Kilohertz high power extracavity KGW yellow raman lasers based on pulse LD side-pumped ceramic Nd: YAG

Abstract

We report an efficient operation of a kilohertz nanosecond extracavity KGd(WO 4 ) 2 (KGW) crystal Raman yellow laser, which is pumped by a 532 nm lasers based on pulse laser diode (LD) side pumped ceramic Nd : YAG, BBO electro optical Q switched and LBO crystal extracavity frequency doubling. With the 5 W, 10 ns and 1 kHz output power pumped at 532 nm, we obtained 2.58 W, 7.4 ns, 1 kHz second Stokes Raman laser output at 579.54 nm for 768 cm -1 Raman shift of KGW crystal, corresponding to a conversion efficiency of 51.4%. By changing the KGW crystal orientation, we further obtained 3.18 W, 7.8 ns, 1 kHz Raman pulses at 588.33 nm for 901 cm -1 Raman shift, corresponding to a conversion efficiency of 63.3%.The beam quality factors M 2 of 579.54 and 588.33 nm were ( = 5.829, = 6.336) and ( = 6.405, = 6.895), respectively.

Simultaneous brightness enhancement and wavelength conversion to the eye‐safe region in a high‐power diamond Raman laser

“… demonstrated a visible Raman laser with an improved beam quality factor from 11 to 6.5 to provide a deduced value of of approximately 0.8. Similar enhancement factors have also been observed in KGW and diamond . In our case, is much higher than previously achieved due to the good efficiency and large increase in beam quality, and for the first time is shown to exceed unity.…”

High power tungstate-crystal Raman laser operating in the strong thermal lensing regime

“…Laser threshold was achieved for an average pump power of 18 W which corresponds to peak power intensity in the waist of approximately 54 MW/cm 2 . The threshold intensity is approximately twice that seen in similar 532 nm-pumped KGW lasers [17,18], consistent with the lower gain coefficient expected for the our longer pump wavelength. The output power increases with pump power as shown in Fig.…”

“…For instance, athermal crystal cuts of KGW have been investigated [11][12][13][14][15][16] where the phase shifts due to the thermo-optical effect and thermal expansion are balanced with the aim to ameliorate thermal induced phase distortions. However, maximum Raman laser powers investigated for this crystal class thus far have been in a low power regime in which thermal effects are small [17][18][19][20]. An improved knowledge in the response of double metal tungstates at higher power is important for enabling the crystal properties to be better understood and to assist high power laser design.…”