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Home » Page 364

Soft medical robots show promise for performing wireless surgery

Scissoring device
Magnetic control: A scissoring device rolls to the target location and cuts a tissue-like structure using radiofrequency heating. (Courtesy: CC BY 4.0/M Li et al. Sci. Adv. 10.1126/sciadv.abm5616)

Wireless miniature soft robots that can safely navigate confined spaces in response to an external magnetic field are highly desirable for medical applications such as minimally invasive surgery. In addition to locomotion, soft robots must be able to perform other complex tasks if they are to replace conventional rigid tools. Such tasks, however, require high force or torque outputs that softer materials alone cannot produce. Instead, a combination of different materials, ingenious mechanics and structural optimization is required to store and release the large amounts of mechanical energy needed to wirelessly perform complex surgical tasks.

To achieve this, scientists from the Max Planck Institute for Intelligent Systems in Stuttgart have developed a small-scale coiled muscle actuator that relies on tunable mechanical properties and radiofrequency magnetic heating to perform surgical tasks that require a high force output and work capacity, including suturing, cutting, drilling and clamping tissues. The researchers describe the capabilities of the miniature soft medical robots in Science Advances.

Coiled artificial muscles

Artificial muscles in soft robotics aim to reproduce the mechanical versatility of natural muscles – contracting, expanding, rotating or bending to efficiently generate motion or perform tasks. To fabricate the muscle actuator, the group used a high-strength nylon fibre as the stiff muscle core and covered it with a polymer layer to insulate it from external mechanical and thermal stimuli.

Between the core and the outer cover, the researchers embedded a high-toughness resin matrix layer containing superparamagnetic Fe3O4 nanoparticles and graphene oxide platelets. These magnetic nanoparticles produce heat when exposed to radiofrequencies, actuating the muscle core and enhancing the mechanical strength of the actuator. Finally, they twisted the resulting structure into a coil to form artificial muscle with an approximate diameter of 1 mm.

The researchers applied an external radiofrequency magnetic field to wirelessly heat the embedded nanoparticles. The artificial coiled muscle then contracts if the fibre ends are free but cannot rotate, or twists if one end of the fibre is fixed and the rest can rotate. The team systematically optimized the concentration of graphene oxide platelets and thickness of the active layer to achieve an actuation force and work capacity of roughly 3.1 N and 3.5 J/g, respectively. These values are more than five and four orders of magnitude greater than those previously reported for magnetic soft actuators.

“Thanks to the muscle actuators integrated to wireless soft medical devices, we can now achieve surgical functions that require high force outputs, such as suturing, cutting, clamping and drilling. Such functions have not been possible so far for wireless soft medical devices,” explain senior authors Wenqi Hu and Metin Sitti.

Performing surgery with soft robots

To fully exploit the potential wireless applications of their coiled artificial muscles, the researchers devised five proof-of-concept surgical scenarios to demonstrate their utility.

Wireless suturing device
Wireless suturing device: A coiled muscle sutures ex vivo pig skin. (Courtesy: CC BY 4.0/M Li et al. Sci. Adv. 10.1126/sciadv.abm5616)

First, they sutured a previously punctured ex vivo pig skin sample by attaching two nylon fibre bars and a cylindrical permanent magnet to the ends of the coiled muscle. By using precise magnetic field control and leveraging the large output force of the coiled muscle, the team showed how the device magnetically reorients itself to suture around the wound and contracts to close it.

Second, they 3D printed a circular polymer frame and embedded magnetic microparticles in a silicone elastomer distributed throughout the frame circumference. This enabled the frame to perform rolling locomotion and positioning using a teleoperated magnet. In the demonstration, the researchers used the force generated by contracting the coiled muscle to cut a synthetic tissue-like material in half using two glass blades located at the opening of the frame.

Next, to test the torque performance, the team leveraged the high energy-release of the artificial coiled muscle and combined it with a 3D-printed driller frame and screw to wirelessly penetrate a synthetic tissue-like material by applying radiofrequency magnetic heating to untwist the coil.

The researchers then engineered a bistable clamper that uses coiled muscle contraction and stored mechanical energy to rapidly pinch tissues during surgical operations. The continuous contraction of the coiled muscle drives the clamper from a stable to an unstable energy state. This triggers the snap-through, amplifying the output force of the coiled muscle up to 14 N – allowing the researchers to clamp an ex vivo chicken tissue wound.

