SPIE News

The rapid growth of large language models is placing increasing demands on data centers, where large volumes of data must be transferred efficiently between servers. Optical interconnects are essential for enabling this communication, but as data rates continue to rise, these systems must deliver higher bandwidth while maintaining low latency and energy efficiency. However, integrating electronic and photonic components remains challenging, as conventional approaches often introduce signal loss, limit interconnect density, and restrict scalability.

Pairs of correlated or entangled photons are a foundational resource in quantum optics. They are most commonly produced through spontaneous parametric down-conversion (SPDC), a nonlinear optical process that typically relies on a stable, coherent laser to pump a nonlinear crystal. Because of this requirement, SPDC has long been viewed as impractical without laboratory-grade laser systems.

As large medical imaging datasets become widely available, researchers are increasingly turning to artificial intelligence to extract useful information from scans that were never manually annotated. Automated "anatomy segmentation" tools—programs that label organs and structures in images such as CT scans—promise to make large-scale studies feasible. But as many new models appear, an important question remains: how can researchers compare these tools when no ground truth exists?

Simulating the nonlinear optical physics that underlies ultrafast laser systems is computationally demanding—a practical bottleneck in settings that require rapid feedback. A study by researchers at Stanford University, University of California, Los Angeles (UCLA), and SLAC National Accelerator Laboratory introduces a deep learning surrogate that delivers orders-of-magnitude acceleration over conventional simulation methods, while maintaining high fidelity across a challenging range of pulse shapes.

Keratoconus is a progressive eye disease that weakens and thins the cornea, the clear front surface of the eye. In its early, subclinical stage, the cornea can still appear normal on routine exams. Yet this is when accurate diagnosis matters most, especially when patients are being evaluated for refractive surgery.

White matter pathways allow distant parts of the brain to communicate, supporting memory, emotion, and language. One such pathway, the uncinate fasciculus, connects the front of the temporal lobe with regions of the frontal cortex involved in decision-making and social behavior. Despite its importance, little is known about the microscopic structure of this tract in the human brain.

Gamma-ray bursts (GRBs) rank among the most powerful explosions in the universe, releasing immense energy in intense flashes of gamma rays. The most distant GRBs originate from the era when the first stars and galaxies formed. Detecting them allows astronomers to probe the early universe and understand how the first heavy elements formed and how the earliest stellar populations lived and died. Missions like HiZ-GUNDAM, a satellite planned for launch in the 2030s by the Japan Aerospace Exploration Agency (JAXA), aim to detect these distant explosions in real time.

Near-infrared spectroscopy, or fNIRS, offers a way to monitor brain activity without surgery or radiation by tracking changes in blood flow and oxygenation. Light sources placed on the scalp send near-infrared light into the head, and detectors measure the light that scatters back. Because this light must pass through the scalp and skull before reaching the brain, the measured signal always includes a mix of superficial and cerebral contributions. Separating those signals has long been a central challenge for fNIRS researchers.

Modern life depends on fast and reliable wireless connections. Video calls, streaming services, virtual reality, and smart devices all place growing demands on networks that already serve billions of users. Most wireless data today travels through radio-based technologies such as Wi-Fi and cellular systems.

Ovarian cancer remains the deadliest gynecologic cancer, largely because it is rarely found early. Symptoms are often vague, and existing screening approaches—such as blood tests and transvaginal ultrasound—can miss the disease at stages when treatment is most effective. In recent years, research has reshaped understanding of how many aggressive ovarian cancers begin, pointing not to the ovary itself, but to the fallopian tubes. That shift has created a need for tools that can safely examine these narrow structures for early changes linked to cancer.

Light can carry angular momentum in two distinct ways. One comes from polarization, which describes how the electric field rotates. The other comes from the shape of the wavefront itself, which can twist like a corkscrew as it travels. This second form, known as orbital angular momentum, has attracted wide interest because it allows light to encode information, interact with matter in new ways, and probe physical and biological systems. Despite this promise, producing well-defined twisted light in free space remains technically challenging, especially when the light originates from small or localized sources.

