Sign in to Purchase Instantly. Temporarily Out of Stock Online Please check back later for updated availability. Overview The present book covers the application technology of lasers, focusing more on the vast range of processes than on individual applications, in order to motivate and enable future innovations. About the Author Prof.
Table of Contents Preface. Average Review. Write a Review. A traditional polarizer, like a lens from polarized sunglasses, filters out light oscillating along all but one direction.
The filtered light is referred to as polarized light. Wang's group achieved a design that can tailor light intensity, phase and polarization. These advancements can be used to improve a variety of optical systems. In super-resolution microscopy, for instance, manipulating polarization can be used to achieve far-field focusing beyond normal diffraction limitations. The physicists increased polarizer efficiency and flexibility by using a new liquid-crystal-based design that relies on birefringence, where specific polarizations are filtered based on their refractive indexes.
Wang explained that they customized the orientation of liquid crystal molecules by using stringent photo-alignment techniques. They determined the dichroic dye film structure within the thin glass compartment before adding the liquid crystal. The new vector polarizers also feature manufacturing advantages.
For example, we need to improve its alignment quality, i. We also need to improve the spatial resolution for controlling the orientation of liquid crystal molecules. Their light is visible. Dye lasers are often used in vascular indications: treatment of angiomas in children and infants, treatment of spider naevi, treatment of rosacea  . Less frequently, this type of laser is used in other diseases such as psoriasis where it is effective against new lesions  . The medium is a crystal ruby, sapphire titanium In a non-exhaustive list, there are also laser diodes, such as those found in the CD.
The alexandrite laser is based on the production of light using a crystal of alexandrite.
The light is calibrated to a specific wavelength of nanometers deep red. This wavelength is strongly absorbed by the melanin in the skin and in particular that of the hair. It is this property that is used to heat the hair and help to destroy it  . Laser hair removal of the eyebrows can lead to ocular damage and should be avoided .
These particular lasers are indicated for the treatment of age spots and tattoos ablations. The Nd:YAG laser is relatively versatile, with the ability to penetrate deep into the skin. It enables aesthetic treatment of superficial veins of the skin, acne, rosacea, warts, birthmarks. These lasers also have photorejuvenation properties  . The light generated has a wavelength of nm. This enables efficient ablation of hard dental tissues without the risk of microand macro-fractures  .
The Er:YAG laser is used for ablation of the epithelium on the non-pigmented skin of the eyelid in preparation for melanocyte transplantation in the treatment of segmental eyelid vitiligo . It is a Nd:YAG laser where a crystal possessing the property of dividing the wavelength by 2 is added.
The KTP laser then emits light at a nanometers wavelength yellow green. The mechanism of KTP laser ablation remains unclear, but successful laser treatment of both vascular and non-vascular lesions has been described . It is primarily used for vascular treatment and also has indications in the treatment of superficial pigmented lesions, pregnancy mask melasma , dermatitis ocher, some pigmentation related to drugs, certain types of scarring or ulcers .
There are several types of diodes with different wavelengths between and nm infrared. Diode lasers are most often used in hair removal and aesthetic vascular treatments applications  . The laser diode is an effective treatment for patients with glaucoma . The Effects of Lasers on Biological Tissues. After the text edit has been completed, the paper is ready for the template. Duplicate the template file by using the Save As command, and use the naming convention prescribed by your journal for the name of your paper.
The present book covers the application technology of lasers, focusing more on the vast range of processes than on individual applications, in order to motivate. inandegeschest.tk: Tailored Light 2: Laser Application Technology (RWTHedition) ( ): Reinhart Poprawe: Books.
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The laser on biological tissue results from the conversion of light to heat, heat transfer and a tissue reaction to the temperature and the duration of the heating . This interaction leads to distortion or the destruction of a tissue volume. Depending on the degree to which time is heated, and the heating time, the thermal effect of the laser produces coagulation necrosis as in the treatment of angiomas with Nd:YAG laser, or volatilization as in the treatment of skin lesions with CO 2 laser.