Finally, to showcase the versatility of multiple coiled muscles, the team coated an additional polymeric layer with a spatially varying magnetization profile in the coil, and linked four coiled muscles together using softer connectors to amplify the magnetic deformation. This new structural configuration allowed the multi-linked coils to “walk” forwards, backwards or move axially by combining magnetic torque and magnetic gradients. This could enable the device to perform more complex manipulations as well as the high force output demonstrations.

“Our new approach extends the capabilities of wireless medical soft robots to surgical applications. As next steps, we will demonstrate such functions in small animal surgeries in in vivo conditions,” Hu and Sitti tell Physics World.

Anomalous Josephson effect appears in a topological insulator

Researchers at the Institute of Physics, Chinese Academy of Sciences in Beijing, say they have found unambiguous evidence for a condensed-matter phenomenon known as the anomalous Josephson effect (AJE). The phenomenon emerged in structures called Josephson trijunctions, which the researchers constructed from a material that acts as an electrical insulator in its bulk while conducting electricity on its surface. Members of the team say that the discovery could aid the development of quantum computers that exploit similar topological effects to shield their quantum bits, or qubits, from environmental noise.

Josephson junctions consist of two superconducting layers separated by a thin insulating gap. Pairs of electrons in the superconductor can tunnel across this gap thanks to their quantum properties, meaning that current flows through the junction even without an applied voltage. The theory for how this happens was developed in the early 1960s by the British physicist Brian Josephson, who went on to receive the 1973 Nobel Prize for Physics for his work.

Since then, Josephson junctions have found numerous applications. Superconducting quantum interference devices (SQUIDs), for example, are highly sensitive magnetometers, and use either one or two Josephson junctions depending on their design. Josephson junctions are also key components in superconducting qubits, which have at their heart a loop of superconducting material broken by one or two such junctions.

The Josephson effect

The supercurrent Is in an ordinary Josephson junction follows the relation Is=Ic sinj, where Ic is the critical supercurrent of the junction and j is the phase difference across it. However, this straightforward version of the Josephson effect does not apply to certain situations. For example, if the supercurrent in the junction is mediated by special bound states in materials with spin-orbital coupling (a relativistic interaction between an electron’s spin and its motion), the supercurrent can acquire an additional phase shift j0, explains Li Lu, who led the Beijing team’s research. This phase shift leads to the appearance of the AJE, in which Is is instead equal to Ic sin(j+j0).

The AJE is difficult to study because distinguishing which part of the total phase shift is caused by the conventional Josephson mechanism and which part is caused by the AJE is no easy task. One way to do it, Lu explains, is to tune the spin-orbital coupling using an applied gate voltage and therefore identify the j0. Another is to use a reference apparatus on the same device to tease out the relative contributions of the normal and anomalous phase shifts.

In the new work, Lu and colleagues identified the existence of such an anomalous phase shift in a three-way Josephson junction, or trijunction, based on bismuth selenide (Bi2Se3). This material is a topological insulator, meaning that while the bulk material is an electrical insulator, it conducts electrons extremely well on its surface thanks to special, topologically protected electronic states. Electrons in these states travel forward without backscattering, which allows them to carry electrical current without dissipating much energy. For this reason, topological materials are promising candidates for future energy-efficient electronic devices.

Anomalous phase shift

The trijunction studied by Lu’s team contains two single junctions aligned in one direction and third junction aligned perpendicular to the first two, forming a T shape. The researchers found that in this junction, exotic particles known as Majorana bound states behave differently when an in-plane magnetic field is applied parallel to the two inline single junctions, compared to when it is applied parallel to the third. From this behaviour they were able to unambiguously identity the anomalous phase shift and hence the AJE.

The behaviour of these Majorana bound states was predicted back in 2008 by Liang Fu and Charles Kane, who suggested that Josephson trijunctions based on topological insulators could serve as the building blocks for braiding so-called “Majorana zero modes”. Such modes should show up as peaks (technically termed zero bias conductance peaks) in the spectra of electrons tunnelling across the junction. They are also the core ingredient of topological qubits, which could provide a stable and fault-tolerant building block for quantum computing because these special modes are resistant to disturbances caused by external noise.

