Time filter

Source Type

Wei L.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Wei L.,Jinan University | Su K.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Su K.,Jinan University | And 9 more authors.
Spectroscopy Letters | Year: 2017

Harmful algal blooms can lead to serious environment problems, and thus monitoring and classifying microalgae have received increasing attention. Microcystis aeruginosa, Chlorella pyrenoidosa, and Nannochloris oculata all are small in size and have a similar morphology, which lead to discriminant difficulties using a traditional optical microscope. In this experiment, an independently developed hyperspectral microscopic imaging system was used to obtain the hyperspectral images of microalgae samples, and a hyperspectral dataset was developed through pretreated steps. Then the Fisher algorithm was employed to identify the species of the microalgae, and its sensitivity and specificity were found to be high. The result demonstrated that this method can classify the microalgae in a quick and convenient manner; in addition, the quantity and spatial information of the samples can be acquired. © 2017 Taylor & Francis.


Ye P.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Ye P.,Jinan University | Zhu S.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Zhu S.,Jinan University | And 10 more authors.
Optics Express | Year: 2017

A compact dual-wavelength passively Q-switched green laser by intra-cavity frequency doubling of a Yb:YAG/Cr4+:YAG/YAG composite crystal was demonstrated for the first time to our best knowledge. The maximum green laser output power of 1.0 W was obtained under the pump power of 9.7 W, and the corresponding slope efficiency is 15.2%. The shortest pulse width, largest pulse energy, and highest peak power were achieved to be 5.54 ns, 246.1μJ, and 40.76 KW, respectively. Dual-wavelength laser oscillation simultaneously at 515 nm and 524.5 nm has been achieved. This passively Q-switched dualwavelength green laser can be used as a laser source for Terahertz generation. © 2017 Optical Society of America.


Zhu S.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Zhu S.,Jinan University | Wang C.,State Key Laboratory of Luminescence Materials and Devices | Li Z.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | And 12 more authors.
Optics Letters | Year: 2016

We investigate the broadband anti-Stokes emission (BASE) from Yb 3+ -doped crystals with a laser diode (LD) pumping at 940 nm. Our experiment reveals that Yb 3+ -doped crystals with random cracks are able to generate bright BASE at room temperature and atmospheric pressure. By examining the various characteristics of the crystals and the emitted light, we supply a theory for interpreting the underlying physics for this variety of BASE. In particular, we take into consideration the effects of energy migration, avalanche process, and charge-transfer luminescence. This represents the first time, to the best of our knowledge, that BASE was obtained from Yb 3+ -doped bulk crystals with a high opticaloptical efficiency © 2016 Optical Society of America.


Zhu S.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Zhu S.,Jinan University | Zhou H.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Zhou H.,Jinan University | And 9 more authors.
Applied Optics | Year: 2016

An Nd:YAG?YAG?Cr 4+ :YAG?YAG composite crystal and an LBO crystal were used to generate a passively Q-switched frequency-doubling 473 nm blue laser for the first time, to the best of our knowledge. The result demonstrated that the slope efficiency of this system reaches 18%, which is the highest in all the passively Q-switched 473 nm laser systems reported, to the best of our knowledge. Under the pumped power of 8.64 W, the maximum average output power of 0.93 W was obtained with a pulsewidth of 78 ns, and the repetition rate of 18.5 kHz. © 2016 Optical Society of America.


Zhou H.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Zhou H.,Jinan University | Zhu S.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Zhu S.,Jinan University | And 11 more authors.
Optik | Year: 2016

For obtaining efficient passively Q-switched laser at 473 nm, an Nd:YAG/YAG/Cr4+:YAG/YAG composite crystal and a coupled cavity were employed to reduce the thermal lens effect and enable the laser system operating on high pumped power. In our experiment, the maximum average output power of 0.81 W was obtained with the repetition rate of 28.5 kHz and the pulse width of 104 ns at the pumped power of 9.79 W, corresponding to an optical-to-optical conversion efficiency of 8.27%. © 2016


Zhu S.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Zhu S.,Jinan University | Su K.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Su K.,Jinan University | And 7 more authors.
Optik | Year: 2016

We present a hyper-spectral microscopic imaging system capable of obtaining both transmission- and fluorescence-spectral images for biological measurements. For obtaining high quality images of samples with low self-fluorescence, large aperture optics and low vibration elements were implemented in the system. This study focused on obtaining different types of spectral information, i.e., transmission and fluorescence, to study the structure of the objects and observe the similarities and differences in composition at different positions. By employing this system to investigate bee pollen, we observed a special thin-film structure, which cannot be detected using conventional microscopic systems. © 2016 Elsevier GmbH


Su K.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Su K.,Jinan University | Zhu S.,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications | Zhu S.,Jinan University | And 13 more authors.
Optical Engineering | Year: 2016

The rapid and accurate classification of bee pollen grains is still a challenge. The purpose of this paper is to develop a method which could directly classify bee pollen grains based on fluorescence spectra. Bee pollen grain samples of six species were excited by a 409-nm laser diode source, and their fluorescence images were acquired by a hyperspectral microscopy imaging (HMI) system. One hundred pixels in the region of interest were randomly selected from each single bee pollen species. The fluorescence spectral information in all the selected pixels was stored in an n-dimensional hyperspectral data set, where n=37 for a total of 37 hyperspectral bands (465 to 645 nm). The hyperspectral data set was classified using a Fisher linear classifier. The performance of the Fisher linear classifier was measured by the leave-one-out cross-validation method, which yielded an overall accuracy of 89.2%. Finally, additional blinded samples were used to evaluate the established classification model, which demonstrated that bee pollen mixtures could be classified efficiently with the HMI system. © 2016 Society of Photo-Optical Instrumentation Engineers (SPIE).

Loading Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications collaborators
Loading Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications collaborators