Advanced Photon Research Articles

Room temperature stable twist-bend nematic materials without crystallization over 1 year

The twist-bend nematic (NTB) phase of achiral liquid crystals (LCs) manifests a unique self-assembled heliconical structure with nanometer-scale pitch length, mirroring the chiral symmetry-breaking phenomena in nature, thus sparking widespread research interest. However, the ingenious NTB phase is only stable at high temperatures within a very limited temperature interval, often undergoing inevitable crystallization at low temperatures. Herein, room temperature supercooled NTB material systems composed of meticulously designed LC dimer mixtures with varying molecular curvatures and central flexibility were developed, resulting in complete resistance to crystallization even after 1 year of storage. Furthermore, the proposed NTB material systems demonstrated exceptional compatibility with common nematic LCs, facilitating the tailoring of overall physical parameters, particularly to achieve a sufficiently low bend elastic constant with excellent stability. This work represents a paradigmatic advancement forward in realizing stable NTB phase materials with a broad temperature range and resistance to crystallization, thereby tackling the enduring and seemingly insurmountable challenge while providing impetus for further exploration of their applications in soft matter, crystallography, and advanced photonics.

Piezochromic Behavior of 2,4,6‐Triphenylpyrylium Tetrachloroferrate

In advanced photonics, there is a growing interest in piezochromic luminescent materials that exhibit multicolor switching, driven by their potential applications in optical recording, memory, and sensors. Here, the piezochromic behavior of 2,4,6‐triphenylpyrylium tetrachloroferrate (Py‐FeCl4) under high pressures from 0 to 9 GPa is reported. The observed multicolor changing properties of Py‐FeCl4 (yellow–orange–red–maroon–black) are found to be fully reversible upon decompression to ambient conditions. The mechanism of Py‐FeCl4 piezochromism is investigated via Raman, infrared, and UV–vis spectroscopy combined with powder X‐ray Diffraction. The absence of structural phase transitions as well as the abrupt shifts of bandgap values together with characteristic Raman and IR peaks within 0‐9 GPa suggests that the Py‐FeCl4 multicoloring switching behavior is driven by an electron transfer between the inorganic FeCl4− anion and the organic pyrylium cation. The obtained results demonstrate that Py‐FeCl4 dye is a good candidate for developing high‐pressure sensing technologies designed to function in extreme environments. Moreover, due to the inherent role of molecular‐structure relationships in the pyrylium salt's photophysical properties, findings suggest the potential discovery of piezochromic behavior in other pyrylium compounds.

Advanced Photonics: Thank you for five wonderful years

Advanced Photonics: Thank you for five wonderful years

Machine learning for optical quantum metrology

<i>Advanced Photonics</i>, co-published by SPIE and Chinese Laser Press, is a highly selective, Gold Open Access, international journal publishing innovative research in all areas of optics and photonics, including fundamental and applied research.

Advanced Photonics: serving optical sciences and scientists

<i>Advanced Photonics</i>, co-published by SPIE and Chinese Laser Press, is a highly selective, Gold Open Access, international journal publishing innovative research in all areas of optics and photonics, including fundamental and applied research.

Synthesis and Upconversion Luminescence Properties of BaBiO2Cl:Yb3+,Er3+ Phosphor

The interaction of near-infrared (NIR) light with matter that produces high-energy visible light emissions is known as photon upconversion, which has shown promising applications in different fields, including optoelectronics, biomedicine and photovoltaics. In this paper, a novel BaBiO2Cl:Yb3+,Er3+ upconversion phosphor was successfully synthesized through a simple high-temperature solid-state reaction route. The crystal structure, phase purity, microstructure and upconversion luminescence properties of the as-prepared phosphor were characterized comprehensively. The XRD and SEM results clearly demonstrate the successful synthesis of the target phosphors with high purity. When excited by a 980 nm NIR laser, the as-prepared BaBiO2Cl:Yb3+,Er3+ phosphor exhibited intense red upconversion luminescence due to the Er3+ 4F9/2→4I15/2 transition, which enabled this phosphor to have high promise for important applications, such as anti-counterfeiting and advanced photonics.

Hyperentanglement goes deterministic and large-scale

<i>Advanced Photonics</i>, co-published by SPIE and Chinese Laser Press, is a highly selective, Gold Open Access, international journal publishing innovative research in all areas of optics and photonics, including fundamental and applied research.

