Mirror Transmittance, Reflectance And Absorption Ratio Test

Transmittance,reflectance as well as absorptance are not only a very importantquantity to describe the performance of some optical materials and some kinds of films,butalso used to evaluate the characteristics of the new photoelectric matrial.The transmittance and reflectance of the matrial are made separately in the previousmethods.It is then difficult to reach a same precision.In this thesis,a new and automaticmeasurement technique is proposed,which has the capability to measure transmittance,reflectance and absorptance at the same time under the illumination of a white light andsourse with S-polarization and P-polarization,respectively.The theoretical analysis of thetransmittance and reflectance measurements are then given.The optical arrangement,themechanical structure,the electric control system ,and the software and data processingsystems of the new device are described in detail.The innovations of this thesis are:(1) Design a sample rotation stage.It can adjust the detector to its positionautomatically,in order to achieve the relation of the incident light changing oneαangleand the reflected light changing twoαangle.(2) Measure the transmittance and reflectance at the same time and with the sameaccuracy.(3) The incident angle can be changed continuously between 6°and 80°(4) Append some concave mirrors as collectors to improve precision.The experimentshowed that the test precision was better than 1%.(5) The measured data was processed by a computer, then was showed at real time.(6) The miniaturization of the apparatus was carried out,its dimension size is39cm(width)×25cm(depth)×19.5cm(height).The method of two optical path are used for this apparatus to overcome the influenceof fluctuation of light source,the nonlinear of PMT and its electric circuit.The C++Builderis used to programme to control the testing and data collecting process by a computer, andthe MATLAB is added to the software to carry out wavelet denoise,to fit the least twomultiplication,then to draw out its test figure.