High-intensity Laser Light Research Articles

Functional light diffusers based on hybrid CsPbBr3/SiO2 aero-framework structures for laser light illumination and conversion

The new generation of laser-based solid-state lighting (SSL) white light sources requires new material systems capable of withstanding, diffusing, and converting high intensity laser light. State-of-the-art systems use a blue light emitting diode or laser diode in combination with color conversion materials, such as yellow emitting Ce-doped phosphors or red and green emitting quantum dots (QD), to produce white light. However, for laser-based high-brightness illumination thermal management and uniform light diffusion are still major challenges in the quest to convert a highly focused laser beam into an efficient lighting solution. Here, we present a material system consisting of a highly open porous (> 99%) framework structure of hollow SiO2 microtubes. This framework structure enables efficient and uniform light distribution as well as ensuring good thermal management even at high laser powers of up to 5 W, while drastically reducing the speckle contrast. By further functionalizing the microtubes with halide perovskite QDs (SiO2@CsPbBr3 as model system) color conversion from UV to visible light is achieved. By depositing an ultrathin (~ 5.5 nm) film of poly(ethylene glycol dimethyl acrylate) (pEGDMA) via initiated chemical vapor deposition (iCVD), the luminescent stability of the QDs against moisture is enhanced. The demonstrated hybrid material system paves the way for the design of advanced and functional laser light diffusers and converters that can meet the challenges associated with laser-based SSL applications.Graphical

High-Intensity Illuminated Annealing of Industrial SHJ Solar Cells: A Pilot Study

Here, we demonstrate the effectiveness of illuminated annealing using high-intensity light to improve the efficiency of industrial n-type silicon heterojunction (SHJ) solar cells. The application of high intensity laser light during annealing at 200 °C led to efficiency improvements as large as 0.7% <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">abs</sub> and final efficiencies as high as 24.5%. This was demonstrated on industrial SHJ solar cells from five different manufacturers, indicating the robust application of this technique. We show that the annealing process with high-intensity light leads to significant efficiency enhancements compared to previous observations using light soaking under 1-sun conditions, meaning the process can be completed in 30 s, rather than hours. The observed enhancements were related to increased V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OC</sub> and fill factor. If this approach can be tailored to time scales amenable with mass production, the associated efficiency enhancements could drive reductions in the levelized cost of electricity for SHJ solar cells, making them more competitive in the face of existing technologies.

Effectiveness of high-intensity laser light for treating large kidney stones

Introduction. This work analyzes efficacy, convenience, and safety of a high-energy laser light technique for destructing large kidney stones in patients with nephrolithiasis in comparison to other contact methods of nephrolithotripsy.Material and methods. The effectiveness of contact laser nephrolithotripsy is compared to that of hydropneumatic and ultrasonic lithotripsy. Holmium green laser light was used in this laser procedure. For other techniques, Swiss LithoClast Master devices were used. The authors have analyzed outcomes obtained after operating on 73 patients with large and complex kidney stones.Results. To evaluate the effectiveness, basic parameters were taken (degree of kidney cleaning of stones and their fragments, probability of migration of stone fragments, blood loss, duration of surgery, complications, etc.). In addition, the correlation between basic parameters was obtained and analyzed.Conclusion. The present trial has shown that laser contact lithotripsy is the most optimal technique for destructing large and complex kidney stones in comparison to traditional modalities such as contact hydropneumatic and ultrasonic lithotripsy. It takes more time but provides more effective cleaning from calculi.

Hirshfeld surface analysis, enrichment ratio, energy frameworks and third-order nonlinear optical studies of a hydrazone derivative for optical limiting applications

