Abstract:
System for converting relatively long pulses from rep-rate variable ultrafast optical sources to shorter, high-energy pulses suitable for sources in high-energy ultrafast lasers. Fibers with positive group velocity dispersion (GVD) and self phase modulation are advantageously employed with the optical sources. These systems take advantage of the need for higher pulse energies at lower repetition rates so that such sources can be cost effective.
Abstract:
The invention describes techniques for the control of the spatial as well as spectral beam quality of multi-mode fiber amplification of high peak power pulses as well as using such a configuration to replace the present diode-pumped, Neodynium based sources. Perfect spatial beam-quality can be ensured by exciting the fundamental mode in the multi-mode fibers with appropriate mode-matching optics and techniques. The loss of spatial beam-quality in the multi-mode fibers along the fiber length can be minimized by using multi-mode fibers with large cladding diameters. Near diffraction-limited coherent multi-mode amplifiers can be conveniently cladding pumped, allowing for the generation of high average power. Moreover, the polarization state in the multi-mode fiber amplifiers can be preserved by implementing multi-mode fibers with stress producing regions or elliptical fiber cores These lasers find application as a general replacement of Nd:based lasers, especially Nd:YAG lasers. Particularly utility is disclosed for applications in the marking, micro-machining and drilling areas.
Abstract:
The present invention is directed to methods and apparatuses for performing temporal scanning using ultra-short pulsewidth lasers in which only minimal (micro-scale) mechanical movement is required. The invention also relates to methods for obtaining high-accuracy timing calibration, on the order of femtoseconds. A dual laser system is disclosed in which the cavity of one or more of the lasers is dithered, by using a piezoelectric element. A Fabry-Perot etalon is used to generate a sequence of timing pulses used in conjunction with a laser beam produced by the laser having the dithered laser cavity. A correlator correlates a laser pulse from one of the lasers with the sequence of timing pulses to produce a calibrated time scale. The methods and apparatuses of the present invention are applicable to many applications requiring rapid scanning and time calibration, including, but not limited to metrology, characterization of charge dynamics in semiconductors, electro-optic testing of ultrafast electronic and optoelectronic devices, optical time domain reflectometry, and electro-optic sampling oscilloscopes.
Abstract:
A multiple-wavelength ultrashort-pulse laser system includes a laser generator producing ultrashort pulses at a fixed wavelength, and at least one and preferably a plurality of wavelength conversion channels. Preferably, a fiber laser system is used for generating single-wavelength, ultrashort pulses. An optical split switch matrix directs the pulses from the laser generator into at least one of the wavelength conversion channels. An optical combining switch matrix is disposed downstream of the wavelength-conversion channels and combines outputs from separate wavelength-conversion channels into a single output channel. Preferably, waveguides formed in a ferroelectric substrate by titanium indiffusion (TI) and/or proton exchange (PE) form the wavelength conversion channels and the splitting and combining matrices. Use of the waveguide allows efficient optical parametric generation to occur in the wavelength-conversion channels at pulse energies achievable with a mode-locked laser source. The multiple-wavelength laser system can replace a plurality of different, single-wavelength laser systems. One particular application for the system is a multi-photon microscope, where the ability to select the ultrashort-signal wavelength of the laser source accommodates any single fluorescent dye or several fluorescent dyes simultaneously. In its simplest form, the system can be used to convert the laser wavelength to a more favorable wavelength For example, pulses generated at 1.55 nullm by a mode-locked erbium fiber laser can be converted to 1.3 nullm for use in optical coherence tomography or to 1.04-1.12 nullm for amplification by a Yterbium amplifier, allowing amplification of pulses which can be used in a display, printing or machining system.