Lu says that the AJE he and his colleagues have observed could serve as an additional knob for controlling the Majorana zero modes via an in-plane magnetic field. In their work, the researchers fabricated Josephson trijunctions based on three-dimensional Bi2Se3 and connected the terminal of the junctions with the superconducting loops in the structure. They then used the out-of-plane magnetic flux in the loops to control the phase difference in the trijunctions.

“With this approach, we were able to experimentally verify the behaviour of the Majorana phase diagram predicted by Fu and Kane,” Lu tells Physics World. “We further found that by applying an in-plane magnetic field, the whole Majorana phase diagram shifts in phase space thanks to the AJE induced by the in-plane magnetic field.”

The researchers, who detail their work in Chinese Physics Letters, are now looking into possible applications of the AJE in manipulating the Majorana zero modes in the trijunctions they studied.

Mirror nuclei shed light on mysterious EMC effect

The internal structures of nuclei containing mirrored numbers of protons and neutrons have been studied to a high degree of precision. The research has revealed that neutrons are more prone than protons to modifying their internal structure when bound up in nuclei, and it could help resolve an important mystery of nuclear physics.

The study was done by the international Jefferson Lab Angular Momentum (JAM) collaboration using data from the MARATHON experiment, which is at the Thomas Jefferson National Accelerator Facility in the US. The team’s results could help physicists better understand how quarks are distributed inside protons and neutrons and why these distributions are different when protons and neutrons are incorporated within nuclei.

The proton comprises two up quarks and a down quark, whereas the neutron contains two down quarks and an up quark. Since 2018, MARATHON has used beams of high-energy electrons to probe how these quarks are distributed within protons and neutrons. When fired at ultra-cold targets, these electrons undergo deep inelastic scattering as they interact with quarks. Afterwards, the scattered electrons are detected by a pair of high-resolution spectrometers.

Structure functions

By measuring the change in momentum of the electrons as they scatter, physicists can determine the arrangements of quarks inside protons and neutrons within the target nuclei. These distributions are described by the structure function of the proton or neutron.

For several decades physicists have known that the structure functions of free protons and neutrons are different from those of protons and neutrons bound up within nuclei. This is called the EMC effect – named after the European Muon Collaboration, which discovered it in 1983 – and it remains an important mystery of nuclear physics.

In their latest study, the MARATHON team measured the ratio of the structure functions of protons and neutrons in the simplest pair of mirror nuclei: helium-3 – which contains two protons and one neutron – and tritium (hydrogen-3), which has one proton and two neutrons. Studying mirror nuclei meant that several theoretical uncertainties were eliminated from their measurement of the ratio.

Stronger for down quarks

The team used a 10.59 GeV electron beam, which is the highest energy ever used to measure nucleon structure functions. Using a new error correction technique, they extracted the structure function ratio from their scattering data. They found that the EMC effect is stronger for down quarks than up quarks, which means that it has a greater effect of the structure of neutrons compared to protons.

While the results are in broad agreement with theoretical calculations and previous experimental work, they offer a significant improvement in accuracy.

In future studies, the team will aim to fine-tune their approach, allowing them to study nucleon structure functions within larger, more complex nuclei. Their results could open promising new routes to enhancing our knowledge of the strong nuclear force, which binds quarks together, as well as the mysterious origins of the EMC effect.

The research is reported in two papers in Physical Review Letters. One paper describes the Marathon experimental results and the other describes the JAM analysis.

The physics of Oreo splitting, metamaterial chocolates taste better

 

In case you have never eaten one, an Oreo is sandwich of two round biscuits with a sweet creme filling. Many folks will separate the two biscuits and eat the filling first. Crystal Owens at the Massachusetts Institute of Technology is probably one of those people, because she and her colleagues have published a paper about the physics of how that separation occurs.

Oreo fans will know that the cookie almost always comes apart leaving most – if not all – of the filling on one biscuit. And now Owens and team have created an “oerometer” to find out why.

Their device is a rheometer that grasps the two biscuits and gives the cookie a twist until it separates in two. The team then quantified how much filling was on each biscuit.

