SPIE Photonics West, the world’s largest photonics technologies event, takes place in San Francisco, California, from 25 to 30 January. Showcasing cutting-edge research in lasers, biomedical optics, biophotonics, quantum technologies, optoelectronics and more, Photonics West features leaders in the field discussing the industry’s challenges and breakthroughs, and sharing their research and visions of the future.

As well as 100 technical conferences with over 5000 presentations, the event brings together several world-class exhibitions, kicking off on 25 January with the BiOS Expo, the world’s largest biomedical optics and biophotonics exhibition.

The main Photonics West Exhibition starts on 28 January. Hosting more than 1200 companies, the event highlights the latest developments in laser technologies, optoelectronics, photonic components, materials and devices, and system support. The newest and fastest growing expo, Quantum West, showcases photonics as an enabling technology for a quantum future. Finally, the co-located AR | VR | MR exhibition features the latest extended reality hardware and systems. Here are some of the innovative products on show at this year’s event.

HydraHarp 500: a new era in time-correlated single-photon counting

Photonics West sees PicoQuant introduce its newest generation of event timer and time-correlated single-photon counting (TCSPC) unit – the HydraHarp 500. Setting a new standard in speed, precision and flexibility, the TCSPC unit is freely scalable with up to 16 independent channels and a common sync channel, which can also serve as an additional detection channel if no sync is required.

At the core of the HydraHarp 500 is its outstanding timing precision and accuracy, enabling precise photon timing measurements at exceptionally high data rates, even in demanding applications.

In addition to the scalable channel configuration, the HydraHarp 500 offers flexible trigger options to support a wide range of detectors, from single-photon avalanche diodes to superconducting nanowire single-photon detectors. Seamless integration is ensured through versatile interfaces such as USB 3.0 or an external FPGA interface for data transfer, while White Rabbit synchronization allows precise cross-device coordination for distributed setups.

The HydraHarp 500 is engineered for high-throughput applications, making it ideal for rapid, large-volume data acquisition. It offers 16+1 fully independent channels for true simultaneous multi-channel data recording and efficient data transfer via USB or the dedicated FPGA interface. Additionally, the HydraHarp 500 boasts industry-leading, extremely low dead-time per channel and no dead-time across channels, ensuring comprehensive datasets for precise statistical analysis.

Step into the future of photonics and quantum research with the HydraHarp 500. Whether it’s achieving precise photon correlation measurements, ensuring reproducible results or integrating advanced setups, the HydraHarp 500 redefines what’s possible – offering
precision, flexibility and efficiency combined with reliability and seamless integration to
achieve breakthrough results.

For more information, visit www.picoquant.com or contact us at info@picoquant.com.

• Meet PicoQuant at BiOS booth #8511 and Photonics West booth #3511.

SmarAct: shaping the future of precision

SmarAct is set to make waves at the upcoming SPIE Photonics West, the world’s leading exhibition for photonics, biomedical optics and laser technologies, and the parallel BiOS trade fair. SmarAct will showcase a portfolio of cutting-edge solutions designed to redefine precision and performance across a wide range of applications.

At Photonics West, SmarAct will unveil its latest innovations, as well as its well-established and appreciated iris diaphragms and optomechanical systems. All of the highlighted technologies exemplify SmarAct’s commitment to enabling superior control in optical setups, a critical requirement for research and industrial environments.

Attendees can also experience the unparalleled capabilities of electromagnetic positioners and SmarPod systems. With their hexapod-like design, these systems offer nanometre-scale precision and flexibility, making them indispensable tools for complex alignment tasks in photonics and beyond.

