Stefan Spiekermann

Generation of turquoise light by sum frequency mixing of a diode-pumped solid-state laser and a laser diode in periodically poled KTP

We report a simple and efficient method to achieve visible light by sum-frequency mixing radiation from a diode-pumped solid-state laser and a laser diode in a periodically poled KTiOPO4 crystal. Since high-power laser diodes are available at a wide range of wavelengths, it is thereby possible to obtain essentially any wavelength in the visible spectrum by appropriate choice of lasers. For demonstration we choose to construct a light source in the blue-green region. A turquoise output power of 4.0 mW was achieved.

Efficient frequency conversion of a passively Q-switched Nd:YAG laser at 946 nm in periodically poled KTiOPO 4

Efficient continuous-wave and passively Q-switched diode-laser-pumped Nd:YAG lasers at 946 nm are reported together with results on highly efficient frequency doubling. Periodically poled KTiOPO(4) was employed as the nonlinear material because of its high nonlinearity and its resistance to photorefractive damage. In the blue spectral region we measured 76 mW in continuous wave and 285 mW in the Q-switched mode.

Ultraviolet single-frequency pulses with high average power using frequency-converted passively Q-switched quasimonolithic Nd:yttrium–aluminum–garnet ring lasers

We demonstrate a compact ultraviolet light source based on frequency-converted diode-pumped passively Q-switched miniature Nd:yttrium–aluminum–garnet (YAG) ring lasers. A unique pulse-to-pulse stability in single-frequency operation is obtained by diffusion-bonding the Nd:YAG crystal with the Cr4+:YAG saturable absorber crystal to form an all-solid-state quasimonolithic ring laser cavity. Amplified in a longitudinally pumped Nd:vanadate (YVO4) crystal and single-pass frequency quadrupled in periodically poled potassium titanyl phosphate and barium borate crystals, an average output power of 485 mW at 266 nm with 25 μJ pulse energy is achieved with an overall efficiency of 3.3% with respect to the diode pump power.

Recent developments of periodically poled KTP and isomorphs

Summary form only given. We discuss material related issues of relevance for periodic poling of PPKTP and discuss the performance of this new ferroelectric material in various nonlinear optical experiments, including second harmonic generation, optical parametric generation, optical parametric oscillation. Recent results on mode-locking using PPKTP as a nonlinear mirror are also discussed.

Periodically poled KTP for nonlinear optical applications

As periodically poled KTP (PPKTP) maintain the high photorefractive resistance of KTP this new material is well suited for wavelength shorter than what is accessible by birefringent phasematching. PPKTP has been investigated for blue and UV second harmonic generation, and initial results show that it is a quite promising alternative to KNbO/sub 3/, LBO, BBO and other commonly used nonlinear crystals for this wavelength region. In this presentation we will discuss material related issues of relevance for periodic poling of PPKTP and discuss the performance of this new material in various nonlinear optical experiments, including second harmonic generation, optical parametric generation, optical parametric oscillation.

Ultraviolet single-frequency ns-pulses with high average output power

Summary form only given. There is a high demand for ultrastable, ultra-violet single-frequency pulses in a large number of applications. Two examples are writing fiber Bragg gratings and LIDAR systems. Both applications need high average output power. However, a very compact approach to obtain single-frequency UV pulses has been realized, but the average output power was low. Other similar laser systems lead to sufficiently high average output power, but suffer from low pulse to pulse stability. We report on a laser system that combines the advantages of both of the previous laser systems, single-frequency operation and high average output power.