Search

Photonic crystals can integrate plasmonic materials such as Indium Tin Oxide (ITO) in their structure. Exploiting ITO plasmonic properties, it is possible to tune the photonic band gap of the photonic crystal upon the application of an external stimuli. In this work, we have fabricated a one-dimensional multilayer photonic crystal alternating ITO and Titanium Dioxide (TiO2) via radio frequency sputtering and we have triggered its optical response with ultrafast pump-probe spectroscopy. Upon photoexcitation, we observe a change in the refractive index of ITO. Such an effect has been used to create a photonic crystal that changes its photonic bandgap in an ultrafast time scale. All optical modulation in the visible region, that can be tuned by designing the photonic crystal, has been demonstrated.

Here, we show that a hybrid plasmonic/photonic crystal consisting of a thin layer of bioactive plasmonic material (i.e. silver) deposited on top a 1D PhC can detect one of the most common bacterial contaminant, namely Escherichia coli. We speculate that the change in the plasmon charge density brought about by metal/bacterium interaction results in a variation of the plasmon resonance that, in turns, translates in a shift of the photonic structural color.

Nanolasers that operate under the continuous-wave pump and are robust in diverse environments will make possible compact optoelectronic devices, biomedical imaging, and large-scale quantum photonics. However, current nanolasers require low temperatures or pulsed excitation because their small mode volumes severely limit gain relative to cavity loss. Here, I will present continuous-wave upconverting micro- and nanolasing at room temperature with record-low thresholds and high photostability. I will explore the future implications of such a low-threshold laser for optofluidics.

In this paper, we aimed to highlight functional and safety outcomes of highly-comorbid patients undergoing transperineal laser ablation (TPLA) of prostate at a referral academic center. Patients undergoing TPLA from April 2021 and February 2023 with moderate to severe lower urinary tract symptoms (LUTS), prostate volume ranging from 30 to 100 mL, and an American Society of Anesthesiologists (ASA) Score ≥3 were included. All patients were evaluated as unfit for standard surgery. Procedures were performed in an outpatient setting using local anesthesia. Failure after the procedure was defined as the shift to other ultra-minimally invasive surgical treatment or the need for long-term indwelling catheter replacement. Overall, 23 patients were enrolled with a median age of 76 years. Median ASA Score and Charlson Comorbidity Index were 3 and 5, respectively. Of these, 11 (48%) were under antiplatelets, 4 (17%) under new oral anticoagulants (NOACs) and 3 (13%) under warfarin. Six (26%) patients had an indwelling catheter preoperatively. Median prostate volume was 42 mL. Median follow-up was 12 months. No Clavien-Dindo Grade ≥2 complications were recorded. Four/six (66%) patients with an indwelling catheter before TPLA achieved spontaneous micturition. Treatment failure occurred in 2 (8.5%) patients. Of the remaining 21 patients, 12/21 (57%) patients reported an improvement in International Prostate Symptoms Score (IPSS) symptoms class (i.e., severe to moderate, moderate to mild, etc.); all patients whose IPSS symptoms class remained stable (N.=8 [38%]) had a significant improvement of the IPSS score as compared to the preoperative period, while 1 (4.5%) patient reported worsening of LUTS. In conclusion, TPLA appears to be a safe and feasible ultra-minimally-invasive option for LUTS due to benign prostatic obstruction (BPO) in patients with significant comorbidities at high-risk for standard surgical options.

Despite transrectal prostate biopsy (TRPB) being still widespread globally, the EAU Guidelines strongly recommend the transperineal approach, due to the reported lower infectious risk. Our study aims to evaluate the impact of a standardized clinical pathway for TRPB on post-operative complications. We prospectively collected data from all patients undergoing mpMRI-targeted TRPB at our Academic Centre from January 2020 to December 2022. All patients followed a standardized, structured multistep pathway. Post-procedural complications were collected and classified according to the Clavien-Dindo (CD) Classification. Among 458 patients, post-procedural adverse events were reported by 203 (44.3%), of which 161 (35.2%) experienced CD grade 1 complications (hematuria [124, 27.1%], hematochezia [22, 4.8%], hematospermia [14, 3.1%], or a combination [20, 4.4%]), and 45 (9.0%) reported CD grade 2 complications (acute urinary retention or hematuria needing catheterization, as well as urinary tract infections, of which 2 cases required hospitalization). No major complications, including sepsis, were observed. At uni- and multivariable analysis, age > 70 years and BMI > 25 kg/ m 2 for patients were identified as predictors of post-operative complications. The results of our study confirm that TRPB is a safe and cost-effective procedure with a low risk of severe adverse events in experienced hands and following a standardized pathway.

