What's old is new again: Klastech (Dortmund, Germany) has taken the ruby laser—the very first type of laser ever demonstrated—and redone the technology to create a thoroughly modern version.
As most laser engineers know, the first operating laser was built by Ted Maiman in 1960 at Hughes Research Laboratories (Malibu, CA). As is typical of ruby lasers, his prototype emitted pulses at a 694.3 nm wavelength and was flashlamp-pumped. The ruby laser has often been used to create pulsed holograms of objects and people, as its relatively high-energy pulses are brief enough and of good beam quality in both lateral and longitudinal modes.
Klastech's version, however, is not at all typical. Although it lases at the standard deep-red 694.3 nm wavelength, it is both diode-pumped (making it very stable and efficient) and continuous-wave (opening up many uses not available to pulsed ruby lasers).
Called the Crescendo, the new laser is available with output powers of up to 150 mW, with 500 mW under development. The laser emits in single longitudinal mode with a linewidth typically less than 1 MHz and a coherence length in excess of 100 m.
According to the manufacturer, an exceptionally low noise figure of under 0.05% rms is allied with a near-perfect Gaussian beam that has a pointing stability of better than 10 µrad/°C, allowing the laser to meet the requirements of a range of applications that cannot be usually met by typical diode-based lasers. Some examples are biofluorescence, flow cytometry, confocal microscopy, holography, interferometry, disc mastering, hematology, food sorting, spectroscopy, and retinal imaging.
The laser will be officially launched and demonstrated at the Klastech booth (# 359, Hall B1) at June's Laser World of Photonics Exhibition (Munich, Germany). However, Elliot Scientific (Hertfordshire, England) is now taking advanced orders for the Crescendo laser. The single-frequency laser is designed to be capable of output-power modulation while still maintaining the original diode-laser current; this mode of operation extends laser lifetime and ensures stable operating parameters, but is only available by special request at present.
