Intense pulse light

Femtosecond optical parametric oscillators (OPOs) are widely used in ultrafast nonlinear frequency conversion and quantum information. However, conventional OPOs based on quasi-phase-matching (QPM) crystals have many parasitic non-phase-matched processes which decrease the conversion efficiency. Here, we propose nine-wave coupled equations (NWCEs) to simulate all phase-matched and non-phase-matched interactions in QPM crystals to improve conventional three-wave coupled equations (TWCEs), especially for the situation of high intensity ultrashort pulses and complexly structured crystals...

A standardized phase retrieval algorithm is presented and applied to an industry-grade high-energy ultrashort pulsed laser to uncover its spatial phase distribution. We describe in detail how to modify the well-known algorithm in order to characterize particularly strong light sources from intensity measurements only. With complete information about the optical field of the unknown light source at hand, virtual back propagation can reveal weak points in the light path such as apertures or damaged components...

Pulsed light detecting and ranging (Lidar) is capable of acquiring comprehensive target information within a single pulse, including distance and intensity data. Intensity data reflects the target's backscattered intensity and is commonly regarded as a crucial observational parameter associated with target reflectivity information. Multiple studies have indicated the potential of intensity data in various applications within pulsed Lidar contexts. However, the intensity data is influenced by the incident angle and distance; hence it cannot directly manifest target characteristics...

Intense laser pulses can be used to demagnetize a magnetic material on an extremely short timescale. While this ultrafast demagnetization offers the potential for new magneto-optical devices, it poses challenges in capturing coupled spin-electron and spin-lattice dynamics. In this article, we study the photoinduced ultrafast demagnetization of a prototype monolayer ferromagnet Fe3 GeTe2 and resolve the three-stage demagnetization process characterized by an ultrafast and substantial demagnetization on a timescale of 100 fs, followed by light-induced coherent A1g phonon dynamics which is strongly coupled to the spin dynamics in the next 200-800 fs...

Increasing hurricane frequency and intensity with climate change is likely to affect soil organic carbon (C) stocks in tropical forests. We examined the cycling of C between soil pools and with depth at the Luquillo Experimental Forest in Puerto Rico in soils over a 30-year period that spanned repeated hurricanes. We used a nonlinear matrix model of soil C pools and fluxes ("soilR") and constrained the parameters with soil and litter survey data. Soil chemistry and stable and radiocarbon isotopes were measured from three soil depths across a topographic gradient in 1988 and 2018...

Critical coupling in integrated photonic devices enables the efficient transfer of energy from a waveguide to a resonator, a key operation for many applications. This condition is achieved when the resonator loss rate is equal to the coupling rate to the bus waveguide. Carefully matching these quantities is challenging in practice, due to variations in the resonator properties resulting from fabrication and external conditions. Here, we demonstrate that efficient energy transfer to a non-critically coupled resonator can be achieved by tailoring the excitation signal in time...

Background : Facial telangiectasias is a prevalent cosmetic disorder that can be associated with several conditions such as rosacea. IPL (intensity pulsed light) therapy is commonly used for the treatment of vascular lesions. This study tested the efficacy of an IPL system emitting selected vascular chromophore-specific wavelengths in the range of 500-1200 nm for the treatment of vascular lesions. Materials and Methods : A total of 39 patients affected by different vascular lesions on their face were enrolled...

With the wide application of intense lasers, the protection of human eyes and detectors from laser damage is becoming more and more strict. In this paper, we study the nonlinear optical limiting (OL) properties of porous carbon with a super large specific surface area (2.9 × 103 m2 /g) using the nanosecond Z-scan technique. Compared to the traditional OL material C60 , the porous carbon material shows an excellent broadband limiting effect, and the limiting thresholds correspond to 0.11 J/cm2 for 532 nm and 0...

Malignant cardiac tachyarrhythmias are associated with complex spatiotemporal excitation of the heart. The termination of these life-threatening arrhythmias requires high-energy electrical shocks that have significant side effects, including tissue damage, excruciating pain, and worsening prognosis. This significant medical need has motivated the search for alternative approaches that mitigate the side effects, based on a comprehensive understanding of the nonlinear dynamics of the heart. Cardiac optogenetics enables the manipulation of cellular function using light, enhancing our understanding of nonlinear cardiac function and control...

PURPOSE: The purpose of the study was to evaluate the quality of life (QOL) improvement in evaporative dry eye patients after treatment with intense pulsed light (IPL) therapy compared to punctal plug insertion. METHODS: A prospective comparative interventional study included 30 patients with moderate-to-severe evaporative dry eye. Patients' QOL affection before and after treatment was assessed by the Ocular Surface Disease Index (OSDI) questionnaire. Fifteen patients were treated with IPL therapy (Group 1)...

