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Photothermal effect is a phenomenon associated with electromagnetic radiation. It is produced by the photoexcitation of material, resulting in the production of thermal energy (heat).
It is sometimes used during treatment of blood vessel lesions, laser resurfacing, laser hair removal and laser surgery.
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Absorption spectroscopy is spectroscopy that involves techniques that measure the absorption of electromagnetic radiation, as a function of frequency or wavelength, due to its interaction with a sample. The sample absorbs energy, i.e., photons, from the radiating field. The intensity of the absorption varies as a function of frequency, and this variation is the absorption spectrum. Absorption spectroscopy is performed across the electromagnetic spectrum.
The term biophotonics denotes a combination of biology and photonics, with photonics being the science and technology of generation, manipulation, and detection of photons, quantum units of light. Photonics is related to electronics and photons. Photons play a central role in information technologies, such as fiber optics, the way electrons do in electronics.
Light therapy, also called phototherapy or bright light therapy is the exposure to direct sunlight or artificial light at controlled wavelengths in order to treat a variety of medical disorders, including seasonal affective disorder (SAD), circadian rhythm sleep-wake disorders, cancers, and skin wound infections. Treating skin conditions such as neurodermatitis, psoriasis, acne vulgaris, and eczema with ultraviolet light is called ultraviolet light therapy.
In chemistry, chromism is a process that induces a change, often reversible, in the colors of compounds. In most cases, chromism is based on a change in the electron states of molecules, especially the π- or d-electron state, so this phenomenon is induced by various external stimuli which can alter the electron density of substances. It is known that there are many natural compounds that have chromism, and many artificial compounds with specific chromism have been synthesized to date. It is usually synonymous with chromotropism, the (reversible) change in color of a substance due to the physical and chemical properties of its ambient surrounding medium, such as temperature and pressure, light, solvent, and presence of ions and electrons.
Laser-ultrasonics uses lasers to generate and detect ultrasonic waves. It is a non-contact technique used to measure materials thickness, detect flaws and carry out materials characterization. The basic components of a laser-ultrasonic system are a generation laser, a detection laser and a detector.
Laser surgery is a type of surgery that uses a laser to cut tissue.
Photothermal therapy (PTT) refers to efforts to use electromagnetic radiation for the treatment of various medical conditions, including cancer. This approach is an extension of photodynamic therapy, in which a photosensitizer is excited with specific band light. This activation brings the sensitizer to an excited state where it then releases vibrational energy (heat), which is what kills the targeted cells.
Photothermal microspectroscopy (PTMS), alternatively known as photothermal temperature fluctuation (PTTF), is derived from two parent instrumental techniques: infrared spectroscopy and atomic force microscopy (AFM). In one particular type of AFM, known as scanning thermal microscopy (SThM), the imaging probe is a sub-miniature temperature sensor, which may be a thermocouple or a resistance thermometer. This same type of detector is employed in a PTMS instrument, enabling it to provide AFM/SThM images: However, the chief additional use of PTMS is to yield infrared spectra from sample regions below a micrometer, as outlined below.
Photothermal spectroscopy is a group of high sensitivity spectroscopy techniques used to measure optical absorption and thermal characteristics of a sample. The basis of photothermal spectroscopy is the change in thermal state of the sample resulting from the absorption of radiation. Light absorbed and not lost by emission results in heating. The heat raises temperature thereby influencing the thermodynamic properties of the sample or of a suitable material adjacent to it. Measurement of the temperature, pressure, or density changes that occur due to optical absorption are ultimately the basis for the photothermal spectroscopic measurements.
Photothermal optical microscopy / "photothermal single particle microscopy" is a technique that is based on detection of non-fluorescent labels. It relies on absorption properties of labels, and can be realized on a conventional microscope using a resonant modulated heating beam, non-resonant probe beam and lock-in detection of photothermal signals from a single nanoparticle. It is the extension of the macroscopic photothermal spectroscopy to the nanoscopic domain. The high sensitivity and selectivity of photothermal microscopy allows even the detection of single molecules by their absorption. Similar to Fluorescence Correlation Spectroscopy (FCS), the photothermal signal may be recorded with respect to time to study the diffusion and advection characteristics of absorbing nanoparticles in a solution. This technique is called photothermal correlation spectroscopy (PhoCS).
