Biomedical Engineering Laboratory for Photoelectric Sensing Technology

Shenzhen, China

Biomedical Engineering Laboratory for Photoelectric Sensing Technology

Shenzhen, China
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Zhang Y.,CAS Shenzhen Institutes of Advanced Technology | Zhang Y.,Chinese University of Hong Kong | Zhang Y.,Biomedical Engineering Laboratory for Photoelectric Sensing Technology | Lu Y.,CAS Shenzhen Institutes of Advanced Technology | And 10 more authors.
Journal of Applied Optics | Year: 2017

A laser alignment measurement method based on a focusing objective and PSD is proposed in order to solve the problem of mathematical model in traditional laser alignment method, which is complex and difficult to work out. Misalignment angle deviation and position deviation are acquired using relations between field of view and focal length of the optical system, and the principle of similar triangle. The measurement principle is simple and easy solving. The experiment results show that when position measurement range is 0.5 mm~1.5 mm and angle measurement range is 0.0477°~0.1432°, accuracy of position deviation measurement and angle deviation measurement are 0.035 mm~0.207 mm and 0.0002°~0.012 8° respectively. Finally, error of accuracy is analyzed and a method considered for eliminating influence of installation error is proposed, and a theoretical formula is given. © 2017, Editorial Board, Journal of Applied Optics. All right reserved.


Liu W.-Q.,CAS Shenzhen Institutes of Advanced Technology | Liu W.-Q.,Biomedical Engineering Laboratory for Photoelectric Sensing Technology | Liu W.-Q.,University of Chinese Academy of Sciences | Liu W.-Q.,Chinese University of Hong Kong | And 23 more authors.
Chinese Physics B | Year: 2016

Spectroscopic measurements and terahertz imaging of the cornea are carried out by using a rapid scanning terahertz time domain spectroscopy (THz-TDS) system. A voice coil motor stage based optical delay line (VCM-ODL) is developed to provide a rather simple and robust structure with both the high scanning speed and the large delay length. The developed system is used for THz spectroscopic measurements and imaging of the corneal tissue with different amounts of water content, and the measurement results show the consistence with the reported results, in which the measurement time using VCM-ODL is a factor of 360 shorter than the traditional motorized optical delay line (MDL). With reducing the water content a monotonic decrease of the complex permittivity of the cornea is observed. The two-term Debye relaxation model is employed to explain our experimental results, revealing that the fast relaxation time of a dehydrated cornea is much larger than that of a hydrated cornea and its dielectric behavior can be affected by the presence of the biological macromolecules. These results demonstrate that our THz spectrometer may be a promising candidate for tissue hydration sensing and practical application of THz technology. © 2016 Chinese Physical Society and IOP Publishing Ltd.


Liu W.-Q.,CAS Shenzhen Institutes of Advanced Technology | Liu W.-Q.,Biomedical Engineering Laboratory for Photoelectric Sensing Technology | Liu W.-Q.,Chinese University of Hong Kong | Lu Y.-F.,CAS Shenzhen Institutes of Advanced Technology | And 16 more authors.
Optics Communications | Year: 2016

We present a study aimed at developing a terahertz time domain spectroscopy (THz-TDS) system for detection of the optical properties of ex vivo rabbit corneal tissues with different water content at terahertz frequencies (0.1-0.3 THz). The refractive index decreased with frequency while the absorption coefficient increased with frequency. Our experimental results matched the theoretical calculation very well revealing that both the absorption coefficient and the refractive index of a hydrated cornea were much larger than that of a dehydrated cornea and the terahertz properties depended on the hydrate conditions of the biosamples. © 2015 Elsevier B.V. All rights reserved.


Zhou Z.,CAS Shenzhen Institutes of Advanced Technology | Zhou Z.,Chinese University of Hong Kong | Zhou Z.,Biomedical Engineering Laboratory for Photoelectric Sensing Technology | Dong Y.,CAS Shenzhen Institutes of Advanced Technology | And 14 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2016

A phase shift extraction algorithm based on the special points in two-step generalized phase-shifting interferometry is proposed. This algorithm searches the special points that meet specific requirements and calculates the phase shift via the latter's relationship with these special points. It is divided into two modes according to whether the intensity distributions of the two interference beams are recorded or not. Theoretical analysis, computer simulation and experimental verification are carried out. Experimental results show that this algorithm reaches the same level of other algorithms in speed and accuracy. Moreover, when the interferogram's fringe number is less than one, a better phase shift extraction accuracy can be obtained. © 2016, Chinese Lasers Press. All right reserved.


Liu W.,CAS Shenzhen Institutes of Advanced Technology | Liu W.,Biomedical Engineering Laboratory for Photoelectric Sensing Technology | Liu W.,Chinese University of Hong Kong | Lu Y.,CAS Shenzhen Institutes of Advanced Technology | And 14 more authors.
Guangxue Xuebao/Acta Optica Sinica | Year: 2014

Terahertz time domain spectroscopy (THz-TDS) moves from the laboratory to the real world applications, and an important aspect of system design that will need addressing is further investigations on improving the signal acquisition speed. The fast-scanning terahertz time domain spectroscopy system is set up based on the rapid scanning of optical delay using a voice coil motor (VCM) stage. It is shown that the terahertz pulse can be rapidly swept at a scanning rate of 70 Hz on a time delay window of 100 ps. Compared to the traditional motor based step scanning approach, the measurement time by using the voice coil motor based fast scanning delay line at a scanning rate of 1 Hz is shortened to 1/360 of the time by traditional motor. To the best of our knowledge, the new method for realizing the fast scanning THz-TDS using the VCM stage has a reference significance for the study of fast terahertz spectroscopy and imaging techniques.


Guo J.-F.,Lanzhou University of Technology | Liu P.,Lanzhou University of Technology | Liu P.,CAS Shenzhen Institutes of Advanced Technology | Liu P.,Biomedical Engineering Laboratory for Photoelectric Sensing Technology | And 6 more authors.
Guangxue Jingmi Gongcheng/Optics and Precision Engineering | Year: 2014

As domestic industrial endoscopes are only limited in sample observations and can not measure the three-dimensional shapes of workpieces, this paper designs an industrial endoscope whose probe has an outside diameter of 6 mm and is bendable in any directions. It introduces the endoscopic binocular optical system and the endoscopic internal structure. First, a new type of binocular optical system with a dual objective lens and a single image sensor was proposed based on the binocular stereo imaging principle. Then, the endoscopic head structure was designed according to the technical requirements of optical system. In consideration of the complex internal structures of some workpieces, a bendable structure and a back-end control device of endoscope were respectively designed to facilitate detecting precision parts, and the working principle of two structures were described. Finally, the length of two feature points on the surface of target was measured by the three-dimensional image processing software to obtain the distance between the two points. The experiment shows that the length measurement error of the two feature points is within ±0.2 mm. It basically realizes the three-dimensional measurement function of the industrial endoscope systems.

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