Self-Induced Instabilities in Nd:Y₃Al₅O₁₂Ceramic Lasers

Abstract

We systematically studied dynamic effects in Nd-doped Y3Al5O12 (YAG) ceramic lasers having different Nd concentrations. A variety of dynamic instabilities, including square wave periodic pulsations, were found to take place due to the increased grain boundaries in highly-doped samples.

Ultrafast Transparent Ceramic Scintillators Using the Yb$^{3+}$ Charge Transfer Luminescence in RE$_{2}$O$_{3}$ Host

“…The development of ceramic laser materials triggered the manufacturing technology and such materials became available with arbitrary shape and in large optical elements. [13][14][15][16][17][18] In the present study, we report the first results of the scintillation properties of Yb 3þ -doped transparent ceramic sesquioxides.…”

Polarization Properties of Laser-Diode-Pumped Microchip Nd:YAG Ceramic Lasers

“…In this section, our experimental results concerning lasing pattern formations due to grain boundaries and the resultant dynamic instabilities observed in Nd:YAG ceramic lasers (Kawai et al, 2004;Narita et al, 2005;Otsuka et al, 2006) are reviewed.…”

Nonlinear dynamics in thin-slice Nd:YAG ceramic lasers: Coupled local-mode laser model

“…[1][2][3][4][5][6][7] In this letter, we propose the model of coupled localmode lasers for understanding instabilities in thin-slice Nd:YAG ceramic lasers with coated end mirrors reported before. 8,9 With a generalized model of coupled local-mode ͑i.e., filament͒ lasers proposed here, observed dynamic effects are shown to be explained from various aspects, without assuming a conjectured formation of "nonorthogonal transverse modes," [8][9][10] although both models can explain modal-beating type of high-speed modulations.…”

“…The experimental setup is the same as before. 9 A collimated elliptical-shape pump beam from the LD was passed through a pair of anamorphic prisms to transform the elliptical shape into a circular one, and then it was focused onto the surface of Nd:YAG ceramic lasers by microscope objective lenses with different magnifications, i.e., M =10ϫ ͓numerical aperture ͑NA͒ = 0.25͔ and 20ϫ ͑NA= 0.4͒. All the samples were 5 mm in diameter and 1 mm in thickness, and end surfaces were coated by the same dielectric mirrors M 1 ͑99.9% reflection at l064 nm and high transmission at 808 nm͒ and M 2 ͑98% reflection at 1064 nm͒.…”

“…Various modulation patterns featuring periodic and breathing-type wave forms at beating frequencies of adjacent local modes were observed by slight changes, e.g., several tens of microns, in pump positions similarly to the previous results observed in Baikowski samples. 9 Examples of highfrequency modulation wave forms and corresponding power spectra observed for different pump-beam ͑i.e., lasing beam͒ diameters observed in a 3.6 at. % doped sample are shown in Fig.…”