The World Health Organization (WHO) recommends that babies be exclusively breastfed for the first six months of life, since breastfeeding plays an important role in public health. Nevertheless, many mothers struggle with initiating and maintaining breastfeeding. Although this can be ascribed to a variety of limiting factors, many mothers (40% to 60%) stop breastfeeding due to a perception of low milk supply. Evidence is increasing that low milk supply is certainly not a perception only, with an estimated incidence of actual lactation insufficiency of 10% to 15%. The underlying causes of actual lactation insufficiency are currently poorly understood.

Controlling light with light is a long-sought goal for computing and communication technologies. Achieving this capability would allow optical signals to be processed without converting them into electrical signals, potentially enabling faster and more energy-efficient devices. In recent years, researchers have begun exploring an unexpected platform for this purpose: soft matter.

Most space missions rely on chemical rockets for propulsion. Rockets must carry fuel, which increases spacecraft mass and limits their speed and travel distance. For decades, researchers have explored light sails as an alternative. These devices use radiation pressure—the force exerted when light reflects from a surface—to generate thrust. When driven by a powerful laser, a light sail can accelerate continuously without onboard propellant, enabling faster travel across the solar system.

Light is an unusually rich carrier of information. Its direction of travel, wavelength, and polarization can all be used to encode signals or images. Yet controlling these properties independently remains difficult, especially when light can enter a device from either side.

Atomically thin semiconductors such as tungsten disulfide (WS2) are promising materials for future photonic technologies. Despite being only a single layer of atoms thick, they host tightly bound excitons—pairs of electrons and holes that interact strongly with light—and can efficiently generate new colors of light through nonlinear optical processes such as second-harmonic generation.

Cochlear implant surgery helps people with severe hearing loss by placing an electronic device inside the inner ear. To reach the inner ear, surgeons must first remove part of a bone behind the ear, in a procedure called mastoidectomy. The shape of this surgically created cavity varies from patient to patient and has no clear outer boundary, making it difficult to anticipate using traditional image-analysis tools. Better prediction of this shape before surgery could support navigation systems, robotic tools, and improved visualization for surgeons, along with better outcomes for patients.

Acoustic frequency combs organize sound or mechanical vibrations into a series of evenly spaced frequencies, much like the teeth on a comb. They are the acoustic counterparts of optical frequency combs, which consist of equally spaced spectral lines and act as extraordinarily precise rulers for measuring light.

Ehlers–Danlos syndromes (EDS) are inherited conditions that affect the body's connective tissue, which provides strength and support to the skin, joints, and blood vessels. People with EDS are often affected by stretchy skin, loose joints, and fragile tissues. Two common subtypes are classical EDS (cEDS) and hypermobile EDS (hEDS).

As quantum computers continue to advance, many of today's encryption systems face the risk of becoming obsolete. A powerful alternative—quantum cryptography—offers security based on the laws of physics instead of computational difficulty. But to turn quantum communication into a practical technology, researchers need compact and reliable devices that can decode fragile quantum states carried by light.

For the millions of people living with end-stage kidney disease, hemodialysis is more than a medical procedure, it is a thrice-weekly lifeline that keeps the body's chemistry in balance. Yet even with decades of clinical experience and numerous technological advances, one stubborn challenge persists: determining how much fluid to remove during treatment without tipping a patient into dangerous instability.

Selecting the healthiest embryo is one of the most important steps in in‑vitro fertilization (IVF), yet it remains one of the most uncertain. Roughly 15% of couples worldwide experience infertility, and IVF success rates often remain below 33%. A major challenge is that embryologists must choose a single embryo to implant, relying on what they can see under a microscope.

