A high-energy and simple structure switchable dual-wavelength lamp-pumped Nd:YAG MOPA laser system is introduced. A simple and robust method that improves the conversion efficiency of the second harmonic of a Nd:YAG MOPA laser system is reported, as a demonstration of the concept, through engineering a beam profile with uniform intensity distribution via glass soft-edge diaphragm. With the proposed scheme, an MOPA laser system at 487 ps pulse width and 10 Hz repetition rate with the pulse energy of 702 mJ at 1064 nm and 433 mJ at 532 nm among the switchable dual-wavelength amplifier is demonstrated. Our work provides a promising approach for achieving high energy and uniform intensity distribution Nd:YAG MOPA laser system that can be readily used in the field of medical aesthetics.
Specialty of optoelectronic information science and engineering is aim to cultivate senior specialized talents of photoelectric system design and implementation. The optical signal transmission is indispensable in the photovoltaic system. The problems existing in the teaching of information classes of the specialty at present are analysed and the teaching mode aiming to engineering training is proposed. The specific content is as follows: The principle problem of optical information transmission system is solved in the theoretical teaching in the classroom, the problem of the system design and simulation implementation is solved in the course design, the problem of the hardware implementation of the system is solved in the professional experiments. The training of the whole process from the principle of optical information transmission system design, software simulation to hardware implementation is achieved through this kind of teaching mode.
Q-switched Short pulse laser has been widely applied in many fields, such as optical ranging, remote sensing,
communications, nonlinear optics and spectroscopy etc. Q-switched Nd3+: YAG laser, with its high thermal conductivity
and resistance to damage threshold, longer energy levels were generally used especially. Second harmonics generation
was usually obtained through optical nonlinear effects in crystal. To the frequency doubling technology, poor conversion
efficiency and multi-output frequency are the main problems. Researchers focus more on phase and group velocity
matching induced by nonlinear effects, but pays less attention on theoretical modeling and numerical calculation of
factors affecting frequency doubling of pulsed laser. In this article, nonlinear effects of double frequency crystals in
Q-switched Nd3+: YAG laser was first analyzed in theory, then we deduced the relation expressions between factors
affecting the efficiency of frequency doubling( thickness of frequency doubling crystal, cross section area of incident
beam, power of the fundamental field, phase matching of incidence light)and double frequency efficiency. Secondly,
taken KTP Crystal for example; numerical results and theirs' corresponding curves on these relation expressions was
calculated and drawn with MATLAB software. These findings can be used for processing the specific requests of
frequency doubling crystal. Finally, Theory modeling and numerical calculation were tested in experiment. The
experiment results are in good agreement with those obtained in theory.
A method of encoding eight objects simultaneously in a detour computer generated hologram(CGH) is
proposed. In the method, we divide eight objects into two groups and multiple objects are encoded
through synthesized spectrum. The simulation demonstrated the effectiveness of the method. In the
reconstruction two groups of objects were reconstructed around the same diffraction order along x, y directions, respectively. The result showed that the method can improve the information capacity in
a CGH efficiently.
It is important to accurately obtain micro displacement in industry, especially in numerical controlled
machine. But traditional methods encountered some difficulties in high-precision measurement. A new
approach based on moiré fringes digital image processing technique (DIP) is proposed in this paper. A
smartly designed experiment is done to grasp moiré fringes from two same gratings, so complicated
equipments are not necessary which has obvious advantages. A CCD is used to acquire digital images.
Then the images are done by digital image processing, including filtering and gray-scale transformation,
fringes identification. A smart way to calibrate the distance represented by each pixel is given in this
paper with DIP technique. The distance of a certain fringe between two images is obtained to display
the micro displacement of any object. The result of this approach is compared with a higher accurate
micro displacement, their similarity identify the correct of this method. We are sure that the result will
be more satisfactory if higher accurate equipment is applied in inspection.
Resolution of optical system is a critical index to judge the quality of optical system. Measuring the
resolution of optical system has become more and more important in optical measurement. But
traditionally the method to evaluate the resolution of optical system is mainly subjective because of
man's eye seeing. Although this method is simple and intuitive, it is very easy for the introduction of
the subjective error. To solve this problem, an approach based on digital image processing technique is
brought out to achieve this subjective processing in this paper. An experiment is done to grasp image of
resolving power test target formed by a teleobjective, its extreme resolution is obtained. The result
matches ideal resolution by calculation. This way has the advantage of rapid processing and objective.
It is the tendency of measuring resolution in the future.
Due to properties required of optical elements, it is very important to detect the surface of non-contact object in modern
science and technology fields. There are so many methods for detection of object surface, most of which are for isotropic
and optical uniform media devices, and mainly utilize optical plane reflection of device under test to obtain. But ones for
crystal optical surface are few. The method is put forward to use interference of convergent polarized light to measure
optical surface of uniaxial and biaxial crystal in the paper. The basic principle is analyzed that is about interference of
polarized light, and the relationship is derivate that is between interference pattern of polarized light formed after
spherical light via crystal devices and crystal optical surface. The numerical computation is done by means of MATLAB.
Data processing software is programmed. The data relationship is simulated and calculated between interference pattern
of polarized light and crystal optical surface. And corresponding curve is plotted out. The testing experimental equipment
is designed and set up, which can measure the surface of uniaxial crystal (wave-plate) and biaxial crystal (KTP) whose
accuracy may come up to 0.5μm.
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