For this experiment let’s consider that we have an unpolarized light passing through two polarizer T1 and T2, here line on polarizer shows plane of vibration i.e., the plane in which electric field vector can vibrate freely, whereas electric field perpendicular to this line will be eliminated completely.

The most common side effects were erythema and vesicles in four of 14 patients (28.6%). Among these four patients, two reported mild post-inflammatory hyperpigmentation on the side that they received long-pulsed Nd:YAG laser treatment. However, those cutaneous reactions showed improvement without scarring (Fig. 3). No unbearable pain was noted in this study, and all patients tolerated the treatment well.

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1. Linear polarization is when the oscillation of a wave is constrained to a single plane. This is the plane of polarization.

In this study, we investigated the clinical efficacy, side effects, and subjective satisfaction of Korean patients after they underwent long-pulsed Nd:YAG laser treatment for diverse vascular disorders.

Among the lasers for vascular lesions, the ratio of melanin to blood absorption is similar at 585 and 1064 nm, whereas the absolute values of absorption and scattering coefficients are considerably lower at 1064 nm as compared with 585 nm.7,8 It might imply that 1064 nm pulses can treat deeper vessels selectively. Lower absolute values of blood absorption at 1064 nm can be compensated for by increasing the fluence. Although a very high fluence of more than 150 J/cm2 must be applied, this increase in treatment fluence does not necessarily damage the epidermis, because the absolute absorption of melanin is lower at 1064 nm as well.4 In addition, the absorption coefficient of blood at 1064 nm is 0.4/mm, which is much higher than that of the surrounding dermis (0.05/mm) at the same wavelength. This difference in absorption coefficients makes 1064 nm light more selective for treatment of deep blood vessels than shorter wavelengths of light.8,9

When light wave propagates it consists of vibration of electric field in all possible direction, which are perpendicular to its direction of propagation and such light waves are said to be unpolarized light.

There is a clear demand for laser treatment of various vascular lesions, but there are still challenges when using laser energy in a therapeutic context. PDL and IPL are used to treat superficial vascular lesions, but are not ideal for treating deeper lesions.3 With the advent of lasers with longer pulse durations and wavelengths than those used for PDL and IPL, deeper and larger caliber vessels can be managed more effectively without frequent treatment sessions and side effects. Long-pulsed Nd:YAG laser treatment of deeper vessels has been shown to be effective; however, the long-term effects of this laser treatment have not been evaluated.4 In this study, we demonstrated that diverse vascular lesions responded favorably to long-pulsed Nd:YAG laser therapy. As expected, we found that selective photothermolysis of vessels in vascular disorders including erythema, telangiectasia, port wine stain, cherry angioma, and hemangioma could be achieved by 1064 nm Nd:YAG laser pulses. Both PGA scores and patient satisfaction ratings after laser treatment were good. Long-pulsed Nd:YAG laser therapy can therefore potentially be used to treat both superficial and deep vascular disorders.

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For monoclinic or tetragonal crystals, we get the above result i.e., One O-ray and one e-ray can be observed. Whereas for orthorhombic, monoclinic, and triclinic crystals, there will be two E-rays

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When we restrict vibration to an electrical vector in an unpolarized light we get plane polarized light. In this the direction of vibration of electric vector and direction of light propagation are perpendicular to each other as shown below.

If the plane of vibration of both polarizers are parallel to each other in such polarized light from the first polarizer can easily pass through the second polarizer as shown below.

Among 16 enrolled patients, two patients dropped out for personal reasons unrelated to the treatment. The remaining 14 patients completed this study. Patients’ age ranged from 16 to 62 years (mean, 45.4 years). Subtypes of vascular disorders were facial telangiectasia, rosacea, port wine stain, hemangioma, cherry angioma, and acne erythema. Detailed demographic information is provided in Table 1.

And hence from this experiment we can conclude that electric fields are vibrating perpendicular to its direction of propagation, hence light is a transverse wave.

Circularly polarized light

So, as we discussed above, light is a transverse wave, and confining the plane of vibration of such a transverse wave by the principle of scattering is termed Polarization by scattering.