Advanced photonic and optofluidic devices fabricated in glass via femtosecond laser micromachining [Invited

Thanks to its unique properties, glass plays a fundamental role in science and technology, especially in optics and photonics. For instance, its transparency has been exploited in the last decades for efficiently guiding light in optical fibers for long distances, while its versatility makes it the perfect material in different research fields, ranging from fundamental science to biology and chemistry. On the occasion of the International Year of Glass, we would like to discuss a powerful microfabrication technique for devices in this material: femtosecond laser micromachining (FLM). This technique can process different types of glass, and thanks to the nonlinear nature of the induced modification, it enables the fabrication of complex three-dimensional micro-structures capable of guiding light or transporting fluids. The purpose of this review article is to celebrate the multidisciplinary nature of FLM by discussing, without claim for completeness and after a brief introduction about the process, a selection of its applications in the diverse fields of biology, strong-field physics, and astronomy.

Photonics with Thin Film Lithium Niobate

<i>Advanced Photonics</i>, co-published by SPIE and Chinese Laser Press, is a highly selective, Gold Open Access, international journal publishing innovative research in all areas of optics and photonics, including fundamental and applied research.

Photonic bandgap engineering in (VO2) n /(WSe2) n photonic superlattice for versatile near- and mid-infrared phase transition applications

The application of the photonic superlattice in advanced photonics has become a demanding field, especially for two-dimensional and strongly correlated oxides. Because it experiences an abrupt metal–insulator transition near ambient temperature, where the electrical resistivity varies by orders of magnitude, vanadium oxide (VO2) shows potential as a building block for infrared switching and sensing devices. We reported a first principle study of superlattice structures of VO2 as a strongly correlated phase transition material and tungsten diselenide (WSe2) as a two-dimensional transition metal dichalcogenide layer. Based on first-principles calculations, we exploit the effect of semiconductor monoclinic and metallic tetragonal state of VO2 with WSe2 in a photonic superlattices structure through the near and mid-infrared (NIR–MIR) thermochromic phase transition regions. By increasing the thickness of the VO2 layer, the photonic bandgap (PhB) gets red-shifted. We observed linear dependence of the PhB width on the VO2 thickness. For the monoclinic case of VO2, the number of the forbidden bands increase with the number of layers of WSe2. New forbidden gaps are preferred to appear at a slight angle of incidence, and the wider one can predominate at larger angles. We presented an efficient way to control the flow of the NIR–MIR in both summer and winter environments for phase transition and photonic thermochromic applications. This study’s findings may help understand vanadium oxide’s role in tunable photonic superlattice for infrared switchable devices and optical filters.

A randomized controlled phase III study comparing hadrontherapy with carbon ions versus conventional radiotherapy – including photon and proton therapy – for the treatment of radioresistant tumors: the ETOILE trial

BackgroundSome cancers such as sarcomas (bone and soft tissue sarcomas) and adenoid cystic carcinomas are considered as radioresistant to low linear energy transfer radiation (including photons and protons) and may therefore beneficiate from a carbon ion therapy. Despite encouraging results obtained in phase I/II trials compared to historical data with photons, the spread of carbon ions has been limited mainly because of the absence of randomized medical data. The French health authorities stressed the importance of having randomized data for carbon ion therapy.MethodsThe ETOILE study is a multicenter prospective randomized phase III trial comparing carbon ion therapy to either advanced photon or proton radiotherapy for inoperable or macroscopically incompletely resected (R2) radioresistant cancers including sarcomas and adenoid cystic carcinomas.In the experimental arm, carbon ion therapy will be performed at the National Center for Oncological Hadrontherapy (CNAO) in Pavia, Italy. In the control arm, photon or proton radiotherapy will be carried out in referent centers in France.The primary endpoint is progression-free survival (PFS). Secondary endpoints are overall survival and local control, toxicity profile, and quality of life. In addition, a prospective health-economic study and a radiobiological analysis will be conducted.To demonstrate an absolute improvement in the 5-year PFS rate of 20% in favor of carbon ion therapy, 250 patients have to be included in the study.DiscussionSo far, no clinical study of phase III has demonstrated the superiority of carbon ion therapy compared to conventional radiotherapy, including proton therapy, for the treatment of radioresistant tumors.Trial registrationClinicalTrials.gov identifier: NCT02838602. Date of registration: July 20, 2016. The posted information will be updated as needed to reflect protocol amendments and study progress.