For decades, the ability to visualize the chemical composition of materials, whether for diagnosing a disease, assessing food quality, or analyzing pollution, depended on large, expensive laboratory instruments called spectrometers. These devices work by taking light, spreading it out into a rainbow using a prism or grating, and measuring the intensity of each color. The problem is that spreading light requires a long physical path, making the device inherently bulky.

Terahertz (THz) radiation, which occupies the frequency band between microwaves and infrared light, is essential in many next-generation applications, including high-speed wireless communications, chemical sensing, and advanced material analysis.

Imagine driving down a busy highway. You need to check your speed and navigation, but glancing down at the dashboard takes your eyes off the road for a critical second. This is where head-up displays (HUDs) come in, projecting information directly onto the windshield. However, current HUD technologies are often bulky and limited to displaying flat, 2D images at a fixed distance, forcing your eyes to constantly refocus between the data and the road.

Thyroid cancer is the most common endocrine cancer, affecting more people each year as detection rates continue to rise. During tumor excision, surgeons often struggle to determine exactly how much tissue should be removed, as distinguishing cancer from healthy tissue in real time is challenging and nearby structures are extremely delicate.

Scientists at the University of Oxford demonstrate an approach to interpreting how materials interact with polarized light, which could help advance biomedical imaging and material design.

Photoplethysmography (PPG) is an optical sensing technique that measures blood volume changes and underpins devices ranging from hospital-grade pulse oximeters to consumer wearables that track heart rate, sleep, and oxygenation.

Conventional telescopes are limited in detecting low-surface-brightness (LSB) structures, which are essential for studying galaxy evolution. Now, researchers have developed a new telescope system featuring a confocal off-axis design with three freeform mirrors, optimized for deep LSB imaging. This system enables astronomers to observe faint galactic features more clearly, revealing how galaxies evolve over time.

Thulium fiber lasers, operating at a wavelength of 2 micrometers, are valued for applications in medicine, materials processing, and defense. Their longer wavelength makes stray light less damaging compared to the more common ytterbium lasers at 1 micrometer.

The rapid growth of large language models is placing increasing demands on data centers, where large volumes of data must be transferred efficiently between servers. Optical interconnects are essential for enabling this communication, but as data rates continue to rise, these systems must deliver higher bandwidth while maintaining low latency and energy efficiency. However, integrating electronic and photonic components remains challenging, as conventional approaches often introduce signal loss, limit interconnect density, and restrict scalability.

Pairs of correlated or entangled photons are a foundational resource in quantum optics. They are most commonly produced through spontaneous parametric down-conversion (SPDC), a nonlinear optical process that typically relies on a stable, coherent laser to pump a nonlinear crystal. Because of this requirement, SPDC has long been viewed as impractical without laboratory-grade laser systems.

As large medical imaging datasets become widely available, researchers are increasingly turning to artificial intelligence to extract useful information from scans that were never manually annotated. Automated "anatomy segmentation" tools—programs that label organs and structures in images such as CT scans—promise to make large-scale studies feasible. But as many new models appear, an important question remains: how can researchers compare these tools when no ground truth exists?

Simulating the nonlinear optical physics that underlies ultrafast laser systems is computationally demanding—a practical bottleneck in settings that require rapid feedback. A study by researchers at Stanford University, University of California, Los Angeles (UCLA), and SLAC National Accelerator Laboratory introduces a deep learning surrogate that delivers orders-of-magnitude acceleration over conventional simulation methods, while maintaining high fidelity across a challenging range of pulse shapes.

Keratoconus is a progressive eye disease that weakens and thins the cornea, the clear front surface of the eye. In its early, subclinical stage, the cornea can still appear normal on routine exams. Yet this is when accurate diagnosis matters most, especially when patients are being evaluated for refractive surgery.

White matter pathways allow distant parts of the brain to communicate, supporting memory, emotion, and language. One such pathway, the uncinate fasciculus, connects the front of the temporal lobe with regions of the frontal cortex involved in decision-making and social behavior. Despite its importance, little is known about the microscopic structure of this tract in the human brain.

