Emission: Terahertz Surface State Diagnostics" at 11:15 CDT on 27th July 2017 in Astor Ballroom I/II.

The Emergent Photonics Website has Launched

17th July 2017

The EPic research group have launched their website, containing all you need to know about the latest research in Nonlinear Optics and Terahertz Photonics from the University of Sussex, how to find us, contact us, our publication record and if there are any vacancies open in the group.

The World of Photonics Congress is Over

24th June 2017

After six amazing days, four oral presentations and one poster presentation, CLEO Europe is over and the Emergent Photonics group is heading home.

group photo cleo

EPic at The World of Photonics Congress

24th June 2017

The EPic research group have landed in Munich and will be presenting throughout the week at the 2017 Conference on Lasers and Electro-Optics (CLEO-EU).

EPic Research Group Website

20th February 2017

The EPic research group are developing their website, the place to see all the latest research in Nonlinear Optics and Terahertz Photonics from the University of Sussex.

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RT @Trycage: Congrats to Luigi of #Epic_Sussex for passing his PhD Viva!!! pic.twitter.com/14o7c2Kb65

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RT @Trycage: Congrats to Luigi of #Epic_Sussex for passing his PhD Viva!!! pic.twitter.com/14o7c2Kb65

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RT @Trycage: Congrats to Luigi of #Epic_Sussex for passing his PhD Viva!!! pic.twitter.com/14o7c2Kb65

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Congrats to Luigi of #Epic_Sussex for passing his PhD Viva!!! pic.twitter.com/14o7c2Kb65

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RT @Trycage: @PhysicsAtSussex #Epic_Sussex Congrats to Luana for winning the poster competition!!! At @WarwickTHz pic.twitter.com/KQcoZjLA77