Innovation in metamaterials and beyond: an interview with Prof. Xiang Zhang

<i>Advanced Photonics</i>, co-published by SPIE and Chinese Laser Press, is a highly selective, Gold Open Access, international journal publishing innovative research in all areas of optics and photonics, including fundamental and applied research.

Towards extremely high-order optical nonlinearity at the nanoscale

<i>Advanced Photonics</i>, co-published by SPIE and Chinese Laser Press, is a highly selective, Gold Open Access, international journal publishing innovative research in all areas of optics and photonics, including fundamental and applied research.

Advanced Photonics: exciting news all around

<i>Advanced Photonics</i>, co-published by SPIE and Chinese Laser Press, is a highly selective, Gold Open Access, international journal publishing innovative research in all areas of optics and photonics, including fundamental and applied research.

Explorer of light, and more: an interview with Sir Michael Berry

<i>Advanced Photonics</i>, co-published by SPIE and Chinese Laser Press, is a highly selective, Gold Open Access, international journal publishing innovative research in all areas of optics and photonics, including fundamental and applied research.

Photonics for net zero

<i>Advanced Photonics</i>, co-published by SPIE and Chinese Laser Press, is a highly selective, Gold Open Access, international journal publishing innovative research in all areas of optics and photonics, including fundamental and applied research.

Stronger quantum advantages with photons

<i>Advanced Photonics</i>, co-published by SPIE and Chinese Laser Press, is a highly selective, Gold Open Access, international journal publishing innovative research in all areas of optics and photonics, including fundamental and applied research.

From fundamental quantum optics to quantum information technology: the personal journey of Sir Peter Knight

<i>Advanced Photonics</i>, co-published by SPIE and Chinese Laser Press, is a highly selective, Gold Open Access, international journal publishing innovative research in all areas of optics and photonics, including fundamental and applied research.

Large-energy mode-locked Er-doped fiber laser based Cr2Si2Te6 as a modulator

Ultrafast photonic devices based on two-dimensional (2D) materials attract the attentions of researchers. In order to expand the range and diversity of ultrafast lasers and advanced photonics, it is necessary to explore new 2D materials with excellent nonlinear absorption properties. Ferromagnetic insulators (FIs) have the suitable band structure and they can be stripped into single layer structure easily, however, few related works have been reported. In this work, Cr2Si2Te6 (CST) thin film modulator was prepared through the method of liquid-phase exfoliation (LPE) and investigated its nonlinear optical properties and application in obtaining large energy mode-locking pulse output. The modulation depth and saturable intensity of the CST were 4.40% and 12.51 MW/cm2, respectively. Transferring it into the ring cavity, the all-fiber laser can generate a large energy pulse with a center wavelength of 1558.53 nm and a repetition frequency of 1.61 MHz. The energy of single pulse was 53.03 nJ. The maximum average output power was 85.54 mW under the pump power of 1659 mW. To our knowledge, the energy of single pulse is the highest among the reported all-fiber lasers with FIs saturable absorbers (SAs). Our experimental results proved that CST-SA has excellent modulation properties, which provides a basis for future research.

Porous nickel oxide micron polyhedral particles for high-performance ultrafast photonics

As a member of organic porous crystal structure, metal organic frameworks (MOFs) material has more unique properties due to its large specific surface area, high porosity, diversified structure and functions, it has been successfully applied in new energy, microelectronics, chemical reaction medical science and other fields. However, no study about NiO-MOF for the ultrafast optics application has been reported till now. In this paper, NiO-MOF polyhedral particles is prepared by hydrothermal method and successfully applied to ultrafast photonics. The modulation depth of NiO-MOF is 18.98 % through a dual-balance detection system. Most importantly, the 109th harmonic solitons are realized for the first time based on NiO-MOF in a compact mode-locked fiber laser at 1.55 μm, the fiber laser has pulse duration of 766 fs and repetition frequency of 413 MHz. As far as we know, this is the first time NiO-MOF has been applied to realize harmonic mode-locking at the fs level of more than 400 MHz. Due to the rich variability of MOFs structure, this study successfully provides support for the application of MOFs material in advanced photonics.