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Nevertheless, we demonstrated that long-pulsed Nd:YAG laser treatment is an alternative treatment modality for various vascular problems recalcitrant to standard therapy. Our study could also contribute to the establishment of appropriate treatment parameters. It is important to note that the use of bulk skin cooling, no overlapping of pulses, use of subpurpuric fluences, and use of a small spot size can limit dermal injury and improve the safety of Nd:YAG lasers. Further studies comparing the effects of variations in each of the treatment parameters or different treatment intervals should be performed to determine optimal treatment conditions.

Ellipticalpolarization

Polarization by scattering is generally observed in liquid or gas randomness in motion of atoms. However, in perfect crystals we don’t see as good results as fluids.

3. Elliptical polarization is the same as circular polarization except that the amplitudes and phase differences are not the same.

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For calcite, one of the two rays does indeed obey Snell’s Law (angle of incidence is equal to the angle of refraction), this ray is called the ordinary ray (or O-ray). The other ray (and any ray that does not obey Snell’s Law) is an extraordinary ray (or E-ray). For normal incidence (a Snell’s law angle of 0°), the two planes of polarization are also perpendicular to the plane of incidence.

Light passing through a calcite crystal is split into two rays as shown below. This process is called double refraction or polarization by refraction.

Thus using Brewster’s law, we can conclude that polarizing angle depends on frequency of incident ray i.e., colour of incident ray hence polarizing angle will be different for different colour.

There are several possible causes for the steep fluence-response curve of Nd:YAG laser treatment. When blood is heated to 50–54°C, partial oxidation of oxyhemoglobin leads to met-hemoglobin (met-Hb) formation.7,10 Optical absorption by met-Hb is much higher than that of either Hb or hemoglobin.11,12 Several in vitro studies13,14 have demonstrated that when blood is photocoagulated by 1064 nm Nd:YAG laser pulses, absorption at 1064 nm increases on the millisecond time scale by a factor of about 3, which may be due to partial conversion of oxyhemoglobin to met-Hb. When the lumen is thermally coagulated, optical scattering is increased and formation of a coagulum results in concentration of chromophores.1 In summary, long-pulsed Nd:YAG laser irradiation can heat up the entire vessel wall and coagulate the vessel at high fluence, which aids in the clearance of vascular lesions, unlike PDL and IPL.

Double refraction, also known as birefringence, is an optical property in which a single ray of unpolarized light entering an anisotropic medium is split into two rays i.e., ordinary & extraordinary rays, each traveling in a different direction.The concept of Double refraction can be observed by comparing two materials, glass and calcite.

This is the reason the sky scatters more blue light than red because of the natural frequency of molecules in our atmosphere.

Patients were generally satisfied with the cosmetic outcomes of their treatment. Mean score was 4.0, and 10 of 14 patients stated that they were ‘very satisfied’ or ‘satisfied’ with their appearance. The boxes of ‘somewhat satisfied’ and ‘little satisfied’ were checked by one of the patients who experienced adverse effects (Table 1).

A polarimeter is an instrument used to determine the angle through which plane-polarized light has been rotated by a given sample.

Suppose if a pencil mark is drawn upon a sheet of paper and then covered with a piece of glass, only one image will be seen. But if the same paper is covered with a piece of calcite and the crystal is oriented in a specific direction then two marks will become visible. This is because a refracted beam acquires some degree of polarization. Most often, the polarization occurs in a plane perpendicular to the surface.

Patient’s satisfaction: 1 = not satisfied, 2 = little satisfied, 3 = somewhat satisfied, 4 = satisfied, 5 = very satisfied.

Electricpolarization

2. Circular polarization is when two linear components of a wave oscillate perpendicular to each other such that their amplitudes are equal.

Five men and nine women were finally enrolled (mean age 45.4 ± 16.4 years) in this study. Thirteen of 14 patients (92.9%) had good or excellent PGA results. Ten of 14 patients were very satisfied or satisfied with the clinical results (71.4%), and all patients reported that immediate treatment discomfort was tolerable. Side effects were minimal; four patients (28.6%) reported erythema, vesicles, or hyperpigmentation which recovered without scarring.