One major highlight is SmarAct’s debut of a 3D pick-and-place system designed for handling optical fibres. This state-of-the-art solution integrates precision and flexibility, offering a glimpse into the future of fibre alignment and assembly. Complementing this is a sophisticated gantry system for microassembly of optical components. Designed to handle large travel ranges with remarkable accuracy, this system meets the growing demand for precision in the assembly of intricate optical technologies. It combines the best of SmarAct’s drive technologies, such as fast (up to 1 m/s) and durable electromagnetic positioners and scanner stages based on piezo-driven mechanical flexures with maximum scanning speed and minimum scanning error.

Simultaneously, at the BiOS trade fair SmarAct will spotlight its new electromagnetic microscopy stage, a breakthrough specifically tailored for life sciences applications. This advanced stage delivers exceptional stability and adaptability, enabling researchers to push the boundaries of imaging and experimental precision. This innovation underscores SmarAct’s dedication to addressing the unique challenges faced by the biomedical and life sciences sectors, as well as bioprinting and tissue engineering companies.

Throughout the event, SmarAct’s experts will demonstrate these solutions in action, offering visitors an interactive and hands-on understanding of how these technologies can meet their specific needs. Visit SmarAct’s booths to engage with experts and discover how SmarAct solutions can empower your projects.

Whether you’re advancing research in semiconductors, developing next-generation photonic devices or pioneering breakthroughs in life sciences, SmarAct’s solutions are tailored to help you achieve your goals with unmatched precision and reliability.

• For more information, visit SmarAct at Photonics West booth #3439, BiOS booth #8439 or explore SmarAct’s application examples here.

Precision positioning systems enable diverse applications 

For 25 years Mad City Labs has provided precision instrumentation for research and industry – including nanopositioning systems, micropositioners, microscope stages and platforms, single-molecule microscopes, atomic-force microscopes (AFMs) and customized solutions.

The company’s newest micropositioning system – the MMP-UHV50 – is a modular, linear micropositioner designed for ultrahigh-vacuum (UHV) environments. Constructed entirely from UHV-compatible materials and carefully designed to eliminate sources of virtual leaks, the MMP-UHV50 offers 50 mm travel range with 190 nm step size and a maximum vertical payload of 2 kg.

Uniquely, the MMP-UHV50 incorporates a zero-power feature when not in motion, to minimize heating and drift. Safety features include limit switches and overheat protection – critical features when operating in vacuum environments. The system includes the Micro-Drive-UHV digital electronic controller, supplied with LabVIEW-based software and compatible with user-written software via the supplied DLL file (for example, Python, Matlab or C++).

Other products from Mad City Labs include piezo nanopositioners featuring the company’s proprietary PicoQ sensors, which provide ultralow noise and excellent stability to yield sub-nanometre resolution. These high-performance sensors enable motion control down to the single picometre level.

For scanning probe microscopy, Mad City Labs’s nanopositioning systems provide true decoupled motion with virtually undetectable out-of-plane movement, while their precision and stability yields high positioning performance and control. The company offers both an optical deflection AFM – the MadAFM, a multimodal sample scanning AFM in a compact, tabletop design and designed for simple installation – plus resonant probe AFM models.

The resonant probe products include the company’s AFM controllers, MadPLL and QS-PLL, which enable users to build their own flexibly configured AFMs using Mad City Labs’ micro- and nanopositioners.  All AFM instruments are ideal for material characterization, but the resonant probe AFMs are uniquely suitable for quantum sensing and nano-magnetometry applications.

Mad City Labs also offers standalone micropositioning products, including optical microscope stages, compact positioners for photonics and the Mad-Deck XYZ stage platform, all of which employ proprietary intelligent control to optimize stability and precision. They are also compatible with the high-resolution nanopositioning systems, enabling motion control across micro-to-picometre length scales.

Finally, for high-end microscopy applications, the RM21 single-molecule microscope, featuring the unique MicroMirror TIRF system, offers multi-colour total internal-reflection fluorescence microscopy with an excellent signal-to-noise ratio and efficient data collection, along with an array of options to support multiple single-molecule techniques.