Perfect twist

“I had in my mind that if you twist the Oreos perfectly, you should split the creme perfectly in the middle,” said Owens. Instead, they found that filling was always on one biscuit, suggesting that the effect was not caused by how people twist Oreos.

The team found that the flavour of the Oreo and the amount of filling did not affect the separation process. What did have an effect was the twisting speed, with the conclusion being that a slow twist is best for a clean break.

As for why the filling always ends up on one side, the team is not much wiser and suggests that it might have something to do with how the Oreos are manufactured. They say this because they found that cookies in the same box separate with the same orientation to how they were packaged.

If want to try their experiments at home, the team has designed an open-source, 3D-printed  oreometer (see above video). They describe all of this in “On Oreology, the fracture and flow of ‘milk’s favorite cookie®’”, which is published in Physics of Fluids.

Edible metamaterials

Moving from cookies to chocolate, researchers at the University of Amsterdam, Delft University, and Unilever in the Netherlands say that they have designed the perfect piece of chocolate. The team has shown that the mouthfeel of chocolate can be engineered by creating chocolate metamaterials. Physicists will know that metamaterials are artificial materials with internal structures that are specifically designed to give the metamaterial specific properties – having a certain optical response, for example.

The team heated chocolate and then created various metamaterials using a 3D printer. They found that how the chocolate cracked when chewed could be controlled by altering the design of the metamaterial. Subjects who ate the chocolates reported that pieces with more cracks had a better mouthfeel.

The team says that this is the first study of edible metamaterials and report their results in “Edible mechanical metamaterials with designed fracture for mouthfeel control”, which is published in Soft Matter.

MANDELA nuclear-physics laboratories open in South Africa

South Africa has completed the construction of two new nuclear labs that will be used to train students and develop novel nuclear-physics detector technology. The Modern African Nuclear Detector Laboratories, or MANDELA, is a partnership between the University of York in the UK and the universities of Western Cape (UWC) and Zululand in South Africa. 

Officially opened in late March, the MANDELA labs were built by  refurbishing the nuclear laboratories at UWC and Zululand. Funding also went towards the development of fast digital electronics and data-acquisition systems at the lab. UWC nuclear physicist Nico Orce adds that the labs will allow scientists to develop technology for cancer imaging that can be “brought to the poor communities of South Africa and the African continent as a whole”.  

The UK’s Science and Technology Funding Council provided £500,000 from its Global Challenge Research Fund to the project while South African universities also financially contributed. Part of that partnership between South Africa and the UK saw some 20 students from the two South African universities travel to York in 2018 and 2019, where they worked on radiation detectors and ran Monte Carlo computer simulations of new detector designs. 

In the second phase of the project, which will begin this year, the students will carry out computer simulations to create prototypes of next generation positron-emission tomography scanners and develop new detectors for environmental monitoring and mining.

“The idea was to upskill young people through training visits to York and to develop detector development laboratories at the South African universities with similar equipment to what we have at York so they can lead their own efforts and can collaborate with us,” says York nuclear physicist David Jenkins, who led the project. 

Nokuthula Kunene, deputy vice-chancellor of research and innovation at the University of Zululand, hailed the lab for giving students the opportunities and confidence. “We appreciate the labs because it will not only be a case of getting data to analyse, but now students have the opportunity to create the data, which is essential for learning,” she says. 

Transient superconducting states could have practical applications, say physicists

The physics of high-temperature superconductors in unstable, transient states is surprisingly similar to that of the same materials at equilibrium, raising hopes that these out-of-equilibrium states could be stabilized and used in practical applications. The finding, which researchers at the US Department of Energy’s SLAC National Accelerator Laboratory obtained by using a flash of light to kick-start superconductivity in materials known as cuprates, could help us better understand high-temperature superconductors and how to trigger the formation of these transient states.

Superconductors are materials that conduct electricity without any resistance when cooled to below their superconducting transition temperature, Tc. In the Bardeen-Cooper-Schrieffer (BCS) theory of conventional superconductivity, this occurs when electrons overcome their mutual repulsion and form so-called Cooper pairs that travel unimpeded through the material as a supercurrent.

The first conventional superconductors to be discovered (beginning with solid mercury in 1911) had transition temperatures only a few Kelvin above absolute zero. Beginning in the late 1980s, however, a new class of superconductors with much higher Tc began to emerge. These materials were not metals, but ceramic compounds known as cuprates that are made up of layers of copper and oxygen atoms, interleaved with atoms of other elements. The BCS theory does not apply to these high-temperature superconductors and the way their electrons pair up is not fully understood.

