News Feature | March 15, 2023

Bright Ideas — Exceptionally Brief Hard X-Ray Pulses, Silicon Photonics Kicking Down Doors, Gh-Gh-Gh-Ghost (Imaging), Butterfly Wings, And More

John Oncea

By John Oncea, Editor


Bright Ideas presents the most captivating news and innovations in optics and photonics. This week, we look at a couple of pieces of Optica news, a Texas A&M professor wins a major award, a photodetector shows enhanced sensitivity and speed, and more.

Let’s start with a couple of stories courtesy of our friends at Optica. First, researchers in China have created all-silicon structures that can transmit terahertz waves over four distinct optical channels, allowing multiple functions to be performed at the same time. Big news considering, such a device could offer a more versatile solution for terahertz imaging and quantum-information encoding, not to mention for future 6G wireless networks. “In 6G networks, the multiple channels produced by our devices could be used to simultaneously achieve beam deflection at multiple frequencies,” said team leader Fuyu Li from the University of Electronic Science and Technology of China. “That would reduce the need for more base stations that would otherwise be needed to achieve full signal coverage.”

Next up, a team of U.K. and U.S. researchers have simulated the generation, transport, and conversion into X-rays of energetic electrons accelerated in a plasma wakefield device. The discovery confirms that the electrons’ energy spread and emittance remain largely unchanged — which would allow for exceptionally brief hard X-ray pulses to be produced. “Plasma accelerators could generate electron beams orders of magnitude brighter and over far smaller distances than the handful of gigantic free-electron lasers (FELs) operating in the world today. That is the conclusion of a collaboration led by a research team in the United Kingdom, which has carried out an end-to-end simulation of an FEL powered by a plasma-wakefield device in which the accelerated electrons are extracted from gas within the plasma—a setup that the team calculates could yield coherent hard X-ray pulses each just 100 attoseconds long.”

Data and denser designs are opening the door for silicon photonics and, according to Semiconductor Engineering, silicon photonics is kicking the door down. “For the past three decades, photonics largely has been an enabler for high-speed communications, a lucrative market that now tops $1 billion. But with the need for high-speed, low-power communication becoming more pervasive — especially as more data needs to be moved and processed — photonics is gaining traction across a variety of markets. Pushing all that data through thin wires and over longer distances requires power and generates heat, and photonics offers a proven alternative.” The key: standards. “There isn’t a commercialized, turnkey production test solution today,” said Matt Griffin, product manager at Teradyne. “There is simultaneously the challenge of combining electrical and optical measurements into the same test system at the wafer level and the lack of standardization on what test coverage will be needed. But high throughput test is going to be a critical capability to have as volumes continue to increase and these challenges will have to be solved to get there.”

An international research group headed by Akhil Kallepalli (Kallepalli Lab) – collaborating with the Optics Group at the University of Glasgow – developed and tested a new ghost imaging algorithm that functions from an optics point of view. Azo Optics reports, “The algorithm discovers that researchers could generate an image with enhanced resolution and contrast with the help of lower flux illumination, which could help decrease sample damage.” This new algorithm developed by the authors makes the utmost use of patterns irrespective of their orthogonality. They term their new technique “orthogonalized ghost imaging.”

Dr. Christi Madsen, professor in the Department of Electrical and Computer Engineering at Texas A&M University (Gig 'em!), was named a 2023 fellow of the International Society for Optics and Photonics (SPIE) for her technical achievements in the multidisciplinary fields of optics, photonics, and imaging, and for her service to SPIE and the optics and photonics community. According to a Texas A&M release, “For 30 years, Madsen has contributed to the field of optics and photonics. She is a fellow of the optics and photonics society, Optica; was a distinguished member of technical staff at Bell Labs, Lucent Technologies; and is the founder of Sunstrike Optics LLC. Her research interests include photonic signal processing, integrated optics, optical filters, microwave photonics, polarization optics, optical ring resonators, and dispersion and high-speed optical signals.”

San Francisco State University announced a team of SFSU (go Gators!) researchers photodetector shows enhanced sensitivity and speed, possibly pointing the way to improved data communications, night vision, and bioimaging. SFSU Physics & Astronomy Associate Professor AKM Newaz, graduate student Hon-Loen Sinn, and Stanford University (go Cardinal!) collaborators describe the impressive properties of their photodetector that has improved sensitivity in the ultraviolet (UV) to near-infrared light range. They’ve submitted a provisional patent for their device and are working on the main patent application. “A UV [ultraviolet] photodetector is very useful for [a range of applications from] biology to space astronomy to fire monitors. All these current communication channels [use] the visible range and infrared …,” Newaz said. “We don’t have many higher efficiency UV photodetector devices, so people don’t use UV.”

Finally, reports scientists have devised a way of fabricating a complex structure, previously found only in nature, to open up new ways for manipulating and controlling light. “The structure, which naturally occurs in the wing scales of some species of butterfly, can function as a photonic crystal, according to a new study by researchers at the University of Birmingham. It can be used to control light in the visible range of the spectrum, for applications for lasers, sensors, and also devices for harvesting solar energy.” Dr. Angela Demetriadou, a co-author from the School of Physics and Astronomy, has said, “This is a new and exciting way to fabricate nanophotonic media with exceptional and tailored chiro-optical properties, with immense control over their properties.”