Near-infrared supercontinuum laser beam source in the second and third near-infrared optical windows used to image more deeply through thick tissue as compared with images from a lamp source

Abstract Laser technology has many advantages in welding for the manufacture of EV battery packs. Aluminum (Al) and copper (Cu) are welded using a dual laser beam, suggesting the optimum power distribution for the core and ring beams. Due to the very high reflectance of Cu and Al exposed to near-infrared lasers, the material absorbs a very small amount of energy. Compared to single beam laser welding, dual beam welding has significantly improved surface quality by controlling surface solidification. The study focused on the quality of weld surface beads, weld properties and tensile strength by varying the output ratio of the core beam to the ring beam. Optimal conditions of Al6061 were a 700 W core beam, a 500 W ring beam and 200 mm/s of weld speed. For the C1020P, the optimum conditions were a center beam of 2500 W, a ring beam of 3000 W and a welding speed of 200 mm/s. In laser lap welding of Al-Al and Al-Cu, the bead width and the interfacial bead width of the joint increased as the output increased. The penetration depth did not change significantly, but small pores were formed at the interface of the junction. Tensile tests were performed to demonstrate the reliability of the weld zone, and computer simulations provided analysis of the heat distribution for optimal heat input conditions.

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Melanoma Cancer Therapy Using PEGylated Nanoparticles and Semiconductor Laser

Advanced Pharmaceutical Bulletin ◽

10.34172/apb.2022.055 ◽

2021 ◽

Author(s):

Abdorreza Asrar ◽

Zahra Sobhani ◽

Mohammad Ali Behnam

Keyword(s):

Cancer Therapy ◽

Laser Beam ◽

Photothermal Therapy ◽

Near Infrared ◽

Histopathological Study ◽

Melanoma Tumor ◽

Tio2 Nps ◽

Melanoma Cancer ◽

Murine Melanoma ◽

Pegylated Nanoparticles

Purpose: Photothermal therapy is a procedure that converts laser beam energy to heat so can disturb tumor cells. Carbon nanotubes (CNTs) have unique properties in absorption optical energy and could change optical power into heat in photothermal therapy procedures. Additionally, titanium dioxide (TiO2) NPs have a unique feature in absorbing and scattering light. Therefore, these mentioned NPs could play a synergistic role in the photothermal therapy method. Methods: CNTs and TiO2 NPs were injected into the melanoma tumor sites of cancerous mice. Then sites were excited using the laser beam (λ= 808nm, P= 2W, and I= 4W/cm2). Injected NPs caused hyperthermia in solid tumors. Tumor size assay, statistical analysis, and histopathological study of the treated cases were performed to assess the role of mentioned NPs in photothermal therapy of murine melanoma cancer. Results: The results showed that CNTs performed better than TiO2 NPs in destroying murine melanoma cancer cells in animals. Conclusion: The present study compared the photothermal activity of excited CNTs and TiO2 NPs in cancer therapy at the near-infrared spectrum of light. Tumors were destroyed selectively because of their weakened heat resistance versus normal tissue. Photothermal therapy of malignant melanoma through CNTs caused remarkable necrosis into the tumor tissues versus TiO2 NPs.

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Single-Step Photochemical Formation of Near-Infrared-Absorbing Gold Nanomosaic within PNIPAm Microgels: Candidates for Photothermal Drug Delivery

Nanomaterials ◽

10.3390/nano10071251 ◽

2020 ◽

Vol 10 (7) ◽

pp. 1251

Author(s):

Sreekar B. Marpu ◽

Brian Leon Kamras ◽

Nooshin MirzaNasiri ◽

Oussama Elbjeirami ◽

Denise Perry Simmons ◽

...

Keyword(s):