With the increasing demand for new materials for light-harvesting applications, spatiotemporal microscopy techniques are receiving increasing attention as they allow direct observation of the nanoscale diffusion of excitons. However, the use of pulsed and tightly focused laser beams generates light intensities far above those expected under sunlight illumination, leading to photodamage and nonlinear effects that seriously limit the accuracy and applicability of these techniques, especially in biological or atomically thin materials...

Traditionally, manipulation of spatiotemporal coupling (STC) of the ultrafast light fields can be actualized in the space-spectrum domain with some 4-f pulse shapers, which suffers usually from some limitations, such as spectral/pixel resolution and information crosstalk associated with the 4-f pulse shapers. This work introduces a novel mechanism for direct space-time manipulation of ultrafast light fields to overcome the limitations. This mechanism combines a space-dependent time delay with some spatial geometrical transformations, which has been experimentally proved by generating a high-quality STC light field, called light spring (LS)...

BACKGROUND: Intense pulsed light (IPL) is used for the treatment and improvement of various skin issues. However, patients often experience local skin burning and pain after IPL treatment. Cooling and analgesic measures are indispensable. AIMS: To investigate the clinical effect of thermal shock therapy on pain relief and reduction of adverse reactions during IPL therapy. PATIENTS/METHODS: A total of 60 female patients with facial photoaging who received IPL therapy were enrolled in the study...

Experiments have shown that photon exploitation efficiency in unicellular algal biomass production under a pulsed-light regime with a high-photon flux is higher than the efficiency under continuous illumination with the same flux. This observation has been explained theoretically to be a consequence of the improved efficiency of exploitation of photons by Photosystem II (PS II) thanks to the combined effect of photon-absorption statistics, a rate-limiting time scale and the size of the PQ pool. Exploiting the same ideas, it is shown in this paper that, under a pulsed-light regime, there is a pulse-time length, for which the average exploitation efficiency of PS II absorbed photons is maximal...

In this study, the spatiotemporal evolution of full cycle of high-intensity dc argon arc discharge at atmospheric pressure is investigated by using a transferred arc device, which is easy to be directly observed in the experiment. Combining the voltage and current waveforms with high-speed images, the full cycle evolution process of high-intensity atmospheric dc arc can be divided into five different stages: breakdown pulse stage, cathode heating stage, current climbing stage, stable arc discharge stage, and finally arc extinguishing stage...

INTRODUCTION: To assess the efficacy and safety of the combination of microblepharoexfoliation (MBE), intense pulse light (IPL) and meibomian gland expression (MGX) for treatment of meibomian gland dysfunction (MGD). METHODS: This was a prospective, parallel-control trial conducted from April 2022 to January 2023. Participants were assigned to receive either three sessions of MBE-IPL-MGX treatment and home-based therapy (treatment group) or home-based therapy alone (control group)...

BACKGROUND: There is no standardized and effective treatment modality for Riehl's melanosis. AIMS: To compare the efficacy and safety of oral tranexamic acid (TXA) combined with intense pulsed light (IPL) versus TXA alone in the treatment of refractory Riehl's melanosis. METHODS: A prospective study of 28 subjects with refractory Riehl's melanosis and Fitzpatrick Skin Types III or IV was conducted. All subjects received oral TXA 500 mg daily and 11 of them were treated in combination with monthly IPL therapy for 6 months...

Conventional ocean wave observation instruments are powered by batteries, limiting the continuous observation time. Besides, the waste of batteries brings environmental contaminations. Triboelectric nanogenerators (TENGs) can reveal ocean wave information through their electrical output, taking the triboelectric charge as the information carrier. However, charge amplification is necessary, consuming additional energy. Herein, taking the photons rather than electrons as the information carrier, we developed a fully self-powered natural light-enabled sensing system for ocean wave monitoring by coupling two rotary-freestanding sliding TENGs (RFS-TENGs) and a polymer network liquid crystal (PNLC)-triggered optical system...

Superfluorescence (SF) is collective spontaneous emission wherein radiators spontaneously synchronize, resulting in an intense single-pulse emission. The avalanche radiation of photons is initiated by the first photon emitted into the SF propagation mode. Because this process is stochastic, the absolute phase of the SF changes randomly from shot to shot. We demonstrate that this phase can be controlled by seeding the SF with a resonant continuous-wave (CW) laser. The seed light was weak enough not to cause the stimulated emission but strong enough to inject the first photon into the SF propagation mode prior to injection by the radiators themselves...

INTRODUCTION: The lipid layer of the tear film is critical to maintaining the integrity of the tear film and absence in the tear film lipid layer (TFLL) is one of the main causes of evaporative dry eye (EDE) in dry eye disease patients, resulting in excessive evaporation (so-called hyperevaporative dry eye). This study protocol will be designed to assess and compare the effects of intense pulsed light (IPL), heated eye mask (HEM), vectored thermal pulsation system (VTPS) and eyelid massage device (EMD) for improving signs and symptoms of EDE...