Cyclic shearing interferometer for collimating short coherence-length laser beams

Henning, T.; Carlsten, J. L.

doi:10.1364/ao.31.001199

“…Basing on equation 5.2 -5.4, x can be calculated to be 130.9 µm, Vs is 6.86 µm and Hs is only 0.1794 µm which is much smaller than Vs. In addition, the vertical shear will only impact the interference pattern when it is close to the diameter of the light source because one beam becomes above the other and the interference cannot happen [164]. Therefore, the change of the tilting axis can be ignored.…”

Section: Interference Pattern Shifts Caused By the Variation Of The Titling Axismentioning

confidence: 99%

Development of an Electromagnetic Actuator based Translation Micromirror as a Movable Mirror in a Miniaturized FTIR Spectrometer

Yang¹

2023

Preprint

0

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Miniaturized FTIR spectrometer has been developed rapidly in recent years due to the increasing demands. MEMS micromirrors have been used to replace the movable mirror system, which is the largest part in conventional FTIRs. Electromagnetic actuators are suitable to drive the micromirrors because of their relatively large quasi-static translation range and high response speed. In addition, high surface quality is required for the micromirror. However, current MEMS based micromachining technologies cannot provide satisfactory surface quality. Therefore, a translation mircomirror with a large displacement, i.e., > 120 µm, and a novel magnetic field pulling-force assisted bonding technology are developed to bond a high surface quality (i.e., roughness of 2 nm and radius curvature over 15 m) mirror plate with a released microactuator using an adhesive. However, the touching points between the moving film and the substrate lead to a large starting position variation and low repeatability in operation. To solve these limitations, a repulsive force based translation micromirror utilizes a novel driving mechanism, i.e., permanent magnet ring above and electromagnet underneath the moving film, to lift and push the moving film away from the substrate for translation. As a result, the starting position of the repulsive force translating mirror is consistent and the repeatability is <1%. A maximum displacement of 144 µm can be achieved when a 140 mA current is applied. To eliminate the tilt of the translation micromirror during motion, a compensation system is developed which includes the translation mirror, a correcting mirror and a reflecting mirror. The correcting micromirror corrects the tilt by rotating the same angle as the translation micromirror with its rotating axis parallel to the tilting axis. The tilt of the attractive force translation micromirror can be reduced to 0.026° after compensation, so it can be used as a movable mirror in FTIRs to measure half of the midinfrared region between 13.6 µm an 25 µm. Therefore, the electromagnetic actuator based translation micromirror with large displacement, high surface quality can be successfully used as the movable mirror in the miniaturized FTIRs with the tilt compensation system.

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“…Basing on equation 5.2 -5.4, x can be calculated to be 130.9 µm, Vs is 6.86 µm and Hs is only 0.1794 µm which is much smaller than Vs. In addition, the vertical shear will only impact the interference pattern when it is close to the diameter of the light source because one beam becomes above the other and the interference cannot happen [164]. Therefore, the change of the tilting axis can be ignored.…”

Section: Interference Pattern Shifts Caused By the Variation Of The Titling Axismentioning

confidence: 99%

Development of an Electromagnetic Actuator based Translation Micromirror as a Movable Mirror in a Miniaturized FTIR Spectrometer

Yang¹

2023

Preprint

0

View full text Add to dashboard Cite

Miniaturized FTIR spectrometer has been developed rapidly in recent years due to the increasing demands. MEMS micromirrors have been used to replace the movable mirror system, which is the largest part in conventional FTIRs. Electromagnetic actuators are suitable to drive the micromirrors because of their relatively large quasi-static translation range and high response speed. In addition, high surface quality is required for the micromirror. However, current MEMS based micromachining technologies cannot provide satisfactory surface quality. Therefore, a translation mircomirror with a large displacement, i.e., > 120 µm, and a novel magnetic field pulling-force assisted bonding technology are developed to bond a high surface quality (i.e., roughness of 2 nm and radius curvature over 15 m) mirror plate with a released microactuator using an adhesive. However, the touching points between the moving film and the substrate lead to a large starting position variation and low repeatability in operation. To solve these limitations, a repulsive force based translation micromirror utilizes a novel driving mechanism, i.e., permanent magnet ring above and electromagnet underneath the moving film, to lift and push the moving film away from the substrate for translation. As a result, the starting position of the repulsive force translating mirror is consistent and the repeatability is <1%. A maximum displacement of 144 µm can be achieved when a 140 mA current is applied. To eliminate the tilt of the translation micromirror during motion, a compensation system is developed which includes the translation mirror, a correcting mirror and a reflecting mirror. The correcting micromirror corrects the tilt by rotating the same angle as the translation micromirror with its rotating axis parallel to the tilting axis. The tilt of the attractive force translation micromirror can be reduced to 0.026° after compensation, so it can be used as a movable mirror in FTIRs to measure half of the midinfrared region between 13.6 µm an 25 µm. Therefore, the electromagnetic actuator based translation micromirror with large displacement, high surface quality can be successfully used as the movable mirror in the miniaturized FTIRs with the tilt compensation system.

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“…The second advantage is that the two counterrotating beam path lengths will be nearly the same. A path-length difference very close to zero means that the cyclic interferometer could be used with sources that have short coherence lengths (short coherence times) such as broadband lasers or short pulse-length lasers [6].…”

Section: Theorymentioning

confidence: 99%

Optical system for the supervision of the operation of a induction motor

Villanueva-Reyes

¹

,

Vázquez-Nava

²

2011

SPIE Proceedings

0

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In this work we present an optical system for the supervision of the operation of an induction motor. We used a Cyclic interferometer for the measurement of the vibrations produced by the motor motion and obtain a frequency spectrum via a Fourier transform of the signal. According to the spectrum, we can know the operation conditions of the induction motor. The optical system consists of a Cyclic Interferometer, a data acquisition board and virtual instrument.

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Cyclic shearing interferometer for collimating short coherence-length laser beams

Cited by 15 publications

References 17 publications

Development of an Electromagnetic Actuator based Translation Micromirror as a Movable Mirror in a Miniaturized FTIR Spectrometer

Development of an Electromagnetic Actuator based Translation Micromirror as a Movable Mirror in a Miniaturized FTIR Spectrometer

Development of an Electromagnetic Actuator based Translation Micromirror as a Movable Mirror in a Miniaturized FTIR Spectrometer

Optical system for the supervision of the operation of a induction motor

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