Takayuki Yanagisawa

Diode proximity-coupled Nd:GdVO 4 planar waveguide laser

We demonstrated a compact linear-polarized planer waveguide laser with diode proximity-coupling pump geometry, and uniaxial laser material of Nd:GdVO4 The laser cavity size is as small as 4-mm times 1 mm including the 5-stripe pumping diode, the total output power of 1.7-W for five independent nearly diffraction- limited beams was obtained at the pumping diode output power of 5.7-W.

1.5-/spl mu/m coherent lidar using a single-longitudinal-mode diode-pumped Q-switched Er,Yb:glass laser

Summary form only given. Coherent lidar is a useful sensor for wind velocity detection in clear air conditions. Coherent lidars in the eye-safe wavelength region (>1.4 /spl mu/m) with 2-/spl mu/m pulsed lasers such as Ho,Tm:YAG or Tm:YAG were developed because eye-safety is required for laser equipment used in the field. Compared to the wavelength of 2-/spl mu/m, the maximum permissible exposure for human eyes is ten times higher at the wavelength of 1.5-/spl mu/m. In addition, reliable optical fiber components and devices for optical fiber communication are easily available at this wavelength. We have developed a 1.5-/spl mu/m coherent lidar using a single-longitudinal-mode diode-pumped Q-switched Er,Yb:glass laser with an injection seeding and a cavity length controller.

High average power conductive-cooled diode-pumped Nd:YLF MOPA system

Summary form only given. Recent progress of diode pumped solid state lasers (DPSSL) has demonstrated its potential for highly efficient and high power operation with good beam quality, compactness and high reliability. Moreover, for space-borne use, conductive-cooling is the preferred system compared with conventional liquid-cooling in ground-based system. However, the cooling techniques for the active medium have been at the development stage. In particular, conductive-cooling for simple rod-type active medium is more difficult than that for slab-type active medium. We have developed a conductive-cooled Q-switched diode-pumped Nd:YLF MOPA system which provides an output average power as high as 50-W. To our knowledge, this is the highest average power for this kind of systems, being an order of magnitude greater than the previously reported conductive-cooled Q-switched rod laser systems.

Development of Ti:sapphire laser for airborne water vapor DIAL

Summary form only given. Airborne and spaceborne water vapor differential absorption lidars (DIALs) are very useful for understanding the global hydrological cycle. From the system requirements, the output wavelength accuracy, multi-wavelength operation and high repetition rate operation are required to obtain high measurement accuracy and high spatial resolution. To realize these requirements, we have developed a high repetition rate wavelength switching Ti:sapphire laser by means of a three wavelength switching injection seeder and rapid cavity tuning corresponding to the seeding wavelength. The system consists of KTP-SHG and conductive-cooled diode-pumped Q-switched Nd:YLF MOPA system for pumping, a three wavelength switching injection seeder unit and a gain-switched Ti:sapphire laser.

High-average-power conductive-cooled diode-pumped Nd:YLF laser

Summary form only given. We have demonstrated a 72 W average power conductive-cooled diode pumped Nd:LiYF/sub 4/ laser with optical efficiency of 43%. We believe this power and efficiency is high enough for almost spaceborne use.