Organic materials with good third-order nonlinear optical (NLO) properties are used in optoelectronics for protecting human eyes and sensors from high intensity laser light. In this regard, herein we report the synthesis, structural analysis, and third-order NLO properties of an organic molecule N'-[(E)-(4-fluorophenyl)methylidene]biphenyl-4-carbohydrazide (FMBC) containing hydrazone moiety. The formation of the synthesized molecule is confirmed by identifying the functional groups through FTIR spectral analysis. The material possesses good thermal stability before the melting point of 242.5∘C and transparent in the entire visible region of the EM spectrum. The photoluminescence study revealed the blue light-emitting property of FMBC. The crystal structure is stabilized by N-H···O, C-H···O, and C-H···F hydrogen bond interactions. The interconnects in the crystal packing were envisioned quantitatively using Hirshfeld surfaces (HS) by 2D fingerprint plots. The main contribution to the HS comes mainly from C-H, H-H, and O-H interconnects which cover about 80 % of the total HS surface. The enrichment ratios show that the favorable contacts accountable for the crystal packing are C···H, N···H, O···H, and F···H. The breakdown of the interaction energies obtained for various molecular pairs shows the nature and strength of the interactions. The calculation of 3D energy frameworks suggests that contacts formed in the structure are largely due to the dispersion force followed by the electrostatic potential. Third-order NLO coefficients were extracted under the continuous wave (CW) regime using z -scan technique. The material is an excellent optical limiter with a threshold value of 3.42 kJ/cm2. [Display omitted]

Pulsed laser annealing of amorphous two-dimensional transition metal dichalcogenides

Large-area, flexible, two-dimensional transition metal dichalcogenide semiconductor materials (MoS2 and WSe2) were synthesized via magnetron sputtering of amorphous stoichiometric precursor materials on polydimethylsiloxane polymer substrates. Purely amorphous precursor materials and amorphous materials with pre-existing nanocrystalline regions observed via transmission electron microscopy were grown for the studies presented here. The MoS2 and WSe2 material precursors were then illuminated with a pulsed 532 nm laser to induce crystallization to their semiconducting hexagonal phases. The laser optics included an axicon lens to shape the Gaussian pulsed laser into a “Bessel beam” characterized by annular ring geometry. The pattern of the beam, with its rings of high-intensity laser light around a higher-intensity core, produced crystalline rings of the material around an ablation zone on the polymer substrate for MoS2 and WSe2 materials. The crystalline structure and density of atomic defects over the crystalline regions decreased as the same sample area was illuminated with additional pulses. The lateral coherence of the crystal lattice increased with the first 4 pulses but decreased with each subsequent pulse. The impact of preexisting nanocrystalline nanoinclusions in an amorphous film on the crystallization rate for WSe2 precursor materials was examined. The presence of nanocrystalline regions in the amorphous materials increased the crystallization rate under the photonic annealing conditions examined here. This approach of direct synthesis and patterning of materials is a route toward the fabrication of inexpensive flexible electronic devices.

Two-Photon-Induced Fluorescence Study of Rhodamine-6G Dye in Different Sets of Binary Solvents.

This study deals with the effects of different sets of binary solvents on the Two-Photon Induced Fluorescence (TPIF), a non-linear process, of the Rhodamine-6G (Rh6G) dye, which is a well-known xanthene dye. This work examines the importance of inter-molecular interactions, which results in the modulation of the TPIF of the Rh6G. In this work, we have investigated three binary solvent mixtures representing varying polarity and intermolecular interactions. Specific solvent mixtures used are methanol-water, methanol-dimethyl formamide, and methanol-chloroform. Since the solvent polarity across these binary solvents differs, there are significant intermolecular interactions in the binary mixture solvents, which modulate the two-photon process of Rh6G when irradiated with high-intensity laser light at 780nm. In our studies, we find that Rh6G in the MeOH-H2O binary solvent has maximum red-shift and minimum intensity as compared to other pairs of binary liquids when the volume fraction of methanol decreases due to more extensive hydrogen bonding between the two components. Additionally, at 1:1 ratio of binary mixtures, Rh6G is found to have the highest TPEACS value for methanol-chloroform binary solvent and reason for that is related to the formation of weak H-bond networks between proton donor chloroform and proton acceptor methanol.

Fluorescence Recovery after Photobleaching of Yellow Fluorescent Protein Tagged p62 in Aggresome-like Induced Structures.

Fluorescence recovery after photobleaching (FRAP)is a microscopy technique that can be used to quantify protein mobility in live cells. In a typical FRAP experiment, steady-state fluorescence is observed by repeated imaging with low-intensity laser light. Subsequently, the fluorescent molecules are rapidly and irreversibly impaired via brief exposure to high-intensity laser light. Information about protein mobility is obtained by monitoring the recovery of fluorescence. We used FRAP to determine the mobility of p62 in aggresome-like induced structures (ALIS) in murine macrophages after stimulation with lipopolysaccharide (LPS). Because many existing FRAP protocols are either incomplete or complex, our goal was to provide a comprehensive, practical, and straightforward step-by-step protocol for FRAP experiments with live cells. Here, we describe RAW264.7 macrophage transfection with yellow fluorescent protein-p62 (YFP-p62), induction of ALIS by exposing the cells to LPS, and a step-by-step method for collecting prebleach and postbleach FRAP images and data analysis. Finally, we discuss important factors to consider when conducting a FRAP experiment.