They are obtained with lasers emitting extremely short pulses, in the nanosecond to picosecond range on very small surfaces, which causes a destructive shock wave mainly induced by the mechanism of explosive vaporization of the target as used to treat haemangiomas . In this case, the vessels of the angioma explode, which explains the vessel wall rupture, and hemorrhage.
This is also what happens during a tattoo removal when large fragments of pigment explode and give birth to smaller fragments. An effect that requires high-energy photons wavelength less than nm , with extremely short pulses 10 ns to ns. It induces a clean ablation of tissue without thermal lesions.
It is used to treat corneal pathologies such as ulcers and scars, and its use in keratorefractive surgery has become a rapidly evolving field . The operation is performed under local anesthesia using topical drops. The first step of the procedure involves cutting a corneal flap surface 90 to micrometers. Until the early s, the most common way of cutting the corneal flap was the use of a microkeratome, a miniaturized and highly sophisticated mechanical device.
This first very delicate cutting phase is now done by a laser, the femtosecond laser. The cutting of the corneal flap is achieved in about ten seconds, and then the refractive sculpture is carried out using an excimer laser. Excimer lasers are powered by a chemical reaction involving an excited dimer, or excimer, which is a short-lived dimeric or heterodimeric molecule formed from two atoms, at least one of which is in an excited electronic state.
Commonly used excimer molecules include fluorine emitting at nm and noble gas compounds Argon nm, Krypton nm, etc. The femtosecond laser is the new scalpel for biologists.
Since , they have gradually become familiar with this tool, which opens up great prospects in life sciences . They are obtained with lasers emitting extremely short pulses, in the nanosecond to picosecond range on very small surfaces, which causes a destructive shock wave mainly induced by the mechanism of explosive vaporization of the target as used to treat haemangiomas .
The lasers used in biology have a wavelength located either in the infrared range or in the ultra-violet range; they operate in continuous or pulse mode. The high power density and the precise location of the laser beam suits its application to the cutting of biological tissue. The high concentration of photons will destroy existing chemical bridges in the tissues. Laser-assisted microdissection LAM is a well-established technology in molecular pathology, cell biology and oncology studies, where very small tissue samples must be isolated from the surrounding material in order to perform an analysis without risk of contamination.
LAM overcomes the problem of the cellular heterogeneity that characterizes tissues. It aims to recover a target cluster of cells, or a single cell precisely selected under microscope guidance, from a complex tissue section frozen or fixed by prior paraffin-embedding for subsequent molecular analysis   Figure 1. With the advent of PCR Polymerase Chain Reactions techniques, a technique for million-fold amplification of a single DNA molecule, microdissection enables a molecular approach of biological tissues, but with the certainty of having a highly purified cellular material for the molecular studies.
Over the past 15 years, this technique for isolating specific cells from a sample responds to the need for miniaturization of analytical techniques applicable to very small cell numbers. LAM devices have gradually become more user-friendly. The development of this approach using a laser beam has greatly increased the precision and effectiveness of biological material collection Figure 2. In this system, unlike the others, the tissue section remains stationary on the microscope and the UV laser beam moves over it when cutting.
However, UV solid-state lasers nm are commonly used in each device. For the LMPC device, a gas laser operating in the ultraviolet range is used with molecular nitrogen as its gain medium, pumped by an electrical discharge. The LMD microsys-.
Figure 1. Chronological succession of steps showing the laser beam cutting of a biological tissue: a Scope display of the region to recover; b Selection of cells of interest through a graphical wizard on the computer blue line ; c Cut made by the laser beam along the path as defined above; d The region that has been selected and cut is then recovered for analyses.
Figure 2. Blue light of a laser beam cutting a specific region, or cells of interest from a biological tissue laid after treatment on a microscope slide. Neoplasia is the main field of application of this technique for selecting tissue, but other fields have gradually opened up to these new methodological approaches, for instance for micro-dissecting living cells from a cell culture with the possibility of re-culturing the isolated cells .
De Spiegelaere W et al. Sethi et al. Thus, from cell fragments, one of the most common applications of LAM has been the search for loss of heterozygosity LOH in malignant tumors.