Abstract: A method and apparatus for surgical and dermatological treatment using a multi-wavelength laser system includes a primary laser beam generator optically pumped by a semiconductor laser diode. A portion or all of the optical pumping energy may be outputted with the primary laser beam output to form a multi-wavelength treatment beam. A frequency doubling medium, such as a KTP or LBO crystal, may be imposed in the output of the laser beam generator to produce an additional wavelength that may be combined into the multi-wavelength treatment beam. To achieve high peak power pulse laser output, a Q-switch element can be placed in front or in back of the laser crystal. Alternatively, the laser system may output only the wavelength of the semiconductor laser diode pumping system. The selection of one or more wavelengths provides a wider range of treatment modalities using a single laser system, without creating problems attendant with the complexity and maintenance of prior art multi-wavelength laser systems.

Abstract: Optical circulators including a first beam displacer/combiner, a first nonreciprocal rotator, a first beam angle turner, a second beam angle turner, a second nonreciprocal rotator, and a second beam displacer/combiner, together with methods of using the optical circulators and telecommunications systems including the optical circulators.

Abstract: Optical circulators including a first beam displacer/combiner, a first nonreciprocal rotator, a first beam angle turner, a second beam angle turner, a second nonreciprocal rotator, and a second beam displacer/combiner, together with methods of using the optical circulators and telecommunications systems including the optical circulators.

Abstract: A single mode laser implementation and associated method are disclosed. The laser may accommodate a frequency multiplying material to provide an intracavity doubled single frequency laser. The laser implementation includes an input mirror and an output mirror defining a resonant cavity and a light path within the resonant cavity and between the mirrors. A lasant material is positioned in the light path for lasing at a desired fundamental wavelength and possibly other, unwanted wavelengths. A first birefringent member is also positioned in the light path for refracting in different directions the different wavelengths of light which are present along the path.

Abstract: A two-mode, amplitude-stable laser is disclosed which provides two-mode operation (i.e., two fundamental lasing modes of similar, but distinct frequencies), resulting in low noise output at harmonic frequencies of the fundamental mode frequencies. An associated method is also disclosed. A nonlinear material is positioned in the path of lasing light for converting light from fundamental frequencies to particular harmonic frequencies of those fundamental frequencies such that the fundamental frequencies incur a nonlinear loss. The nonlinear material establishes the nonlinear loss at a level which is greater than the linear loss within the cavity such that two of the fundamental frequencies lase while unwanted fundamental frequencies are extinguished. A two-mode criterion is introduced which ensures two-mode laser operation. A stability criterion is also introduced which cooperates with the two-mode criterion in a way which provides a high level of beam output intensity stability.

Abstract: An intracavity doubled single longitudinal mode laser is disclosed which provides stable (i.e., low amplitude variation in its output beam intensity), efficient operation. An associated method is also disclosed. The laser includes an input mirror and an output mirror defining a resonant cavity and a light path within the resonant cavity and between the mirrors. The output mirror is configured to be substantially transparent to an output wavelength produced within the cavity. A lasant material is positioned in the light path for producing light at a desired fundamental wavelength and possibly other, unwanted wavelengths. Polarizing element and a type I doubling material are also positioned in the light path. During operation of the laser, the polarizing element polarizes the desired fundamental wavelength as well as the unwanted wavelengths of light produced by the lasant material. The type I doubling material then produces output wavelengths at twice the frequency of any wavelengths passing therethrough.

Abstract: A laser includes a pumping light source for producing a pumping beam and a laser resonator having an input mirror optically coupled to the pumping light source for receiving the pumping beam. The laser resonator also includes an output mirror, a lasant material, and a nonlinear optical material. The nonlinear optical material is placed inside the laser cavity and configured as a half-wave plate or a multiple of a half-wave plate at a first given fundamental lasing wavelength. The lasant material is placed against or near the input mirror of the laser resonator and oscillates in response to the pumping beam so as to generate a fundamental wave including (i) two substantially orthogonal linearly polarized modes at wavelengths at and/or about the first given wavelength, (ii) an additional mode at and/or about a second given wavelength that is relatively close to but different from the first given wavelength.

Abstract: A single mode laser implementation and associated method are disclosed. The laser may accommodate a frequency multiplying material to provide an intracavity doubled single frequency laser. The laser implementation includes an input mirror and an output mirror defining a resonant cavity and a light path within the resonant cavity and between the mirrors. A lasant material is positioned in the light path for lasing at a desired fundamental wavelength and possibly other, unwanted wavelengths. A first birefringent member is also positioned in the light path for refracting in different directions the different wavelengths of light which are present along the path.

Abstract: A system and method is described for permitting the simultaneous automated collection of data with regard to the presence of diseased cells, in particular neo-plastic, dysplastic or cancerous cells, or normal cells at a given site in a section of tissue. This is accomplished according to the following steps. First, IR spectral data are collected simultaneously for each cell or pixel of the tissue. Next, these data are analyzed by identifying the cell types encountered in the sample by comparing them with reference data sets for healthy and diseased cells. Finally, a false color mapping of the distribution of different types of cells in the tissue section is presented that permits assessment of the prevalence of diseased cells.

Abstract: A laser for outputting visible light at the wavelengths of blue, green, orange and red light. This is accomplished through the doping of a substrate, such as an optical fiber or waveguide, with Pr.sup.3+ ions and Yb.sup.3+ ions. A light pump such as a diode laser is used to excite these ions into energy states which will produce lasing at the desired wavelengths. Tuning elements such as prisms and gratings can be employed to select desired wavelengths for output.

Abstract: Conductive cement-based compositions exhibiting both good electrical conductivity and mechanical strength have been obtained by ensuring proper dispersion of conductive phase within the composition. The content of the ingredients depends on the preparation method, for instance conventional mixing or slurry infiltration, and on the type of the composition, i.e. conductive paste, mortar or concrete. The broad content ranges of the conductive composition are:a cement binder,a conductive phase consisting of one or more of the following:conductive fibers in the amount from 0 to 15% by volume of the composition;conductive particles in the amount from 0 to 80% by volume of the composition;water, at the weight ratio relative to cement binder from 0.2 to 0.75,fine agregates at the weight ratio relative to cement binder from 0.0 to 2.0, andcoarse aggregates at the weight ratio relative to cement binder from 0.0 to 2.0,conventional additives or admixtures, and optionally a dispersant.

Abstract: Four-fold and higher order lasers pumped by multiphoton absorption, avalanche mechanisms, or other means of internal upconversion for continuous-wave and continuous-wave mode-locked lasers. A solid-state laser system is contained within an astigmatically compensated cavity containing first and second mirrors. The gain medium is formed of a crystal of lithium yttrium fluoride heavily doped (5%) with trivalent erbium, or another form of crystal, such as CaF.sub.2 where the dopant atoms are clustered in quartets. The crystal, in a lithium yttrium fluoride embodiment, is approximately 3 mm thick with both sides thereof being polished flat to a laser grade finish. A pumping source supplies a pumping energy having a wavelength of 1.5 .mu.m to the gain medium, which wavelength is considerable longer than the output wavelength (701.5 nm) of the laser system. The gain medium may additionally be an alkali vapor formed of Cesium or Rubidium.