In order to study the output characteristics of 808nm vertical cavity surface emitting laser(VCSEL) with large aperture at different temperature, 808nm VCSEL with 500μm emitting diameter are fabricated with Reticular Electrode Structure(RES). Lasing wavelength, optical power and the threshold current are measured by changing the temperature of heat sink. And an output power of 0.42W is achieved at 1.3A at room temperature under continuous wave operation. The central wavelength is 803.32nm, and the full width at half maximum is 0.16nm, the temperature shift is 0.06nm/℃, the thermal resistance is 0.098℃/mW. The testing results show that 808nm VCSEL with large aperture is good temperature characteristic.
The optical system transmittance is the ratio of optical instrument emergent light flux with incident light flux, and
embodies the ability that transmitting light radiant energy of an optical instrument. It is an important performance index
in optical system, especially in the telescopic optical system. In order to decrease the effect of the backlight, the
traditional single channel detection method must be achieved in the darkroom. But it can not avoid the interference of 1/f
noise and the illuminant wave because the detected signal is direct current signal, and the detecting accuracy is low. The
paper proposes an optical transmittance detecting method with double beams and double frequencies based on the
correlation detection technology. The method avoid the influences of 1/f, background light and illuminant wave
effectively because of adopting the correlation detecting technology, and it not only can achieve the detecting in the
bright field, but also improves the detecting accuracy finer than 1%, and could replace the single channel detection
method that adopted at present.
Many 3D displays have been proposed for medical use. When we design and evaluate new system, there are three
demands from surgeons. Priority is the precision. Secondly, displayed images should be easy to understand, In addition,
surgery lasts hours and hours, they do not like fatiguing display. The stereo television endoscope researched in this paper
make celiac viscera image on the photosurface of the left and right CCD by imitating human binocular stereo vision
effect by using the double-optical lines system. The left and right video signal will be processed by frequency
multiplication and display on the monitor, people can observe the stereo image which has depth impression by using a
polarized LCD screen and a pair of polarized glasses. Clinical experiments show that by using the stereo TV endoscope
people can make minimally invasive surgery more safe and reliable, and can shorten the operation time, and can improve
the operation accuracy.
The paper introduces a method that uses the video signal digitized processing module to display the stereo image. In the paper, it introduces a realization project using time-division stereo analog display, discusses a realization method of stereo display which uses video signal of twin-channel video synchronous camera and the digital scanning processing chip that bases on the programming under the bus, analyzes the cause of producing the image flicker during the common stereo image display, adopts the advanced PHILIPS MK-9 module to carry out the data acquisition and memory to the video signal, resolves the problem of image flicker by using "multi-field scanning" and "sequential scanning", it can make the observers acquire more comfortable stereo feeling.
This paper introduces a non-contact measuring system —measuring thread system using laser fiber sensor. It can solve some problems of the traditional measuring methods, such as complicated technical process, long re-testing periods, waste workpiece. A low noise amplifier used to match the photo-electronic detecting element due to the weak signal is applied in this system. Furthermore, it presents a new measuring system with phase-sensitive detecting circuit controlled by computer program, an interface circuit of microcomputer, laser fiber sensor system and digital processing system, the system based on the above elements has high resolution and sensitivity, the measuring errors ?20 ?m.