To address the problem of online measurement of the base vector angle of beacon light in satellite-ground quantum optical communication, a measurement scheme is proposed to decouple the spatial base vector angle by using RGB tri-color combined beam as the beacon light with different light intensity values after beam splitting. The RGB combined beam with three different polarization angles carries the optical basis vector angle information of the carrier platform. After transmitted in free space, the RGB combined beam is decoupled from the basis vector angle by the ground receiving system. The receiving system reflects the RGB tri-color light in a split beam, uses photo detectors to obtain the intensity values of different wavelengths. According to the differential and ratio operation of the intensity values of the tri-color wavelengths, the receiving system obtains the characteristic parameter β and establishes the θ-β curve. With this curve, it is possible to inverse perform the spatial base vector angle θ information of the beacon light carrier platform in real time. The corresponding values of σ are inverted by analyzing the results of different operations on β. The verification of the experimental system shows that the accuracy of the beacon base vector angle θ obtained by the inversion of the real-time parameter β can reach ±0.05°, the standard deviation value of 3σ for random fluctuations is less than 0.1°, and the value of 3σ in the case of complex outdoor interference is less than 0.5°.
Absolute measurement is an effective way to obtain high-precision optical surface measurements. This paper describes a convenient absolute testing approach that allows reconstruction of surfaces using Zernike polynomials. This method requires a classical three-flat measurement and a one-rotation measurement before reconstructing the surface. Utilizing a well-established procedure, the absolute surface profile of the testing surface can be reconstructed with more Zernike orders than are provided by Fritz’s method. In particular, simulation of the testing error through recalculation of the test surface profile at a different angle could provide the optimized angle with a minimum testing error. This implies that an additional rotation measurement for the optimized angle can improve testing accuracy. The experimental results of a 100-mm flat surface provided a reflected root mean square (RMS) of 2.6 nm and a residual RMS of 0.1 nm.
As a result of the coupling process between the incident and the guided waves, the zero-order reflection exhibits a
narrow spectral response. There were some investigations on how to control the reflectance response of filters which
have diffractive structures. But these investigations only considered the case at the 0 deg azimuthal angle. In this work,
one optimized structure of ZODF which had conspicuous spectral shift effect and certain spectral response for the TE
polarization mode was given.
The ratio measurement of reactive ion beam etching rate using optical interferometry was investigated. The principle is that the depth of groove could be showed by the bend of interference fringe. Using interferometric measurement, the depths of groove before and after etching were determined and marked as d1, d2. One new groove whose bottom was on the substrate was made. There are three photos before etching and after etching new grooves were got. It is found that the ratio is 10:3 under the conditions of experiment. Compared with traditional measurement, this kind of way has some advantages such as simplicity, higher measurement precision and so on.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.