In the nonlinear optics, the phase matching angle of nonlinear optical crystal has important influence on conversion efficiency and stability of frequency doubling light. This is the typical experiment to study the phase matching angle of nonlinear optical crystal. By analyzing the results of frequency doubling light power measurement for different incidence angles of KTP validates that the relation to frequency doubling efficiency along with the change of phase mismatching angle.
A lot of specific wavelength laser can be obtained by frequency conversion of crystal nonlinear optical effect. And solid state laser by the nonlinear effect has great application prospect in optical communications, laser radar, laser medicine, laser processing and so on.
This is the typical experiment to study and research the crystal nonlinear effect. In the experiment, there is green laser of 532nm output with KTP of extra cavity frequency doubling, then adding LBO and BBO to obtain laser of 355nm and 266nm respectively. The students can master the method of debugging laser, and understand the nonlinear coefficient of frequency doubling, sum-frequency, quadruplicated frequency by the experiment.
Semiconductor laser, with its advantages of high efficiency, small volume, long life, has important applications in many fields. This is the typical experiment to study the characteristics of semiconductor laser. The students can understand the concepts of the threshold, slope efficiency and tunable characteristics by the measurement and analysis of the parameters such as power, wavelength and so on.
Diode-pumped passively Q-swiched solid-state laser is widely used for remote sensing, distance measurement, laser radar, laser medicine, laser micromachining, optics data storage etc. fields with its advantages of narrow pulse width, high peak power, high repetition frequency, high conversion efficiency, compact size.
This is the typical experiment of research on pulsed laser. In the experiment, there is 1064nm pulsed laser output by putting Cr:YAG into the laser cavity with LD pumped Nd:YAG Measure the wave shape, frequency and pulse width with oscilloscope, then observe the change rules of parameters of wave shape, frequency, pulse width by changing the length of cavity and output mirror with different transmissivity. The students can grasp the adjustment method with Cr:YAG and the measurement of pulsed laser parameters, finally coming to conclusion of influence factors and change rules.
Michelson Interferometer is an optical precision instrument used to research spectroscopy and metry cooperative designed by A.A.Michelson and E.W.Morley in 1883. It can be used to measure tiny length and change accurately and the related interferometer by its principle are widely used in many fields such as production and scientific research.
In this experiment, the students can undertstand the principle of Michelson Interferometer and the conception of equal inclination interference, learn how to measure wavelength and the thickness of filmy dielectric with a Michelson Interferometer.
Optical fiber communications have become one of the main pillars of modern communication field with the advantages of high capacity, low energy consumption, high sensitivity, strong anti-interference and high security.
In the experiment, the basic principle of total reflection as the breakthrough point, the students can study the total reflection process and conditions of it, then more profound understand the principle of transmission in the fiber by observing the process.
Laser mode is a very important index to measure the laser characteristic, is an effective way to understand laser and comprehend the theory of laser. Besides, in different fields, the laser requirements are also different, such as laser fine processing requires interferometric measurements need single longitudinal mode laser.
In the experiment, laser longitudinal mode is analyzed with a F-P scanning interferometer, such as longitudinal mode observation (Single longitudinal mode, Multi-longitudinal mode, mode competition), line width of longitudinal mode measurement, frequency interval of longitudinal mode measurement etc. The students can understand the structure and principle of F-P scanning interferometer, grasp how to use it and comprehend the abstract concepts above by the experiment.
Laser induced breakdown spectroscopy technology with its advantage of rapid and uncomplicated operation is widely used in many fields about element identification. The students can understand the procedure of laser induced plasma generation by observing the mechanism of action between laser and substance, searching laser induced breakdown spectroscopy and obtaining corresponding elements wavelength of sample under test through the calibration pf spectral graph.
Laser rangefinder is the instrument that is used for distance measurement. It is widely used in military, science technology, production, construction and many other fields with its advantages of high accuracy, high resolution, strong anti-interference ability, small, light weight etc.
In this experiment pulse laser as a light source, a laser through the plane mirror in the distance, the laser beam reflected is received by the photoelectric element, then oscilloscope to measure and record the time difference from the transmitter to the receiver, so as to calculate the distance between the laser and the mirror-half of the light and the round trip time. The students can understand the principle of laser rangefinder and grasp the method of distance measurement with laser rangefinder.
Cavity Ring Down Spectroscopy Technology
Cavity ring down spectroscopy technology is a emerging method of spectrum detection. The technology is especially suitable for trace absorption of substance with its characteristics of long absorption optical path and unaffected by the change of light intensity. It is applied to the accurate measurement of high reflectivity of lens (accuracy up to 10-4 ~10-6) and trace gas detection because of simple device and easy quantitative measurement.
As shown in the fig 1, optical resonant cavity composed of high reflectivity lens M1 and M2, when the 532nm pulsed laser along the optical axis is injected into the cavity, the laser pulse is reflected back and fourth between the two mirrors and from oscillation. Ringdown process of laser pulse in the cavity is detected by the photodetector behind M2 and ringdown time is recorded. Then the reflectivity of lens can be calculated out according to the ringdown time. The students can learn the method to measure the reflectivity of lens accurately by the experiment.
Analysis of its fluorescence spectrum has great significance to study the characteristics and application of material. This is a research on fluorescence and laser spectrum of He-Ne laser. Besides, fluorescence spectrum of Nd:YVO4 and Nd:YAG are measured and analyzed. The students can grasp the concepts of fluorescence spectrum and the method of measurement. The students can study the concept of fluorescence spectrum and the measurement method, and then the learning process of laser generation, understanding the important significance to improve the pump light source and the conversion efficiency of laser material by the experiment.
