Self-propelled nanomotors, driven by optical actuation, present a revolutionary technological advance in converting ambient energy into mechanical motion. Owing to the photocatalytic nature of semiconductor-based micromotors, these devices have been explored for water purification with promising degradation rates, as they generate reactive radicals upon photoactivation. Addressing the challenge of selectively removing toxic organic pollutants from contaminated water, a novel approach combining surface molecular imprinting and photoactive micromotors is introduced. Molecularly imprinted micromotors exhibit enhanced pollutant removal rates in a liquid mixture. Additionally, bio-catalytic micromotors, designed for green energy fuel production from contaminated water, demonstrated significant ammonia generation through urea decomposition. A deep-learning-based tracking system enables precise micromotor monitoring. Overall, these multifunctional photoresponsive micromotors show potential in photocatalytic disinfection, water treatment, and green energy applications.

DNA has a helical arrangement, consisting of hundreds of millions of base pairs, whose length and configuration depend on the type and origin of DNA. In this work, we investigate the differences in the linear and nonlinear optical properties of circular-shaped plasmid DNA, small-stranded lambda DNA, and extra-long strands of strawberry DNA under the illumination of a 532 nm laser. We compare the linear absorption spectra of each type of DNA and determine the possible damage to DNA after 1 hour of exposure to high-power green laser. Surprisingly, linear absorption spectra and electrophoresis did not detect any significant damage to all 3 types of DNA. Then we use the Z-scan method to determine the nonlinear absorption and nonlinear index of refraction for each DNA. Our results showed that DNA is a moderately nonlinear photonic material with nonlinear coefficients similar to organic polymers.

Video microscopy has a long history of providing insights and breakthroughs for a broad range of disciplines, from physics to biology. Image analysis to extract quantitative information from video microscopy data has traditionally relied on algorithmic approaches, which are often difficult to implement, time consuming, and computationally expensive. Recently, alternative data-driven approaches using deep learning have greatly improved quantitative digital microscopy, potentially offering automatized, accurate, and fast image analysis. However, the combination of deep learning and video microscopy remains underutilized primarily due to the steep learning curve involved in developing custom deep-learning solutions. To overcome this issue, we have introduced a software, currently at version DeepTrack 2.1, to design, train and validate deep-learning solutions for digital microscopy.

The development of structured ultrafast laser sources is a key ingredient to advance our knowledge about the fundamental dynamics of electronic and spin processes in matter. It is widely recognized the relevance of ultrafast sources structured in their spin angular momentum (associated to the polarization of light) and orbital angular momentum (associated with the transverse phase profile, or vorticity of a light beam) to study chiral systems and magnetic materials in their fundamental temporal and spatial scales. In the last decade, the possibility to generate structured ultrafast laser pulses in the shortest time scales known, as attosecond pulses, has triggered substantial developments in nonlinear optics. In this talk we will review several works that have boosted the field of attosecond structured pulses during the last decade. We will focus in the generation of EUV/soft x-ray pulses tailored in their spatiotemporal angular momentum properties and we will review their potential applications in fundamental and applied science. Finally we will review how artificial intelligence has boosted the theoretical advancements in attosecond pulse generation.

Biofilms occur when the environmental conditions for a bacterium become suboptimal and hostile, leading the bacteria to utilize biofilm as a defensive strategy. In our work, we determined how different wavelengths of light impact biofilm development and how optical tweezers can be used to manipulate the spatial distribution of biofilm and assess its strength. In particular, we investigated the biofilm formation of Bacillus subtilis in a minimum salts glycerol glutamate (MSgg) medium. Understanding biofilm formation and control strategies is critical because of its effect on human health and the potential for novel biomaterials in future biodegradable technology.

Laser induced forward transfer (LIFT) is collecting much attention as a nozzle-free, cost-saving and resource-saving printing technology, and LIFT bioprinting has been widely studied to avoid all nozzle-associated negative effects, such as a narrow bioink viscosity range, low spatial resolution and a fairly low cell viability. We have discovered that an optical vortex pulse can twist an irradiated material to eject and propel a picoliter-scale spinning microdroplet of the material with a straight flight. This optical vortex laser-induced forward transfer (OV-LIFT) offers a new direct-print technology with ultrahigh spatial resolution. In this presentation, we review the research achievements of OV-LIFT and address the OV-LIFT bioprinting, which enables the direct print of living cells (cyanobacteria cells) colloidal suspension with a high spatial resolution and high cell viability. Such OV-LIFT bioprinting will also offer new research opportunities to fabricate freeform cell scaffolds towards the bio-solar cells technologies and tissues engineering.

Laser-induced forward transfer (LIFT) has been collecting much attention as a nozzle-free, cost-effective and resource-efficient printing technology for the development of printed electronic/photonic devices and bioprinting with high cell viability. In recent years, we and our co-workers have proposed a novel LIFT technology with optical vortex possessing a helical wavefront (we called OV-LIFT) instead of a conventional Gaussian beam with a plane wavefront, which enables the high definition print of materials even with an extremely long working distance. In our experiments, we demonstrate the 2-dimansionally direct print of cyanobacteria cells water/glycerol suspension including biocompatible materials (polyethylene glycol diacrylate) with OV-LIFT. The printed dots exhibit a diameter of approximately 50 μm with a positioning accuracy of about 6 μm. Also, we address high viability of cyanobacterial cells, as evidenced by photosynthetic activity of cyanobacterial cells in as-printed dots.