Synthesis of Amorphous InSb Nanowires and a Study of the Effects of Laser Radiation and Thermal Annealing on Nanowire Crystallinity.

Although various synthesis and characterization strategies have been employed for the synthesis of crystalline nanowires, there is very little work done on development of low-dimensional amorphous semiconductors. This paper presents a simple strategy to grow amorphous (a-) nanowires (NWs) in a chemical vapor deposition (CVD) system. The NWs were grown on substrate coated with indium film and the lack of crystallinity in the as-grown stoichiometric NWs was ascertained by Raman spectroscopy and electron transport measurements. A model proposed to explain the amorphous NW growth mechanism takes into account the fact that NW growth was carried out at the high temperature ramp-up rate of 75 C/min. This high rate is believed to affect the growth kinematics and determine the arrangement of atoms in the growing NW. Raman spectrum of the as-grown sample shows a broad peak around 155 cm, indicative of the presence of high density of homopolar - bonds in the amorphous matrix. It was also found that high intensity laser light induces localized crystallization of the NW, most likely due to radiation-stimulated diffusion of defects in a-. The nonlinear trend of the current-voltage characteristics for individually contacted a- NWs was analyzed to prove that the non-linearity is not induced by Schottky contacts. At high bias fields, space charge limited conduction was the proposed electron transport mechanism. Post-growth annealing of the as-grown a- NWs was found to be very effective in causing the NWs to undergo a phase transition from amorphous to crystalline.

MEMS Resonant Mass Sensor With Integrated Optical Manipulation

We investigate optical manipulation of particles in fluid as a viable method to achieve better experimental fidelity and extend the application of integrated-fluidic resonant-mass sensing. Fluctuations in sample position or trajectory can lead to measurement error, thereby degrading the resolution with which these devices can accurately characterize mass. Optical trapping offers precise location control in such fluidic environments and can define and fix position to mitigate variability, but requires a novel approach to design, fabrication, and biological viability concerns. Optical considerations are especially imperative when working with biological cells, organic matter, or other materials adversely affected by imposing high intensity laser light, and mandate the use of a photonic-crystal structure. Given these requirements, this letter details a design and fabrication approach embodied by unique devices that demonstrate compatibility with optical trapping and mass sensing. Accordingly, the effects of optical manipulation on the measurement are disclosed, toward long-term biological mass monitoring and sensing. Ultimately, precise measurement of singular cell mass could answer many fundamental biological questions, with implications in cell biology, pharmacology, and medicine.

Modification in oxidative processes in muscle tissues exposed to laser- and light-emitting diode radiation.

Exposure of living tissues to high-intensity red or near-infrared light can produce the oxidative stress effects both in the target zone and adjacent ones. The protein oxidative modification (POM) products can be used as reliable and early markers of oxidative stress. The contents of modified proteins in the investigated specimens can be evaluated by the 2,4-dinitrophenylhydrazine assay (the DNPH assay). Low-intensity red light is able to decrease the activity of oxidative processes and the DNPH assay data about the POM products in the biological tissues could show both an oxidative stress level and an efficiency of physical agent protection against the oxidative processes. Two control groups of white rats were irradiated by laser light, the first control group by red light and the second one by near-infrared radiation (NIR).Two experimental groups were consequently treated with laser and red low-level light-emitting diode radiation (LED). One of them was exposed to red laser light + LED and the other to NIR + LED. The fifth group was intact. Each group included ten animals. The effect of laser light was studied by methods of protein oxidative modifications. We measured levels of both induced and spontaneous POM products by the DNPH assay. The dramatic increase in levels of POM products in the control group samples when compared with the intact group data as well as the sharp decrease in the POM products in the experimental groups treated with LED low-level light were statistically significant (p≤0.05). Exposure of skeletal muscles to high-intensity red and near-infrared laser light causes oxidative stress that continues not less than 3days. The method of measurement of POM product contents by the DNPH assay is a reliable test of an oxidative process rate. Red low-intensity LED radiation can provide rehabilitation of skeletal muscle tissues treated with high-intensity laser light.

