Study On All Solid State Yellow Lasers And Their Noise Characteristics

Laser diode (LD) pumped all-solid-state lasers have the advantages of compact, excellent beam equality, long life, and so on. Combined with nonlinear frequency conversion technology, laser lines can be extended to the yellow band so that all solid yellow lasers can be applied in more new applications. Currently, the yellow lasers have a wide range of applications in biomedicine, bio-detection, laser display technology and other fields. It has become one of the research focus in laser field. However, many applications demand low laser noise, particularly in the biomedical field, which makes it important for all solid and yellow laser noise characteristics research. Based on the solid-state yellow 593 nm,561nm and 578nm laser, the following several aspects of research work on intracavity frequency doubling and sum frequency mixing solid-state lasers output and their noise characteristics has been done.1、Based on the theory on light propagation in nonlinear media, combined the double wave plate Jones matrix, coupling output equations of the intracavity frequency doubling and sum frequency mixing lasers were deduced in detail. The corresponding nonlinear rate equations of the intracavity fundamental laser oscillation were established. According to the ways of phase matching for nonlinear frequency conversion and the types of gain medium, corresponding rate equations were given. Rate equations of different longitudinal mode structure were studied by numerical calculation and the stability of the nonlinear laser systems were analyzed by nonlinear dynamic method.2、Spectral line suppression mechanism of the etalon and the birefringent filter has been researched. The spectral lines of 1112 nm and 1116 nm were suppressed through a birefringent filter in a 3 W LD pumped Nd:YAG laser. The second harmonic generation (SHG) of 561 nm was achieved by placing the nonlinear optical crystal LiB3O5 (LBO) in the cavity. The single wavelength average output power at 561 nm was ～70 mW. The two states of the 561nm single wavelength laser output noise were analyzed based on the theory of the noise for type-Ⅰ phase matching SHG and the corresponding longitudinal mode structure.3、Two fundamental wavelengths are oscillated in a laser diode array (LDA) pumped Nd:YVO4 laser. Continuous wave (CW) sum frequency generation (SFG) of 593.5nm is achieved by placing the LBO crystal cut as type-Ⅰ phase matched in the cavity. Noise characteristics of CW intracavity SFG laser was measured and analyzed in different experiment conditions. Fabry-Perot (F-P) scanning interferometer and beam profile instrument were used to measure the multi-longitudinal modes structure and transverse modes pattern of the SFG laser, respectively. Based on the coupling output equation of the LDA pumped Nd:YVO4 intracavity SFG laser, the relationship between the output laser noise characteristics and the modes structure was analyzed. The output power of 110 mW at 593 nm with a RMS noise below 1.6% was achieved.4. A compact 578nm yellow laser is proposed and demonstrated using the doubly resonant cavity. The two gain mediums which were employed to generate two fundamental waves:Nd:YAG single crystal and Yb:YAG thin-disk crystal. One LDA emitting at the wavelength of 808 nm was employed as the end-pumping source for Nd:YAG and the other LDA emitting at the wavelength of 940 nm was used to pump Yb:YAG disk crystal with a four-pass pump configuration. To optimize the design of the doubly resonant folded cavity, realization of thermal insensitive cavity and optimum focusing at the beam waist in the folded arm were taken into account. The polarization property of the fundamental and the SFG waves were analyzed. Furthermore, the single wavelength laser output at 578 nm was achieved by using the spectral line suppression technology of etalon.