Characteristics Of Semiconductor Disk Frequency Doubled Laser

Semiconductor disk laser was applied widely in Bio-medicin, optical data storage, chemical sensor and as the pump sources of other lasers, because of its advantages of compactness, low power consumption, good beam quality, flexible wavelength and little thermal lens effect. In addition, semiconductor disk lasers hold the advantages of both semiconductor laser and solid-state laser. In one hand, its wavelengths cover from visible to near infrared region by using the well-developed semiconductor band engineering, which is the advantage of semiconductor laser; on the other hand, it has the advantages of solid-state laser, such as the high output power and high beam quality at the same time. The intra-cavity frequency doubling, tunable operating and passively mode-locking can also be realized conveniently.Besides of the applications of the normal Semiconductor disk lasers, Semiconductor disk frequency doubled laser was used in laser projection display, bio-analystical instruments and trace-evidence recovery, as its advantages of tunable wavelength, power scalability, good beam quality, high conversion efficiency. So far, there is no semiconductor laser which could emit green laser directly. In this dissertation, we obtained green laser at 515nm by frequency doubled semiconductor disk laser, which could be applied in laser TV set and some other aspects.The main works in this paper are as follows:1. We briefly reviewed the advances of semiconductor disk laser, and then reviewed the advances and applications of semiconductor disk frequency doubled laser.2. We compared the parameters of some common frequency doubling crystals, and finally selected the LBO, KTP and KN as the frequency doubling crystals in our experiment. The method of how to calculate the phase-match angles and effective nonlinear coefficients of uniaxial crystal and biaxial crystal was introduced and the phase-match anglesθ,φand effective nonlinear coefficients deff of LBO, KTP and KN were also calculated which were used in the experiment.3. The intra-cavity frequency doubled laser was successfully demonstracted in the experiment. Firstly, we introduced the schematics and operating principle of the semiconductor gain chip. Hence, we used two kinds of cavitys to get lasers: straight cavity and folding cavity. Simulated and calculated the lengths of cavity and beam waist radiuse in these two kinds of cavity respectively. In the experiment, we used the LBO, KTP and KN crystals to obtain the frenquency doubled laser and gave the curves of the relationship between frequency doubled laser power and the fundamental laser power. The experimental results were discussed finally.4. The heat produced in the gain chip used in the experiment increased quickly when the pump power increasing. When the heat went to some extent, the oscillating laser will be extinguished. Namely, thermal effect of the gain chip will limit emitting power of the semiconductor disk laser. For all of these reasons, the heat spreading of the semiconductor disk laser is very important. We simulated the heat spreader conditions with two methods: substrat removing and heat spreader bonding and compared these two results.