Non-equilibrium states

To shed more light on these materials, researchers often study them in unstable or non-equilibrium states. In the latest work, the researchers generated such a state in yttrium barium copper oxide (YBCO) by applying a laser pulse to it. In this unstable state, the material remains superconducting at temperatures much higher than its usual Tc of around 100 K.

Until now, researchers were unsure whether the properties of such unstable states bore much relation to how the materials would behave in their stable states – that is, the states that would be exploited in real-world applications. A team led by Jun-Sik Lee has now shown that in fact, these unstable states behave in a very similar way to their stable cousins.

Switching on and off

The researchers studied what happened when the normal superconducting states of YBCO were switched off using pulses of light from SLAC’s Stanford Synchrotron Radiation Light Source (SSRL) and the Pohang Accelerator Laboratory’s X-ray free-electron laser (PAL-XFEL) in Korea. They focused on a particular phase of matter in superconductors known as charge density waves (CDWs), which are wavelike patterns of higher and lower electron density. CDWs are different from ordinary waves in that they are static and they serve as markers of the transition point at which superconductivity turns on or off.

The researchers then repeated their experiments by switching off the superconductivity in YBCO using a magnetic field. This is the conventional way to study CDWs in normal equilibrium states of a high-temperature superconductor.

“Crazy experimental adventure”

The team discovered that regardless of whether they exposed the material to a magnetic field or light, similar patterns of three-dimensional CDWs appeared. Why and how this happens is, they say, still unclear, but the result does show that the states induced by either magnetic fields or laser light have the same fundamental physics. It also suggests that laser light might be a good way to create and explore transient states that could be stabilized for practical applications.

“Our result implies a common ground for normal states attained using a magnetic field and an optical pump,” Lee tells Physics World. “Inversely, with the equilibrium states, optical pump approaches can drive room temperature transient superconductivity.”

And that is not all: Lee says that it may be possible to apply an additional driver in the form of a magnetic pulse. “When three pulses, such as X-ray, magnetic and optical pulses are synchronized, it might be easier to monitor how to recover broken Cooper pairs via the magnetic field in a timely manner.”

“This would be a crazy experimental adventure, but we believe it might provide more insight into understanding high-temperature superconductivity.”

The work is detailed in Science Advances.

Electron rain is driven to Earth by whistler waves, carbon nanotubes encapsulate explosive nitrogen

In this episode of the Physics World Weekly podcast, the space physicist Xiaojia Zhang explains how whistler waves in Earth’s radiation belts are accelerating high-energy electrons towards the North and South poles. As well as causing spectacular aurorae, these energetic particles can also disrupt modern technologies such as GPS, the UCLA-based researcher says.

Also on hand is the University of Genoa polymer scientist and Physics World student contributor Heba Magahd who explains why researchers in China are keen on creating energy-rich chains of nitrogen within carbon nanotubes.

We also chat about the latest meteorite that appears to have fallen on England and give a few tips about what to do if you happen to come across a rock from outer space.

LIGO-style solution for global navigation

Navigation has become incredibly convenient in recent years thanks to the proliferation of devices that use the Global Positioning System (GPS) and other similar global navigation satellite systems. Occasionally, however, you may experience your tracking dot struggle to pinpoint your position – usually when there are obstructions between you and the satellites. Inertial sensors in your phone can help out in these situations but they often become overwhelmed by electrical noise, making them unreliable. 

This video introduces an alternative form of tracking being developed by the physicist Lia Li. Her start-up company, Zero Point Motion, is designing a new type of mass market optomechanical sensor based on a similar mechanism to that found in the Laser Interferometer Gravitational-Wave Observatory (LIGO). If successful, the sensor could find other varied applications – from avoiding blurred photos, to tracking patients’ heart rates and even monitoring wear and tear in civil infrastructure.

Find out more about Zero Point Motion and Li’s personal journey from academia to industry in this special profile article, originally published in the April issue of Physics World.