Circularpolarization

However the scattered light can be unpolarized, partially polarized, or completely polarized based on the direction of the incident ray as shown below.

The two rays of light are each plane-polarized by the calcite such that the planes of its polarization are mutually perpendicular to each other as shown below.

When the electric field vectors are restricted to a single plane by filtration, then the light is said to be polarized with respect to the direction of propagation and it propagates in a single plane. In this article, we are going to learn about the polarization of light, brewster’s law, double refraction, polarization by scattering. Let’s understand the Physics (Optics) phenomenon of unpolarized light first.

Now if we rotate second polarizer in such a way that it becomes perpendicular to first one, in this case as plane polarized light passes through second polarizer it will get eliminated since second polarizer won’t allow it to pass and hence it is called analyzer which is used to determine the plane of polarization as shown below

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Now as this unpolarized light passes through the polarizer, it will polarize the light in either vertical or horizontal direction. This polarized light when again passed through a polarizer there can be two possible outcomes.

The optical rotation is the angle through which the plane of polarization is rotated when polarized light is passed through a layer of a liquid.

Substances are described as dextrorotatory or levorotatory according to whether the plane of polarization is rotated clockwise or counterclockwise, respectively, as determined by viewing towards the light source. Dextrorotation is designated (+) and levorotation is designated (-).

Such a medium contains lots of atoms and when an unpolarized light beam strikes an atom it transfers energy to an atom. As a result, an electron in that atom starts vibrating in response to the electric component of the incident ray. Now, this vibrating electron emits E.M radiation in all directions, and this forces neighboring electrons to undergo a similar process. This phenomenon of absorption and emission of the electromagnetic radiation is known as the scattering of light.

Polarization of Light is a property applying to transverse waves that specify the geometrical orientation of the oscillations. Light is an electromagnetic wave in which electric and magnetic field vectors are sinusoidally perpendicular to each other as well as they are perpendicular to the direction of propagation of light waves.

Long-pulsed Nd:YAG laser treatment is a safe and effective treatment modality for diverse vascular disorders that are unresponsive to conventional therapy.

A 1064 nm long-pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) laser has been proven to be effective for the treatment of leg veins because of its deep penetration into the skin and homogenous heating of large vessel walls.2 Recently, the efficacy of long-pulsed Nd:YAG laser treatment for various vascular disorders such as port wine stain, hemangioma, angiokeratoma, and venous lake was reported.5,6

There are three main types of polarization namely, linear polarization, circular polarization, and elliptical polarization.

All patients underwent a single treatment session using a long-pulsed Nd:YAG (Multiflex, Ellipse A/S®, Denmark). Surface cooling was achieved using a focused stream of cool air (SoftCoolTM) to reduce pain during treatment and to minimize the risk of possible epidermal damage. To treat vessels with a diameter of 0.2–0.3 mm, the following treatment parameters were used: 12.0 ms pulse width and 214.2–260.3 J/cm2 of fluence using a 1.5 mm spot. Larger dilated vessels with a diameter of 0.3–0.5 mm were treated with a pulse width of 16.0 ms and 225.1–252.2 J/cm2 of fluence using a 3.0 mm spot. When the vessel was treated with the laser, the immediate vessel response was carefully tracked. If the vessel disappeared immediately, the next laser shot was applied at the point where the vanishing point stopped. If the vessel did not show any response after the first shot, the fluence was raised to the next level (10–20 J/cm2 higher in general) and the laser firing point was moved up by about 1–2 mm from the initial spot to avoid stacking of laser pulses.

Seven of 14 patients (50%) showed excellent improvement, six patients (42.9%) showed good improvement, and one patient (7.1%) showed moderate improvement. The average PGA score was 2.43 (Table 1, Figs. 1, 2).

Fourteen Korean patients underwent a single treatment session using a long-pulsed Nd:YAG laser. Two blinded clinicians rated cosmetic outcomes using ‘Physician Global Assessment (PGA)’ based on standardized photographs. Patients’ subjective satisfaction and side-effects of treatment were evaluated after treatment.