Our product portfolio, coupled with our expertise in custom design and manufacturing, ensures that we are able to provide solutions for nanoscale motion for diverse applications such as astronomy, photonics, metrology and quantum sensing.

• Learn more at BiOS booth #8525 and Photonics West booth #3525.

 

The post Photonics West shines a light on optical innovation appeared first on Physics World.

Waveguide-based structures can solve partial differential equations by mimicking elements in standard electronic circuits. This novel approach, developed by researchers at Newcastle University in the UK, could boost efforts to use analogue computers to investigate complex mathematical problems.

Many physical phenomena – including heat transfer, fluid flow and electromagnetic wave propagation, to name just three – can be described using partial differential equations (PDEs). Apart from a few simple cases, these equations are hard to solve analytically, and sometimes even impossible. Mathematicians have developed numerical techniques such as finite difference or finite-element methods to solve more complex PDEs. However, these numerical techniques require a lot of conventional computing power, even after using methods such as mesh refinement and parallelization to reduce calculation time.

Alternatives to numerical computing

To address this, researchers have been investigating alternatives to numerical computing. One possibility is electromagnetic (EM)-based analogue computing, where calculations are performed by controlling the propagation of EM signals through a materials-based processor. These processors are typically made up of optical elements such as Bragg gratings, diffractive networks and interferometers as well as optical metamaterials, and the systems that use them are termed “metatronic” by analogy with more familiar electronic circuit elements.

The advantage of such systems is that because they use EM waves, computing can take place literally at light speeds within the processors. Systems of this type have previously been used to solve ordinary differential equations, and to perform operations such as integration, differentiation and matrix multiplication.

Some mathematical operations can also be computed with electronic systems – for example, with grid-like arrays of “lumped” circuit elements (that is, components such as resistors, inductors and capacitors that produce a predictable output from a given input). Importantly, these grids can emulate the mesh elements that feature in the finite-element method of solving various types of PDEs numerically.

Recently, researchers demonstrated that this emulation principle also applies to photonic computing systems. They did this using the splitting and superposition of EM signals within an engineered network of dielectric waveguide junctions known as photonic Kirchhoff nodes. At these nodes, a combination of photonics structures, such as ring resonators and X-junctions, can similarly imitate lumped circuit elements.

Interconnected metatronic elements

In the latest work, Victor Pacheco-Peña of Newcastle’s School of Mathematics, Statistics and Physics and colleagues showed that such waveguide-based structures can be used to calculate solutions to PDEs that take the form of the Helmholtz equation ∇²f(x,y)+k²f(x,y)=0. This equation is used to model many physical processes, including the propagation, scattering and diffraction of light and sound as well as the interactions of light and sound with resonators.

Unlike in previous setups, however, Pacheco-Peña’s team exploited a grid-like network of parallel plate waveguides filled with dielectric materials. This structure behaves like a network of interconnected T-circuits, or metatronic elements, with the waveguide junctions acting as sampling points for the PDE solution, Pacheco-Peña explains. “By carefully manipulating the impedances of the metatronic circuits connecting these points, we can fully control the parameters of the PDE to be solved,” he says.

The researchers used this structure to solve various boundary value problems by inputting signals to the network edges. Such problems frequently crop up in situations where information from the edges of a structure is used to infer details of physical processes in other regions in it. For example, by measuring the electric potential at the edge of a semiconductor, one can calculate the distribution of electric potential near its centre.

Pacheco-Peña says the new technique can be applied to “open” boundary problems, such as calculating how light focuses and scatters, as well as “closed” ones, like sound waves reflecting within a room. However, he acknowledges that the method is not yet perfect because some undesired reflections at the boundary of the waveguide network distort the calculated PDE solution. “We have identified the origin of these reflections and proposed a method to reduce them,” he says.