The Fuchs spot is a degeneration of the macula in cases of high myopia. It is named after the two persons who first described it: Ernst Fuchs, who described a pigmented lesion in 1901, and Forster, who described subretinal neovascularization in 1862. It occurs due to proliferation of retinal pigment epithelium associated with choroidal hemorrhage. The size of the spots are proportionate to the severity of the pathological myopia.
The photoacoustic effect or optoacoustic effect is the formation of sound waves following light absorption in a material sample. In order to obtain this effect the light intensity must vary, either periodically or as a single flash. The photoacoustic effect is quantified by measuring the formed sound with appropriate detectors, such as microphones or piezoelectric sensors. The time variation of the electric output from these detectors is the photoacoustic signal. These measurements are useful to determine certain properties of the studied sample. For example, in photoacoustic spectroscopy, the photoacoustic signal is used to obtain the actual absorption of light in either opaque or transparent objects. It is useful for substances in extremely low concentrations, because very strong pulses of light from a laser can be used to increase sensitivity and very narrow wavelengths can be used for specificity. Furthermore, photoacoustic measurements serve as a valuable research tool in the study of the heat evolved in photochemical reactions, particularly in the study of photosynthesis.
Andreas Mandelis is a professor and researcher at the department of Mechanical and Industrial Engineering at the University of Toronto and director of the Center for Advanced Diffusion-Wave and Photoacoustic Technologies (CADIPT). He is an internationally recognized expert in thermophotonics. His research encompasses the non-destructive evaluation of materials with industrial and biomedical applications. He is considered a pioneer in the fields of diffusion-wave, photothermal and photoacoustic sciences and related technologies. He is the inventor of a photothermal imaging radar which can detect tooth decay at an early stage.
AFM-IR or infrared nanospectroscopy is one of a family of techniques that are derived from a combination of two parent instrumental techniques. AFM-IR combines the chemical analysis power of infrared spectroscopy and the high-spatial resolution of scanning probe microscopy (SPM). The term was first used to denote a method that combined a tuneable free electron laser with an atomic force microscope equipped with a sharp probe that measured the local absorption of infrared light by a sample with nanoscale spatial resolution.
Gold nanoparticles in chemotherapy and radiotherapy is the use of colloidal gold in therapeutic treatments, often for cancer or arthritis. Gold nanoparticle technology shows promise in the advancement of cancer treatments. Some of the properties that gold nanoparticles possess, such as small size, non-toxicity and non-immunogenicity make these molecules useful candidates for targeted drug delivery systems. With tumor-targeting delivery vectors becoming smaller, the ability to by-pass the natural barriers and obstacles of the body becomes more probable. To increase specificity and likelihood of drug delivery, tumor specific ligands may be grafted onto the particles along with the chemotherapeutic drug molecules, to allow these molecules to circulate throughout the tumor without being redistributed into the body.
Dilip Devidas Bhawalkar is an Indian optical physicist and the founder director of the Raja Ramanna Centre for Advanced Technology (CAT), an institute under the Department of Atomic Energy, serving as a centre for higher studies in the fields of lasers and particle accelerators. He is credited with pioneering research in optics and lasers in India and is reported to have contributed in making CAT a partner in the International Linear Collider and Large Hadron Collider experiments of the European Organization for Nuclear Research (CERN). He is a recipient of the Shanti Swarup Bhatnagar Prize, the highest Indian award in science and technology. The Government of India awarded him the fourth highest civilian award of the Padma Shri in 2000.
Hadiyah-Nicole Green (1981) is an American medical physicist, known for the development of a method using laser-activated nanoparticles as a potential cancer treatment. She is one of 66 black women to earn a Ph.D. in physics in the United States between 1973 and 2012, and is the second black woman and the fourth black person ever to earn a doctoral degree in physics from The University of Alabama at Birmingham.
Samy El-Shall is an Egyptian-American physical chemist and a researcher in nanoscience, heterogeneous catalysis, molecular clusters and cluster ions, nucleation and ion mobility. He is the Mary Eugenia Kapp Endowed Chair in Chemistry and Commonwealth Professor at Virginia Commonwealth University (VCU).
Photodynamic/photothermal combination therapy involves the usage of a chemical compound or nanomaterial that, when irradiated at a certain wavelength, converts light energy into reactive oxygen species (ROS) and heat. This has shown to be highly effective in the treatment of skin infections, showing increased wound healing rates and a lower impact on human cell viability than photodynamic (PD) or photothermal (PT) therapies. The compounds involved often employ additional mechanisms of action or side effect reduction mechanisms, further increasing their efficacy.