3 results about "Photoelastic modulator" patented technology

This invention provides a method for measuring dielectric constant based on oblique incidence light reflection difference technology. The probe light emitted by the laser 1 is converted into p-polarized light by the polarizer 2, and then modulated into p-polarized light and s-polarized light by the photoelastic modulator 3. The p-polarized light and s-polarized light are emitted alternately at a frequency of 50 kHz, and after passing through the phase shifter 4, a fixed phase difference is generated. Then, the light is focused by the first lens 5 and obliquely incident on the surface of the sample 6 to be tested, with the incident range between 50° and 60°. The signal light reflected from the surface of the sample 6 to be tested is incident on the analyzer 9 after passing through the second lens 8. The analyzer 9 is used to zero the fundamental frequency signal of the system. The signal light after passing through the analyzer 9 is absorbed by the photodetector 10 and converted into an electrical signal. The electrical signal is demodulated by the first lock-in amplifier 11 and the second lock-in amplifier 12 into a DC signal, a fundamental frequency signal I (Ω), and a harmonic signal I (2Ω). The demodulated signal is acquired and processed by the data acquisition and processing unit 13.

The application discloses a kind of temperature measurement method and device based on photoelastic modulation magneto-optical Kerr optical system, belong to magneto-optical detection and temperature measurement technical field, comprising: S 1, the optical axis azimuth angle of the polarizer and the photoelastic modulator is adjusted, so that the detection light intensity of the photoelectric detector only has direct current component;And the optical axis azimuth angle α of the polarizer is set to be less than 45°, and under the azimuth angle α, the detection light intensity is greater than the quantization error of data acquisition;S2, according to the detection light intensity, the direct current amplitude, the first harmonic amplitude and the second harmonic amplitude of light intensity at photoelastic modulation frequency are obtained by Fourier transform;S3, the magneto-optical signal of magnetic nanometer film sample is calculated;S4, the temperature of the magnetic nanometer film sample is changed, and the numerical relationship between the magneto-optical signal MO (T) and temperature T is calibrated.The application can directly measure temperature based on photoelastic modulation magneto-optical Kerr optical system, and the resolution of temperature measurement on the surface of sample can reach mK level.

This application belongs to the field of precision optical measurement, specifically disclosing a three-photoelastic modulation type Mueller matrix polarization system and its parameter correction method. In this application, the polarizing arm includes a first photoelastic modulator and a second photoelastic modulator, while the analyzing arm contains only a third photoelastic modulator. The three photoelastic modulators have different modulation frequencies. For the optical path after the third photoelastic modulator, a beam splitter divides the optical signal into two sub-beams for separate polarization analysis. By controlling the azimuth angles of the analyzers in the two split paths, two different three-photoelastic azimuth angle polarization system configurations are achieved. The measured two sets of 12 Mueller matrix elements are combined into a complete Mueller matrix element, thus achieving the measurement of the complete Mueller matrix element in a single measurement. This application, by combining three photoelastics with different modulation frequencies and the splitting principle, achieves high-speed acquisition of the entire Mueller matrix of a sample in a single measurement, filling the gap in mid-infrared high-speed Mueller matrix ellipsometers.