Weather could be controlled by making tiny changes to chaotic system

The chaotic nature of weather could be turned to humanity’s advantage by allowing a series of tiny changes to keep weather systems on track. That is the vision of two scientists in Japan who have used computer simulations based on a butterfly attractor to show how even the smallest perturbations could prevent extreme events such as tornadoes or heavy downpours – assuming they are able to confirm their idea with more realistic modelling.

Scientists have been experimenting with weather manipulation for decades and there have been numerous attempts to induce rainfall by releasing aerosols into the atmosphere from aircraft or ground stations to stimulate condensation of water vapour. But while advancing our knowledge of cloud physics, such trials have yielded mixed results when it comes to their practical exploitation, according to Takemasa Miyoshi and Qiwen Sun at the RIKEN Center for Computational Science in Kobe.

The two researchers point out that there are also major efforts under way to investigate the feasibility of altering the climate via geoengineering. But these proposals – including the launching of giant mirrors into space or the dispersal of dust in the upper atmosphere – are controversial given their potential for unintended side effects.

Chaotic control

Miyoshi and Sun have taken a different approach. Rather than attempting to induce irreversible changes to nature, they say that they aim to “control the weather within its natural variability and to aid human activities” – such as by shifting a specific weather system spatially so that rain can be dumped where it does less damage. Their tool in this endeavour is chaos – the fact that chaotic systems are extremely sensitive to changing inputs. “If the proper infinitesimal perturbations are within our engineering capability, we could apply the control in the real world,” they say.

Their work makes use of the simplified system known as Lorenz’s butterfly attractor. Edward Lorenz was an American mathematician and meteorologist whose work on chaos theory inspired the popular idea of a butterfly flapping its wings in Brazil and setting off a tornado in Texas. The butterfly in this case illustrates the same basic idea of a chaotic system’s sensitivity to initial conditions, although the name refers to the shape of a region bounding possible trajectories in phase space.

Lorenz formulated a set of three differential equations to describe in simple terms the convective properties of a layer of fluid in the atmosphere. The equations feature three variables – the rate of convection as well as the horizontal and vertical temperature variation – which are represented as the positions along three orthogonal axes. The equations describe a chaotic system that evolves by tracing out a series of orbits that resemble a butterfly – having two wings connected in the middle. Although the system remains confined to that region of phase space, it can suddenly and unpredictably flip from one wing to the other.

Side-by-side simulations

The aim of Miyoshi and Sun was to establish whether infinitesimal perturbations to a chaotic Lorenz system could keep it confined to just one of the butterfly wings – and thereby avoid dramatic changes in the weather. They did so by running two simulations side-by-side, the first representing unmodified nature while the second, starting from the same initial conditions, they controlled using imperfect knowledge of the former to try and avoid sudden shifts to the other wing.

The researchers ran their simulations using discrete time steps. At every eighth step they updated the second system with noisy information about the natural system’s current coordinates in phase space, then used an ensemble of three models to provide a revised estimate of where the system would end up at a given point in the future. Were any of the models to predict that the system would switch wings, they would then change the coordinates of the controlled system by the same tiny amount at each step until next observing the current state of “nature”.

Each computational experiment carried out by the researchers involved 1000 such cycles, with 40 experiments being run for each of a range of model time horizons and perturbation sizes. By modelling far enough out to the future, they found they could keep the controlled system in the same wing at least 80% of the time, despite nature flipping wings. The perturbations, meanwhile, needed to be not too big and not too small to achieve the best results.

Cost and energy expenditure

Having shown that their chaos-based approach can in principle be used to control the weather, Miyoshi and Sun now plan to apply the technique to more realistic weather simulations. They also say they need to investigate just how small interventions could be in terms of cost and energy expenditure to make a difference to extreme weather events.

Above all, they say that caution is needed. They point out that keeping nature on one wing of the Lorenz attractor may not necessarily guarantee success – it being possible that extreme events could occur without switching sides. “We must consider and assess every potential impact caused by the control and have proper protocols for social, ethical, and legal agreement about real-world operations,” they say.

Eugenia Kalnay at the University of Maryland in the US suggests that perturbations could in principle be generated by increasing or decreasing the drag created by wind turbines in specific ways over short periods of time. “One could imagine reducing the precipitation during a heavy flooding event, or increasing the precipitation during a drought,” she says, stressing that this example is hypothetical.

