Huiming Tan

Efficient generation of a CW 593.5-nm laser by intracavity sum-frequency mixing with a BiB3O6 (BIBO) crystal

A compact, efficient yellow-orange light at 593.5 nm was realized by the intracavity sum-frequency mixing using a BIBO crystal in a diode-pumped Nd:YVO4 laser. At an incident pump power of 3.5 W, up to 126 mW of CW output light at 593.5 nm was achieved with a 1.5-mm-long critical phase-matching BIBO. The optical-to-optical conversion efficiency was up to 3.6%, which was comparable to a 5-mm-long LBO. The beam equality was excellent with an ellipticity of 0.97 and output noise of less than 0.8% (rms). Results confirm that the BIBO is an efficient material for frequency conversion in the visible region.

Compact KTA-based intracavity optical parametric oscillator driven by a passively Q-switched Nd : GdVO4 laser

We present a compact and efficient KTA-based intracavity optical parametric oscillator (IOPO) driven by a diode-end-pumped Nd:GdVO(4)/Cr:YAG passively Q-switched laser. At the incident diode pump power of 9.2 W, signal (1.53 microm) and idler (3.47 microm) average output powers of up to 744 and 356 mW, respectively, have been obtained. The total (signal+idler) optical-to-optical conversion efficiency is as high as 12%. By using the knife-edge method, near-diffraction-limited signal and idler beams have been detected, and the M(2) factors are well within 1.2. In addition, based on the ABCD matrix theory, the impact of mode matching and the thermal lens effect on the OPO output have been analyzed.

Diode-pumped 671 nm laser frequency doubled by CPM LBO

Abstract A design of diode-pumped high-efficiency Nd:YVO4/LBO red laser is reported. Using critical phase-matching (CPM) LBO, 671 nm red laser was obtained from 1342 nm light by intracavity frequency doubling. With an incident pump laser of 800 mW , using type-I and type-II CPM LBO, 97 and 52 mW TEM 00 mode red laser outputs were obtained, with optical-to-optical conversion efficiencies of up to 12.1% and 6.5%, respectively.

Generation of a 578-nm Yellow Laser by the Use of Sum-Frequency Mixing in a Branched Cavity

A compact, continuous-wave, solid-state laser at 578 nm has been demonstrated, for the first time to our knowledge, by use of intracavity sum-frequency mixing from a branched cavity with an LBO crystal. Two gain mediums, namely, the Nd:YAG single crystal and the Yb:YAG single crystal (with a disk laser setup), are used to generate the two fundamental 1319- and 1030-nm waves, respectively. The maximum output power of 37.5 mW is obtained at a total pump power of 14 W. The power stability value of the output laser is better than 4.3% in 30 min.

Analysis of sharpness Fano resonance curve based on eye-like resonators

For given intrinsic losses of a single ring resonator sensor, there exists the maximum sharpness, at the extinction ratio of -6dB. However, the maximum sharpness of a single ring resonator sensor is sensitive for the coupling coefficient. In order to obtain the maximum sharpness, the coupling region of the single rings must have a higher precision of manufacture. To solve this problem, this paper proposed eye-like resonator which is formed by a ring resonator (named inner loop) embedd in the dual-bus-coupled ring resonator (named outer loop). Eye-like resonators can generate the asymmetric Fano-resonance spectra of the drop port, numerical calculation of spectra on the drop port is utilized by the transfer matrix method. As the round trip loss varies, the maximum value of sharpness and the corresponding transmission at the resonant point can be obtained by tuning the phase ratio of the outer loop to the inner loop. The maximum value of sharpness increases with the round trip loss, as the outer loop and inner loop coupling coefficient changing, the maximum value of sharpness of Fano-resonance change slowly in a wide range. As the round trip loss and coupling coefficients of the outer loop and inner loop varies, the corresponding transmission at the resonant point remains almost the same, about -6dB. The sharpness of Fano resonant peak is insensitive for the coupling coefficients, which can reduce the requirements of manufacture of coupling region.

LIBS: A new method for heavy metal in biomedical field and applied in plasma medical

Laser induced breakdown spectroscopy (LIBS) is characterized by non-contract and real-time analysis, which can meet the need of high-speed and automatic in industry and agriculture production and biomedical field. In this paper, the lead concentrations of samples included in glass, pig blood and so on are determinate by LIBS, based on a Nd: YAG Q-switched pulse with wavelength 1064 nm as an exciting source and nongated CCD in common spectrograph as detector. The energy of pulse on the surface of samples is about 100mJ and the width of pulse is 12ns. By the detection of different samples, we definite the detection limit of lead in samples is found to be 0.0074% and the LOD in theory is 0.0074% based on the LIBS system of the instruments all made in China. We found that the difference between the common pig blood and the organic pig blood is the content of K. The results suggest that the accuracy of determination of lead meets the challenge of quantitative analysis and the CCD can displace the ICCD which is very expensive as detector. The feasibility and low cost of the method which uses common spectrometer and CCD to realize the LIBS detection is proved by the result and our investigation will be beneficial to the LIBS application in biomedical field and food safety.