M. Yamazaki

High-power direct green laser oscillation of 598 mW in Pr 3+ -doped waterproof fluoroaluminate glass fiber excited by two-polarization-combined GaN laser diodes

We demonstrated a high-power and highly efficient Pr-doped waterproof fluoride glass fiber laser at 522.2 nm excited by two-polarization-combined GaN laser diodes and achieved a subwatt output power of 598 mW and slope efficiency of 43.0%. This system will enable us to make a vivid laser display, a photocoagulation laser for eye surgery, a color confocal scanning laser microscope, and an effective laser for material processing. Direct visible ultrashort pulse generation is also expected.

Sub-watt output power at 638nm in wavelength by direct oscillation with Pr-doped waterproof fluoro-aluminate glass fiber laser

Many researchers have developed visible laser sources for various applications including laser projectors, laser displays and medical devices. For medical devices, a red laser beam is useful for photocoagulation of bleeding sites due to its minimal absorption by hemoglobin.

Watt-order output power at 638 nm in wavelength by direct oscillation with Pr-doped fiber laser

We have demonstrated a high power red fiber-laser with a Pr3+-doped waterproof fluoro-aluminate glass fiber. The maximum output power of the 638 nm laser beam was measured to be 1.24W.

Stimulated emission cross sections of Pr doped fluoride glass evaluated by Judd-Ofelt analysis

There are many applications on visible lasers, such as display technique, medical equipments, spectroscopy, and microscopy. If the laser power becomes higher around several tens to hundreds watt, it will be very useful tool for metal welding and cutting. Pr3+-ions offer a variety of transitions in the visible and near infrared spectral range. Therefore, Pr3+ doped transparent media are very hopeful for visible lasers.

Visible Q-switched pulse generation in Pr-doped double-clad structured waterproof fluoro-aluminate glass fiber

Development on primary visible solid-state lasers (PVSSL) are very fascinating because the laser has many applications, for example, medicine, biology, and optical measurement systems. We have been developing a visible primary fiber laser with Pr-doped waterproof fluoro-aluminate glass fiber (Pr:WPFGF), and reported a single-mode laser performance in a double-clad structured Pr:WPFGF (Pr:DC-WPFGF) [1]. Recently, some reports on pulse generation in Pr:YLF were published [2, 3], and therefore, it is considered that research of visible laser pulse generation in Pr-doped materials has begun to be activated and another application on the PVSSL will be opened up. In this paper, we report a visible Q-switched pulse generation in Pr:DC-WPFGF.

575 nm laser oscillation in Dy3+-doped waterproof fluoro-aluminate glass fiber pumped by violet GaN laser diodes

We successfully drew a low-loss Dy-doped optical fiber (0.3dB/m at 532nm) of a waterproof fluoro-aluminate glass system and demonstrated yellow laser oscillation in the Dy3+-doped fluoride fiber pumped by a 398.8-nm GaN laser diode. The maximum output power was 10.3 mW and the slope efficiency was 17.1% at 575 nm. Since the fluoro-aluminate- glass system has a remarkable water resistance advantage compared to ZBLAN glass, Dy-doped fluoro-aluminate glass fiber is expected to contribute to making a solid-state yellow fiber laser with high chemical durability without a frequency doubling technique.

Visible laser oscillation in single-mode Pr-doped double-clad structured waterproof fluoro-aluminate glass fiber

We demonstrated a visible laser oscillation in a Pr-doped double-clad structured waterproof fluoro-aluminate glass fiber. The maximum output power and the slope efficiency were measured to be 251.7 mW at 639.0 nm and 43.4%, respectively.

Visible short pulse generation in waterproof fluoro-aluminate glass fibers using graphene thin film

We have successfully generated a Q-switched short pulse in a Pr-doped waterproof fluoro-aluminate glass fiber using a single layer graphene as a saturable absorber. The laser pulse duration was observed to be 17.6 ns.

High power red laser oscillation in Pr3+-doped waterproof fluoroaluminate glass fiber excited by a GaN laser diode

We have demonstrated a high power red fiber laser with a Pr-doped waterproof fluoro-aluminate glass fiber (Pr:WPFGF). When 800 mW pumping power of a blue/violet GaN laser diode (GaN-LD) was launched into the Pr:WPFGF (core diameter 8 μm, length 40 mm) with dielectric coating on both end surfaces to construct a resonator, the maximum output laser power at 638 nm was obtained to be 311.4 mW that is higher than previously reported Pr:ZBLAN fibers. The threshold power was evaluated to be 52.1 mW, and the slope efficiency was calculated to be 41.6%. Assuming the resonator to be a Fabry-Perot resonator, we can calculate the output power to be 336 mW at 800 mW pump power and the slop efficiency to be 44.2%. These theoretical values show good agreement with experimental ones.

Multi-color laser oscillation in a waterproof Pr 3+ -doped fluoro-aluminate glass fiber pumped by GaN laser diode

We successfully drew a Pr-doped optical fiber of a waterproof fluoro-aluminate glass in an AlF<inf>3</inf>-YF<inf>3</inf>-PbF<inf>2</inf> system with low loss (0.1 dB/m) and demonstrated multi-color laser oscillation pumped by a 442.6-nm GaN laser diode.