Papers by Keyword: Optical-Path Difference

Abstract: In order to implement the measurement of two-dimensional small angles, a method of modulating optical-path differences through a wedge is put forward, based on Michelson interference principle. By promoting the wedge with a voice coil motor, optical path that pass through the wedge will be changed. Then the optical-path differences on fixed points of the receiving screen will be cycle changed. Then the interference fringes will be carried out on periodical motion. Utilizing voice coil motor and right angle flexible hinge moving cycle, the relationship between the driving voltage and the displacement of wedge also has been analyzed detailedly. The experiment results show that there is a good linearity while the driving voltage is in the range 3.2v-7.5v. Modulating optical-path in this linear range, precise measurement of two-dimensional angles can be realized.

Abstract: In this paper, we present a Fourier Transform micro-spectrometer which works based on a lamellar grating interferometer. The spectrometer model is electrostatically driven by parallel plate actuators which change the optical path difference (OPD) between movable grating facets and fixed ones. With a 200V input voltage, a maximum OPD of 48.7μm is achieved. The spectrum of a combined light source of a diode-pumped solid-state (DPSS) laser (λ=532.0nm) and a laser diode (λ=637.2nm) is experimentally acquired to demonstrate the performance of the model. The reconstructed spectrum displays two separate spectral peaks at 530.5nm and 635.2nm and the corresponding full-width at half-maximum (FWHM) resolutions are 9.8nm and 12.8nm respectively, indicating good wavelength accuracy and optical resolution.

Abstract: This study presents an enhanced common path interference system designed to measure the refractive index of crystal optical components. The proposed system is based on the classic Michelson interferometer and comprises a frequency stabilized helium-neon (He-Ne) laser, a beam splitter, a fixed mirror, an adjustable mirror, and a light detection system. The waveplate of interest was clamped to a rotatory motor and positioned between the beam splitter and the fixed mirror. The refractive index of the waveplate was then derived from the change in rotational angle of the waveplate as it moved from one position of minimum interference to the next. The measurement system proposed in this study is simple in construction, straightforward in operation, and robust to the effects of experimental noise. Furthermore, the system is a non-contact measurement system, and hence does not damage the optical component of interest. The experimental results are found to be in good agreement with the theoretical results. Therefore, the proposed system provides a viable means for the rapid experimental evaluation of the optical characteristics of quartz components.