Publications by authors named "Karl A Tillman"

Background: Destruction of blood vessels by selective photothermolysis has been successfully achieved using a number of different laser and light systems, none of which provide significant independent variation in parameters such as wavelength.

Objective: To evaluate the safety and efficacy of a novel configurable device in the treatment of nasal telangiectasias.

Methods: Fifteen subjects aged 42-73 with Fitzpatrick skin types I and II were treated for nasal telangiectasias of various sizes.

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The frequency comb from a prism-based Cr:forsterite laser has been frequency stabilized using intracavity prism insertion and pump power modulation. Absolute frequency measurements of a CW fiber laser stabilized to the P(13) transition of acetylene demonstrate a fractional instability of approximately 2 x 10(-11) at a 1 s gate time, limited by a commercial Global Positioning System (GPS)-disciplined rubidium oscillator. Additionally, absolute frequency measurements made simultaneously using a second frequency comb indicate relative instabilities of 3 x 10(-12) for both combs for a 1 s gate time.

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Saturated absorption spectroscopy reveals the narrowest features so far in molecular gas-filled hollow-core photonic crystal fiber. The 48-68 mum core diameter of the kagome-structured fiber used here allows for 8 MHz full-width half-maximum sub-Doppler features, and its wavelength-insensitive transmission is suitable for high-accuracy frequency measurements. A fiber laser is locked to the (12)C2H2 nu(1); + nu(3) P(13) transition inside kagome fiber, and compared with frequency combs based on both a carbon nanotube fiber laser and a Cr:forsterite laser, each of which are referenced to a GPS-disciplined Rb oscillator.

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A frequency comb generated by a 167 MHz repetition frequency erbium-doped fiber ring laser using a carbon nanotube saturable absorber is phase-stabilized for the first time. Measurements of the in-loop phase noise show an integrated phase error on the carrier envelope offset frequency of 0.35 radians.

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We describe a highly efficient monolithic, Q-switched, nanosecond optical parametric oscillator based on a magnesium-oxide-doped periodically poled lithium niobate crystal and containing multiple quasi-phase-matched gratings. The crystal consisted of a single unchirped grating and five gratings containing progressively increasing amounts of longitudinal chirp. The monolithic design makes the device highly compact, stable, and robust, and it demonstrated a pump-to-signal conversion efficiency of around 50%, generating 50 microJ pulses at 1.

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