Nanophotonic structures are crucial for controlling light at scales smaller than its wavelength. While designing for linear polarization is straightforward, creating nanostructures for helically structured light, like circularly polarized light and optical vortices, is challenging due to complex near-field chiral interactions with matters in helical electromagnetic fields. In this presentation, we apply topology optimization, an intelligent design approach, to create 3D nanogap antenna structures with outstanding chiroptical functionalities. With these structures, we demonstrate giant chiral dissymmetry (up to g = 1.70), polarization conversion around the Poincaré sphere, and circularly polarized far-field emission from a linear dipole embedded within the gap. Additionally, our in-depth analysis reveals a physical connection between the flow of spin angular momentum of light within the nanostructure and the local density of optical chirality. The insight, combined with our developed structures, offers a fresh perspective for designing chiral nanophotonic structures for better control of chiral molecules using light.

Integrated photonics offers the potential to realize complex nonlinear photonic systems. I will describe recent work on the synchronization of coupled Kerr microresonators that can be exploited for beam combining, spectral reshaping, and optical frequency division.

Integrated quantum photonics is crucial for the efficient generation, manipulation, and detection of quantum light states, enabling a high density of on-chip photonic qubits and functionalities essential for quantum information processing. Among materials for quantum photonics, silicon nitride emerges as a leading platform due to its unique properties and compatibility with existing foundry fabrication processes. Our research has led to the discovery of intrinsic quantum emitters in low-autofluorescence SiN and the development of techniques for their creation. These emitters are characterized by high single-photon purity and brightness at room temperature. Moreover, we have investigated the operation of these emitters at cryogenic temperatures, addressing the generation of indistinguishable photons. We have achieved successful integration of these emitters with SiN waveguides and established a method for large-scale, site-controlled fabrication. This talk delves into our research effort to engineer novel quantum emitters in SiN, integrate them with on-chip photonic structures, and explore their photophysical properties and potential avenues for their improvement and applications.

We are now experiencing a revolution in optical technologies, where one can print and control massive optical circuits, on a microelectronic chip. This revolution is enabling a whole range of applications that are in need for scalable optical technologies and its opening the door to areas that only a decade ago were unimaginable.

With the rapid development of flexible electronics and soft robotics, the topic of preventing fracture in materials and devices integrated on largely bending film substrates is emerging. The high demand for strategically reducing strain in bending materials requires a facile method to accurately and precisely analyze the surface bending strain in various materials. This study reports the fundamental and efficient techniques for measuring the bending behavior of various polymer films. The fracture limit of a hard coating overlying flexible substrates is successfully determined by the accurate and precise quantification of surface bending strains. Furthermore, a multilayer film substrate with surface bending strain prevents fractures of hard coatings and organic thin film transistors.

Mechanics enabled by photon absorption generates work from materials and is perhaps one of the most important applications of light active matter, which mediates an intensity-to-stress transduction and moves in intensity gradients. Photomechanics can be put at work in surface structuring of materials, which has applications in several areas of science and engineering including photonics and biology and medicine. We demonstrate that photosensitive materials can be unexpectedly micro- nano- textured by a single step irradiation with weakly absorbed low power red light. We report highly efficient surface structuring induced by interference patterns of two coherent non-resonant red (wavelength 632.8 nm), less than 5 mW, laser beams operating in the near-zero absorption tail of azo-polymer fims with optical densities in the 0.02-0.09 range; i.e. 80-95% light transmission. The heights of the observed structures are comparable to those obtained by resonant absorption; a feature which is counter intuitive, and thus never reported to date. Low and high energies n-π^* and π-π^*excitations of the azo dye, are equally efficient in inducing isomerization and mass motion of polymers. Our work is

Photon powered molecular machines can be assembled into crystals that undergo deformations like expansion, bending, twisting, and coiling. We will review various types of photomechanical crystals, emphasizing the importance of morphology, and show that their theoretical work densities are several orders of magnitude greater than standard actuator materials like piezoelectrics. This class of crystals can also support feedback mechanisms that lead to complex oscillations and translational motion that mimics biological flagella. The combination of organic chemistry, crystal engineering and photochemistry provides a promising approach to make light-responsive materials that can do useful amounts of work.

Sculpted light provides a very flexible tool for the production of configurable and flexible confining potentials at the nano- and micro-scale. Sculpted light has been extensively used in diverse fields ranging from optical micromanipulation to quantum atom optics and quantum communication. It enables the production of complex optical potentials. Optically driven nano and micromachines hold a promise of vast applications in interdisciplinary fields of science. These machines can be driven by versatile optical landscapes and provide applications ranging from microfluidics, drag delivery systems to complex biological systems.

Self-propelled nanomotors are tiny devices capable of converting energy from their surroundings into mechanical motion. However, at the nanoscale, motion is highly influenced by Brownian and thermal forces. To overcome these limitations, a constant force must be applied. Among various approaches, optical actuation stands out as a particularly promising method due to its ability to modulate motion through wavelength, polarization, intensity, and direction. Here, we introduce photoactive nanomotors with anisotropic morphologies that move under external light irradiation. Furthermore, to achieve more precise directional motion, we explore the combination of both light and magnetic external fields. The remarkable versatility and potential of these photoactivated nanomachines in the context of selective oxidations is also demonstrated.Consequently, this work introduces an innovative approach to overcome challenges in achieving precise directional motion in light-driven nanomotors, thereby enhancing their photoactivity.