The specific rotation is a characteristic property of a certain substance and is the standard measurement for the optical rotation of that substance.

Optical activity is the ability of a substance to rotate the plane of polarization of a beam of light that passed through it.

Q: A sugar solution in a tube of length 2.0 dm produces optical rotation of 12°. Then, the sugar solution to one half of its initial concentration. If the dilute solute solution is contained in another tube of length 3.0 dm, the optical rotation produced by it will be

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Politicalpolarization

collimate · agree · assimilate · collocate · compare · conform · copy · equal · equate · liken · match · paragon · parallelize. Weak match. keep pace.

polarization极化

Polarization due to scattering can be seen through the sky as we can see below. When an unpolarized beam of sunlight passes through the atmosphere the light scatters down towards earth. Also it has no vertical polarization.

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With regard to side-effects, higher risk of potential collateral damage around vessels and pain during the procedure should be kept in mind when using this laser for vessels.2 Water, a competing chromophore of light at the wavelength of 1064 nm, may be the culprit responsible for additional tissue damage despite the fact that this wavelength is absorbed 10-fold more by oxyhemoglobin than water.2 In our study, all patients tolerated the procedure moderately well without remarkable pain. Two patients experienced postinflammatory hyperpigmentation on the site of the vesicles; this epidermal damage may have been caused by the high fluence. Technically, a non-overlapping technique is very important to avoid subsequent complications like scar formation.15 When we performed laser therapy to treat telangiectatic vessels, we evaluated the therapeutic end point based on the immediate response of the vessels. However, when treating diffuse erythema rather than telangiectasia, clinicians should be cautious when selecting parameters; however, guidelines to reduce adverse reactions have yet to be established.

In this retrospective study, we identified 16 patients with cutaneous vascular disorders who visited the dermatology clinic of Hanyang University Hospital between June 2014 and May 2015. All patients were of Fitzpatrick skin types III and IV. Patients for whom standardized photographs were obtained before and after treatment were considered eligible for inclusion. Patients with a history of deep vein thrombosis, connective tissue disease, predisposition to hypertrophic scars and keloids, oral isotretinoin in the previous 2 months or immunosuppression, or who were pregnant or lactating were excluded.

polarization中文

Several lasers emitting in the green and yellow range of the light spectrum, such as 585 nm and 595 nm pulsed dye lasers (PDLs), the 532 nm KTP laser, and the 578 nm copper vapor laser, are standardly used to treat various vascular disorders including port wine stains, superficial hemangioma, and telangiectasia.1,2 Intense pulsed light (IPL)-emitting noncoherent broadband light is considered to be an effective treatment option for diverse vascular lesions.3 However, this treatment modality tends to be less effective for deeply-situated vascular lesions than superficial vascular lesions due to the limited penetration depth of light.4

Polarization

Long-pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers have recently been used for treatment of large, deep vascular lesions refractory to conventional vascular lasers. The aim of this study was to evaluate the clinical efficacy and safety of long-pulsed Nd:YAG laser treatment of various vascular disorders.

The velocity and refractive index of extraordinary waves changes with direction whereas for ordinary ray velocity remains constant throughout the crystal while propagating.

Clinical assessment was done by two blinded clinicians using Physician Global Assessment (PGA) based on evaluation of pre-treatment photographs and post-treatment photographs taken 1 month after the last treatment. Improvement was assessed on a scale from 0 to 3 (0 = no improvement, 1 = moderate, 2 = good, 3 = excellent). In addition, patients were asked to rate their satisfaction with the cosmetic results (1 = not satisfied, 2 = a little satisfied, 3 = somewhat satisfied, 4 = satisfied, 5 = very satisfied). Side effects after treatment were also assessed.

This study had several limitations. First, we included only a small number of patients. Second, this was not a randomized controlled study and we did not directly compare the long-pulsed Nd:YAG laser with PDL and IPL. Third, long-term follow-up was not performed.

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