A compact and fast-response wavelength monitor is described that can determine the wavelength of individual laser pulses with a resolution of a few pm. It combines a position-sensitive photo detector with an optical coating that converts the wavelength information of the incident light into a spatial intensity distribution on the photo detector. Differential read-out of the photo detector is used to determine the centroid of this distribution. Wavelength change between individual laser pulses is detected as a shift of the centroid of the spatial light distribution on the detector. The wavelength monitor is demonstrated with results from a wavelength-tunable fiber laser that can produce randomly accessible sequences of laser pulses.
In this paper, pulsed operation of the 980 nm diode-pumped Yb:Er:glass solid-state-laser operating at 1543 nm using Co:Spinel saturable absorber is described. The Yb:Er:glass gain medium was end-pumped using a 10 W fiber-coupled 980 nm laser diode. Passively q-switched laser operation was accomplished for both CW and quasi-CW operations. Up to 2 mm thick uncoated Co:Spinel samples were used for our tests. With quasi-CW pumping, pulsewidths greater than 20 ns, pulse energies of greater than 250 μJ and free-running PRFs up to 1.2 kHz have been demonstrated. So far, up to 3 % optical-to-optical efficiency has been achieved with uncoated q-switch materials. Currently, this laser is being developed for pumping a long-wave IR (8-12 μm) optical parametric oscillator for use in spectrapolarimetric applications.
HF mirror metrology is currently costly and time consuming, requiring laser component delivery to an HF laser site, and operation of another HF laser to reach relevant wavelengths. Coherent Technologies, Inc. has developed a solid state Cr:ZnSe laser pumped by a Tm:YALO laser that provides up to 1.1W of output power with 1.1nm linewidth at 2.64micrometers , an HF laser line. The laser can also tune to other HF laser liens in the wavelength range of 2.64micrometers to 2.8micrometers . The Cr:ZnSe laser was used to measure the reflectivity of HF mirror samples provided by TRW. Examples of other possible applications of this source include beam train alignment and preliminary testing of diagnostic subsystems that measure HF laser output power, wavefronts, and beam profiles. Such a direct laser source is simple and can potentially achieve high intensity stability, allowing for a robust and compact HF laser surrogate. Moreover, power scaling is straightforward.