Nanoparticle tracking velocimetry by observing light scattering from individual particles

Nanoparticle tracking velocimetry (NPTV), a novel particle tracking velocimetry method using nano-sized tracer particles, was investigated as a hybrid tool for the determination of the flow velocity in a microscale area. In contrast to the common optical microscopic velocimetry techniques with submicron/micron sized tracer particles, the NPTV method is based on the observation of the motion of bright spots attributed to the light scattering from individual nano-sized tracer particles. We observed light scattering from individual nano-sized tracers induced by high-intensity laser light, which are difficult to observe by direct observation of tracers using optical microscope in common flow velocimetry systems. Although the PTV/PIV method using fluorescent nano-tracer such as quantum dots make it possible to use nano-tracer in the flow velocity assessment, our light scattering observable optical system can be applied to nano-tracers of any kinds of materials. Because the determination of the flow velocity in the NPTV method is affected by the random Brownian motion of the nano-sized tracers, we demonstrated that reliable flow velocity values could be successfully obtained by ensemble averaging the displacement of each particle with an accurate correction of the effect of the Brownian motion of the nano-sized tracers. The NPTV method developed in this study can be utilized for various liquid samples owing to non-limited variety of nano-sized tracer materials. In addition, because the velocimetry by nano-sized tracers enables the determination of the flow velocity in a narrower area than that studied with submicron/micron tracers, this novel method could play an important role in the flow velocity measurement in the design of nanoscale/microscale reaction/mixing channel processes.

Evaluation of a temperature measurement method developed for laser metal deposition

Measuring temperatures in the material during laser metal deposition (LMD) has an inherent challenge caused by the laser. When thermocouples are radiated by the high intensity laser light overheating occurs which causes the thermocouple to fail. Another identified difficulty is that when the laser passes a thermocouple, emitted light heats the thermocouple to a higher temperature than the material actually experience. In order to cope with these challenges, a method of measuring temperatures during LMD of materials using protective sheets has been developed and evaluated as presented in this paper. The method has substantially decreased the risk of destroying the thermocouple wires during laser deposition. Measurements using 10 mm2 and 100 mm2 protective sheets have been compared. These measurements show small variations in the cooling time (∼0.1 s from 850°C to 500°C) between the small and large protective sheets which indicate a negligible effect on the temperature measurement.

Interatomic Coulombic decay cascades in multiply excited neon clusters.

In high-intensity laser light, matter can be ionized by direct multiphoton absorption even at photon energies below the ionization threshold. However on tuning the laser to the lowest resonant transition, the system becomes multiply excited, and more efficient, indirect ionization pathways become operative. These mechanisms are known as interatomic Coulombic decay (ICD), where one of the species de-excites to its ground state, transferring its energy to ionize another excited species. Here we show that on tuning to a higher resonant transition, a previously unknown type of interatomic Coulombic decay, intra-Rydberg ICD occurs. In it, de-excitation of an atom to a close-lying Rydberg state leads to electron emission from another neighbouring Rydberg atom. Moreover, systems multiply excited to higher Rydberg states will decay by a cascade of such processes, producing even more ions. The intra-Rydberg ICD and cascades are expected to be ubiquitous in weakly-bound systems exposed to high-intensity resonant radiation.

Nonlinear threshold effect in the Z-scan method of characterizing limiters for high-intensity laser light

A threshold model is described which permits one to determine the properties of limiters for high-powered laser light. It takes into account the threshold characteristics of the nonlinear optical interaction between the laser beam and the limiter working material. The traditional non-threshold model is a particular case of the threshold model when the limiting threshold is zero. The nonlinear characteristics of carbon nanotubes in liquid and solid media are obtained from experimental Z-scan data. Specifically, the nonlinear threshold effect was observed for aqueous dispersions of nanotubes, but not for nanotubes in solid polymethylmethacrylate. The threshold model fits the experimental Z-scan data better than the non-threshold model. Output characteristics were obtained that integrally describe the nonlinear properties of the optical limiters.