In this work, which is detailed in Advanced Photonics Nexus, the researchers numerically simulated the PDE solving scheme at microwave frequencies. In the next stages of their work, they aim to extend their technique to higher frequency ranges. “Previous works have demonstrated metatronic elements working in these frequency ranges, so we believe this should be possible,” Pacheco-Peña tells Physics World. “This might also allow the waveguide-based structure to be integrated with silicon photonics or plasmonic devices.”

The post Electromagnetic waves solve partial differential equations appeared first on Physics World.

The effect of quantum entanglement on the emission time of photoelectrons has been calculated by physicists in China and Austria. Their result includes several counter-intuitive predictions that could be testable with improved free-electron lasers.

The photoelectric effect involves quantum particles of light (photons) interacting with electrons in atoms, molecules and solids. This can result in the emission of an electron (called a photoelectron), but only if the photon energy is greater than the binding energy of the electron.

“Typically when people calculate the photoelectric effect they assume it’s a very weak perturbation on an otherwise inert atom or solid surface and most of the time does not suffer anything from these other atoms or photons coming in,” explains Wei-Chao Jiang of Shenzhen University in China. In very intense radiation fields, however, the atom may simultaneously absorb multiple photons, and these can give rise to multiple emission pathways.

Jiang and colleagues have done a theoretical study of the ionization of a helium atom from its ground state by intense pulses of extreme ultraviolet (XUV) light. At sufficient photon intensities, there are two possible pathways by which a photoelectron can be produced. In the first, called direct single ionization, the photon in the ground state simply absorbs an electron and escapes the potential well. The second is a two-photon pathway called excitation ionization, in which both of the helium electrons absorb a photon from the same light pulse. One of them subsequently escapes, while the other remains in a higher energy level in the residual ion.

Distinct pathways

The two photoemission pathways are distinct, so making a measurement of the emitted electron reveals information about the state of the bound electron that was left behind. The light pulse therefore creates an entangled state in which the two electrons are described by the same quantum wavefunction. To better understand the system, the researchers modelled the emission time for an electron undergoing excitation ionization relative to an electron undergoing direct single ionization.

“The naïve expectation is that, if I have a process that takes two photons, that process will take longer than one where one photon does the whole thing,” says team member Joachim Burgdörfer of the Vienna University of Technology. What the researchers calculated, however, is that photoelectrons emitted by excitation ionization were most likely to be detected about 200 as earlier than photons detected by direct single ionization. This can be explained semi-classically by assuming that the photoionization event must precede the creation of the  helium ion (He⁺) for the second excitation step to occur. Excitation ionization therefore requires earlier photoemission.

The researchers believe that, in principle, it should be possible to test their model using attosecond streaking or RABBITT (reconstruction of attosecond beating by interference of two-photon transitions). These are special types of pump-probe spectroscopy that can observe interactions at ultrashort timescales. “Naïve thinking would say that, using a 500 as pulse as a pump and a 10 fs pulse as a probe, there is no way you can get time resolution down to say, 10 as,” says Burgdörfer. “This is where recently developed techniques such as streaking or RABBITT  come in. You no longer try to keep the pump and probe pulses apart, instead you want overlap between the pump and probe and you extract the time information from the phase information.”

Simulated streaking

The team also did numerical simulations of the expected streaking patterns at one energy and found that they were consistent with an analytical calculation based on their intuitive picture. “Within a theory paper, we can only check for mutual consistency,” says Burgdörfer.

The principal hurdle to actual experiments lies in generating the required XUV pulses. Pulses from high harmonic generation may not be sufficiently strong to excite the two-photon emission. Free electron laser pulses can be extremely high powered, but are prone to phase noise. However, the researchers note that entanglement between a photoelectron and an ion has been achieved recently at the FERMI free electron laser facility in Italy.

“Testing these predictions employing experimentally realizable pulse shapes should certainly be the next important step.” Burgdörfer says. Beyond this, the researchers intend to study entanglement in more complex systems such as multi-electron atoms or simple molecules.

