Passively Q-switched sub-100 ps Yb3+:YAG/Cr4+:YAG microchip laser: experimental results and numerical analysis

Abstract

We demonstrate sub-100 ps pulses with a Yb 3+ :YAG microchip laser passively Q-switched by a Cr 4+ :YAG saturable absorber. By introducing a subcavity, the laser threshold and the saturation energy are decreased which helps to prevent damage and to vary the effective emission and absorption cross sections. Pulse widths of 84 ps, repetition rates of 3.3 kHz and pulse energies of 32 µJ are achieved. This allows direct micromaterial processing e.g. for ophthalmic surgeries. To the best of our knowledge, this is the first sub-100 ps Yb 3+ :YAG/Cr 4+ :YAG microchip laser. A new approximation is used to calculate the rate equations for multiple longitudinal modes and to determine the threshold for single-longitudinal-mode operation.

Ophthalmic surgeries on post mortem porcine eyes with picosecond ultrashort laser pulses

“…Therefore, the size- and cost-related disadvantages of former picosecond lasers are counteracted, as these systems consist of a two-stage set-up with two different laser resonators. The new approach is just one single micro-chip resonator with (if needed) subsequent pulse compression and/or pulse amplification ( 24 , 25 ). Thus, the new technology is much simpler than existing systems, leading to a cost reduction and prices comparable to that of state-of-the-art ophthalmic nanosecond lasers.…”

“…This paper discusses the use of an ultrashort pulse laser source emitting in the picosecond regime for ophthalmic surgeries and evaluates the potential benefits of these lasers, particularly for iridotomy, capsulotomy/post-cataract treatment and selective laser-trabeculoplasty (SLT). This research was motivated by ultra-compact Q-switched picosecond lasers recently becoming available, combining the advantages of the low price of currently used ns laser sources with cold material ablation capabilities of high-end femtosecond lasers ( 24 , 25 ).…”

Rate Equations Model to Simulate the Performance of Passive Q-Switched Laser with Raman Medium Optical System

“…The novelty of model included six rate equations, it is represents the development of rate equations models consisting of five equations as the reference (10) , or four equations as the reference (11) . In order to as certain the physical concepts and the mathematical relations https://www.indjst.org/ (8,9) of this model, the model was tested theoretically by numerical simulation of a laser system consist of Nd:YVO 4 used as AM and Cr +4 : YAG as a SA, and PbWO 4 crystal used as the RM. showed good agreement with studies which dealt the Stokes anti-Stokes pulses generation by Raman scattering theory as shown in reference exhibit a steeper gaussian pulse shape and smoother pulse edges.as shown in ref (12) .…”

Rate Equations Model to Simulate the Dual Generation of Nd+3: YAG Passive Q-Switched Laser Pulses

“…Materials commonly used for PQS are organic dyes, doped crystals, and semiconductors (4)(5)(6) . The Neodymium (ND +3 ) additive to another host for using active medium laser is the one of commonly used type of the solid state laser (5)(6)(7) . ND +3 ions doped fiber (AM) used as active medium in this study.…”

“…Lasing takes place from 4 F 3/2 to 4 I 11/2 or 4 I 9/2 spectrum lines as a four and quise-three levels schemes respectively. However, there population is replenished by thermal transition until both levels are depleted (7,8) , resulting in the emission of photons, has 1064 nm and 964 nm wavelength as shown in Figure 1. PQS technique using saturable absorber (SA) is one of the techniques that can be utilized in obtaining high power pulses, Cr +4 : YAG has wide absorption band, it is an excellent SA material for passive Q-switching in the wavelength range 800 nm to 1200 nm.…”