Gamma-ray bursts (GRBs) rank among the most powerful explosions in the universe, releasing immense energy in intense flashes of gamma rays. The most distant GRBs originate from the era when the first stars and galaxies formed. Detecting them allows astronomers to probe the early universe and understand how the first heavy elements formed and how the earliest stellar populations lived and died. Missions like HiZ-GUNDAM, a satellite planned for launch in the 2030s by the Japan Aerospace Exploration Agency (JAXA), aim to detect these distant explosions in real time.

Near-infrared spectroscopy, or fNIRS, offers a way to monitor brain activity without surgery or radiation by tracking changes in blood flow and oxygenation. Light sources placed on the scalp send near-infrared light into the head, and detectors measure the light that scatters back. Because this light must pass through the scalp and skull before reaching the brain, the measured signal always includes a mix of superficial and cerebral contributions. Separating those signals has long been a central challenge for fNIRS researchers.

Modern life depends on fast and reliable wireless connections. Video calls, streaming services, virtual reality, and smart devices all place growing demands on networks that already serve billions of users. Most wireless data today travels through radio-based technologies such as Wi-Fi and cellular systems.

Ovarian cancer remains the deadliest gynecologic cancer, largely because it is rarely found early. Symptoms are often vague, and existing screening approaches—such as blood tests and transvaginal ultrasound—can miss the disease at stages when treatment is most effective. In recent years, research has reshaped understanding of how many aggressive ovarian cancers begin, pointing not to the ovary itself, but to the fallopian tubes. That shift has created a need for tools that can safely examine these narrow structures for early changes linked to cancer.

Light can carry angular momentum in two distinct ways. One comes from polarization, which describes how the electric field rotates. The other comes from the shape of the wavefront itself, which can twist like a corkscrew as it travels. This second form, known as orbital angular momentum, has attracted wide interest because it allows light to encode information, interact with matter in new ways, and probe physical and biological systems. Despite this promise, producing well-defined twisted light in free space remains technically challenging, especially when the light originates from small or localized sources.

The World Health Organization (WHO) recommends that babies be exclusively breastfed for the first six months of life, since breastfeeding plays an important role in public health. Nevertheless, many mothers struggle with initiating and maintaining breastfeeding. Although this can be ascribed to a variety of limiting factors, many mothers (40% to 60%) stop breastfeeding due to a perception of low milk supply. Evidence is increasing that low milk supply is certainly not a perception only, with an estimated incidence of actual lactation insufficiency of 10% to 15%. The underlying causes of actual lactation insufficiency are currently poorly understood.

Controlling light with light is a long-sought goal for computing and communication technologies. Achieving this capability would allow optical signals to be processed without converting them into electrical signals, potentially enabling faster and more energy-efficient devices. In recent years, researchers have begun exploring an unexpected platform for this purpose: soft matter.

Most space missions rely on chemical rockets for propulsion. Rockets must carry fuel, which increases spacecraft mass and limits their speed and travel distance. For decades, researchers have explored light sails as an alternative. These devices use radiation pressure—the force exerted when light reflects from a surface—to generate thrust. When driven by a powerful laser, a light sail can accelerate continuously without onboard propellant, enabling faster travel across the solar system.

Light is an unusually rich carrier of information. Its direction of travel, wavelength, and polarization can all be used to encode signals or images. Yet controlling these properties independently remains difficult, especially when light can enter a device from either side.

Atomically thin semiconductors such as tungsten disulfide (WS2) are promising materials for future photonic technologies. Despite being only a single layer of atoms thick, they host tightly bound excitons—pairs of electrons and holes that interact strongly with light—and can efficiently generate new colors of light through nonlinear optical processes such as second-harmonic generation.