Velocity field characteristics of the turbulent jet induced by direct contact condensation of steam jet in crossflow of water in a vertical pipe

Direct contact condensation of jets in fluid has been widely applied in many industrial applications owing to the low requirement of driving potential and high efficiency of heat and mass transfer. Here, experiments are carried out to investigate the velocity field characteristics of the turbulent jet induced by direct contact condensation of steam jet in crossflow of water in a vertical pipe. Visual equipment is specially invented to investigate the velocity field characteristics by using Particle Image Velocimetry (PIV) measurement technique. The high intensity laser light reflected by the pure steam region just outside the nozzle-exit brings out severe damage to the CCD camera. To solve this technical problem, a black plate is adopted to shield the pure steam region. According to the contours of the velocity fields and streamlines, the influences of jet momentum ratio, jet Reynolds number and water temperature on the jet flow field are explored. The jet centerline trajectory equations in exponential form are established based on the local maximum mean velocity. By introducing the jet Reynolds number and jet momentum ratio, the correlation for prediction of jet centerline trajectory equations is proposed, and the predicted results are within 30% of the experimental data. The reciprocal of the local maximum mean velocity and the half-width of the jet are proportional to the downstream coordinate along the jet velocity centerline trajectory. The scaled velocity field complies with the self-similarity principle.

Simulation of the characteristics of InGaAs/InP-based photovoltaic laser-power converters

A method for mathematical simulation is used to analyze the efficiencies attainable in photovoltaic laser-power conversion at wavelengths of 1.3 and 1.55 μm in In0.53Ga0.47As/InP heterostructures with light input on the side of the n-InP substrate. The influence exerted on the efficiency by the parameters of the In0.53Ga0.47As/InP heterostructure and by the design of the photovoltaic laser-power converter is examined. The simulated characteristics of In0.53Ga0.47As/InP photovoltaic converters are compared with those of GaAs-based photovoltaic converters for a wavelength of 809 nm. It is shown that efficiencies of 40% at a wavelength of 1.3 μm and nearly 50% at 1.55 μm can be attained at a laser power of about 2–6 W, but the efficiency noticeably decreases at higher laser-light intensities. It is found that the main factor that hinders the achievement of a high efficiency in the conversion of high-intensity laser light is loss in the n-InP substrate. The optimal doping level of n-InP substrates to be used in the photovoltaic converters intended for varied laser-light intensities is estimated.

Homogenous smooth sol gel films doped with organic compounds for nonlinear optics

The demand for protection of various types of optical sensors from laser-beam pulses has resulted in the search for optical limiting devices that have the property of being transparent at low intensity of light (normal light), but no transparent towards high intensity (laser) light. Organic material with nonlinear optical (NLO) properties as reverse saturable absorption and two-photon absorption can be used for optical limiting with the advantage of a very fast response and self-activation. A promising approach in the fabrication of thin films by low cost/easy use deposition methods for second-order nonlinear optics is sol–gel technique. The present paper reports on the sol–gel synthesis of some pyrazolone derivative doped SiO2–P2O5 smooth and homogenous films (Root mean square roughness (Rq)=1.1nm) using as precursors tetraethylorthosilicate (TEOS) and phosphoric acid (H3PO4). The structure of the deposited azo-derivatives doped thin films was examined by Fourier transform infrared spectroscopy and atomic force microscopy, while their optical properties of the films by UV–VIS spectroscopy. The nonlinear optical efficiencies due to the interaction of the NLO-active chromophores with the inorganic matrix have a significant influence on the second harmonic generation capabilities that was measured using a femtosecond Ti:Sapphire laser. The properties of the films were investigated and correlated with the concentration of the organic dopant and the thermal treatment temperature.

Asymmetrically Β-Substituted Porphyrins: Synthesis, Photophysical, and Electrochemical Redox Properties