The research is reported in Nonlinear Processes in Geophysics.

LASER offers quantum focus

In this second instalment of innovations being presented at LASER World of PHOTONICS, the international trade fair taking place at Messe München in Germany on 26–29 April, we highlight several exhibitors who are taking part in the inaugural World of QUANTUM event. They will be showcasing laser solutions designed specifically for current and future applications of quantum technologies, including sensing and imaging, computing, and secure communications systems.

Meanwhile, other innovations featured in this preview address the need for greater automation in microassembly processes and the perennial need for easy-to-use software for laser simulation. Read on to find out more.

TOPTICA showcases lasers for quantum applications

Specializing in state-of-the-art diode-laser technologies, TOPTICA is a key enabler for applications in quantum optics and spectroscopy. Highlights for this year’s LASER World of Photonics include complete frequency-comb solutions for quantum experiments that are built around the robust and reliable DFC CORE +, a device that delivers more power per tooth along with a larger frequency spacing. These complete DFC systems can be customized to include any desired wavelength extension, beat units, stabilization electronics, wavelength meters, counters and lasers.

DFC CORE +
Strong and stable: Complete systems based on the DFC CORE + frequency comb are suitable for a variety of quantum experiments. (Courtesy: TOPTICA)

TOPTICA has also introduced modular and compact 19-inch laser-rack systems for quantum applications that save valuable bench space when configuring complex laser set-ups. For experiments with quantum dots, meanwhile, the company has expanded its family of continuously tunable lasers. The new CTL 900 laser extends the wavelength range down to down to 880 nm, while still maintaining the upper limit of 1630 nm.

In addition, the company’s versatile range of tunable diode lasers are now available with an intra-cavity electro-optic modulator. The high bandwidth provided by these lasers, which are suitable for a variety of applications, lock to narrowest linewidth and lowest phase noise. The DLC pro all-digital controller, which can be used to drive all of TOPTICA’s tunable diode lasers, also now includes a MOTORpro option for motorized wavelength selection and the AutoPID wizard for frequency locking with automatically optimized parameters.

Frequency-converted lasers are also available at any wavelength between 205 and 4000 nm, with higher powers now available in the visible range for standard systems (e.g. 2 W at 556 nm) and in the UV for fibre-amplified systems (e.g. 3W at 317 nm).

  • TOPTICA will display their latest laser systems at booth 103, hall B5, while dedicated solutions for quantum applications will be shown at booth 171, hall A4, in the WORLD of QUANTUM exhibition.

High-performance fibre lasers shine on quantum experiments

A new range of Koheras HARMONIK frequency-converted fibre lasers from NKT Photonics have been designed with quantum applications in mind, offering new wavelengths for working with rubidium, strontium, barium and ytterbium, along with low noise, up to 10 W of power and a linewidth below 200 Hz.

Koheras HARMONIK power spectrum
Quantum focus: The power output from the new range of Koheras HARMONIK lasers at different wavelengths. They are all pumped by low-noise fibre lasers operating in the near infrared, allowing them to be locked to frequency references at either their fundamental or converted wavelengths. (Courtesy: NKT Photonics)

The fibre lasers are inherently stable, providing industrial-level reliability and ease-of-use to maximize experimental time. They do not require any alignment or maintenance, benefitting from the experience that Koheras has gained from installing lasers in demanding industrial applications and even in space.

Koheras HARMONIK lasers are now available at the following wavelengths as standard:

  • 780, 840 and 1064 nm for rubidium
  • 317, 813 and 1064 nm for strontium
  • 532 and 1762 nm for barium
  • 399, 556, 638, 770 and 1064 nm for ytterbium

For any other wavelength, contact NKT Photonics to discuss your requirements.

  • NKT Photonics will be displaying its full range of laser solutions for applications in quantum technologies, life science and industrial manufacturing at booth 328 in hall B5.

PicoQuant celebrates 25 years of laser expertise

PicoQuant will not only showcase its latest product innovations, but also conclude its celebrations marking the company’s 25th anniversary. “I am really excited and happy that we can mark this occasion with an in-person gathering at the exhibition,” says Rainer Erdmann, managing director of PicoQuant. “I’d like to invite everyone to our booth [Hall B5, number 425] at 16:00 on Wednesday 27 April to raise a glass of sparkling wine.”