Near Infrared ◽

Dimethyl Sulfide ◽

Test Sample ◽

Single Step ◽

Step Method ◽

Photochemical Reduction ◽

Order Of Magnitude ◽

Post Synthesis ◽

Lamp Source ◽

Hybrid Microgels

This work demonstrates the dynamic potential for tailoring the surface plasmon resonance (SPR), size, and shapes of gold nanoparticles (AuNPs) starting from an Au(I) precursor, chloro(dimethyl sulfide)gold (I) (Au(Me2S)Cl), in lieu of the conventional Au(III) precursor hydrogen tetrachloroaurate (III) hydrate (HAuCl4). Our approach presents a one-step method that permits regulation of an Au(I) precursor to form either visible-absorbing gold nanospheres or near-infrared-window (NIRW)-absorbing anisotropic AuNPs. A collection of shapes is obtained for the NIR-absorbing AuNPs herein, giving rise to spontaneously formed nanomosaic (NIR-absorbing anisotropic gold nanomosaic, NIRAuNM) without a dominant geometry for the tesserae elements that comprise the mosaic. Nonetheless, NIRAuNM exhibited high stability; one test sample remains stable with the same SPR absorption profile 7 years post-synthesis thus far. These NIRAuNM are generated within thermoresponsive poly(N-isopropylacrylamide) (PNIPAm) microgels, without the addition of any growth-assisting surfactants or reducing agents. Our directed-selection methodology is based on the photochemical reduction of a light-, heat-, and water-sensitive Au(I) precursor via a disproportionation mechanism. The NIRAuNM stabilized within the thermoresponsive microgels demonstrates a light-activated size decrease of the microgels. On irradiation with a NIR lamp source, the percent decrease in the size of the microgels loaded with NIRAuNM is at least five times greater compared to the control microgels. The concept of photothermal shrinkage of hybrid microgels is further demonstrated by the release of a model luminescent dye, as a drug release model. The absorbance and emission of the model dye released from the hybrid microgels are over an order of magnitude higher compared to the absorbance and emission of the dye released from the unloaded-control microgels.

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Laser-Controlled Association of Poly(N-vinylcarbazole) in Organic Solvents: Radiation Pressure Effect of a Focused Near-Infrared Laser Beam

The Journal of Physical Chemistry B ◽

10.1021/jp9711149 ◽

1997 ◽

Vol 101 (31) ◽

pp. 5900-5904 ◽

Cited By ~ 30

Author(s):

Pawel Borowicz ◽

Jun-ichi Hotta ◽

Keiji Sasaki ◽

Hiroshi Masuhara

Keyword(s):

Laser Beam ◽

Organic Solvents ◽

Radiation Pressure ◽

Near Infrared ◽

Pressure Effect ◽

Infrared Laser ◽

Infrared Laser Beam

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Raman Signal Enhancement in Deep Spectroscopy of Turbid Media

Applied Spectroscopy ◽

10.1366/000370207781540178 ◽

2007 ◽

Vol 61 (8) ◽

pp. 845-854 ◽

Cited By ~ 49

Author(s):

P. Matousek

Keyword(s):

Raman Spectroscopy ◽

Laser Radiation ◽

Laser Beam ◽

Near Infrared ◽

Optical Element ◽

Disease Diagnosis ◽

Pharmaceutical Products ◽

Turbid Media ◽

Raman Signal

A new, passive method for enhancing spontaneous Raman signals for the spectroscopic investigation of turbid media is presented. The main areas to benefit are transmission Raman and spatially offset Raman spectroscopy approaches for deep probing of turbid media. The enhancement, which is typically several fold, is achieved using a multilayer dielectric optical element, such as a bandpass filter, placed within the laser beam over the sample. This element prevents loss of the photons that re-emerge from the medium at the critical point where the laser beam enters the sample, the point where major photon loss occurs. This leads to a substantial increase of the coupling of laser radiation into the sample and consequently an enhanced laser photon–medium interaction process. The method utilizes the angular dependence of dielectric optical elements on impacting photon direction with its transmission spectral profile shifting to the blue with increase in the deviation of photons away from normal incidence. This feature enables it to act as a unidirectional mirror passing a semi-collimated laser beam through unhindered from one side, and at the other side, reflecting photons emerging from the sample at random directions back into it with no restrictions to the detected Raman signal. With substantial restrictions to the spectral range, the concept can also be applied to conventional backscattering Raman spectroscopy. The use of additional reflective elements around the sample to enhance the Raman signal further is also discussed. The increased signal strength yields higher signal quality, a feature important in many applications. Potential uses include sensitive noninvasive disease diagnosis in vivo, security screening, and quality control of pharmaceutical products. The concept is also applicable in an analogous manner to other types of analytical methods such as fluorescence or near-infrared (NIR) absorption spectroscopy of turbid media or it can be used to enhance the effectiveness of the coupling of laser radiation into tissue in applications such as photodynamic therapy for cancer treatment.

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