Asymmetrically meso-substituted porphyrins constitute a promising group of nonlinear optical (NLO) materials due to high nonlinearities upon irradiation with high intensity laser light.1a The major advantage of porphyrins is their chemical versatility which provides a tool for tailoring the linear and NLO properties for specific applications.1b Particularly, push-pull porphyrins have potential applications in nonlinear optics, photodynamic therapy (PDT),1c and dye-sensitized solar cell (DSSC).1d Meso-substituted push-pull porphyrins have been widely explored due to their ease of synthesis and facile functionalisation whereas limited reports on β-substituted push-pull porphyrins, probably due to limited synthetic methodologies. But it is found that the effect is more pronounced for β-substitution as compared to meso-phenyl substitution. Herein, we report the synthesis, structural, phtotophysical and electrochemical redox properties of two new families of asymmetrically β-substituted porphyrins.2 The crystal structure analyses and DFT fully optimized geometries of MTPP(NO2)X6 and MOPP(X)Y2 revealed highly nonplanar saddle shape conformation. Notably, nonplanarity of porphyrin core was controlled and modified by varying in size, shape, number and electronic nature of β-substituents.2 These porphyrins exhibited a dramatic red-shift in their B and Qx(0,0) bands as compared to MTPP(NO2) and MOPP. We have also utilized some of these electron deficient nonplanar free base porphyrins for the detection of various anions.3 Figure 1. Molecular structures of β-substituted porphyrins and their metal complexes. To determine the influence of macrocyclic nonplanarity and the combined effects of electron-donor and -acceptor groups at the β-pyrrole positions, we examined the electrochemical redox properties of these porphyrins by cyclic voltammetric studies. Data analysis of free base and metalloporphyrins revealed the following important facts: (1) the redox tunability was achieved by introducing electron donors (Ph, Th, and CH2OH) and acceptor groups (NO2, CHO, PE, Br and CN) on MTPP or MOPP back bone as evidenced from a fairly broader range of first ring redox potentials and σ values of these porphyrins. (2) Notably, we could detect the unusual metal-centered oxidation of NiII to NiIIIdication radical in NiOPP(R)X2 (X = H, CHO and CH2OH) due to highly nonplanar conformation as well as electron rich porphyrin Figure 2. NiII/NiIIIoxidation of β-substituted octaphenylporphyrins. π-system4 is strongly influenced by nature of β-substituent (Figure 2) which is demonstrated for the first time.2b The reversible metal-centered redox behavior of CuII/CuIII in CuOPP(NO2)(CN)2 is due to modulated HOMOs (dx2-y2 situated above a1u and a2u).2b The significant shift in redox potentials of these porphyrins are interpreted in terms of both an inductive and resonance interactions of susbtituents on porphyrin π-system as well as nonplanarity of the macrocycle. By means of β-pyrrole mixed substitution on the porphyrin macrocycle, we were able to achieve remarkable bathochromic shift in electronic spectral bands, higher ground state dipole moment, varying degrees of nonplanarity, and tunable electrochemical redox properties with dramatic reduction in HOMO-LUMO gap (Figure 3). Figure 3. HOMO-LUMO variation of CuTPP(NO2)X6, where X = PE, Br, Ph, and Th, in comparison to CuTPP(NO2) and CuTPP.

Radiation from free electrons in a laser focus at 10^18 W/cm^2: modeling of photon yields and required focal conditions

In support of an experiment designed to measure the strength of radiation scattered from low-density free electrons in an intense laser focus, we model a variety of physical parameters that impact the rate of scattered photons. We employ a classical model to characterize duration of electron exposure to high-intensity laser light in a situation where the electrons are driven by strong ponderomotive gradients. Free electrons are modeled as being donated by low-density helium, which undergoes strong-field ionization early in the pulse or during a prepulse. When exposed to relativistic intensities, free electrons experience a Lorentz drift that causes redshifting of the scattered 800 nm light. This redshift can be used as a signature to discern light scattered from the more intense regions of the focus. We characterize the focal volume of initial positions leading to significant redshifting, given a peak intensity of 2×1018 W/cm2. Under this scenario, the beam waist needs to be larger than several wavelengths for a pulse duration of 35 fs. We compute the rate of redshifted scattered photons from an ensemble of electrons distributed throughout the focus and relate the result to the scattered-photon rate of a single electron. We also estimate to what extent the ionization process may produce unwanted light in the redshifted spectral region.

Improved laser ablation model for asteroid deflection

This paper presents an improved laser ablation model and compares the performance – momentum coupling and deflection system mass – of laser ablation against contactless deflection methods based on ion-propulsion. The deflection of an asteroid through laser ablation is achieved by illuminating the surface of the asteroid with high intensity laser light. The absorbed energy induces the sublimation of the surface material and the generation of a plume of gas and ejecta. Similar to a rocket engine, the flow of expelled material produces a continuous and controllable thrust that could be used to modify the trajectory and tumbling motion of the asteroid. Recent results gained from a series of laser ablation experiments were used to improve the sublimation and deflection models. In each experiment a terrestrial olivine sample was ablated, under vacuum, with a 90W continuous wave laser. The paper presents a model that better fits the outcomes of the experimental campaign, in particular in terms of mass flow rate and spot temperature.