4.5-ns Pulse generation at a 500-kHz repetition rate from a short-cavity acoustooptically Q-switched Nd:YVO4 laser

High efficiency 355 nm laser by employing a flat-flat cavity with improved harmonic beam quality

“…A photoelectric detector (DET10A/M, Thorlabs Corporation) and a digital oscilloscope (DPO 4104B, Tektronix Corporation) are used to detect and measure the pulse duration, respectively. The pulse duration increases from 8.6 ns to 16.4 ns for 355 nm laser in the whole process, due to the weakened gain in the shortened pulse period [9], as shown in figure 3. The output power increases monotonically with the repetition rate from 10 kHz to 50 kHz.…”

A fundamental mode miniature acousto-optically Q-switched Nd:YVO4 laser with short pulse width at high repetition rates

“…We had obtained 4.5 ns pulses at 500 kHz repetition rate [17]. However, due to the severe thermal lens effect, the mode area in the cross section was small, which led to low modematching efficiency and higher order modes oscillation, with beam quality factor about 5 [17]. In this paper, the mode-matching efficiency is improved by improving the pump beam quality and utilizing the optimal pump beam waist radius and location.…”

“…To achieve short pulses at high repetition rates, high gain is necessary, so high intensity pump light is launched into the gain medium, which leads to short thermal focal length. The focal length can be shorter than 40 mm under high pump intensity in the miniature solid-state laser, which is comparable to the crystal length [17]. The thin lens approximation condition is not well satisfied [19], and the thermal lens should be treated as thick lens.…”

“…By increasing the pump intensity, miniature lasers can be operated at much higher repetition rates. We had obtained 4.5 ns pulses at 500 kHz repetition rate [17]. However, due to the severe thermal lens effect, the mode area in the cross section was small, which led to low modematching efficiency and higher order modes oscillation, with beam quality factor about 5 [17].…”