Prima laser module
Exciting times: The Prima laser module from PicoQuant generates single-frequency light at red, green and blue wavelengths, in either continuous-wave or pulsed-picosecond modes. (Courtesy: PicoQuant)

New product developments include Prima, a standalone diode-laser module that provides access to three individual wavelengths in either picosecond-pulsed or continuous-wave mode. This fully computer-controlled laser module generates laser light at 635, 510 or 450 nm, to meet the excitation needs for daily lab tasks, including lifetime or quantum yield measurements, and photoluminescence and fluorescence measurements.

The company’s VisUV/VisIR laser modules have also been updated to be fully remote controllable via a graphical user interface. Two new VisIR laser models expand the covered emission range towards the mid-infrared at 1950 nm, and deliver an average output power of more than 0.5 W with pulse duration below 100 ps FWHM. Flexible repetition rates with constant pulse parameters, combined with a compact form factor, make those models of particular interest for metrology, ranging measurements, and for testing detectors and cameras.

PicoQuant has also updated the MultiHarp 160, a scalable plug-and-play unit for event timing and time-correlated single-photon counting (TCSPC), to include on-board event filters that can be defined by the user. These offer an efficient way to reduce the file sizes and amount of data that must be sent via the instrument’s external interfaces. The MultiHarp 160 is optimized for applications requiring up to 64 timing channels with high sustained count rates, a time resolution of 5 ps, and an ultrashort dead time of less than 650 ps.

  • Find out more about these latest product innovations at booth 425, Hall B5, in the main exhibition or booth 113, Hall A4, in WORLD of QUANTUM.

SmarAct launches new company to focus on high-precision automation

SmarAct Automation, the newest company of the SmarAct Group, was founded in November 2021 to address the increasing demand for automated microassembly solutions. At this year’s LASER World of PHOTONICS, SmarAct Automation will introduce itself as a partner for developing applications where miniaturization is necessary for future development. Such applications demand high-precision alignment, handling and joining of components – whether on a nano-, micro- or meso-scale.

SmarAct Automation
New kid on the block: SmarAct Automation develop high-precision solutions for automating microassembly processes. (Courtesy: SmarAct)

As part of the SmarAct Group, SmarAct Automation benefits from 15 years of know-how in high-precision positioning technology, as well as customized engineering and application development. The company exploits a strict modular framework to develop both partially and fully automated systems, combining the most advanced products from the SmarAct Group along with other state-of-the-art technologies to deliver precise, fast and reliable automation solutions.

To complete its portfolio, SmarAct Automation also offers process development, outsourced manufacturing options, and the mandatory maintenance and service packages for these products – enabling rapid development and future-proof integration of microassembly processes into a production environment.

  • Contact SmarAct Automation to discuss your microassembly requirements, or talk to company representatives at booth 113, hall B5. SmarAct Group will also be exhibiting in World of QUANTUM at booth 201, hall A4.

Laser-simulation software locates aberrations within seconds

Berlin-based start-up BeamXpert has updated its laser-simulation software to quickly identify the source of aberrations in optical systems, and to directly display the impact that any changes in the laser set-up have on the key parameters, particularly the beam quality M². The software, called BeamXpertDESIGNER, is an easy-to-use 3D simulator of laser-beam propagation that returns ISO-compliant results.

BeamXpertDESIGNER
Laser simulator: BeamXpertDESIGNER determines the variations in beam quality when an astigmatic laser beam passes through an optical system with aberrations. (Courtesy: BeamXpert GmbH)

The software now offers Monte Carlo ray generation and multi-core support for its ray model. Together with the addition of a new ray analyser, the influence of aberrations on the beam quality can be evaluated almost in real time, while the laser-beam parameters can be displayed on the surface of any optical component. An improved grating object and a new compression algorithm for data storage adds to the software’s appeal as a universal tool that can be used by all laser system engineers.

BeamXpert has welcomed the positive response it has received from customers working in both basic research and more applied opto-mechanical engineering. Additionally, these clients appreciate that the BeamXpertDESIGNER software is available through a single-purchase license that is not time limited.

  • For more information visit booth 528, hall B5, at the LASER World of PHOTONICS trade show, or go directly to beamxpert.com.

 

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