We aimed to review the current evidence on surgical and functional outcomes of Transperineal Laser Ablation for LUTS due to BPH. A comprehensive review of the English-language literature was performed using the MEDLINE and Web of Science databases until 1 August 2022, aiming to select studies evaluating TPLA for the treatment of LUTS due to BPH. Additional records were found from Google Scholar. Data were extracted and summarized in Tables. An appropriate form was used for qualitative data synthesis. Seven studies were included in the review, with all being single arm, non-comparative studies. In all studies, functional outcomes were evaluated with uroflowmetry parameters and validated questionnaires, showing a promising effectiveness at short- and mid-term follow-up. There is a lack of standardized pathways for preoperative assessment of patients suitable for TPLA, and even the technique itself has been reported with a few nuances. A good safety profile has been reported by all the authors. Although promising results have been reported by different groups, selection criteria for TPLA and few technical nuances regarding the procedure were found to be heterogeneous across the published series that should be standardized in the future. Further research is needed to confirm these findings.

The colour purity and versatility of fabrication of one-dimensional photonic crystals (1D PhCs) make them ideal candidates for colorimetric sensing of a variety of analytes. For instance, the detection of bacterial contaminants in food via colorimetric sensors can be highly appealing, as most of the existing detection techniques are in general time-consuming and the read-out requires specialised personnel. Here, we present a colorimetric sensor based on hybrid plasmonic/photonic 1D crystals. We demonstrate that the modification of the silver plasmon resonance brought about by the effective silver/bacterium interaction can be translated into the visible spectral region, producing a change in the structural colour. In addition, we observe a superior colorimetric sensitivity against the Gram negative Escherichia coli compared to the Gram positive Micrococcus luteus, a result that we attribute to the more efficient electrostatic interaction and cellular adhesion between the silver surface and the Gram-negative bacteria outer membrane. This approach demonstrates that in principle an easy colorimetric detection of bacterial contaminants can be achieved through the use of bio-responsive plasmonic materials, such as silver, whose selective electrostatic interaction with bacterial cell wall is well-known and occurs without the need of chemical functionalisation.

We present an innovative beamline for extreme ultraviolet (XUV)-infrared (IR) pump-probe reflection spectroscopy in solids with attosecond temporal resolution. The setup uses an actively stabilized interferometer, where attosecond pulse trains or isolated attosecond pulses are produced by high-order harmonic generation in gases. After collinear recombination, the attosecond XUV pulses and the femtosecond IR pulses are focused twice in sequence by toroidal mirrors, giving two spatially separated interaction regions. In the first region, the combination of a gas target with a time-of-flight spectrometer allows for attosecond photoelectron spectroscopy experiments. In the second focal region, an XUV reflectometer is used for attosecond transient reflection spectroscopy (ATRS) experiments. Since the two measurements can be performed simultaneously, precise pump-probe delay calibration can be achieved, thus opening the possibility for a new class of attosecond experiments on solids. Successful operation of the beamline is demonstrated by the generation and characterization of isolated attosecond pulses, the measurement of the absolute reflectivity of SiO 2 , and by performing simultaneous photoemission/ATRS in Ge.

Indium tin oxide (ITO) is a heavily doped semiconductor with a plasmonic response in the near infrared region. When exposed to light, the distribution of conduction band electron induces a change in the real and imaginary parts of the dielectric permittivity. The coupling of the electromagnetic waves with the electrons in the conduction band of metallic nanostructures with ultrashort light pulses results in a nonlinear plasmonic response. Such optical modulation occurring on ultrafast time scales, e.g. picosecond response times, can be exploited and used to create integrated optical components with terahertz modulation speed. Here, we present a photophysical study on a one dimensional ITO grating, realized using a femtosecond micromachining process, a very industrially accessible technology. The geometries, dimensions and pitch of the various gratings analyzed are obtained by means of direct ablation in a controlled atmosphere of a homogeneous thin layer of ITO deposited on a glass substrate. The pitch has been selected in order to obtain a higher order of the photonic band gap in the visible spectral region. Femtosecond micromachining technology guarantees precision, repeatability and extreme manufacturing flexibility. By means of ultrafast pump-probe spectroscopy, we characterize both the plasmon and inter-band temporal dynamics. We observe a large optical nonlinearity of the ITO grating in the visible range, where the photonic band gap occurs, when pumped at the surface plasmon resonance in the near infrared (1500 nm) region. All together, we show the possibility of all-optical signal modulation with heavily doped semiconductors in their transparency window with a picosecond response time through the formation of ITO grating structures.

Photonic crystal-based biosensors hold great promise as low-cost devices for real-time monitoring of a variety of biotargets, for example, bacterial contaminants in food. Here, we report the proof-of-concept for a new colorimetric sensor of bacterial contamination, which is based on a novel hybrid plasmonic-photonic device. Our system consists of a layer of silver, a plasmonic metal exhibiting a well-known bioactivity, on top of a one-dimensional photonic crystal. We attribute the bioresponsivity to the formation of polarization charges at the Ag/bacterium interface within a sort of "bio-doping" mechanism. Interestingly, this triggers a blue shift in the photonic response. As an example, we assessed the validity of our approach by detecting one of the most hazardous contaminants, Escherichia coli . This work demonstrates that our device can be a low-cost and portable platform for the detection of common bacterial contaminants.