We describe composite optical fibers with rare-earth co-doped phosphate-glass core in a silica-glass cladding. High RE-ion concentrations in the phosphate core of the composite fiber allow fiber length reduction in comparison with silica fibers. The silica cladding provides high mechanical strength and protects the phosphate core from air moisture while making it easier to splice with silica fibers.
The paper compares the absorption and emission properties of bulk glasses prepared by sintered in an iridium crucible
and optical fibers fabricated by the powder-in-tube method. Both the bulk glasses and fibers were prepared from
identical mixtures. The emission properties of the bulk samples and fibers were similar, while the "gray losses" in the
fibers were an order of magnitude lower than those in the crucible melted glasses.
The properties near infrared (NIR) - emitting centers were investigated in Bi-doped Mg.Al-silicate and phosphate
glasses. The NIR-emitting optical centers containing a pair of bismuth ions were shown to be formed in a reversible
redox chemical reaction. The common electric charge (+5) of bismuth ions in such centers was determined. The NIR-emission saturation measurements have made it possible to calculate the ground-state absorption cross-section
(~4.4×~10-19 cm2) of these centers at 532 nm and their absolute concentration in the glass. It was found that similar
emitting centers can also be formed in a colorless and non-luminescent Bi-doped glass by γ-irradiation. This fact
allowed deriving some conclusions on an optical center structure.
Passive Q-Switch characteristics of Co2+:MgAl2O3 sample were evaluated in a diode pumped QX/Er Erbium glass laser at 1535 nm, a flashlamp pumped Nd:YAG laser at 1.44 micrometers and Nd3+:KGd(WO4)2 laser at 1.34 micrometers .
The dose-response relationship for producing different grades of burns on skin produced by single Er-glass laser pulse were determined for energy densities within the range 0.5-35 J/cm2 and pulse duration 100 ns and 2.5 ms. The persistent lesions on skin were subdivided into four morphologically different groups vs. radiant exposure of laser pulses. Histological investigation were made at 1- and 3-days post-exposure. Different methods of tissue preparation were tried to obtain better contrast of laser induced changes in skin tissue. At the 1-day post-exposure we observed on the histological samples coagulation of surface tissue, epidermis and dermis of skin depending on radiant exposure. 3-days histological samples revealed tearing of tissue detrit and active epitalization of damaged tissue.
Radiant exposure of an Er-glass laser producing 50 percent probability (ED50) of a minimum erythema on porcine skin was measured in vivo for laser pulses 100 ns and 2.5 ms pulse duration. ED50 at 24 hours post-exposure was found 3.5 J/cm2 for short laser pulses and 6.5 J/cm2 for long ones. The single pulse dose in a chain of repetitive pulses producing minimum erythema were determined for 2n(n equals 16) pulses. The minimum reaction of skin on laser irradiance were studied for different beam diameter. The reaction of skin is mostly considered as local super heating. THe data obtained in the study are adequate to update safety standards for cutaneous injury.
The skin response was studied for different radiant exposure of short and long laser pulses and reaction to multipulse action using Er-glass laser radiation. Lesion ranging from a mild erytherma to tissue coagulation were produced on porcine skin. Radiant exposure producing 50 percent probability of a particular grade of lesion were established. A dependence of ED50 of minimum erythema versus number of pulses and beam cross section were studied. Histological investigation of the damage zone was made for qualitative study of injured skin. The dose-response relationship for producing different grades of burns were determined for energy densities of single laser pulse within the range 0.5-35 J/cm2 and pulse duration 100 ns and 3 ms. The single pulse dose in a chain of repetitive pulses producing minimum erythema were determined for 2n(n equals 1-6) pulses. The minimum reaction of skin on laser irradiance were studied for different beam diameter. The reaction of skin in mostly considered as local super heating. The data obtained are adequate to update safety standards for cutaneous injury within these ranges of radiant exposure and beam spotsize.
The skin response was studied for different radiant exposure of short and long laser pulses and reaction to multipulse action using Er-glass laser radiation. Lesion ranging from a mild erythema to tissue coagulation were produced on porcine skin. Radiant exposure producing 50 percent probability of a particular grade of lesion were established. A dependence of ED50 of minimum erythema versus number of pulses and beam cross section were studied. The dose-response relationship for producing different grades of burns were determined for energy densities of single laser pulse within the range 0.5- 35 J/cm2 and pulse duration 100 ns and 3 ms. The single pulse dose in a chain of repetitive pluses producing minimum erythema were determined for 2n(n equals 1-6 pulses). The minimum reaction of skin on laser irradiance were studied for different beam diameter. The reaction of skin is mostly considered as local super heating. The data obtained are adequate to update safety standards for cutaneous injury within thee ranges of radiant exposure and beam spotsize.
The strong angular and base dependence of the Fabry-Perot interferometer reflectivity is used for the increase of beam quality and power of medical lasers. The smaller divergency makes the use of thinner (more bendable) optical fiber possible.
The effect on living tissues of different pulsed solid state lasers: Nd:YAG ((lambda) equals 1.06 micrometers ) Er:glass (1.54 micrometers ), Ho:YAG (2.1 micrometers ) and Er:YAG (2.94 micrometers ) is compared with the continuous wave Nd:YAG- and CO2-lasers used in operating theaters. Portable Er:glass- and Er:YAG-lasers are developed for surgery/cosmetics and HIV-safe blood testing.
The search for simple and effective methods of erbium glass lasers (lasing wavelength 1.54 microns) Q-switching is a task of present interest. It is interesting because this wavelength radiation is relatively eyesafe and may be used in medicine, lidars, and fiberoptics. Nowadays, existing active methods of Q switching are rather inconvenient for practical use (rotating prism) or complex and not too efficient (electrooptic cell). As for passive shutters based on color centers in crystals, or organic dyes, nowadays they are only under development, and Q—switching is obtained in them only as a small effect. In this report, two new simple methods of passive Q-switching of erbium glass lasers are suggested, and the main properties of obtained giant pulses are investigated.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.