The blue and violet laser beams are pretty useful in the micro-lithography, massive storage device and biomedical instruments. Also it is attracting more interests in the fiber sensing application because of its wavelength. The coupling from the blue and violet laser diode to a fiber still suffers from low coupling efficiency and instability. In Blue Sky Research, we utilized patented microlens technology to facilitate the coupling for 405nm laser diode and got as high as more than 70% efficiency with superior stability. It is an ideal fiber-coupled source for various kinds of application and accommodate wavelength from 375nm to 440nm. The design and the testing are reported in this paper.
The prototype of a novel high resolution vibration sensor based on HeNe laser frequency splitting technology is presented in this paper and the results of a series of experiments are reported. A seismic inertial structure has been developed to realize the absolute measurement. The parameters of the inertial structure can be selected to be suitable for different vibration frequency bands and different sensitivities. In the experiments the highest resolution of 15nm on the measurement of vibration amplitudes are obtained. The sensor has a good potential perspective to be applied in the high-resolution and high- sensitivity, low or middle frequency vibration measurements.
A novel method for measurement of optical retardation angles of wave plates is presented based on laser birefringent longitudinal mode splitting technology. With this method, a measurement system was developed that the related experiments were conducted. The method has relatively concise setup and reaches high resolution and accuracy. With a intensity-contrasting beat locking unit, the error level is less than 8 angular minutes for the measurement of 0.6382micrometers crystal quarter wave plate.
This paper provides a method to test some parameters of CDs. These parameters show the quality of the disks directly. The method is based on a commercial CD-ROM and a common computer. Some necessary circuits and software are added in. The analytic results can be provided.
A new method of measuring vibration is presented based on HeNe laser frequency splitting phenomenon and a series of experiments have been done. While a quartz crystal wedge which vibrates with the vibration of measured object is inserted to a HeNe laser cavity, each laser mode is split to two orthogonal laser modes with a frequency difference. The variation of the frequency difference is proportional to the displacement of the quartz wedge so that the frequency difference is modulated by vibration displacement signal. The vibration signal is demodulated to electrical signal through a photo-electric detector and signal processing circuit. A computer is used to adopt and analyze the vibration signal. By the system a 15nm resolution and 28nm repeatability of vibration amplitude are obtained. The method has good potential prospective to be applied in high resolution, low and middle frequency vibration measurement or random vibration measurement.
Modern instruments such as laser anemometers connected to automatic traversing and data collection systems generate large amounts of data which can be difficult to interpret. An interface has been developed which makes use of existing commercial software to display the data in multi-dimensional vector format.
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