Abstract: Apparatus for generating ultraviolet (UV) pulsed laser-radiation for material-processing includes a laser-source providing infrared (IR) pulsed laser-radiation and a frequency-conversion module. A lithium tetraborate (Li2B4O7) crystal located within the frequency-conversion module converts the IR pulsed laser-radiation to UV pulsed laser-radiation by non-linear harmonic generation. The frequency-conversion module is an airtight enclosure that may be evacuated or contain a dry gas. A flexible optical fiber-assembly transports the IR pulsed laser-radiation from the laser-source to the frequency-conversion module.
Abstract: A solid-state MOPA includes a mode-locked laser delivering a train of pulses. The pulses are input to a fast E-O shutter, including polarization-rotating elements, polarizing beam-splitters, and a Pockels cell that can be driven alternatively by high voltage (HV) pulses of fixed long and short durations. A multi-pass amplifier follows the E-O shutter. The E-O shutter selects every Nth pulse from the input train and delivers the selected pulses to the multi-pass amplifier. The multi-pass amplifier returns amplified seed-pulses to the E-O shutter. The shutter rejects or transmits the amplified pulses depending on whether the HV-pulse duration is respectively short or long. Transmitted amplified pulses are delivered to a transient amplifier configured for separately suppressing first-pulse over-amplification and residual pulse leakage.
Type:
Application
Filed:
September 9, 2013
Publication date:
March 12, 2015
Applicant:
COHERENT KAISERSLAUTERN GMBH
Inventors:
Ralf KNAPPE, Albert SEIFERT, Alexander Weis
Abstract: An optically pumped laser oscillator or amplifier includes a laser head having a gain medium exhibiting polarization-dependent absorption along two crystallographic axes and a pump source producing a pump beam. The medium's absorption coefficients along both said crystallographic axes are equal or the difference between the absorption coefficients relative to the lowest absorption coefficients R=Abs(?c-?a)/(min(?c, ?a)) is reduced at least by a factor of two compared to the same relative difference between the two absorption coefficients at the medium's absorption peaks, used for conventional pumping by pumping with unpolarized or partially polarized pump light at a wavelength around which the average absorption coefficients along both of said crystal-lographic axes are equal or present a relative difference that is reduced by a factor of two or better compared to conventional pumping around the medium's absorption peaks.
Type:
Application
Filed:
August 14, 2013
Publication date:
December 12, 2013
Applicant:
COHERENT KAISERSLAUTERN GMBH
Inventors:
Louis MCDONAGH, Achim NEBEL, Ralf KNAPPE