Tuesday, 18 April, 2017 - 10:20

Pim Venderbosch has joined the COPS group at the 18th of April. During his bachelor project he will work on the project of White LEDs.

COPS article listed as one of the top downloads in March 2017 of Optics Express!
Monday, 10 April, 2017 - 22:36

Our article "Transmitting more than 10 bit with a single photon", by Tristan B. H. Tentrup, Thomas Hummel, Tom A. W. Wolterink, Ravitej Uppu, Allard P. Mosk, and Pepijn W. H. Pinkse, has been listed by Optics Express as one of the top downloads of March 2017

Postdoc Vacancy for Ultrafast Switching of Higher-Dimensional Photonic Information in Silicon Nanostructures
Monday, 6 March, 2017 - 20:17

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The successful candidate will be a physicist or engineer with a PhD, preferentially in physics with a focus on optics. Experience with ultrafast lasers is an advantage. He or she will bring excellent experimental skills to the team. We expect the candidate to have an excellent command of the English language as well as professional communication and team working skills.  Although this project is initially funded for one year, follow-up projects are likely to open up during the course of the project. 

Project Summary

We fabricate 2D and 3D silicon nanostructures that the candidate will study with ultrafast laser pulses for routing and ultrafast switching of higher-dimensional photonic information. In addition, we will study nonlinear pulse propagation in silicon nitride waveguide arrays fabricated by project partners. This project is a pilot that stimulates further larger project in integrated nanophotonic as well as quantum information processing. 

Supervisors / host groups

Prof. dr. Willem Vos, Complex Photonic Systems (COPS), MESA+ Institute for Nanotechology 
Prof. dr. Klaus Boller, Laser Physics and Nonlinear Optics (LPNO), MESA+ Institute for Nanotechology 
Prof. dr. Pepijn Pinkse, Complex Photonic Systems (COPS), MESA+ Institute for Nanotechology 

Project plan

Currently, routing and switching of photonic information on a chip is pursued mainly in 1D photonic structures, e.g., in silicon waveguide circuits. We want to extend routing and switching of photonic information A) to 2D and even 3D nanostructures and B) to ultrashort time scales, in order to gain decisive advantages:

A) Higher dimensionality Routing of photonic information in 2D and 3D arrays of waveguides offers a significantly increased freedom and richness, notably new topologies. This allows us to greatly increase the photonic information density and simultaneously reduce device footprint. Photonic networks with 2D and 3D architectures open up a plethora of novel possibilities such as high-dimensional quantum optics, quantum image processing, or Boson sampling. MESA+ has potential to become a leading player in these new fields. 

B) Ultrafast switching All-optical switching gives access to encoding and processing of information at ultrafast (femtosecond) timescales and concomitant ultrahigh (THz) clock rates, far beyond the current limits of electronics (GHz-range). These intrinsic advantages of optics, when combined with higher-dimensional photonic information in 2-D and 3-D nanostructures, give rise to extreme rates of optical information processing. 

We are currently working to realize high-dimensional (2D, 3D) arrays of waveguides in silicon, using the advanced nanotechnology available in the MESA+ Nanolab. Silicon provides high nonlinear coefficients in addition to its high index of refraction, thereby offering a strong switching response in sharp contours and structures of small overall dimensions and hence, cost. In addition, Si photonic structures can be readily integrated in CMOS electronics. 

Available infrastructure 

Available for a fast start of the project are our advanced laser systems and expertise on ultrafast switching (Boller, Vos), our quantum light source (Pinkse), our expertise to fabricate Si nanophotonic structures in MESA+ Nanolab (Vos).  Junior scientists with relevant expertise for this project: Dr. Bert Bastiaens, Dr. Ravi Uppu, Tristan Tentrup, Diana Grishina, Cock Harteveld (technician), and Dr. Lyuba Amitonova. 

For contact information:


COPS congratulates alumnus Prof. Jaime Gomez Rivas (Differ) with his VICI grant!
Friday, 24 February, 2017 - 17:46

COPS alumnus prof. Jaime Gomez Rivas is among the recent winners of a prestigious NWO-Vici personal grant for his proposal Strongly Coupled OPtoElectronics (SCOPE). Jaime Gomez Rivas did his Ph.D. research at COPS on Anderson localization of light and defended his thesis in 2002 (click here) . He now leads the "Photonics for Energy" group at the DIFFER Institute in Eindhoven: Congratulations! (Felicitaciones! :-)

Researchers transmit 10 bits of information with a single photon
Friday, 3 February, 2017 - 17:17

COPS researchers at the University of Twente’s MESA+ research institute have managed to transmit more than 10 bit of information with a single photon. They achieved this using an ingenious method for detecting individual photons. The knowledge gained from this study can be used to improve the security and speed of quantum communication. The research results were published today in the scientific journal Optics Express.

When asked “How much information can you transmit using just a single photon?” most scientists would answer ‘one bit’ (either a ‘1’ or a ‘0’). In theory, however, there is no limit to the amount of information you can transmit with a single photon. There are, however, many practical considerations that limit the amount of information per photon. Using an innovative method, University of Twente researchers have now managed to transmit no less than 10.5 bits of information with a single particle of light. 


Prof. Pepijn Pinkse, one of the researchers involved, explains how the system works. “You can compare it to shining a laser pointer onto letters mounted on a groove board. The illuminated letter is the information contained in the laser pointer’s light. The number of letters on the groove board determines the amount of information you can transmit with the light.” The main difference is that Prof. Pinkse and his team created an alphabet of 9072 characters, and they – unlike the laser pointer in the analogy above – transmitted the information with a single photon. That was the key challenge in this study: single photon detection. This is because noise (random photons) can impede measurement. The researchers devised a clever ruse to eliminate any noise. They exploited the fact that individual blue photons can split into exactly two red photons. The researchers arranged for the first photon to send a signal to the detector (which is comparable to a digital camera), which then opened up very briefly. Using a mirror, the second photon was directed at the desired letter of the specially created alphabet. However, they forced this photon to make a slight detour, so that it arrived at the target letter at exactly the same time as the detector opened up. That was the only instant at which photons were able to pass into the detector. In this way, the researchers were able to eliminate noise.

In practical terms, it is difficult to specify the maximum amount of information you can transmit with a single photon, according to Pinkse. “Using our method, there is no theoretical limit to the amount of information that can be sent. The amount of information depends on the size of the alphabet you create. But, even if you could create an alphabet with as many characters as there are atoms in our entire universe, you would still only be able to transmit a maximum of 270 bits with one photon.” 


Prof. Pinkse, who originally made a reputation by developing an unhackable credit card, says that the main objective of this study is to raise quantum communications to a higher level. “The more information you can transmit with photon, the more secure and the faster you can make quantum communication.”

The research published in OSA journal Optics Express entitled "Transmitting more than 10 bit of information with a single photon" was carried out by Tristan Tentrup, Thomas Hummel, Tom Wolterink, Ravitej Uppu, Allard Mosk and Pepijn Pinkse of the Complex Photonic Systems (COPS) and Laser Physics and Nonlinear Optics (LPNO) chairs at the University of Twente’s MESA+ Institute for Nanotechnology. The study was partly funded by the European Union and the Foundation for Fundamental Research on Matter (FOM).