Optimization algorithm for the pump structure of diode side-pumped solid-state lasers

Ogawa

et al. 2010

J. Opt.

Self Cite

In this paper, the birefringence in an LD-side-pumped solid-state laser (LSPSSL) system is studied by using a quasi plane-wave probe beam. The effects on birefringence compensation have been investigated for different coupling systems arranged between two tandem-set rods. Both the aperture obstruction and the thermally induced lens effect have been taken into consideration in the theoretical explanation. It is shown that most birefringence can be successfully removed by using a suitable lens system as well as a quartz 90° rotator. In construction of a real resonator, such performances as the birefringence compensation, the extraction efficiency, and the high-order-mode control must be carefully balanced at the same time. Although the conclusions are based on analyses of a one-way travelling wave, the methodology introduced in this paper is thought to be useful for a stationary-wave design of the laser oscillator.

Section: Experiments and Discussionmentioning

confidence: 99%

Analyses of different configurations for a multiple rod Nd:YAG system with a one-way travelling probe beam

You

Ogawa

et al. 2010

J. Opt.

Self Cite

“…The pump structure has been designed on the basis of a published algorithm with both high absorption efficiency and homogeneous absorption distribution [17]. Figure 5…”

Section: Experiments and Discussionmentioning

confidence: 99%

“…in various challenging diode pumped solid-state lasers (DPSSLs) [11][12][13][14]. Conquering thermal effects in DPSSLs will undoubtedly bring about an increasing utilization in many industrial fields [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Study on thermally induced depolarization of a probe beam by considering the thermal lens effect

Wang

Inoue

J. Phys. D: Appl. Phys.

et al. 2009

Self Cite

In this paper, we present an accurate theoretical description of the birefringence characteristics in a Nd : YAG rod by taking the thermal lens effect into account. Considering that the birefringence is strongly dependent on the distance away from the centre of a birefringent rod, the convergent features of an incident probe beam were first evaluated for a side-pumped laser rod. A segmental accumulation method was then employed to calculate the total phase shift between the radial and the tangential components of polarization of a converged probe beam. The theoretical conclusions were compared with the measured results in both the degree of depolarization and the spatial birefringent distribution of a transmitted He–Ne laser beam. The experimental results are in good agreement with the theoretical ones so that we believe the algorithm given in this paper should be effective for the construction of a high-powered laser or amplifier system.

“…Among the techniques in elimination of TIB, a method using two laser rods in tandem and an optical rotator located between two rods that rotates the polarization direction by 90 • is very popular with the researchers in the field of laser engineering [20][21][22][23][24][25][26][27]. Because the birefringence strongly depends on the pump structure and shape of a laser medium, the thermal lens effect, which is another main thermally induced phenomenon caused by refractive-index gradient and stress strain within a laser rod, will definitely interfere with the TIB evaluation in particular for a highpowered DPSSL system [28][29][30][31][32][33]. Nevertheless, for the purpose of simplification of the mathematical processing, the thermal lens effect is often neglected during the design of a resonator or an amplifier with the configuration with tandemset multiple rods [34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Aperture obstruction influences birefringence evaluation of a Nd : YAG laser system with tandem-set rods

Wang

J. Phys. D: Appl. Phys.

Ogawa

et al. 2010

Self Cite

In this study, we derive a theoretical and experimental expression for evaluating the thermally induced birefringence (TIB) in a Nd : YAG laser system with double rods in tandem. The analytical solution determines the optimum oscillator geometry corresponding to the minimum depolarization loss while the so-called aperture obstruction is considered in the calculation model. It can be seen that the experimental results closely follow the theoretical evaluation for both the depolarized degree and the birefringent distribution of a probe beam. We also find that the traditional evaluation method, which neglects the thermally induced lens effect and aperture truncation during the optical design, leads to an obvious deviation in determining the optimum arrangement of a laser system for compensation of birefringence. The method presented in this paper is thought to be useful in analysing any high-powered oscillators or amplifiers with high pulse energy.