Paul Corkum at Canada’s University of Ottawa is intrigued by the research. “If all we’re going to do with attosecond science is measure single electron processes, probably we understood them before, and it would be disappointing if we didn’t do something more,” he says. “It would be nice to learn about atoms, and this is beginning to go into an atom or at least its theory thereof.” He cautions, however, that “If you want to do an experiment this way, it is hard.”

The research is described in Physical Review Letters.  

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Optical traps and tweezers can be used to capture and manipulate particles using non-contact forces. A focused beam of light allows precise control over the position of and force applied to an object, at the micron scale or below, enabling particles to be pulled and captured by the beam.

Optical manipulation techniques are garnering increased interest for biological applications. Researchers from Massachusetts Institute of Technology (MIT) have now developed a miniature, chip-based optical trap that acts as a “tractor beam” for studying DNA, classifying cells and investigating disease mechanisms. The device – which is small enough to fit in your hand – is made from a silicon-photonics chip and can manipulate particles up to 5 mm away from the chip surface, while maintaining a sterile environment for cells.

The promise of integrated optical tweezers

Integrated optical trapping provides a compact route to accessible optical manipulation compared with bulk optical tweezers, and has already been demonstrated using planar waveguides, optical resonators and plasmonic devices. However, many such tweezers can only trap particles directly on (or within several microns of) the chip’s surface and only offer passive trapping.

To make optical traps sterile for cell research, 150-µm thick glass coverslips are required. However, the short focal heights of many integrated optical tweezers means that the light beams can’t penetrate into standard sample chambers. Because such devices can only trap particles a few microns above the chip, they are incompatible with biological research that requires particles and cells to be trapped at much larger distances from the chip’s surface.

With current approaches, the only way to overcome this is to remove the cells and place them on the surface of the chip itself. This process contaminates the chip, however, meaning that each chip must be discarded after use and a new chip used for every experiment.

Trapping device for biological particles

Lead author Tal Sneh and colleagues developed an integrated optical phased array (OPA) that can focus emitted light at a specific point in the radiative near field of the chip. To date, many OPA devices have been motivated by LiDAR and optical communications applications, so their capabilities were limited to steering light beams in the far field using linear phase gradients. However, this approach does not generate the tightly focused beam required for optical trapping.

In their new approach, the MIT researchers used semiconductor manufacturing processes to fabricate a series of micro-antennas onto the chip. By creating specific phase patterns for each antenna, the researchers found that they could generate a tightly focused beam of light.

Each antenna’s optical signal was also tightly controlled by varying the input laser wavelength to provide an active spatial tuning for tweezing particles. The focused light beam emitted by the chip could therefore be shaped and steered to capture particles located millimetres above the surface of the chip, making it suitable for biological studies.

The researchers used the OPA tweezers to optically steer and non-mechanically trap polystyrene microparticles at up to 5 mm above the chip’s surface. They also demonstrated stretching of mouse lymphoblast cells, in the first known cell experiment to use single-beam integrated optical tweezers.

The researchers point out that this is the first demonstration of trapping particles over millimetre ranges, with the operating distance of the new device orders of magnitude greater than other integrated optical tweezers. Plasmonic, waveguide and resonator tweezers, for example, can only operate at 1 µm above the surface, while microlens-based tweezers have been able to operate at 20 µm distances.

Importantly, the device is completely reusable and biocompatible, because the biological samples can be trapped and undergo manipulation while remaining within a sterile coverslip. This ensures that both the biological media and the chip stay free from contamination without needing complex microfluidics packaging.

The work in this study provides a new type of modality for integrated optical tweezers, expanding their use into the biological domain to perform experiments on proteins and DNA, for example, as well as to sort and manipulate cells.

The researchers say that they hope to build on this research by creating a device with an adjustable focal height for the light beam, as well as introduce multiple trap sites to manipulate biological particles in more complex ways and employ the device to examine more biological systems.

The optical trap is described in Nature Communications.

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