Cochlear implant surgery helps people with severe hearing loss by placing an electronic device inside the inner ear. To reach the inner ear, surgeons must first remove part of a bone behind the ear, in a procedure called mastoidectomy. The shape of this surgically created cavity varies from patient to patient and has no clear outer boundary, making it difficult to anticipate using traditional image-analysis tools. Better prediction of this shape before surgery could support navigation systems, robotic tools, and improved visualization for surgeons, along with better outcomes for patients.

Acoustic frequency combs organize sound or mechanical vibrations into a series of evenly spaced frequencies, much like the teeth on a comb. They are the acoustic counterparts of optical frequency combs, which consist of equally spaced spectral lines and act as extraordinarily precise rulers for measuring light.

Ehlers–Danlos syndromes (EDS) are inherited conditions that affect the body's connective tissue, which provides strength and support to the skin, joints, and blood vessels. People with EDS are often affected by stretchy skin, loose joints, and fragile tissues. Two common subtypes are classical EDS (cEDS) and hypermobile EDS (hEDS).

As quantum computers continue to advance, many of today's encryption systems face the risk of becoming obsolete. A powerful alternative—quantum cryptography—offers security based on the laws of physics instead of computational difficulty. But to turn quantum communication into a practical technology, researchers need compact and reliable devices that can decode fragile quantum states carried by light.

For the millions of people living with end-stage kidney disease, hemodialysis is more than a medical procedure, it is a thrice-weekly lifeline that keeps the body's chemistry in balance. Yet even with decades of clinical experience and numerous technological advances, one stubborn challenge persists: determining how much fluid to remove during treatment without tipping a patient into dangerous instability.

Selecting the healthiest embryo is one of the most important steps in in‑vitro fertilization (IVF), yet it remains one of the most uncertain. Roughly 15% of couples worldwide experience infertility, and IVF success rates often remain below 33%. A major challenge is that embryologists must choose a single embryo to implant, relying on what they can see under a microscope.

For decades, the ability to visualize the chemical composition of materials, whether for diagnosing a disease, assessing food quality, or analyzing pollution, depended on large, expensive laboratory instruments called spectrometers. These devices work by taking light, spreading it out into a rainbow using a prism or grating, and measuring the intensity of each color. The problem is that spreading light requires a long physical path, making the device inherently bulky.

Terahertz (THz) radiation, which occupies the frequency band between microwaves and infrared light, is essential in many next-generation applications, including high-speed wireless communications, chemical sensing, and advanced material analysis.

Imagine driving down a busy highway. You need to check your speed and navigation, but glancing down at the dashboard takes your eyes off the road for a critical second. This is where head-up displays (HUDs) come in, projecting information directly onto the windshield. However, current HUD technologies are often bulky and limited to displaying flat, 2D images at a fixed distance, forcing your eyes to constantly refocus between the data and the road.

Thyroid cancer is the most common endocrine cancer, affecting more people each year as detection rates continue to rise. During tumor excision, surgeons often struggle to determine exactly how much tissue should be removed, as distinguishing cancer from healthy tissue in real time is challenging and nearby structures are extremely delicate.

Scientists at the University of Oxford demonstrate an approach to interpreting how materials interact with polarized light, which could help advance biomedical imaging and material design.

Photoplethysmography (PPG) is an optical sensing technique that measures blood volume changes and underpins devices ranging from hospital-grade pulse oximeters to consumer wearables that track heart rate, sleep, and oxygenation.

Conventional telescopes are limited in detecting low-surface-brightness (LSB) structures, which are essential for studying galaxy evolution. Now, researchers have developed a new telescope system featuring a confocal off-axis design with three freeform mirrors, optimized for deep LSB imaging. This system enables astronomers to observe faint galactic features more clearly, revealing how galaxies evolve over time.

Thulium fiber lasers, operating at a wavelength of 2 micrometers, are valued for applications in medicine, materials processing, and defense. Their longer wavelength makes stray light less damaging compared to the more common ytterbium lasers at 1 micrometer.